Patent Publication Number: US-2021168059-A1

Title: Facilitating the Resolution of Address Conflicts in a Networked Media Playback System

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This disclosure claims the benefit of priority as a continuation under 35 U.S.C. § 120 to U.S. application Ser. No. 15/943,367, entitled “Facilitating the Resolution of Address Conflicts in a Networked Media Playback System,” which is a continuation of U.S. application Ser. No. 15/359,252 filed Nov. 22, 2016, entitled “Facilitating the Resolution of Address Conflicts in a Networked Media Playback System,” which is a continuation of U.S. application Ser. No. 14/041,900 filed Sep. 30, 2013, entitled “Facilitating the Resolution of Address Conflicts in a Networked Media Playback System,” the contents of each of which are hereby incorporated by reference in their entirety for all purposes. 
    
    
     FIELD OF THE DISCLOSURE 
     The disclosure is related to consumer goods and, more particularly, to methods, systems, products, features, services, and other items directed to media playback or some aspect thereof. 
     BACKGROUND 
     Digital music has become readily available due in part to the development of consumer level technology that has allowed people to listen to digital music on a personal audio device. The consumer&#39;s increasing preference for digital audio has also resulted in the integration of personal audio devices into PDAs, cellular phones, and other mobile devices. The portability of these mobile devices has enabled people to take the music listening experience with them and outside of the home. People have become able to consume digital music, like digital music files or even Internet radio, in the home through the use of their computer or similar devices. Now there are many different ways to consume digital music, in addition to other digital content including digital video and photos, stimulated in many ways by high-speed Internet access at home, mobile broadband Internet access, and the consumer&#39;s hunger for digital media. 
     Until recently, options for accessing and listening to digital audio in an out-loud setting were severely limited. In 2005, Sonos offered for sale its first digital audio system that enabled people to, among many other things, access virtually unlimited sources of audio via one or more networked connected zone players, dynamically group or ungroup zone players upon command, wirelessly send the audio over a local network amongst zone players, and play the digital audio out loud in synchrony. The Sonos system can be controlled by software applications downloaded to certain network capable, mobile devices and computers. 
     Given the insatiable appetite of consumers towards digital media, there continues to be a need to develop consumer technology that revolutionizes the way people access and consume digital media. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features, aspects, and advantages of the presently disclosed technology may be better understood with regard to the following description, appended claims, and accompanying drawings where: 
         FIG. 1  shows an example configuration in which certain embodiments may be practiced; 
         FIG. 2A  shows an illustration of an example zone player having a built-in amplifier and transducers; 
         FIG. 2B  shows an illustration of an example zone player having a built-in amplifier and connected to external speakers; 
         FIG. 2C  shows an illustration of an example zone player connected to an AN receiver and speakers; 
         FIG. 3  shows an illustration of an example controller; 
         FIG. 4  shows an internal functional block diagram of an example zone player; 
         FIG. 5  shows an internal functional block diagram of an example controller; 
         FIG. 6  shows an example network for media content playback; 
         FIG. 7  shows an example ad-hoc playback network; 
         FIG. 8  shows a system including a plurality of networks including a cloud-based network and at least one local playback network; 
         FIG. 9  shows an internal functional block diagram of the example passive resolver of  FIG. 4 ; 
         FIG. 10  shows an internal functional block diagram of the example active resolver of  FIG. 4 ; 
         FIG. 11  shows an illustrative flowchart for an example method for resolving IP address conflicts; 
         FIGS. 12 a  and 12 b    show illustrative flow paths for resolving IP address conflicts in an example environment; 
         FIG. 13  shows an illustrative flowchart for another example method for resolving IP address conflicts; 
         FIG. 14  shows an illustrative flowchart for another example method for resolving IP address conflicts; 
         FIGS. 15 a  and 15 b    show illustrative flow paths for resolving IP address conflicts in another example environment; 
     
    
    
     In addition, the drawings are for the purpose of illustrating example embodiments, but it is understood that the inventions are not limited to the arrangements and instrumentality shown in the drawings. 
     DETAILED DESCRIPTION 
     I. Overview 
     Embodiments disclosed herein enable resolving conflicts of addresses (such as an Internet Protocol (IP) address) in a networked media playback system. In some embodiments, a network includes an access point and at least a first playback device of a media playback system. In some embodiments, the first playback device in the network monitors data sent to the access point from playback devices in the network. In some embodiments, when data sent to the access point includes a request for a new IP address, the first playback device determines whether the IP address included in the request is the same as the IP address currently assigned to the first playback device. That is, the first playback device monitors the network to determine if any other playback device(s) in the network is requesting an IP address that conflicts with the first playback device IP address. In some embodiments, when the first playback device makes an IP address conflict determination, the first playback device requests a new IP address form the access point to facilitate resolution of the IP address conflict. 
     In some embodiments, the first playback device monitors the network for events indicative of a status change of the access point. In some embodiments, when the first playback device detects a change in status of the access point, the first playback device obtains a new IP address from the access point. Unlike prior systems, embodiments disclosed herein enable the first playback device to alert other playback device(s) in the network to obtain new IP addresses. To this end, in some embodiments, the first playback device periodically broadcasts probe messages over the network to the other playback devices. When a status change is detected, in some embodiments, the first playback device sets an IP address renew flag in a subsequent probe message. In some embodiments, when another playback device obtains a probe message with an IP address renew flag set, the playback device obtains a new IP address from the access point. 
     Other embodiments, as those discussed in the following and others as can be appreciated by one having ordinary skill in the art are also possible. 
     II. Example Operating Environment 
     Referring now to the drawings, in which like numerals can refer to like parts throughout the figures,  FIG. 1  shows an example media system configuration  100  in which one or more embodiments disclosed herein can be practiced or implemented. 
     By way of illustration, the media system configuration  100  is associated with a home having multiple zones, though the home could have been configured with only one zone. Additionally, one or more zones can be added over time. Each zone may be assigned by a user to a different room or space, such as, for example, an office, bathroom, bedroom, kitchen, dining room, family room, home theater room, utility or laundry room, and patio. A single zone might also include multiple rooms or spaces if so configured. With respect to  FIG. 1 , one or more of zone players  102 - 124  are shown in each respective zone. A zone player  102 - 124 , also referred to herein as a playback device, multimedia unit, speaker, player, and so on, provides audio, video, and/or audiovisual output. A controller  130  (e.g., shown in the kitchen for purposes of this illustration) provides control to the media system configuration  100 . Controller  130  may be fixed to a zone, or alternatively, mobile such that it can be moved about the zones. The media system configuration  100  may also include more than one controller  130 , and additional controllers may be added to the system over time. 
     The media system configuration  100  illustrates an example whole house media system, though it is understood that the technology described herein is not limited to, among other things, its particular place of application or to an expansive system like a whole house media system configuration  100  of  FIG. 1 . 
     a. Example Zone Players 
       FIGS. 2A, 2B, and 2C  show example types of zone players. Zone players  200 ,  202 ,  204  of  FIGS. 2A, 2B, and 2C , respectively, can correspond to any of the zone players  102 - 124  of  FIG. 1 , for example. In some embodiments, audio is reproduced using only a single zone player, such as by a full-range player. In some embodiments, audio is reproduced using two or more zone players, such as by using a combination of full-range players or a combination of full-range and specialized players. In some embodiments, zone players  200 ,  202 ,  204  may also be referred to as a “smart speaker,” because they contain processing capabilities beyond the reproduction of audio, more of which is described below. 
       FIG. 2A  illustrates zone player  200  that includes sound producing equipment  208  capable of reproducing full-range sound. The sound may come from an audio signal that is received and processed by zone player  200  over a wired or wireless data network. Sound producing equipment  208  includes one or more built-in amplifiers and one or more acoustic transducers (e.g., speakers). A built-in amplifier is described more below with respect to  FIG. 4 . A speaker or acoustic transducer can include, for example, any of a tweeter, a mid-range driver, a low-range driver, and a subwoofer. In some embodiments, zone player  200  can be statically or dynamically configured to play stereophonic audio, monaural audio, or both. In some embodiments, zone player  200  may be dynamically configured to reproduce a subset of full-range sound, such as when zone player  200  is grouped with other zone players to play stereophonic audio, monaural audio, and/or surround audio or when the audio content received by zone player  200  is less than full-range. 
       FIG. 2B  illustrates zone player  202  that includes a built-in amplifier to power a set of detached speakers  210 . A detached speaker can include, for example, any type of loudspeaker. Zone player  202  may be configured to power one, two, or more separate loudspeakers. Zone player  202  may be configured to communicate an audio signal (e.g., right and left channel audio or more channels depending on its configuration) to the detached speakers  210  via a wired path. 
       FIG. 2C  illustrates zone player  204  that does not include a built-in amplifier, but is configured to communicate an audio signal, received over a data network, to an audio (or “audio/video”) receiver  214  with built-in amplification. 
     Referring back to  FIG. 1 , in some embodiments, one, some, or all of the zone players  102  to  124  can retrieve audio directly from a source. For example, a particular zone player in a zone or zone group may be assigned to a playback queue (or “queue”). The playback queue contains information corresponding to zero or more audio items for playback by the associated zone or zone group. The playback queue may be stored in memory on a zone player or some other designated device. Each item contained in the playback queue may comprise a uniform resource identifier (URI) or some other identifier that can be used by the zone player(s) to seek out and/or retrieve the audio items from the identified audio source(s). Depending on the item, the audio source might be found on the Internet (e.g., the cloud), locally from another device over a data network  128  (described further below), from the controller  130 , stored on the zone player itself, or from an audio source communicating directly to the zone player. In some embodiments, the zone player can reproduce the audio itself (e.g., play the audio), send the audio to another zone player for reproduction, or both where the audio is reproduced by the zone player as well as one or more additional zone players (possibly in synchrony). In some embodiments, the zone player may play a first audio content (or alternatively, may not play the content at all), while sending a second, different audio content to another zone player(s) for reproduction. To the user, each item in a playback queue is represented on an interface of a controller by an element such as a track name, album name, playlist, or some other representation. A user can populate the playback queue with audio items of interest. The user may also modify and clear the playback queue, if so desired. 
     By way of illustration, SONOS, Inc. of Santa Barbara, Calif. presently offers for sale zone players referred to as a “PLAY:5,” “PLAY:3,” “PLAYBAR,” “CONNECT:AMP,” “CONNECT,” and “SUB.” Any other past, present, and/or future zone players can additionally or alternatively be used to implement the zone players of example embodiments disclosed herein. Additionally, it is understood that a zone player is not limited to the particular examples illustrated in  FIGS. 2A, 2B, and 2C  or to the SONOS product offerings. For example, a zone player may include a wired or wireless headphone. In yet another example, a zone player might include a sound bar for television. In yet another example, a zone player may include or interact with a docking station for an Apple IPOD™ or similar device. 
     b. Example Controllers 
       FIG. 3  illustrates an example wireless controller  300  in docking station  302 . By way of illustration, the controller  300  may correspond to the controlling device  130  of  FIG. 1 . Docking station  302 , if provided or used, may provide power to the controller  300  and additionally may charge a battery of the controller  300 . In some embodiments, the controller  300  may be provided with a touch screen  304  that allows a user to interact through touch with the controller  300 , for example, to retrieve and navigate a playlist of audio items, control operations of one or more zone players, and provide overall control of the media system configuration  100 . In other embodiments, other input mechanisms such as voice control may be used to interact with the controller  300 . In certain embodiments, any number of controllers can be used to control the media system configuration  100 . In some embodiments, there may be a limit set on the number of controllers that can control the media system configuration  100 . The controllers might be wireless like the wireless controller  300  or wired to the data network  128 . 
     In some embodiments, if more than one controller is used in the media system configuration  100  of  FIG. 1 , each controller may be coordinated to display common content, and may all be dynamically updated to indicate changes made to the media system configuration  100  from a single controller. Coordination can occur, for instance, by a controller periodically requesting a state variable directly or indirectly from one or more of the zone players. For example, the state variable may provide information about the media system configuration  100 , such as current zone group configuration, what is playing in one or more zones, volume levels, and other items of interest. The state variable may be passed around on the data network  128  between zone players (and controllers, if so desired) as needed or as often as programmed. 
     In addition, an application running on any network-enabled portable device, such as an IPHONE™ IPAD™ ANDROID™ powered phone or tablet, or any other smart phone or network-enabled device can be used as the controller  130  in the example media system configuration  100 . An application running on a laptop or desktop personal computer (PC) or Mac™ can also be used as the controller  130 . Such controllers may connect to the media system configuration  100  through an interface with the data network  128 , a zone player, a wireless router, or using some other configured connection path. Example controllers offered by Sonos, Inc. of Santa Barbara, Calif. include a “Controller  200 ,” “SONOS® CONTROL,” “SONOS® Controller for IPHONE™,” “SONOS® Controller for IPAD™,” “SONOS® Controller for ANDROID™,” “SONOS® Controller for MAC™ or PC.” 
     c. Example Data Connection 
     The zone players  102  to  124  of  FIG. 1  are coupled directly or indirectly to a data network, such as the data network  128 . The example controller  130  may also be coupled directly or indirectly to the data network  128  or individual zone players. The data network  128  is represented by an octagon in the figure to stand out from other representative components. While the data network  128  is shown in a single location, it is understood that such a network is distributed in and around the media system configuration  100 . Particularly, the data network  128  can be a wired network, a wireless network, or a combination of both wired and wireless networks. In some embodiments, one or more of the zone players  102 - 124  are wirelessly coupled to the data network  128  based on a proprietary mesh network. In some embodiments, one or more of the zone players are coupled to the data network  128  using a centralized access point such as a wired or wireless router. In some embodiments, one or more of the zone players  102 - 124  are coupled via a wire to the data network  128  using Ethernet or similar technology. In addition to the one or more zone players  102 - 124  connecting to the data network  128 , the data network  128  can further allow access to a wide area network, such as the Internet. 
     In some embodiments, connecting any of the zone players  102 - 124 , or some other connecting device, to a broadband router, can create the data network  128 . Other zone players  102 - 124  can then be added wired or wirelessly to the data network  128 . For example, a zone player (e.g., any of zone players  102 - 124 ) can be added to the media system configuration  100  by simply pressing a button on the zone player itself (or perform some other action), which enables a connection to be made to the data network  128 . The broadband router can be connected to an Internet Service Provider (ISP), for example. The broadband router can be used to form another data network within the media system configuration  100 , which can be used in other applications (e.g., web surfing). The data network  128  can also be used in other applications, if so programmed. An example, second network may implement SONOSNET™ protocol, developed by SONOS, Inc. of Santa Barbara. SONOSNET™ represents a secure, AES-encrypted, peer-to-peer wireless mesh network. Alternatively, in certain embodiments, the data network  128  is the same network, such as a traditional wired or wireless network, used for other applications in the household. 
     d. Example Zone Configurations 
     A particular zone can contain one or more zone players. For example, the family room of  FIG. 1  contains two zone players  106 ,  108 , while the kitchen is shown with one zone player  102 . In another example, the home theater room contains additional zone players to play audio from a 5.1 channel or greater audio source (e.g., a movie encoded with 5.1 or greater audio channels). In some embodiments, one can position a zone player in a room or space and assign the zone player to a new or existing zone via the controller  130 . As such, zones may be created, combined with another zone, removed, and given a specific name (e.g., “Kitchen”), if so desired and programmed to do so with the controller  130 . Moreover, in some embodiments, zone configurations may be dynamically changed even after being configured using the controller  130  or some other mechanism. 
     In some embodiments, a “bonded zone” contains two or more zone players, such as the two zone players  106 ,  108  in the family room, whereby the two zone players  106 ,  108  can be configured to play the same audio source in synchrony. In one example, the two zone players  106 ,  108  can be paired to play two separate sounds in left and right channels, for example. In other words, the stereo effects of a sound can be reproduced or enhanced through the two zone players  106 ,  108 , one for the left sound and the other for the right sound. In another example, two or more zone players can be sonically consolidated to form a single, consolidated zone player. A consolidated zone player (though made up of multiple, separate devices) can be configured to process and reproduce sound differently than an unconsolidated zone player or zone players that are paired, because a consolidated zone player has additional speaker drivers from which sound can be passed. The consolidated zone player can further be paired with a single zone player or yet another consolidated zone player. Each playback device of a consolidated playback device can be set in a consolidated mode, for example. 
     In certain embodiments, paired or consolidated zone players (also referred to as “bonded zone players”) can play audio in synchrony with other zone players in the same or different zones. 
     According to some embodiments, one can continue to do any of: group, consolidate, and pair zone players, for example, until a desired configuration is complete. The actions of grouping, consolidation, and pairing are preferably performed through a control interface, such as using the controller  130 , and not by physically connecting and re-connecting speaker wire, for example, to individual, discrete speakers to create different configurations. As such, certain embodiments described herein provide a more flexible and dynamic platform through which sound reproduction can be offered to the end-user. 
     e. Example Audio Sources 
     In some embodiments, each zone can play from the same audio source as another zone or each zone can play from a different audio source. For example, someone can be grilling on the patio and listening to jazz music via the zone player  124 , while someone is preparing food in the kitchen and listening to classical music via the zone player  102 . Further, someone can be in the office listening to the same jazz music via the zone player  110  that is playing on the patio via the zone player  124 . In some embodiments, the jazz music played via the zone players  110 ,  124  is played in synchrony. Synchronizing playback amongst zones allows for someone to pass through zones while seamlessly (or substantially seamlessly) listening to the audio. Further, zones can be put into a “party mode” such that all associated zones will play audio in synchrony. 
     Sources of audio content to be played by zone players  102 - 124  are numerous. In some embodiments, audio on a zone player itself may be accessed and played. In some embodiments, audio on a controller may be accessed via the data network  128  and played. In some embodiments, music from a personal library stored on a computer or networked-attached storage (NAS) may be accessed via the data network  128  and played. In some embodiments, Internet radio stations, shows, and podcasts may be accessed via the data network  128  and played. Music or cloud services that let a user stream and/or download music and audio content may be accessed via the data network  128  and played. Further, music may be obtained from traditional sources, such as a turntable or CD player, via a line-in connection to a zone player, for example. Audio content may also be accessed using a different protocol, such as AIRPLAY™, which is a wireless technology by Apple, Inc., for example. Audio content received from one or more sources can be shared amongst the zone players  102  to  124  via the data network  128  and/or the controller  130 . The above-disclosed sources of audio content are referred to herein as network-based audio information sources. However, network-based audio information sources are not limited thereto. 
     In some embodiments, the example home theater zone players  116 ,  118 ,  120  are coupled to an audio information source such as a television  132 . In some examples, the television  132  is used as a source of audio for the home theater zone players  116 ,  118 ,  120 , while in other examples audio information from the television  132  may be shared with any of the zone players  102 - 124  in the media system configuration  100 . 
     III. Example Zone Players 
     Referring now to  FIG. 4 , there is shown an example block diagram of a zone player  400  in accordance with an embodiment. Zone player  400  includes a network interface  402 , a processor  408 , a memory  410 , an audio processing component  412 , one or more modules  414 , an audio amplifier  416 , a speaker unit  418  coupled to the audio amplifier  416 , an address resolver  422 , an IP leaser  428  and a database  430 . In the illustrated example of  FIG. 4 , the database  430  includes state information about the zone player  400 . For example, the database  430  may include the currently assigned internet protocol (IP) address of the zone player  400 , the media access control (MAC) address of the zone player  400 , which (if any) other zone players the zone player  400  is in communication with, whether the zone player  400  is to forward messages received at the zone player  400  to other zone players, etc.  FIG. 2A  shows an example illustration of such a zone player. Other types of zone players may not include the speaker unit  418  (e.g., such as shown in  FIG. 2B ) or the audio amplifier  416  (e.g., such as shown in  FIG. 2C ). Further, it is contemplated that the zone player  400  can be integrated into another component. For example, the zone player  400  could be constructed as part of a television, lighting, or some other device for indoor or outdoor use. 
     In some embodiments, the network interface  402  facilitates a data flow between the zone player  400  and other devices on the data network  128 . In some embodiments, in addition to getting audio from another zone player or device on the data network  128 , the zone player  400  may access audio directly from the audio source, such as over a wide area network or on the local network. In some embodiments, the network interface  402  can further handle the address part of each packet so that it gets to the right destination or intercepts packets destined for the zone player  400 . Accordingly, in certain embodiments, each of the packets includes an Internet Protocol (IP)-based source address as well as an IP-based destination address. 
     In some embodiments, the network interface  402  can include one or both of a wireless interface  404  and a wired interface  406 . The wireless interface  404 , also referred to as a radio frequency (RF) interface, provides network interface functions for the zone player  400  to wirelessly communicate with other devices (e.g., other zone player(s), speaker(s), receiver(s), component(s) associated with the data network  128 , and so on) in accordance with a communication protocol (e.g., any wireless standard including IEEE 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, 802.11ad, 802.15, 4G mobile communication standard, and so on). The wireless interface  404  may include one or more radios. To receive wireless signals and to provide the wireless signals to the wireless interface  404  and to transmit wireless signals, the zone player  400  includes one or more antennas  420 . The wired interface  406  provides network interface functions for the zone player  400  to communicate over a wire with other devices in accordance with a communication protocol (e.g., IEEE 802.3). In some embodiments, a zone player includes multiple wireless  404  interfaces. In some embodiments, a zone player includes multiple wired  406  interfaces. In some embodiments, a zone player includes both of the interfaces  404  and  406 . In some embodiments, a zone player  400  includes only the wireless interface  404  or the wired interface  406 . 
     In some embodiments, the processor  408  is a clock-driven electronic device that is configured to process input data according to instructions stored in the memory  410 . The memory  410  is data storage that can be loaded with one or more software module(s)  414 , which can be executed by the processor  408  to achieve certain tasks. In the illustrated embodiment, the memory  410  is a tangible machine-readable medium storing instructions that can be executed by the processor  408 . In some embodiments, a task might be for the zone player  400  to retrieve audio data from another zone player or a device on a network (e.g., using a uniform resource locator (URL) or some other identifier). In some embodiments, a task may be for the zone player  400  to send audio data to another zone player or device on a network. In some embodiments, a task may be for the zone player  400  to synchronize playback of audio with one or more additional zone players. In some embodiments, a task may be to pair the zone player  400  with one or more zone players to create a multi-channel audio environment. Additional or alternative tasks can be achieved via the one or more software module(s)  414  and the processor  408 . 
     The audio processing component  412  can include one or more digital-to-analog converters (DAC), an audio preprocessing component, an audio enhancement component or a digital signal processor, and so on. In some embodiments, the audio processing component  412  may be part of the processor  408 . In some embodiments, the audio that is retrieved via the network interface  402  is processed and/or intentionally altered by the audio processing component  412 . Further, the audio processing component  412  can produce analog audio signals. The processed analog audio signals are then provided to the audio amplifier  416  for playback through speakers  418 . In addition, the audio processing component  412  can include circuitry to process analog or digital signals as inputs to play from the zone player  400 , send to another zone player on a network, or both play and send to another zone player on the network. An example input includes a line-in connection (e.g., an auto-detecting 3.5 mm audio line-in connection). 
     The audio amplifier  416  is a device(s) that amplifies audio signals to a level for driving one or more speakers  418 . The one or more speakers  418  can include an individual transducer (e.g., a “driver”) or a complete speaker system that includes an enclosure including one or more drivers. A particular driver can be a subwoofer (e.g., for low frequencies), a mid-range driver (e.g., for middle frequencies), and a tweeter (e.g., for high frequencies), for example. An enclosure can be sealed or ported, for example. Each transducer may be driven by its own individual amplifier. 
     A commercial example, presently known as the PLAY:5™, is a zone player with a built-in amplifier and speakers that is capable of retrieving audio directly from the source, such as on the Internet or on the local network, for example. In particular, the PLAY:5™ is a five-amp, five-driver speaker system that includes two tweeters, two mid-range drivers, and one woofer. When playing audio content via the PLAY:5™, the left audio data of a track is sent out of the left tweeter and left mid-range driver, the right audio data of a track is sent out of the right tweeter and the right mid-range driver, and mono bass is sent out of the subwoofer. Further, both mid-range drivers and both tweeters have the same equalization (or substantially the same equalization). That is, they are both sent the same frequencies but from different channels of audio. Audio from Internet radio stations, online music and video services, downloaded music, analog audio inputs, television, DVD, and so on, can be played from the PLAY:5™. 
     In the illustrated example of  FIG. 4 , the example zone player  400  includes the example address resolver  422  to facilitate resolution of internet protocol (IP) address conflicts that may occur in a network (e.g., the example data network  128  ( FIG. 1 )). For example, two or more zone players in the data network  128  may use the same IP address. In the illustrated example, the zone player  400  of  FIG. 4  includes a passive resolver  424  and an active resolver  426 . 
     In the illustrated example of  FIG. 4 , the example passive resolver  424  monitors the data network  128  to determine when a new IP address is assigned to a device (e.g., the zone player  400 ) in the data network  128 . For example, the passive resolver  424  may monitor an access point (e.g., a wired router, a wireless router, etc.) to detect when the access point assigns a device in the data network  128  a new IP address. For example, the passive resolver  424  may “listen” to an input port of the access point, such as a server port (e.g., a user datagram protocol (UDP) server port  67 ), and identify when the access point obtains a request packet from another zone player. The example passive resolver  424  may then compare an IP address included in the request packet with its own IP address and determine whether an IP address conflict exists. For example, the passive resolver  424  may retrieve the currently assigned IP address of the zone player  400  from the example database  430  and compare it to the IP address included in the request packet. In some embodiments, the passive resolver  424  may initiate the example IP leaser  428  to renew the IP address of the zone player  400  in response to an IP address conflict. In some embodiments, the passive resolver  424  may initiate renewing the IP address of the zone player  400  in response to detecting that the access point obtained a request packet. 
     In the illustrated example of  FIG. 4 , the example active resolver  426  monitors the power status of a wired connection to an access point to determine when the zone player  400  is to renew its IP address or to lease a new IP address. For example, the active resolver  426  may monitor the power status (e.g., power ON, power OFF) of the example wired interface  406  of the example network interface  402 . In response to detecting a change in power status (e.g., power OFF to power ON), the example active resolver  426  of  FIG. 4  initiates the example IP leaser  428  to renew the IP address of the zone player  400  or to lease a new IP address. In some embodiments, the example active resolver  426  propagates the change in power status of the wired interface  406  to (if any) other zone players in the same network as the zone player  400 . For example, the active resolver  426  may periodically (e.g., every thirty minutes) and/or aperiodically (e.g., in response to a detected power status change) broadcast probe messages to other zone players in the example data network  128 . Probe messages may include a message identifier (e.g., a 16-bit number) identifying the probe message, a zone player identifier (e.g., a MAC address) of the zone player broadcasting the probe message, a forwarding flag indicative of whether a zone player that obtains the probe message is to forward the probe message, and a renew IP flag indicative of whether the zone player that obtains the probe message is to renew its IP address in response to processing the probe message. 
     In the illustrated example of  FIG. 4 , the example zone player  400  includes the example IP leaser  428  to renew IP addresses when initiated or to lease a new IP address. The example IP leaser  428  may be initiated when the zone player  400  is rebooted (e.g., the IP leaser  428  is to lease a new IP address), when a currently leased IP address is expiring (e.g., the IP leaser  428  is to renew its currently leased (or assigned) IP address), in response to a message from the passive resolver  424 , in response to a message from the active resolver  424 , etc. That is, the example IP leaser  428  may be initiated when the zone player  400  is in a bind state, in a renew state and/or in a discover state. In the illustrated example of  FIG. 4 , the example IP leaser  428  uses the dynamic host configuration protocol (DHCP) when communicating with a host (e.g., a DHCP server such as an access point). 
     In the illustrated example, the IP leaser  428  generates and unicasts a request message to the access point to renew its IP lease. For example, the IP leaser  428  may send a DHCP_REQUEST packet to the access point when the currently leased IP address lease is expiring and/or when the example address resolver  422  detects the access point rebooting. When the access point accepts the request to renew the IP address, the access point returns an IP address renewal message (e.g., a DHCP_ACK packet) to the IP leaser  428 . Otherwise, when the access point denies the request to renew the IP address, the access point returns a negative acknowledgement message (e.g., a DHCP_NACK packet) to the IP leaser  428 . For example, when the access point is rebooted, the access point may lose IP address binding information for the one or more zone players leasing IP addresses from the access point. Thus, the access point is unable to renew any IP address lease. 
     In some embodiments, in response to receiving a negative acknowledgement message from the access point, the IP leaser  428  initiates a new binding process. For example, the IP leaser  428  may broadcast discover message (e.g., a DHCP DISCOVER packet) on the example data network  128  to identify all available DHCP servers. In some embodiments, the IP leaser  428  obtains an offer message for an IP address lease. For example, a DHCP server (e.g., an access point) may unicast to the IP leaser  428  or broadcast over the data network  128  a response message (e.g., a DHCP OFFER packet) offering an IP address lease to the IP leaser  428 . The offer message may include an IP address and a lease duration. In some embodiments, the example IP leaser  428  responds to the offer message by broadcasting a request message (e.g., a DHCP_REQUEST packet). For example, the IP leaser  428  may request the offered IP address from the access point. The request message includes the IP address offered. For example, the offered IP address may be included in a “Your IP Address” (YIPADDR) field (e.g., an options field) of the request message. In some embodiments, the example IP leaser  428  configures the example network interface  402  with the IP address lease information (e.g., the IP address, the lease duration, the DHCP server accepting the IP address lease, etc.) in response to an acknowledgement message (e.g., a DHCP_ACK packet) obtained by the IP leaser  428 . For example, the access point may unicast to the IP leaser  428  or broadcast over the data network  128  the acknowledgement message when the access point accepts the binding request (e.g., request to lease an IP address). The example IP leaser  428  may then store the leased IP address in the example database  430 . In some embodiments, the access point determines whether to unicast or broadcast a message based on a broadcast flag included in a message obtained from a client (e.g., the zone player  400 ). For example, if the broadcast flag (e.g., a bit) is set (e.g., one, on, yes, true, etc.), the access point broadcasts its response message over the data network  128 . Otherwise, if the broadcast flag is not set (e.g., zero, off, no, false, etc.), the access point unicasts its response message to the client. In some examples, the access point may send an address resolution protocol (ARP) packet first. 
     IV. Example Controller 
     Referring now to  FIG. 5 , there is shown an example block diagram for a controller  500 , which can correspond to the controlling device  130  in  FIG. 1 . The controller  500  can be used to facilitate the control of multi-media applications, automation and others in a system. In particular, the controller  500  may be configured to facilitate a selection of a plurality of audio sources available on the network and enable control of one or more zone players (e.g., the zone players  102 - 124  in  FIG. 1 ) through a wireless or wired network interface  508 . According to one embodiment, the wireless communications is based on an industry standard (e.g., infrared, radio, wireless standards including IEEE 802.11a, 802.11b, 802.11g, 802.11n, 802.15, 4G mobile communication standard, and so on). Further, when a particular audio is being accessed via the controller  500  or being played via a zone player, a picture (e.g., album art) or any other data, associated with the audio and/or audio source can be transmitted from a zone player or other electronic device to the controller  500  for display. 
     The example controller  500  is provided with a screen  502  and an input interface  514  that allows a user to interact with the controller  500 , for example, to navigate a playlist of many multimedia items and to control operations of one or more zone players. The screen  502  on the controller  500  can be an LCD screen, for example. The screen  502  communicates with and is commanded by a screen driver  504  that is controlled by a microcontroller  506  (e.g., a processor). A memory  510  can be loaded with one or more application modules  512  that can be executed by the microcontroller  506  with or without a user input via a user interface  514  to achieve certain tasks. In some embodiments, an application module  512  is configured to facilitate grouping a number of selected zone players into a zone group and synchronizing the zone players for audio playback. In some embodiments, an application module  512  is configured to control the audio sounds (e.g., volume) of the zone players in a zone group. In operation, when the microcontroller  506  executes one or more of the application modules  512 , the screen driver  504  generates control signals to drive the screen  502  to display an application specific user interface accordingly. 
     The controller  500  includes the network interface  508  that facilitates wired or wireless communication with a zone player. In some embodiments, the commands such as volume control and audio playback synchronization are sent via the network interface  508 . In some embodiments, a saved zone group configuration is transmitted between a zone player and a controller via the network interface  508 . The controller  500  can control one or more zone players, such as  102 - 124  of  FIG. 1 . There can be more than one controller for a particular system, and each controller may share common information with another controller, or retrieve the common information from a zone player, if such a zone player stores configuration data (e.g., such as a state variable). Further, a controller can be integrated into a zone player. 
     It should be noted that other network-enabled devices such as an IPHONE™, IPAD™ or any other smart phone or network-enabled device (e.g., a networked computer such as a PC or MAC′) can also be used as a controller to interact or control zone players in a particular environment. In some embodiments, a software application or upgrade can be downloaded onto a network-enabled device to perform the functions described herein. 
     In certain embodiments, a user can create a zone group (also referred to as a bonded zone) including at least two zone players from the controller  500 . The zone players in the zone group can play audio in a synchronized fashion, such that all of the zone players in the zone group playback an identical audio source or a list of identical audio sources in a synchronized manner such that no (or substantially no) audible delays or hiccups are to be heard. Similarly, in some embodiments, when a user increases the audio volume of the group from the controller  500 , the signals or data of increasing the audio volume for the group are sent to one of the zone players and causes other zone players in the group to be increased together in volume. 
     A user via the controller  500  can group zone players into a zone group by activating a “Link Zones” or “Add Zone” soft button, or de-grouping a zone group by activating an “Unlink Zones” or “Drop Zone” button. For example, one mechanism for ‘joining’ zone players together for audio playback is to link a number of zone players together to form a group. To link a number of zone players together, a user can manually link each zone player or room one after the other. For example, assume that there is a multi-zone system that includes the following zones: Bathroom, Bedroom, Den, Dining Room, Family Room, and Foyer. 
     In certain embodiments, a user can link any number of the six zone players, for example, by starting with a single zone and then manually linking each zone to that zone. 
     In certain embodiments, a set of zones can be dynamically linked together using a command to create a zone scene or theme (subsequent to first creating the zone scene). For instance, a “Morning” zone scene command can link the Bedroom, Office, and Kitchen zones together in one action. Without this single command, the user would manually and individually link each zone. The single command may include a mouse click, a double mouse click, a button press, a gesture, or some other programmed or learned action. Other kinds of zone scenes can be programmed or learned by the system over time. 
     In certain embodiments, a zone scene can be triggered based on time (e.g., an alarm clock function). For instance, a zone scene can be set to apply at 8:00 am. The system can link appropriate zones automatically, set specific music to play, and then stop the music after a defined duration. Although any particular zone can be triggered to an “On” or “Off” state based on time, for example, a zone scene enables any zone(s) linked to the scene to play a predefined audio (e.g., a favorable song, a predefined playlist) at a specific time and/or for a specific duration. If, for any reason, the scheduled music failed to be played (e.g., an empty playlist, no connection to a share, failed Universal Plug and Play (UPnP), no Internet connection for an Internet Radio station, and so on), a backup buzzer can be programmed to sound. The buzzer can include a sound file that is stored in a zone player, for example. 
     V. Playback Queue 
     As discussed above, in some embodiments, a zone player may be assigned to or otherwise associated with a playback queue identifying zero or more media items for playback by the zone player. The media items identified in a playback queue may be represented to the user via an interface on a controller. For instance, the representation may show the user (or users if more than one controller is connected to the system) how the zone player is traversing the playback queue, such as by highlighting the “now playing” item, graying out the previously played item(s), highlighting the to-be-played item(s), and so on. 
     In some embodiments, a single zone player is assigned to a playback queue. For example, the zone player  114  in the bathroom of  FIG. 1  may be linked or assigned to a “Bathroom” playback queue. In an embodiment, the “Bathroom” playback queue might have been established by the system as a result of the user naming the zone player  114  to the bathroom. As such, contents populated and identified in the “Bathroom” playback queue can be played via the zone player  114  (the bathroom zone). 
     In some embodiments, a zone or zone group is assigned to a playback queue. For example, zone players  106 ,  108  in the family room of  FIG. 1  may be linked or assigned to a “Family room” playback queue. In another example, if family room and dining room zones were grouped, then the new group would be linked or assigned to or otherwise associated with a “family room+dining room” playback queue. In some embodiments, the family room+dining room playback queue may be established based upon the creation of the group. In some embodiments, upon establishment of the new group, the family room+dining room playback queue can automatically include the contents of one (or both) of the playback queues associated with either the family room or dining room or both. In one instance, if the user started with the family room and added the dining room, then the contents of the family room playback queue would become the contents of the family room+dining room playback queue. In another instance, if the user started with the family room and added the dining room, then the family room playback queue would be renamed to the family room+dining room playback queue. If the new group was “ungrouped,” then the family room+dining room playback queue may be removed from the system and/or renamed to one of the zones (e.g., renamed to “family room” or “dining room”). After ungrouping, each of the family room and the dining room will be assigned to a separate playback queue. One or more of the zone players in the zone or zone group may store in memory the associated playback queue. 
     As such, when zones or zone groups are “grouped” or “ungrouped” dynamically by the user via a controller, the system will, in some embodiments, establish or remove/rename playback queues respectively, as each zone or zone group is to be assigned to a playback queue. In other words, the playback queue operates as a container that can be populated with media items for playback by the assigned zone. In some embodiments, the media items identified in a playback queue can be manipulated (e.g., re-arranged, added to, deleted from, and so on). 
     By way of illustration,  FIG. 6  shows an example network  600  for media content playback. As shown, the example network  600  includes example zone players  612 ,  614 , example audio sources  662 ,  664 , and example media items  620 . The example media items  620  may include playlist  622 , music track  624 , favorite Internet radio station  626 , playlists  628 ,  630 , and album  632 . In one embodiment, the zone players  612 ,  614  may be any of the zone players shown in  FIGS. 1, 2, and 4 . For instance, zone players  612 ,  614  may be the zone players  106 ,  108  in the Family Room. 
     In one example, the example audio sources  662 ,  664 , and example media items  620  may be partially stored on a cloud network, discussed more below in connection to  FIG. 8 . In some cases, the portions of the audio sources  662 ,  664 , and example media items  620  may be stored locally on one or both of the zone players  612 ,  614 . In one embodiment, playlist  622 , favorite Internet radio station  626 , and playlist  630  may be stored locally, and music track  624 , playlist  628 , and album  632  may be stored on the cloud network. 
     Each of the example media items  620  may be a list of media items playable by a zone player(s). In one embodiment, the example media items may be a collection of links or pointers (e.g., URI) to the underlying data for media items that are stored elsewhere, such as the audio sources  662 ,  664 . In another embodiment, the media items may include pointers to media content stored on the local zone player, another zone player over a local network, or a controller device connected to the local network. 
     As shown, the example network  600  may also include an example queue  602  associated with the zone player  612 , and an example queue  604  associated with the zone player  614 . The playback queue  606  may be associated with a group, when in existence, comprising the zone player  612  and the zone player  614 . The playback queue  606  might comprise a new queue or exist as a renamed version of the queue  602  or  604 . In some embodiments, in a group, the zone players  612 ,  614  would be assigned to the playback queue  606 , and the playback queues  602 ,  604  would not be available at that time. In some embodiments, when the group is no longer in existence, the playback queue  606  is no longer available. Each zone player and each combination of zone players in a network of zone players, such as those shown in  FIG. 1  or that of the example zone players  612 ,  614 , and the example combination  616 , may be uniquely assigned to a corresponding playback queue. 
     A playback queue, such as the playback queues  602 ,  604 ,  606 , may include identification of media content to be played by the corresponding zone player or combination of zone players. As such, media items added to the playback queue are to be played by the corresponding zone player or combination of zone players. The zone player may be configured to play items in the queue according to a specific order (such as an order in which the items were added), in a random order, or in some other order. 
     The playback queue may include a combination of playlists and other media items added to the queue. In one embodiment, the items in the playback queue  602  to be played by the zone player  612  may include items from the audio sources  662 ,  664 , or any of the media items  622 - 632 . The playback queue  602  may also include items stored locally on the zone player  612 , or items accessible from the zone player  614 . For instance, the playback queue  602  may include the Internet radio  626  and the album  632  items from the audio source  662 , and items stored on the zone player  612 . 
     When a media item is added to the queue via an interface of a controller, a link to the item may be added to the queue. In a case of adding a playlist to the queue, links to the media items in the playlist may be provided to the queue. For example, the playback queue  602  may include pointers from the Internet radio  626  and the album  632 , pointers to items on the audio source  662 , and pointers to items on the zone player  612 . In another case, a link to the playlist, for example, rather than a link to the media items in the playlist may be provided to the queue, and the zone player or combination of zone players may play the media items in the playlist by accessing the media items via the playlist. For example, the album  632  may include pointers to items stored on the audio source  662 . Rather than adding links to the items on the audio source  662 , a link to the album  632  may be added to the playback queue  602 , such that the zone player  612  may play the items on the audio source  662  by accessing the items via pointers in the playlist  632 . 
     In some cases, contents as they exist at a point in time within a playback queue may be stored as a playlist, and subsequently added to the same queue later or added to another queue. For example, contents of the playback queue  602 , at a particular point in time, may be saved as a playlist, stored locally on the zone player  612  and/or on the cloud network. The saved playlist may then be added to the playback queue  604  to be played by the zone player  614 . 
     VI. Example Ad-Hoc Network 
     Particular examples are now provided in connection with  FIG. 7  to describe, for purposes of illustration, certain embodiments to provide and facilitate connection to a playback network.  FIG. 7  shows that there are three zone players  702 ,  704  and  706  and a controller  708  that form a network branch that is also referred to as an Ad-Hoc network  710 . The network  710  may be wireless, wired, or a combination of wired and wireless technologies. In general, an Ad-Hoc (or “spontaneous”) network is a local area network or other small network in which there is generally no one access point for all traffic. With an established Ad-Hoc network  710 , the devices  702 ,  704 ,  706 ,  708  can all communicate with each other in a “peer-to-peer” style of communication, for example. Furthermore, devices may join and/or leave from the network  710 , and the network  710  will automatically reconfigure itself without needing the user to reconfigure the network  710 . While an Ad-Hoc network is referenced in  FIG. 7 , it is understood that a playback network may be based on a type of network that is completely or partially different from an Ad-Hoc network. 
     Using the Ad-Hoc network  710 , the devices  702 ,  704 ,  706 ,  708  can share or exchange one or more audio sources and be dynamically grouped (or ungrouped) to play the same or different audio sources. For example, the devices  702 ,  704  are grouped to playback one piece of music, and at the same time, the device  706  plays back another piece of music. In other words, the devices  702 ,  704 ,  706 ,  708 , as shown in  FIG. 7 , form a HOUSEHOLD that distributes audio and/or reproduces sound. As used herein, the term HOUSEHOLD (provided in uppercase letters to disambiguate from the user&#39;s domicile) is used to represent a collection of networked devices that are cooperating to provide an application or service. An instance of a HOUSEHOLD is identified with a household  710  (or household identifier), though a HOUSEHOLD may be identified with a different area or place. 
     In certain embodiments, a household identifier (HHID) is a short string or an identifier that is computer-generated to help ensure that it is unique. Accordingly, the network  710  can be characterized by a unique HHID and a unique set of configuration variables or parameters, such as channels (e.g., respective frequency bands), service set identifier (SSID) (a sequence of alphanumeric characters as a name of a wireless network), and WEP keys (wired equivalent privacy) or other security keys. In certain embodiments, SSID is set to be the same as HHID. 
     In certain embodiments, each HOUSEHOLD includes two types of network nodes: a control point (CP) and a zone player (ZP). The control point controls an overall network setup process and sequencing, including an automatic generation of required network parameters (e.g., security keys). In an embodiment, the CP also provides the user with a HOUSEHOLD configuration user interface. The CP function can be provided by a computer running a CP application module, or by a handheld controller (e.g., the controller  708 ) also running a CP application module, for example. The zone player is any other device on the network that is placed to participate in the automatic configuration process. The ZP, as a notation used herein, includes the controller  708  or a computing device, for example. In some embodiments, the functionality, or certain parts of the functionality, in both the CP and the ZP are combined at a single node (e.g., a ZP contains a CP or vice-versa). 
     In certain embodiments, configuration of a HOUSEHOLD involves multiple CPs and ZPs that rendezvous and establish a known configuration such that they can use a standard networking protocol (e.g., IP over Wired or Wireless Ethernet) for communication. In an embodiment, two types of networks/protocols are employed: Ethernet 802.3 and Wireless 802.11g. Interconnections between a CP and a ZP can use either of the networks/protocols. A device in the system as a member of a HOUSEHOLD can connect to both networks simultaneously. 
     In an environment that has both networks in use, it is assumed that at least one device in a system is connected to both as a bridging device, thus providing bridging services between wired/wireless networks for others. The zone player  706  in  FIG. 7  is shown to be connected to both networks, for example. The connectivity to the network  712  is based on Ethernet and/or Wireless, while the connectivity to other devices  702 ,  704 ,  708  is based on Wireless and Ethernet if so desired. 
     It is understood, however, that in some embodiments each zone player  706 ,  704 ,  702  may access the Internet when retrieving media from the cloud (e.g., the Internet) via the bridging device. For example, the zone player  702  may contain a uniform resource locator (URL) that specifies an address to a particular audio track in the cloud. Using the URL, the zone player  702  may retrieve the audio track from the cloud, and ultimately play the audio out of one or more zone players. 
     VII. Another Example System Configuration 
       FIG. 8  shows a system  800  including a plurality of interconnected networks including a cloud-based network and at least one local playback network. A local playback network includes a plurality of playback devices or players, though it is understood that the playback network may contain only one playback device. In certain embodiments, each player has an ability to retrieve its content for playback. Control and content retrieval can be distributed or centralized, for example. Input can include streaming content provider input, third party application input, mobile device input, user input, and/or other playback network input into the cloud for local distribution and playback. 
     As illustrated by the example system  800  of  FIG. 8 , a plurality of content providers  820 - 850  can be connected to one or more local playback networks  860 - 870  via a cloud and/or other network  810 . Using the cloud  810 , a multimedia audio system server  820  (e.g., Sonos™), a mobile device  830 , a third party application  840 , a content provider  850  and so on can provide multimedia content (requested or otherwise) to local playback networks  860 ,  870 . Within each local playback network  860 ,  870 , a controller  862 ,  872  and a playback device  864 ,  874  can be used to playback audio content. 
     VIII. Example Resolution of Internet Protocol Address Conflicts 
     During operation, an access point (e.g., a wired and/or wireless router) enables playback devices such as zone players on a network to communicate on that network. The access point maintains an IP address configuration in a data structure such as a lookup table, a list, a document, etc. For example, the access point may identify an IP address to lease (e.g., assign) to a device on the network based on available IP addresses included in the IP address configuration. However, in some embodiments, when the access point is rebooted (or changes to the power ON state from the power OFF state), the IP address configuration stored in the data structure may be lost. For example, the IP address configuration may be stored in temporary memory that resets when power is removed to the memory. 
     In certain instances, such as, for example, those described above, an IP address conflict may develop in a network, whereby, for example, more than one device on the network may use the same IP address. Duplicate IP addresses may occur when, for example, the access point reboots. Duplicate IP address resolution is not defined for network devices that are not in direct communication (e.g., directly connected via wired or wireless interface) to the access point. For example, the access point may be unaware that a first device is assigned a first IP address when a second device requests a lease for the first IP address because the IP address configuration (e.g., data structure including available IP addresses) was lost when the access point was rebooted. Accordingly, embodiments disclosed herein enable resolving IP address conflicts in a network. 
       FIG. 9  illustrates an example block diagram of the example passive resolver  424  of the zone player depicted in  FIG. 4 . The example passive resolver  424  of  FIG. 9  monitors a data network to detect IP address lease requests from other device(s) communicating on the network. For example, the passive resolver  424  may identify when another zone player (e.g., the example zone player  400  ( FIG. 4 ), a laptop, a smart phone, etc. requests an IP address (either to renew its IP address or to bind to a new IP address) on a data network, such as the data network  128  ( FIG. 1 ), the ad-hoc network  710  ( FIG. 7 ), the Sonos Network  1   860  and/or Sonos Network N  870  ( FIG. 8 ). The example passive resolver  424  may then facilitate resolution of duplicate IP addresses by, for example, requesting a new (or renewing an) IP address. The example passive resolver  424  of  FIG. 9  includes an example server port monitor  902  and an example request handler  904 . 
     In the illustrated example of  FIG. 9 , the example passive resolver  424  includes the example server port monitor  902  to monitor messages (e.g., DHCP messages or packets) sent to a host (e.g., an access point) on a network such as the example data network  128  ( FIG. 1 ). For example, the server port monitor  902  may monitor user datagram protocol (UDP) server port ( 67 ) and UDP client port ( 68 ). The UDP server port ( 67 ) is a destination port to send data to a server. That is, messages that communicate via the UDP server port ( 67 ) correspond to messages sent to a host device such as an access point from a client device such as a playback device. In contrast, the UDP client port ( 68 ) is a destination port for data sent to a client. That is, messages that communicate via the UDP client port ( 68 ) correspond to messages obtained by a client device such as the zone player  400  ( FIG. 4 ) from a host device. Thus, the example server port monitor  902  enables the example passive resolver  424  to detect IP address lease request messages sent from another device on the network to an access point on the network. In some embodiments, the example server port monitor  902  monitors the UDP server port ( 67 ) while the zone player is in a bind state (e.g., the client device is connected to a host device). In some embodiments, the example server port monitor  902  monitors the UDP server port ( 67 ) while the zone player is in a renew state (e.g., trying to renew the currently assigned IP address) or in the discover state (e.g., when the client device is initiating a new binding process). 
     In the illustrated example of  FIG. 9 , the example passive resolver  424  includes the example request handler  904  to determine whether the IP address included in an IP address lease request message is the same as the IP address leased (e.g., currently assigned) to the zone player  400 . For example, request handler  904  may retrieve the zone player  400  IP address from the example database  430  ( FIG. 4 ) and compare it to the IP address included in the “YIPADDR” (e.g., Your IP Address) options field of the request message. In some embodiments, if the IP addresses do not match (e.g., are not the same or equivalent), the example request handler  904  discards the IP address lease request message. Otherwise, in some embodiments, if the IP addresses do match (e.g., are the same or equivalent), the example request handler  904  initiates the example IP leaser  428  ( FIG. 4 ) to obtain a new IP address for the zone player  400 . As discussed above in connection with the IP leaser  428 , when the IP leaser  428  requests to renew an IP address, the IP leaser receives a negative acknowledgement message (e.g., a DHCP_NACK packet) because the IP address included in the renew request message is the same as the IP address of another device on the network. 
     In some embodiments, the example passive resolver  424  may not include the example request handler  904 . That is, in some embodiments, when the example server port monitor  902  detects an IP address lease request, the example server port monitor  902  may initiate the example IP leaser  428  regardless of whether the IP address included in the request message is the same as the IP address of the zone player  400 . 
       FIG. 10  illustrates an example block diagram of the example active resolver  426  of  FIG. 4 . The example active resolver  426  of  FIG. 10  monitors the power status of a wired connection to an access point in a network. For example, the active resolver  426  may monitor the wired interface  406  ( FIG. 4 ) to detect a change in the power status. In some embodiments, a change in power status of the wired interface  406  is indicative of a change in power status (e.g., a reboot) of an access point that is in communication with the wired interface  406 . In some embodiments, the active resolver  426  may then request a new IP address (or request to renew the IP address already assigned (e.g., leased) to the device) and cause other devices in communication with the active resolver  426  and/or the access point to request new IP addresses (or request to renew the existing IP addresses). The example active resolver  426  of  FIG. 10  includes an example wired interface monitor  1002 , an example message generator  1004 , an example probe handler  1006  and an example renew handler  1008 . 
     In the illustrated example of  FIG. 10 , the example wired interface monitor  1002  monitors power status changes in the wired interface of the zone player  400  ( FIG. 4 ). For example, the wired interface monitor  1002  may detect changes in the Ethernet status (e.g., “eth0”) of the wired interface  406 . In some embodiments, the eth0 is a binary status bit that indicates that the Ethernet status is either ON or OFF. In some embodiments, when the wired interface monitor  1002  detects a change in the eth0 from the power OFF state to the power ON state, the example wired interface monitor  1002  initiates the example IP leaser  428  ( FIG. 4 ) to initiate an IP address renew request or a new binding process. For example, the change in the eth0 may indicate that the access point was rebooted. Accordingly, the example active resolver  426  initiates the example IP leaser  428  to cause the access point to update available IP addresses in the IP address configuration of the data network. 
     In the illustrated example of  FIG. 10 , the example message generator  1004  generates probe messages that are broadcast by zone players on a data network, such as the data network  128  ( FIG. 1 ), the ad-hoc network  710  ( FIG. 7 ), the Sonos Network  1   860  and/or Sonos Network N  870  ( FIG. 8 ). Probe messages may include a message identifier (e.g., a 16-bit number) identifying the probe message, a zone player identifier (e.g., a MAC address) of the zone player broadcasting the probe message, a forwarding flag indicative of whether a zone player that obtains the probe message is to forward the probe message, and a renew IP flag indicative of whether the zone player that obtains the probe message is to renew its IP address in response to processing the probe message. In some embodiments, the probe messages are broadcast periodically by the zone players on the data network. For example, a probe message may be sent every 500 milliseconds. In some embodiments, the probe messages are broadcast aperiodically by the zone players on the data network. For example, a zone player may send a probe message in response to a detected change in the eth0 status. 
     In some embodiments, the example message generator  1004  of  FIG. 10  generates a probe message with a new message identifier to identify different probe messages. For example, the message identifier may be a locally generated sequence number such as a 16-bit number. In some embodiments, the active resolver  426  may use the message identifier to determine whether the probe message was previously obtained. For example, a probe message may be forwarded from one zone player on the data network to another zone player until the probe message is obtained by a zone player for a second time. In the illustrated example, the example message generator  1004  of  FIG. 10  stores the new message identifier in the example database  430  ( FIG. 4 ). In some embodiments, the example message generator  1004  of  FIG. 10  includes a MAC address of the zone player that generates a probe message in the probe message. 
     In the illustrated example, the example message generator  1004  of  FIG. 10  updates the status of a renew IP flag included in the probe message in response to determinations made by the example wired interface monitor  1002 . For example, when the wired interface monitor  1002  detects a change in the power status of the eth0, the example message generator  1004  may set (e.g., one, yes, on, true, etc.) the renew IP flag. When the example wired interface monitor  1002  does not detect a change in the power status of the eth0, the example message generator may reset (e.g., zero, no, off, false, etc.) the renew IP flag. The status of the renew IP flag may be used by the example probe handler  1006  to determine whether the active resolver  426  is to initiate the example IP leaser  428 . 
     In the illustrated example of  FIG. 10 , the example active resolver  426  includes the example probe handler  1006  to process probe messages obtained by the active resolver  426  from another zone player. For example, the probe handler  1006  may periodically and/or aperiodically obtain a probe message from another zone player on a data network, such as the data network  128  ( FIG. 1 ), the ad-hoc network  710  ( FIG. 7 ), the Sonos Network  1   860  and/or Sonos Network N  870  ( FIG. 8 ). In the illustrated example, the probe handler  1006  of  FIG. 10  checks the status of the renew IP flag of the probe message. In some embodiments, when the renew IP flag is set (e.g., one, yes, on, true, etc.), the example probe handler  1006  outputs a message indicative of the new probe message to the example renew handler  1008 . 
     In some embodiments, the example probe handler  1006  may determine whether the renew IP flag of the probe message is to be reset in a probe message based on a time-to-live for the renew IP flag. For example, a probe message may include a timestamp indicative of when the example message generator  1004  generated the probe message. In some such embodiments, when the example probe handler  1006  obtains a probe message with a renew IP flag that is set, the example probe handler  1006  may determine whether the time-to-live of the renew IP flag expired based on the timestamp included in the probe message. For example, the time-to-live for a set renew IP flag may be equal to the round trip propagation delay through the network. Thus, the example probe handler  1006  may check whether the set renew IP flag time-to-live (e.g., the difference between the time the probe message is obtained and the time the probe message is generated) is less than the round trip propagation delay. Accordingly, the example probe handler  1006  forwards the probe message to the example renew handler  1008  when the set renew IP flag time-to-live has not expired, and discards the probe message if the time-to-live has expired. 
     In some embodiments, the example probe handler  1006  may also check the status of the forwarding flag in the probe message to determine whether the probe message is to be forwarded to other zone players on the data network. For example, the probe handler  1006  may forward the probe message to the example message generator  1004  when the forwarding flag is set (e.g., one, yes, on, true, etc.) and may discard the probe message when the forwarding flag is reset (e.g., zero, no, off, false, etc.). 
     In the illustrated example of  FIG. 10 , the example active resolver  426  includes the example renew handler  1008  to determine whether the obtained probe message is a new probe message or a previously obtained probe message. For example, the renew handler  1008  may retrieve previously obtained message identifiers from the example database  430  to compare to the message identifier included in the probe message. If the probe message is a new probe message (e.g., not previously obtained), the example renew handler  1008  initiates the example IP leaser  428  ( FIG. 4 ). Otherwise, the example renew handler  1008  may discard the probe message. 
     In some embodiments, the renew handler  1008  may use hysteresis to avoid initiating the example IP leaser  428  multiple times to request renewing the IP address of the zone player. For example, the renew handler  1008  may include a timer that starts each time the renew handler  1008  initiates the example IP leaser  428 . If another request to renew the IP address is obtained before the timer expires, the renew handler  1008  may discard the probe message. This may be useful when, for example, multiple eth0 status events are detected by the example wired interface monitor  1002 . For example, a bad power connection may cause unwanted rapid eth0 status changes. 
       FIG. 11  shows an illustrative flowchart for an example method  1100  to facilitate resolution of IP address conflicts, in accordance with at least some embodiments described herein. For example, the example method  1100  may use the example passive resolver  424  to facilitate resolution of IP address conflicts. The example method  1100  of  FIG. 11  begins at block  1102  when the example passive resolver  424  ( FIGS. 4 and/or 9 ) monitors messages sent to an access point on a data network, such as the data network  128  ( FIG. 1 ), the ad-hoc network  710  ( FIG. 7 ), the Sonos Network  1   860  and/or Sonos Network N  870  ( FIG. 8 ). For example, the server port monitor  902  ( FIG. 9 ) may “listen” to messages sent to the UDP server port ( 67 ) from other devices (e.g., one or more zone players, one or more laptops, one or more smart phones, etc.). At block  1104 , the example passive resolver  424  determines whether a message sent to the access point includes an IP address lease renew request. For example, the server port monitor  902  checks whether the message sent to the UDP server port ( 67 ) includes a DHCP_REQUEST packet. If the example server port monitor  902  determines that the message does not include an IP address lease renew request at block  1104 , then control proceeds to block  1110  to determine whether to continue monitoring for IP address conflicts. 
     Otherwise, if the example server port monitor  902  determines that the message sent to the UDP server port ( 67 ) does include an IP address lease renew request at block  1104 , then, at block  1106 , the example passive resolver  424  determines whether the IP address included in the request message is a duplicate IP address. For example, the request handler  904  ( FIG. 9 ) may retrieve the IP address of the zone player (e.g., the example zone player  400 ) from the example database  430  ( FIG. 4 ) to compare to the IP address included in the IP address lease renew request (e.g., the value of the “YIPADDR” options field of the request). If the example request handler  904  determines the request message is not a duplicate IP address at block  1106 , then control proceeds to block  1110  to determine whether to continue monitoring for IP address conflicts. 
     Otherwise, if the example request handler  904  determines the request message is a duplicate IP address at block  1106 , then, at block  1108 , the example passive resolver  424  requests a new IP address. For example, the request handler  904  may initiate the example IP leaser  428  ( FIG. 4 ) to request an IP address lease renewal. At block  1110 , the example passive resolver  424  determines whether to continue monitoring for IP address conflicts. If the passive resolver  424  determines to continue monitoring for IP address conflicts, control returns to block  1102  to monitor messages sent to the access point. Otherwise, if, at block  1110 , the passive resolver  424  determines not to continue monitoring for IP address conflicts (e.g., due to an application/process shutdown event, a hardware shutdown event, etc.), the example method of  FIG. 11  ends. 
     As an illustrative example,  FIGS. 12 a  and 12 b    show example flow paths for resolving IP address conflicts in an example environment  1200  such as the example media system configuration  100  ( FIG. 1 ). The example environment  1200  includes an example access point  1202  (e.g., a wired and/or wireless router), an example wired zone player  1204 , and example wireless zone players  1206 ,  1207 . The example access point  1202 , the example wired zone player  1204  and the example wireless zone players  1206 ,  1207  are in communication via an example data network  1208 . The example wired zone player  1204  is in communication with the example access point  1202  via a wired interface (e.g., the example wired interface  406  ( FIG. 4 )). The example wireless zone players  1206 ,  1207  are in communication with the example access point  1202  via a wireless interface (e.g., the example wireless interface  404  ( FIG. 4 )). 
       FIG. 12 a    is representative of the state of the example environment  1200  after the access point  1202  reboots. Accordingly, the example access point  1202  includes an IP address configuration  1210  that indicates all IP addresses on the example data network  1208  are available (e.g., are not leased to any devices). Thus, the example access point  1202  is unaware that the example wireless zone player  1206  is leasing IP address  1212  (e.g., 102.168.00.01) and that the example wireless zone player  1207  is leasing IP address  1213  (e.g., 102.168.00.02). In addition, the example wired zone player  1204  having detected the access point reboot, broadcasts an IP address lease renew request  1214  over the data network  1208 . However, because the IP address configuration  1210  does not include any IP address leasing information, the example access point  1202  sends a negative acknowledgement message  1215  to the wired zone player  1204 . 
     Accordingly, the example wired zone player  1204  of  FIG. 12 a    has no IP address  1216  (e.g., 0.0.0.0) and initiates a new binding process  1218  over the data network  1208 . During the binding process  1218 , the example wired zone player  1204  may broadcast a discover message (e.g., a DHCP DISCOVER packet), and receive, in response to the discover message, a DHCP_OFFER packet from the access point  1202 . The DHCP_OFFER packet may include an IP address offered to the wired zone player  1204  (in this example IP address  1222  (e.g., 192.168.00.02)). In response to the DHCP_OFFER packet, the example wired zone player  1204  may broadcast a DHCP_REQUEST packet that includes the IP address  1222  (e.g., 192.168.00.02). 
       FIG. 12 b    is representative of the state of the example environment  1200  after the example access point  1202  leases the IP address  1222  to the wired zone player  1204 . In response to the access point  1202  obtaining an IP address lease request message (e.g., the DHCP_REQUEST message) from the wired zone player  1204 , the example wireless zone players  1206 ,  1207  also detect the request message. For example, the wireless zone players  1206 ,  1207  may include a passive resolver (e.g., the example passive resolver  424  ( FIGS. 4 and/or 9 )) that monitors the UDP server port ( 67 ) for IP address lease request messages sent to the access point  1202 . In the illustrated example, the passive resolver of the wireless zone player  1206  may determine that duplicate IP addresses do not exist. For example, the wireless zone player  1206  may compare its IP address  1212  (e.g., 192.168.00.01) to the IP address  1222  (e.g., 192.168.00.02) included in the example request message  1220  and determine that the two IP addresses do not match (e.g., are not the same or equal). Accordingly, the example wireless zone player  1206  does not request an IP address renewal and the example access point  1202  remains unaware that the IP address  1212  is leased to a device on the date network  1208 . 
     In contrast, the passive resolver of the wireless zone player  1207  may determine that duplicate IP addresses do exist. For example, the wireless zone player  1207  may compare its IP address  1212  (e.g., 192.168.00.02) to the IP address  1222  (e.g., 192.168.00.02) and determine that the two IP addresses match (e.g., are the same or equal). Accordingly, the example wireless zone player  1207  initiates an IP address renewal, which results in the wireless zone player  1207  losing its IP address when the access point  1202  unicasts or broadcasts a negative acknowledgement message to the wireless zone player  1207 . As a result, the example wireless zone player  1207  initiates a new binding process  1224 , which includes an IP address lease request  1226  with an IP address  1228  (e.g., 192.168.00.14). 
     In the illustrated example of  FIG. 12 b   , the example IP Address Configuration  1230  is representative of the state of the data network  1208  after the access point  1202  leases the IP address  1228  to the wireless zone player  1207 . For example, the IP Address Configuration  1230  includes that the IP address  1222  is leased to the wired zone player  1204 , that the IP address  1212  is not leased to a device on the data network  1208 , and that the IP address  1228  is leased to the wireless zone player  1207 . Thus, in the illustrated examples of  FIGS. 12 a  and 12 b   , the wireless zone player  1207  passively facilitated resolution of an IP address conflict in the data network  1208  by monitoring messages sent to the access point  1202  and requesting an IP address renewal when an IP address included in a message sent to the access point  1202  matched the IP address of the zone player  1207 . 
       FIG. 13  shows an illustrative flowchart for another example method  1300  to facilitate resolution of IP address conflicts, in accordance with at least some embodiments described herein. For example, the example method  1300  may use the example active resolver  426  to facilitate resolution of IP address conflicts. The example method  1300  of  FIG. 13  begins at block  1302  when the example active resolver  426  ( FIGS. 4 and/or 10 ) monitors the power status of a wired link of the zone player  400  ( FIG. 4 ). For example, the wired interface monitor  1002  ( FIG. 10 ) may monitor the eth0 status of the wired interface  406  ( FIG. 4 ). At block  1304 , the example active resolver  426  determines whether a detected power status change is indicative of an access point reboot. For example, the wired interface monitor  1002  may determine whether the eth0 status changes from a power OFF state to a power ON state. If, at block  1304 , the wired interface monitor  1002  determines that the detected power status change is not indicative of an access point reboot, then control proceeds to block  1310  to send a probe message. 
     Otherwise, if, at block  1304 , the wired interface monitor  1002  determines that the detected power status change is indicative of an access point reboot, then, at block  1306 , the active resolver  426  requests an IP address lease renewal. For example, the example wired interface monitor  1002  may initiate the example IP leaser  428  ( FIG. 4 ) to initiate an IP address renew request. At block  1308 , the example active resolver  426  generates a probe message indicative of the detected access point reboot. For example, the example message generator  1004  ( FIG. 10 ) may generate a probe message including a set renew IP flag, the MAC address of the zone player  400 , a message identifier, and a set or reset forwarding flag. At block  1310 , the example active resolver  426  broadcasts a probe message. For example, the message generator  1004  may broadcast the probe message generator at block  1308 . Alternatively, if, at block  1304 , the wired interface monitor  1002  did not detect an access point reboot, then, at block  1310 , the example message generator  1004  may broadcast a previously obtained probe message. For example, the message generator  1004  may forward a probe message that includes a set forwarding flag. At block  1312 , the example active resolver  426  determines whether to continue monitoring for IP address conflicts. If the active resolver  426  determines to continue monitoring for IP address conflicts, control returns to block  1302  to monitor the wired interface power status. Otherwise, if, at block  1312 , the active resolver  426  determines not to continue monitoring for IP address conflicts (e.g., due to an application/process shutdown event, a hardware shutdown event, etc.), the example method of  FIG. 13  ends. 
       FIG. 14  shows an illustrative flowchart for another example method  1400  to facilitate resolution of IP address conflicts, in accordance with at least some embodiments described herein. For example, the example method  1400  may use the example active resolver  426  to facilitate resolution of IP address conflicts. The example method  1400  of  FIG. 14  begins at block  1402  when the example active resolver  426  ( FIGS. 4 and/or 10 ) obtains a probe message. For example, the probe handler  1006  ( FIG. 10 ) may obtain a probe message from another zone player on the data network  128  ( FIG. 1 ). At block  1404 , the example active resolver  426  determines whether the probe message includes a set renew IP flag. For example, the probe handler  1006  may parse the obtained probe message to check the status of the renew IP flag. If, at block  1404 , the probe handler  1006  determines that the renew IP flag is not set, then control proceeds to block  1410  to determine whether the probe message includes a set forwarding flag. 
     Otherwise, if, at block  1404 , the probe handler  1006  determines that the probe message does include a set renew IP flag, then, at block  1406 , the example active resolver  426  determines whether the probe message is a new probe message. For example, the renew handler  1008  ( FIG. 10 ) may compare the message identifier of the probe message to previously obtained message identifiers retrieved from the example database  430  ( FIG. 4 ). If, at block  1406 , the example renew handler  1008  determines that the obtained probe message is not a new probe message (e.g., the obtained probe message identifier matches a message identifier retrieved from the database  430 ), then control proceeds to block  1410  to determine whether the probe message includes a set forwarding flag. 
     Otherwise, if, at block  1406 , the renew handler  1008  determines that the obtained probe message is a new probe message (e.g., the obtained probe message identifier does not match a message identifier retrieved from the database  430 ), then, at block  1408 , the example active resolver  426  requests a new IP address. For example, the renew handler  1008  may initiate the example IP leaser  428  ( FIG. 4 ) to request an IP address lease renewal. 
     Regardless of whether the probe handler  1002  determines that the obtained probe message included a reset renew IP flag at block  1404 , or the renew handler  1008  initiates an IP address lease renewal at block  1408 , at block  1410 , the example active resolver  426  determines whether the probe message forwarding flag is set. For example, the probe handler  1006  may parse the probe message obtained at block  1402  to check the status of the forwarding flag. If, at block  1410 , the probe handler  1006  determines that the forwarding flag is not set, then control proceeds to block  1414  to determine whether to continue monitoring for IP address conflicts. 
     Otherwise, if, at block  1410 , the probe handler  1006  determines that the forwarding flag is set, then, at block  1412 , the active resolver  426  forwards the obtained probe message. For example, the message generator  1004  may broadcast the content of the obtained probe message (e.g., whether the renew IP flag is set or reset, etc.) to other zone players on the data network  128 . At block  1414 , the example active resolver  426  determines whether to continue monitoring for IP address conflicts. If the active resolver  426  determines to continue monitoring for IP address conflicts, control returns to block  1402  to obtain a new probe message. Otherwise, if, at block  1414 , the active resolver  426  determines not to continue monitoring for IP address conflicts (e.g., due to an application/process shutdown event, a hardware shutdown event, etc.), the example method of  FIG. 14  ends. 
     As an illustrative example,  FIGS. 15 a  and 15 b    show example flow paths for resolving IP address conflicts in an example environment  1500  such as the example media system configuration  100  ( FIG. 1 ). The example environment  1500  includes an example access point  1502  (e.g., a wired and/or wireless router), an example wired zone player  1504 , and example wireless zone players  1506 ,  1507 . The example access point  1502 , the example wired zone player  1504  and the example wireless zone players  1506 ,  1507  are in communication via an example data network  1508 . The example wired zone player  1504  is in communication with the example access point  1502  via a wired interface (e.g., the example wired interface  406  ( FIG. 4 )). The example wireless zone players  1506 ,  1507  are in communication with the example access point  1502  via a wireless interface (e.g., the example wireless interface  404  ( FIG. 4 )). 
       FIG. 15 a    is representative of the state of the example environment  1500  before an access point reboot is detected. In the illustrated example of  FIG. 12 a   , the wired zone player  1504  is leasing an IP address  1510  (e.g., 192.168.00.01) from the access point  1502 , the example wireless zone player  1506  is leasing an IP address  1511  (e.g., 192.168.00.12) from the access point  1502 , and the example wireless zone player  1507  is leasing an IP address  1512  (e.g., 192.168.00.04) from the access point  1502 . The example wired zone player  1504  periodically (e.g., every 500 milliseconds) broadcasts a probe message  1514  over the data network  1508 . In the illustrated example, the probe message  1514  is obtained by the wireless zone players  1506 ,  1507 , and the probe message  1514  includes a MAC address identifier  1515  (e.g., 01:23:45:67:89:ab), a message identifier  1516  (e.g., 0013), a renew IP flag  1517  (e.g., zero), and a forwarding flag  1518  (e.g., one). The example MAC address identifier  1515  identifies the zone player that generated the probe message (e.g., the wired zone player  1504 ). The example message identifier  1516  is a locally generated identifier (e.g., generated by the example message generator  1004  ( FIG. 10 ) of the zone player generating the probe message). For example, the message identifier  1516  may be a 16-bit alphanumeric identifier. The example renew IP flag  1517  is indicative of whether a receiving zone player is to renew its IP address lease. In the illustrated example of  FIG. 15 a   , a probe handler  1006  ( FIG. 10 ) of the wireless zone player  1506  may parse the obtained probe message  1514  and determine that the wireless zone player  1506  is not to renew its IP address lease with the access point  1502 . The example forwarding flag  1518  is indicative of whether a receiving zone player is to forward the content of the probe message to other zone players on the data network  1508 . For example, the wireless zone player  1507  may parse the obtained probe message  1514  (e.g., via the probe handler  1006 ) and determine not to forward (e.g., broadcast) the content of the probe message  1514  over the data network  1508  to other zone players. 
       FIG. 15 b    is representative of the state of the example environment  1500  after the example wired zone player  1504  detects an access point reboot. For example, the eth0 status of the wired interface  406  ( FIG. 4 ) of the wired zone player  1504  may change from a power ON state to a power OFF state and back to a power ON state. In response to the detected reboot of the example access point  1502 , the example wired zone player  1504  broadcasts an IP address renewal request and subsequently initiates a new binding process  1519  (e.g., in response to a negative acknowledgement from the access point  1502 ). 
     In addition to initiating the new binding process  1519 , the example wired zone player  1504  generates a new probe message  1522  that is broadcast over the data network  1508 . The example probe message  1522  includes a MAC address identifier  1521  (e.g., 01:23:45:67:89:ab), a message identifier  1522  (e.g., 0014), a renew IP flag  1523  (e.g., one), and a forwarding flag  1524  (e.g., one). The example MAC address identifier of the probe message  1514  and the probe message  1520  are the same as both probe messages  1514 ,  1520  are generated by the same zone player. The different message identifier  1522  of the probe message  1520  indicates that the probe message  1520  is different from the probe message  1514 , and, as a result, the renew IP flag of the probe message  1520  is processed rather than discarded. The renew IP flag  1523  of the probe message  1520  is set (e.g., one) and causes receiving zone players of the probe message  1520  to request IP address lease renewals. For example, the wireless zone player  1506  initiates an IP address lease renewal request  1526  and the wireless zone player  1507  initiates an IP address lease renewal request  1527  in response to processing the obtained probe message  1520 . 
     In the illustrated example of  FIG. 15 b   , the example forwarding flag  1524  is set (e.g., one). Thus, in response to the wireless zone players  1506 ,  1507  obtaining the probe message  1520 , each respective wireless zone player generates a probe message including the content of the probe message  1520 . For example, the wireless zone player  1506  generates a probe message  1528  that is broadcast over the data network  1508 . In the illustrated example, the probe message  1528  of  FIG. 15 b    includes a MAC address identifier  1529  (e.g., 01:23:45:67:89:ab) that is the same as the MAC address identifier  1521  of the probe message  1520 , a message identifier  1530  (e.g., 0014) that is the same as the message identifier  1522  of the probe message  1520 , a renew IP flag  1531  (e.g., one) that is the same as the renew IP flag  1523  of the probe message  1520 , and a forwarding flag  1532  that is the same as the forwarding flag  1524  of the probe message  1520 . In some examples, the forwarding flag  1532  may be different than the forwarding flag  1524 . For example, the wireless zone player  1506  may include a state variable that determines whether a zone player is to forward probe messages. 
     Thus, in the illustrated examples of  FIGS. 15 a  and 15 b   , the zone players  1504 ,  1506 ,  1507  of the environment  1500  actively facilitate resolution of IP address conflicts in the data network  1508  by causing other zone players to request an IP address lease renewal in response to detecting an access point reboot on the data network  1508 . 
     IX. Conclusion 
     The descriptions above disclose various example systems, methods, apparatus, and articles of manufacture including, among other components, firmware and/or software executed on hardware. However, such examples are merely illustrative and should not be considered as limiting. For example, it is contemplated that any or all of these firmware, hardware, and/or software components can be embodied exclusively in hardware, exclusively in software, exclusively in firmware, or in any combination of hardware, software, and/or firmware. Accordingly, while the following describes example systems, methods, apparatus, and/or articles of manufacture, the examples provided are not the only way(s) to implement such systems, methods, apparatus, and/or articles of manufacture. 
     As suggested above, the present application involves resolving IP address conflicts. In one aspect, a first method is provided. The first method involves listening, by a first playback device having a first Internet Protocol (IP) address, to a specified server port. The first method also includes receiving, by the first playback device from a second playback device via the specified server port, a message, wherein the message identifies a second IP address, wherein the second IP address has been assigned to the second playback device. The first method also includes determining, by the first playback device, whether the first IP address is the same as the second IP address. The first method also includes, when the first IP address is the same as the second IP address, obtaining, by the first playback device, a new IP address, wherein the new IP address is different from the first IP address and the second IP address. 
     In another aspect, a second method is provided. The second method involves a network comprising at least a playback device and an access point, wherein there is a connection via a wire between the access point and the playback device. The second method includes periodically broadcast, by the playback device over the network, a probe message. The second method also includes detecting, by the playback device, a change in status associated with the connection. The second method also includes, based on the detection, obtaining, by the playback device, a new Internet Protocol (IP) address. The second method also includes, based on the detection, including, by the playback device in at least one probe message broadcast subsequent to the detection, an indication that other playback devices on the network should obtain a new IP address. 
     In a further aspect, a first non-transitory computer readable medium having instructions stored thereon is provided. The instructions are executable by a first playback device having a first Internet Protocol (IP) address to cause the first playback device to perform functions including listening to a specified server port. The instructions also cause the first playback device to receive from a second playback device via the specified server port, a message, wherein the message identifies a second IP address, wherein the second IP address has been assigned to the second playback device. The instructions are also cause the first playback device to determine whether the first IP address is the same as the second IP address. The instructions are also cause the first playback device to, when the first IP address is the same as the second IP address, obtain a new IP address, wherein the new IP address is different from the first IP address and the second IP address. 
     In yet another aspect, a second non-transitory computer readable medium having instructions stored thereon is provided. The instructions are executable by a playback device to cause the playback device to perform functions including periodically broadcasting a probe message over a network. The instructions also cause the playback device to detect a change in status associated with a wired connection to the playback device. The instructions also cause the playback device to, based on the detection, obtain a new Internet Protocol (IP) address. The instructions also cause the playback device to, based on the detection, include in at least one probe message broadcast subsequent to the detection, an indication that other playback devices on the network should obtain a new IP address. 
     In yet another aspect, a first system involves a playback device including a network interface, a processor, data storage, and program logic stored in the data storage and executable by the processor to listen to a specified server port via the network interface. The program logic to also cause the processor to receive from a second playback device via the specified server port, a message, wherein the message identifies a second Internet Protocol (IP) address, wherein the second IP address has been assigned to the second playback device. The program logic to also cause the processor to determine whether a first IP address assigned to the playback device is the same as the second IP address. The program logic to also cause the processor to, when the first IP address is the same as the second IP address, obtain a new IP address, wherein the new IP address is different from the first IP address and the second IP address. 
     In yet another aspect, a second system involves a playback device including a network interface, a processor, data storage, and program logic stored in the data storage and executable by the processor to periodically broadcast a probe message over a network. The program logic to also cause the processor to detect a change in status associated with a wired connection to the playback device. The program logic to also cause the processor to, based on the detection, obtain a new Internet Protocol (IP) address. The program logic to also cause the processor to, based on the detection, include in at least one probe message broadcast subsequent to the detection, an indication that other playback devices on the network should obtain a new IP address. 
     Additionally, references herein to “embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one example embodiment of the invention. The appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. As such, the embodiments described herein, explicitly and implicitly understood by one skilled in the art, can be combined with other embodiments. 
     The specification is presented largely in terms of illustrative environments, systems, procedures, steps, logic blocks, processing, and other symbolic representations that directly or indirectly resemble the operations of data processing devices coupled to networks. These process descriptions and representations are typically used by those skilled in the art to most effectively convey the substance of their work to others skilled in the art. Numerous specific details are set forth to provide a thorough understanding of the present disclosure. However, it is understood to those skilled in the art that certain embodiments of the present disclosure can be practiced without certain, specific details. In other instances, well known methods, procedures, components, and circuitry have not been described in detail to avoid unnecessarily obscuring aspects of the embodiments. Accordingly, the scope of the present disclosure is defined by the appended claims rather than the forgoing description of embodiments. 
     The example processes of  FIGS. 11, 13 and/or 14  may be implemented using coded instructions (e.g., computer and/or machine readable instructions) stored on a tangible computer readable storage medium such as a hard disk drive, a flash memory, a read-only memory (ROM), a compact disk (CD), a digital versatile disk (DVD), a cache, a random-access memory (RAM) and/or any other storage device or storage disk in which information is stored for any duration (e.g., for extended time periods, permanently, for brief instances, for temporarily buffering, and/or for caching of the information). As used herein, the term tangible computer readable storage medium is expressly defined to include any type of computer readable storage device and/or storage disk and to exclude propagating signals and to exclude transmission media. As used herein, “tangible computer readable storage medium” and “tangible machine readable storage medium” are used interchangeably. Additionally or alternatively, the example processes of  FIGS. 11, 13 and/or 14  may be implemented using coded instructions (e.g., computer and/or machine readable instructions) stored on a non-transitory computer and/or machine readable medium such as a hard disk drive, a flash memory, a read-only memory, a compact disk, a digital versatile disk, a cache, a random-access memory and/or any other storage device or storage disk in which information is stored for any duration (e.g., for extended time periods, permanently, for brief instances, for temporarily buffering, and/or for caching of the information). As used herein, the term non-transitory computer readable medium is expressly defined to include any type of computer readable storage device and/or storage disk and to exclude propagating signals and to exclude transmission media. As used herein, when the phrase “at least” is used as the transition term in a preamble of a claim, it is open-ended in the same manner as the term “comprising” is open ended. 
     When any of the appended claims are read to cover a purely software and/or firmware implementation, at least one of the elements in at least one example is hereby expressly defined to include a tangible medium such as a memory, DVD, CD, Blu-ray, and so on, storing the software and/or firmware.