Patent Publication Number: US-2023137507-A1

Title: Telephony Outage Handling Using An On-Premises Telephony Node

Description:
FIELD 
     This disclosure relates to handling telephony outages, such as those that may occur with telephony services implemented over a network. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       This disclosure is best understood from the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that, according to common practice, the various features of the drawings are not to-scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. 
         FIG.  1    is a block diagram of an example of an electronic computing and communications system. 
         FIG.  2    is a block diagram of an example internal configuration of a computing device of an electronic computing and communications system. 
         FIG.  3    is a block diagram of an example of a software platform implemented by an electronic computing and communications system. 
         FIG.  4    illustrates an example system in which handling a telephony outage may be implemented. 
         FIG.  5    is a data flow diagram of an example of a sequence of operations for handling a telephony outage. 
         FIG.  6    illustrates an example system in which telephony load balancing may be implemented. 
         FIG.  7    is a flowchart of an example of a technique for handling a telephony outage. 
         FIG.  8    is a flowchart of an example of a technique for a telephony node to provide telephony services. 
         FIG.  9    is a flowchart of an example of a technique for telephony load balancing. 
     
    
    
     DETAILED DESCRIPTION 
     Enterprise entities rely upon several modes of communication to support their operations, including telephone, email, and internal messaging. These separate modes of communication have historically been implemented by service providers whose services are not integrated with one another. The disconnect between these services, in at least some cases, requires information to be manually passed by users from one service to the next. Furthermore, some services, such as telephony services, are traditionally delivered via on-premises systems, meaning that remote workers and those who are generally increasingly mobile may be unable to rely upon them. 
     In telephony services, such as those implemented over a Unified Communications as a Service (UCaaS) platform or other software platform, a client device may connect to a datacenter. The datacenter handles telephony services for the client device and allows the client device to connect to the public switched telephone network (PSTN). At some point, a telephony outage (e.g., affecting the datacenter or a network used for telephony services) may prevent the client device from accessing the datacenter. During the telephony outage, the client device might not be able to access some or all of the telephony services. This service disruption may result in a considerable negative impact to users. Techniques for allowing the client device to access telephony services during the telephony outage may thus be desirable. 
     Implementations of this disclosure address problems such as these to allow telephony services to survive at a telephony customer premises during a wide telephony outage using a telephony node at the customer premises. A telephony outage condition is determined based on (1) a client-side determination that a client device is at the customer premises and incapable of communicating with a server at a datacenter, and (2) a telephony node-side determination that the telephony node is at the customer premises and incapable of communicating with a server at a datacenter (the same or a different server). In response to the client device attempting to reconnect to telephony services during the telephony outage, an encrypted password which is stored at the client device is transmitted from the client device to the telephony node, which decrypts the password and uses the same to authenticate telephony service access by the client device. The client device may then use the telephony node as an intermediary to use the telephony services during the telephony outage. As used herein, a telephony node may provide telephony services. In some cases, the telephony node may also provide functionality other than telephony services, such as Internet access or local data access. A telephony node may also be referred to as a “node.” 
     While using the telephony node as the intermediary, the client device may be able to use all or a subset of the services provided by the datacenter, depending on the configuration of the client device or the telephony node. In one example, the telephony node may be a “thin” telephony node that provides intra-office calling functionality and access to the PSTN. Other services, such as call recording, online meeting creation, and automated receptionist service might not be available until the client device is able to reconnect to the datacenter. Alternatively, the telephony node may be a “thick” telephony node that provides some or all of the services of the datacenter. These services may be provided by software residing at the telephony node and/or software residing locally at the client device. 
     The password may be a single sign-on (SSO) password of the client device for connecting to the telephony node and/or the datacenter. The password may be stored at the client device, such that the client device may automatically (e.g., without user input or with minimal user input, such as the user selecting a button) connect to the telephony node upon detecting the telephony outage or datacenter unavailability. In some examples, the password is stored in a password manager (e.g., Windows® Credential Manager or iCloud Keychain®) at the client device. Alternatively, the user may manually type the password in order to connect to the telephony node. 
     The implementations of this disclosure are described herein in connection with telephony outages. However, the implementations of this disclosure may be expanded to cover any network or Internet outages. Accordingly, use cases for the implementations of this disclosure are not limited to telephony outages. 
     Implementations of this disclosure describe using a single telephony node or multiple telephony nodes. The telephony nodes may be on-premises telephony nodes residing at a customer&#39;s premises. Different telephony nodes can provide different services, depending on the configuration selected. For example, one telephony node may handle PSTN calls and another telephony node may handle video conferencing between on-premises devices. Alternatively, two or more telephony nodes may provide the same services. In such a case, load balancing may be implemented between multiple telephony nodes to improve user experience, improve functionality, and/or reduce latency. 
     In some implementations, the user may be informed of the telephony outage via a display unit of the client device. For example, the user may be shown a text box saying that a telephony outage is occurring, and that the client device is attempting to connect to the telephony node. In some implementations, the user may be informed of the telephony outage when he/she tries to use telephony services and is told that the telephony services are not available. This information may be provided via the display or via an audio output when the user tries to access telephony services, for example, by dialing a telephone number. 
     In most cases, the telephony outage is resolved at some point after it is detected. After the telephony outage is resolved, telephony services may be provided to the client device by the datacenter. In particular, telephony services by the telephony node may be stopped to allow the client device to begin re-using the subject datacenter for telephony services. Alternatively, there may be load balancing between the datacenter and the telephony node, as described herein, to enable telephony services to be provided by both the telephony node and the datacenter. In some implementations, the telephony node, and not the datacenter, may continue providing telephony services to the client device for some period of time or based on an ongoing call after the telephony outage is resolved. For example, the telephony node may continue to provide telephony services for an ongoing call to prevent interruption during the ongoing call, it being noted that there may be an interruption if an ongoing call is handed over from the telephony node to the datacenter. In some implementations, the user of the client device may receive a notification indicating the restoration of telephony services after the telephony outage is resolved, such as based on the client device and/or the telephony node successfully connecting to the datacenter. 
     To describe some implementations in greater detail, reference is first made to examples of hardware and software structures used to implement telephony outage handling using a telephony node.  FIG.  1    is a block diagram of an example of an electronic computing and communications system  100 , which can be or include a distributed computing system (e.g., a client-server computing system), a cloud computing system, a clustered computing system, or the like. 
     The system  100  includes one or more customers, such as customers  102 A through  102 B, which may each be a public entity, private entity, or another corporate entity or individual that purchases or otherwise uses software services, such as of a UCaaS platform provider. Each customer can include one or more clients. For example, as shown and without limitation, the customer  102 A can include clients  104 A through  104 B, and the customer  102 B can include clients  104 C through  104 D. A customer can include a customer network or domain. For example, and without limitation, the clients  104 A through  104 B can be associated or communicate with a customer network or domain for the customer  102 A and the clients  104 C through  104 D can be associated or communicate with a customer network or domain for the customer  102 B. 
     A client, such as one of the clients  104 A through  104 D, may be or otherwise refer to one or both of a client device or a client application. Where a client is or refers to a client device, the client can comprise a computing system, which can include one or more computing devices, such as a mobile phone, a tablet computer, a laptop computer, a notebook computer, a desktop computer, or another suitable computing device or combination of computing devices. Where a client instead is or refers to a client application, the client can be an instance of software running on a customer device (e.g., a client device or another device). In some implementations, a client can be implemented as a single physical unit or as a combination of physical units. In some implementations, a single physical unit can include multiple clients. 
     The system  100  can include a number of customers and/or clients or can have a configuration of customers or clients different from that generally illustrated in  FIG.  1   . For example, and without limitation, the system  100  can include hundreds or thousands of customers, and at least some of the customers can include or be associated with a number of clients. 
     The system  100  includes a datacenter  106 , which may include one or more servers. The datacenter  106  can represent a geographic location, which can include a facility, where the one or more servers are located. The system  100  can include a number of datacenters and servers or can include a configuration of datacenters and servers different from that generally illustrated in  FIG.  1   . For example, and without limitation, the system  100  can include tens of datacenters, and at least some of the datacenters can include hundreds or another suitable number of servers. In some implementations, the datacenter  106  can be associated or communicate with one or more datacenter networks or domains, which can include domains other than the customer domains for the customers  102 A through  102 B. 
     The datacenter  106  includes servers used for implementing software services of a UCaaS platform. The datacenter  106  as generally illustrated includes an application server  108 , a database server  110 , and a telephony server  112 . The servers  108  through  112  can each be a computing system, which can include one or more computing devices, such as a desktop computer, a server computer, or another computer capable of operating as a server, or a combination thereof. A suitable number of each of the servers  108  through  112  can be implemented at the datacenter  106 . The UCaaS platform uses a multi-tenant architecture in which installations or instantiations of the servers  108  through  112  is shared amongst the customers  102 A through  102 B. 
     In some implementations, one or more of the servers  108  through  112  can be a non-hardware server implemented on a physical device, such as a hardware server. In some implementations, a combination of two or more of the application server  108 , the database server  110 , and the telephony server  112  can be implemented as a single hardware server or as a single non-hardware server implemented on a single hardware server. In some implementations, the datacenter  106  can include servers other than or in addition to the servers  108  through  112 , for example, a media server, a proxy server, or a web server. 
     The application server  108  runs web-based software services deliverable to a client, such as one of the clients  104 A through  104 D. As described above, the software services may be of a UCaaS platform. For example, the application server  108  can implement all or a portion of a UCaaS platform, including conferencing software, messaging software, and/or other intra-party or inter-party communications software. The application server  108  may, for example, be or include a unitary Java Virtual Machine (JVM). 
     In some implementations, the application server  108  can include an application node, which can be a process executed on the application server  108 . For example, and without limitation, the application node can be executed in order to deliver software services to a client, such as one of the clients  104 A through  104 D, as part of a software application. The application node can be implemented using processing threads, virtual machine instantiations, or other computing features of the application server  108 . In some such implementations, the application server  108  can include a suitable number of application nodes, depending upon a system load or other characteristics associated with the application server  108 . For example, and without limitation, the application server  108  can include two or more nodes forming a node cluster. In some such implementations, the application nodes implemented on a single application server  108  can run on different hardware servers. 
     The database server  110  stores, manages, or otherwise provides data for delivering software services of the application server  108  to a client, such as one of the clients  104 A through  104 D. In particular, the database server  110  may implement one or more databases, tables, or other information sources suitable for use with a software application implemented using the application server  108 . The database server  110  may include a data storage unit accessible by software executed on the application server  108 . A database implemented by the database server  110  may be a relational database management system (RDBMS), an object database, an XML database, a configuration management database (CMDB), a management information base (MIB), one or more flat files, other suitable non-transient storage mechanisms, or a combination thereof. The system  100  can include one or more database servers, in which each database server can include one, two, three, or another suitable number of databases configured as or comprising a suitable database type or combination thereof. 
     In some implementations, one or more databases, tables, other suitable information sources, or portions or combinations thereof may be stored, managed, or otherwise provided by one or more of the elements of the system  100  other than the database server  110 , for example, the client  104  or the application server  108 . 
     The telephony server  112  enables network-based telephony and web communications from and to clients of a customer, such as the clients  104 A through  104 B for the customer  102 A or the clients  104 C through  104 D for the customer  102 B. Some or all of the clients  104 A through  104 D may be voice over internet protocol (VOIP)-enabled devices configured to send and receive calls over a network  114 . In particular, the telephony server  112  includes a session initiation protocol (SIP) zone and a web zone. The SIP zone enables a client of a customer, such as the customer  102 A or  102 B, to send and receive calls over the network  114  using SIP requests and responses. The web zone integrates telephony data with the application server  108  to enable telephony-based traffic access to software services run by the application server  108 . Given the combined functionality of the SIP zone and the web zone, the telephony server  112  may be or include a cloud-based private branch exchange (PBX) system. 
     The SIP zone receives telephony traffic from a client of a customer and directs same to a destination device. The SIP zone may include one or more call switches for routing the telephony traffic. For example, to route a VOIP call from a first VOIP-enabled client of a customer to a second VOIP-enabled client of the same customer, the telephony server  112  may initiate a SIP transaction between a first client and the second client using a PBX for the customer. However, in another example, to route a VOIP call from a VOIP-enabled client of a customer to a client or non-client device (e.g., a desktop phone which is not configured for VOIP communication) which is not VOIP-enabled, the telephony server  112  may initiate a SIP transaction via a VOIP gateway that transmits the SIP signal to a PSTN system for outbound communication to the non-VOIP-enabled client or non-client phone. Hence, the telephony server  112  may include a PSTN system and may in some cases access an external PSTN system. 
     The telephony server  112  includes one or more session border controllers (SBCs) for interfacing the SIP zone with one or more aspects external to the telephony server  112 . In particular, an SBC can act as an intermediary to transmit and receive SIP requests and responses between clients or non-client devices of a given customer with clients or non-client devices external to that customer. When incoming telephony traffic for delivery to a client of a customer, such as one of the clients  104 A through  104 D, originating from outside the telephony server  112  is received, a SBC receives the traffic and forwards it to a call switch for routing to the client. 
     In some implementations, the telephony server  112 , via the SIP zone, may enable one or more forms of peering to a carrier or customer premise. For example, Internet peering to a customer premise may be enabled to ease the migration of the customer from a legacy provider to a service provider operating the telephony server  112 . In another example, private peering to a customer premise may be enabled to leverage a private connection terminating at one end at the telephony server  112  and at the other end at a computing aspect of the customer environment. In yet another example, carrier peering may be enabled to leverage a connection of a peered carrier to the telephony server  112 . 
     In some such implementations, a SBC or telephony gateway within the customer environment may operate as an intermediary between the SBC of the telephony server  112  and a PSTN for a peered carrier. When an external SBC is first registered with the telephony server  112 , a call from a client can be routed through the SBC to a load balancer of the SIP zone, which directs the traffic to a call switch of the telephony server  112 . Thereafter, the SBC may be configured to communicate directly with the call switch. 
     The web zone receives telephony traffic from a client of a customer, via the SIP zone, and directs same to the application server  108  via one or more Domain Name System (DNS) resolutions. For example, a first DNS within the web zone may process a request received via the SIP zone and then deliver the processed request to a web service which connects to a second DNS at or otherwise associated with the application server  108 . Once the second DNS resolves the request, it is delivered to the destination service at the application server  108 . The web zone may also include a database for authenticating access to a software application for telephony traffic processed within the SIP zone, for example, a softphone. 
     The clients  104 A through  104 D communicate with the servers  108  through  112  of the datacenter  106  via the network  114 . The network  114  can be or include, for example, the Internet, a local area network (LAN), a wide area network (WAN), a virtual private network (VPN), or another public or private means of electronic computer communication capable of transferring data between a client and one or more servers. In some implementations, a client can connect to the network  114  via a communal connection point, link, or path, or using a distinct connection point, link, or path. For example, a connection point, link, or path can be wired, wireless, use other communications technologies, or a combination thereof. 
     The network  114 , the datacenter  106 , or another element, or combination of elements, of the system  100  can include network hardware such as routers, switches, other network devices, or combinations thereof. For example, the datacenter  106  can include a load balancer  116  for routing traffic from the network  114  to various servers associated with the datacenter  106 . The load balancer  116  can route, or direct, computing communications traffic, such as signals or messages, to respective elements of the datacenter  106 . 
     For example, the load balancer  116  can operate as a proxy, or reverse proxy, for a service, such as a service provided to one or more remote clients, such as one or more of the clients  104 A through  104 D, by the application server  108 , the telephony server  112 , and/or another server. Routing functions of the load balancer  116  can be configured directly or via a DNS. The load balancer  116  can coordinate requests from remote clients and can simplify client access by masking the internal configuration of the datacenter  106  from the remote clients. 
     In some implementations, the load balancer  116  can operate as a firewall, allowing or preventing communications based on configuration settings. Although the load balancer  116  is depicted in  FIG.  1    as being within the datacenter  106 , in some implementations, the load balancer  116  can instead be located outside of the datacenter  106 , for example, when providing global routing for multiple datacenters. In some implementations, load balancers can be included both within and outside of the datacenter  106 . In some implementations, the load balancer  116  can be omitted. 
       FIG.  2    is a block diagram of an example internal configuration of a computing device  200  of an electronic computing and communications system. In one configuration, the computing device  200  may implement one or more of the client  104 , the application server  108 , the database server  110 , or the telephony server  112  of the system  100  shown in  FIG.  1   . 
     The computing device  200  includes components or units, such as a processor  202 , a memory  204 , a bus  206 , a power source  208 , peripherals  210 , a user interface  212 , a network interface  214 , other suitable components, or a combination thereof. One or more of the memory  204 , the power source  208 , the peripherals  210 , the user interface  212 , or the network interface  214  can communicate with the processor  202  via the bus  206 . 
     The processor  202  is a central processing unit, such as a microprocessor, and can include single or multiple processors having single or multiple processing cores. Alternatively, the processor  202  can include another type of device, or multiple devices, configured for manipulating or processing information. For example, the processor  202  can include multiple processors interconnected in one or more manners, including hardwired or networked. The operations of the processor  202  can be distributed across multiple devices or units that can be coupled directly or across a local area or other suitable type of network. The processor  202  can include a cache, or cache memory, for local storage of operating data or instructions. 
     The memory  204  includes one or more memory components, which may each be volatile memory or non-volatile memory. For example, the volatile memory can be random access memory (RAM) (e.g., a DRAM module, such as DDR SDRAM). In another example, the non-volatile memory of the memory  204  can be a disk drive, a solid state drive, flash memory, or phase-change memory. In some implementations, the memory  204  can be distributed across multiple devices. For example, the memory  204  can include network-based memory or memory in multiple clients or servers performing the operations of those multiple devices. 
     The memory  204  can include data for immediate access by the processor  202 . For example, the memory  204  can include executable instructions  216 , application data  218 , and an operating system  220 . The executable instructions  216  can include one or more application programs, which can be loaded or copied, in whole or in part, from non-volatile memory to volatile memory to be executed by the processor  202 . For example, the executable instructions  216  can include instructions for performing some or all of the techniques of this disclosure. The application data  218  can include user data, database data (e.g., database catalogs or dictionaries), or the like. In some implementations, the application data  218  can include functional programs, such as a web browser, a web server, a database server, another program, or a combination thereof. The operating system  220  can be, for example, Microsoft Windows®, Mac OS X®, or Linux®; an operating system for a mobile device, such as a smartphone or tablet device; or an operating system for a non-mobile device, such as a mainframe computer. 
     The power source  208  provides power to the computing device  200 . For example, the power source  208  can be an interface to an external power distribution system. In another example, the power source  208  can be a battery, such as where the computing device  200  is a mobile device or is otherwise configured to operate independently of an external power distribution system. In some implementations, the computing device  200  may include or otherwise use multiple power sources. In some such implementations, the power source  208  can be a backup battery. 
     The peripherals  210  includes one or more sensors, detectors, or other devices configured for monitoring the computing device  200  or the environment around the computing device  200 . For example, the peripherals  210  can include a geolocation component, such as a global positioning system location unit. In another example, the peripherals can include a temperature sensor for measuring temperatures of components of the computing device  200 , such as the processor  202 . In some implementations, the computing device  200  can omit the peripherals  210 . 
     The user interface  212  includes one or more input interfaces and/or output interfaces. An input interface may, for example, be a positional input device, such as a mouse, touchpad, touchscreen, or the like; a keyboard; or another suitable human or machine interface device. An output interface may, for example, be a display, such as a liquid crystal display, a cathode-ray tube, a light emitting diode display, or other suitable display. 
     The network interface  214  provides a connection or link to a network (e.g., the network  114  shown in  FIG.  1   ). The network interface  214  can be a wired network interface or a wireless network interface. The computing device  200  can communicate with other devices via the network interface  214  using one or more network protocols, such as using Ethernet, transmission control protocol (TCP), internet protocol (IP), power line communication, an IEEE 802.X protocol (e.g., Wi-Fi, Bluetooth, or ZigBee), infrared, visible light, general packet radio service (GPRS), global system for mobile communications (GSM), code-division multiple access (CDMA), Z-Wave, another protocol, or a combination thereof. 
       FIG.  3    is a block diagram of an example of a software platform  300  implemented by an electronic computing and communications system, for example, the system  100  shown in  FIG.  1   . The software platform  300  is a UCaaS platform accessible by clients of a customer of a UCaaS platform provider, for example, the clients  104 A through  104 B of the customer  102 A or the clients  104 C through  104 D of the customer  102 B shown in  FIG.  1   . The software platform  300  may be a multi-tenant platform instantiated using one or more servers at one or more datacenters including, for example, the application server  108 , the database server  110 , and the telephony server  112  of the datacenter  106  shown in  FIG.  1   . 
     The software platform  300  includes software services accessible using one or more clients. For example, a customer  302  as shown includes four clients—a desk phone  304 , a computer  306 , a mobile device  308 , and a shared device  310 . The desk phone  304  is a desktop unit configured to at least send and receive calls and includes an input device for receiving a telephone number or extension to dial to and an output device for outputting audio and/or video for a call in progress. The computer  306  is a desktop, laptop, or tablet computer including an input device for receiving some form of user input and an output device for outputting information in an audio and/or visual format. The mobile device  308  is a smartphone, wearable device, or other mobile computing aspect including an input device for receiving some form of user input and an output device for outputting information in an audio and/or visual format. The desk phone  304 , the computer  306 , and the mobile device  308  may generally be considered personal devices configured for use by a single user. The shared device  310  is a desk phone, a computer, a mobile device, or a different device which may instead be configured for use by multiple specified or unspecified users. 
     Each of the clients  304  through  310  includes or runs on a computing device configured to access at least a portion of the software platform  300 . In some implementations, the customer  302  may include additional clients not shown. For example, the customer  302  may include multiple clients of one or more client types (e.g., multiple desk phones or multiple computers) and/or one or more clients of a client type not shown in  FIG.  3    (e.g., wearable devices or televisions other than as shared devices). For example, the customer  302  may have tens or hundreds of desk phones, computers, mobile devices, and/or shared devices. 
     The software services of the software platform  300  generally relate to communications tools, but are in no way limited in scope. As shown, the software services of the software platform  300  include telephony software  312 , conferencing software  314 , messaging software  316 , and other software  318 . Some or all of the software  312  through  318  uses customer configurations  320  specific to the customer  302 . The customer configurations  320  may, for example, be data stored within a database or other data store at a database server, such as the database server  110  shown in  FIG.  1   . 
     The telephony software  312  enables telephony traffic between ones of the clients  304  through  310  and other telephony-enabled devices, which may be other ones of the clients  304  through  310 , other VOIP-enabled clients of the customer  302 , non-VOIP-enabled devices of the customer  302 , VOIP-enabled clients of another customer, non-VOIP-enabled devices of another customer, or other VOIP-enabled clients or non-VOIP-enabled devices. Calls sent or received using the telephony software  312  may, for example, be sent or received using the desk phone  304 , a softphone running on the computer  306 , a mobile application running on the mobile device  308 , or using the shared device  310  that includes telephony features. 
     The telephony software  312  further enables phones that do not include a client application to connect to other software services of the software platform  300 . For example, the telephony software  312  may receive and process calls from phones not associated with the customer  302  to route that telephony traffic to one or more of the conferencing software  314 , the messaging software  316 , or the other software  318 . 
     The conferencing software  314  enables audio, video, and/or other forms of conferences between multiple participants, such as to facilitate a conference between those participants. In some cases, the participants may all be physically present within a single location, for example, a conference room, in which the conferencing software  314  may facilitate a conference between only those participants and using one or more clients within the conference room. In some cases, one or more participants may be physically present within a single location and one or more other participants may be remote, in which the conferencing software  314  may facilitate a conference between all of those participants using one or more clients within the conference room and one or more remote clients. In some cases, the participants may all be remote, in which the conferencing software  314  may facilitate a conference between the participants using different clients for the participants. The conferencing software  314  can include functionality for hosting, presenting scheduling, joining, or otherwise participating in a conference. The conferencing software  314  may further include functionality for recording some or all of a conference and/or documenting a transcript for the conference. 
     The messaging software  316  enables instant messaging, unified messaging, and other types of messaging communications between multiple devices, such as to facilitate a chat or other virtual conversation between users of those devices. The unified messaging functionality of the messaging software  316  may, for example, refer to email messaging which includes a voicemail transcription service delivered in email format. 
     The other software  318  enables other functionality of the software platform  300 . Examples of the other software  318  include, but are not limited to, device management software, resource provisioning and deployment software, administrative software, third party integration software, and the like. In one particular example, the other software  318  can include software for handling a telephony outage and/or software for load balancing. 
     The software  312  through  318  may be implemented using one or more servers, for example, of a datacenter such as the datacenter  106  shown in  FIG.  1   . For example, one or more of the software  312  through  318  may be implemented using an application server, a database server, and/or a telephony server, such as the servers  108  through  112  shown in  FIG.  1   . In another example, one or more of the software  312  through  318  may be implemented using servers not shown in  FIG.  1   , for example, a meeting server, a web server, or another server. In yet another example, one or more of the software  312  through  318  may be implemented using one or more of the servers  108  through  112  and one or more other servers. The software  312  through  318  may be implemented by different servers or by the same server. 
     Features of the software services of the software platform  300  may be integrated with one another to provide a unified experience for users. For example, the messaging software  316  may include a user interface element configured to initiate a call with another user of the customer  302 . In another example, the telephony software  312  may include functionality for elevating a telephone call to a conference. In yet another example, the conferencing software  314  may include functionality for sending and receiving instant messages between participants and/or other users of the customer  302 . In yet another example, the conferencing software  314  may include functionality for file sharing between participants and/or other users of the customer  302 . In some implementations, some or all of the software  312  through  318  may be combined into a single software application run on clients of the customer, such as one or more of the clients  304  through  310 . 
       FIG.  4    illustrates an example system  400  in which handling a telephony outage may be implemented. As shown, the system  400  includes a datacenter  402  and a customer premises  406 . The datacenter  402  may correspond to the datacenter  106 . The customer premises  406  may correspond to one of the customers  102 A through  102 B. The customer premises may be an office space, a shared co-working space, an apartment complex or another space where multiple client devices may be connected with one or multiple telephony nodes. 
     As shown, the datacenter includes servers  404 . While two servers  404 . 1  and  404 . 2  are illustrated, some implementations disclosed herein may be implemented with other numbers of servers  404 . Each of the servers  404  may correspond to at least one of the clients  104 A,  104 B,  104 C or  104 D. The datacenter  402  is connected to the PSTN  412  and is capable of processing incoming or outgoing telephone calls via the PSTN  412 . 
     As illustrated, the customer premises  406  includes client devices  408  and a telephony node  410 . While two client devices  408 . 1  and  408 . 2  are illustrated, some implementations may use other numbers of client devices  408 . As shown, each client device  408  is connected to at least one server  404  in the datacenter  402 , with different client devices  408  potentially being connected to different servers  402 . The telephony node  410  is connected to one or both of the servers  404  in the datacenter  402 . The telephony node  410  is connected to the PSTN  412  for processing incoming and/or outgoing telephone calls via the PSTN  412 . 
     At some point, a telephony outage occurs, which wholly or partially disrupts telephony services previously accessible to the client devices  408 . In some cases, the client device  408 . 1  (or another client device  408 ) determines that a telephony outage is occurring. In some cases, the telephony node  410  may also or instead determine that the telephony outage is occurring. The client device  408  and/or the telephony node  410 , as applicable, may determine that the telephony outage is occurring based on an inability to connect with the server  404  in the datacenter  402 . In response to determining that the telephony outage is occurring, the client device  408 . 1  attempts to connect to the telephony node  410  (or at least one of multiple telephony nodes) using an encrypted password stored at the client device  408 . 1 . 
     The telephony node  410  receives the encrypted password from the client device  408 . 1  attempting to connect with the telephony node  410  to access telephony services. The telephony node  410  decrypts the password. The telephony node  410  authenticates the password. In response to authenticating the password, the telephony node  410  provides access to telephony services for the client device  408 . 1 . The client device  408 . 1  may thus access a set of telephony services via the telephony node  410 . The set of telephony services may include, for example, access to the PSTN  412  and voice, chat or video conferencing with other on-premises devices. 
     In some implementations, when there is no telephony outage and the client devices  408  are able to communicate with both the telephony node  410  and the datacenter  402 , load balancing may be implemented between the servers  404  and the telephony nodes  410 . The load balancing may be based on the pre-existing load on the servers  404  or the telephony node  410  or based on capabilities of the servers  404  or the telephony node  410 . The load balancing may be implemented during times of peak telephony usage (e.g., during business hours). 
       FIG.  5    is a data flow diagram of an example of a sequence  500  of operations for handling a telephony outage. As shown, the sequence  500  is implemented using the client device  408 . 1 , the telephony node  410 , and the datacenter  402  of  FIG.  4   . 
     At block  502 , the client device  408 . 1  attempts to connect to the datacenter  402  (e.g., to the server  404 . 1  in the datacenter  402 ). The attempt by the client device  408 . 1  may be made in response to an attempt, by a user of the client device  408 . 1 , to access telephony services using the client device  408 . 1 . Upon failing to connect to the datacenter  402  after a predefined time period (e.g., 0.5 seconds or 1 second) of the attempt by the client device  408 . 1 , the client device  408 . 1  determines that it cannot connect to the datacenter  402 . In at least some cases, the telephony node  410  may also attempt to connect to the datacenter  402  and fail to connect during the predefined time period. 
     At block  504 , based on the attempt to connect to the datacenter  402  failing, the client device  408 . 1  determines that a telephony outage is happening. Similarly, whether concurrent with the telephony outage determination by the client device  408 . 1  or otherwise, the telephony node  410  determines that a telephony outage is happening based on its attempt to connect to the datacenter  402  failing. In some cases, after determining that the telephony outage is happening, the client device  408 . 1  may attempt to connect to telephony services in other ways (e.g., using other networking or connection techniques). For example, if the telephony outage is due to an outage in Wi-Fi® services, the client device  408 . 1  may attempt to connect to telephony services over a cellular connection or a wired connection (if available). 
     At block  506 , based on a determination by the client device  408 . 1  that the telephony outage is happening, the client device  408 . 1  transmits an encrypted password to the telephony node  410 . In some implementations, the client device  408 . 1  pushes the encrypted password to the telephony node  410 . The client device  408 . 1  may transmit the encrypted password to the telephony node  410  via a local network of the premises, for example, a local wired network or a local Wi-Fi® network. The encrypted password may be transmitted using any encryption technique, for example Diffie-Hellman encryption may be used. 
     At block  508 , the telephony node  410  decrypts the password received from the client device  408 . 1 . In some implementations, the telephony node  410  always decrypts the password. In some implementations, the telephony node  410  decrypts the password if it is unable to connect with the datacenter. Otherwise, the telephony node  410  notifies (e.g., by transmitting a message over the local network of the premises) the client device that the datacenter is available for connection. At block  510 , the telephony node  410  authenticates the client device  408 . 1  based on the decrypted password. The authentication verifies that the client device  408 . 1  has permission to access telephony services via the telephony node  410  based on the password. In some implementations, the password for connecting with the telephony node  410  is different from the password for connecting with the datacenter because, when the client device  408 . 1  tries to connect to the telephony node  410 , the datacenter might be unavailable to verify the password. For example, the datacenter may be offline. 
     At block  512 , the client device  408 . 1  accesses telephony services via the telephony node  410 . Accessing telephony services may entail two-way communication between the client device  408 . 1  and the telephony node  410 . The accessed telephony services may include some or all of the telephony services that are provisioned by the telephony node  410 , such as access to PSTN calls and intra-office virtual meetings. 
       FIG.  6    illustrates an example system  600  in which telephony load balancing may be implemented. As shown, the system  600  includes a datacenter  602  (e.g., corresponding to datacenter  402 ) and a customer premises  606  (e.g., corresponding to customer premises  406 ). As shown in  FIG.  6   , during time periods of high telephony usage, the telephony load may be balanced between servers at the datacenter  602  and telephony nodes at the customer premises  606 . The implementations shown in  FIG.  6    may reduce a likelihood of overloading (e.g., exceeding 95% of cache or processor usage) the servers at the datacenter  602  or the telephony nodes at the customer premises  606 . 
     The datacenter  602  includes multiple servers  604  (e.g., three servers  604 . 1 ,  604 . 2 , and  604 . 3  as shown or another number of servers) and a load balancer  614 . The load balancer  614  balances load (e.g., on processors, memory, and network interfaces) between the servers  604 . The load balancer  614  may reside on one or more of the servers  604  or on another computing machine of the datacenter  602 . 
     The customer premises  606  includes multiple client devices  608  (e.g., three client devices  608 . 1 ,  608 . 2 , and  608 . 3  as shown or another number of client devices) and multiple telephony nodes  610  (e.g., two telephony nodes  610 . 1  and  610 . 2  as shown or another number of telephony nodes). The customer premises  606  also includes a load balancer  616 . The load balancer  616  balances load (e.g., on processors, memory, and network interfaces) between the telephony nodes  610 . The load balancer  616  may reside on one or more of the telephony nodes  610 , on a client device  608  or another computing machine located at the customer premises  606 . 
     In implementations with multiple telephony nodes  610 , load balancing could be implemented between the telephony nodes  610  using the load balancer  616 . In some implementations, different telephony nodes  610  provide different services. For example, one telephony node  610 . 1  may handle PSTN calls and another telephony node  610 . 2  may handle video conferencing between on-premises devices. In some implementations, each of the telephony nodes  610  provides the same services and loads are balanced between the telephony nodes  610  to ensure that no telephony node  610  is overloaded (e.g., using more than 90% of its processing power, memory, cache, and network interface). 
     Similarly, at the datacenter  602 , different servers  604  may be responsible for different functions. For example, one server  604  may be responsible for handling video conferences and another server  604  may be responsible for handling an automated receptionist service. Alternatively, multiple servers  604  may provide the same services and loads may be balanced between the servers  604  to ensure that no server  604  is overloaded (e.g., using more than 90% of its processing power, memory, cache, and network interface). 
     When the datacenter  602  is accessible to the client device  608  and the telephony node  610  of the customer premises  606 , load balancing may be implemented between the datacenter  602  and the telephony node  610 , for example, using the load balancer  614  of the datacenter  602 , the load balancer  616  of the customer premises or a combination of the load balancers  614  and  616 . For example, during low usage times, all telephony services may be provided to the client devices  608  using the datacenter  602 . During high usage times, the datacenter  602  could handle, on behalf of the client device  608 , use cases that cannot be accomplished using the telephony node  610 , such as online meetings or automated receptionist service. The telephony node  610  could be used to handle, on behalf of the client device  608 , features such as PSTN calls that do not require the involvement of the datacenter  602 . Alternatively, if many PSTN calls are occurring simultaneously, the handling of the PSTN calls may be split between the servers  604  of the datacenter  602  and the telephony node  610 . 
     To further describe some implementations in greater detail, reference is next made to examples of techniques which may be performed by telephony outage handling using an on-premises telephony node.  FIG.  7    is a flowchart of an example of a technique  700  for handling a telephony outage.  FIG.  8    is a flowchart of an example of a technique  800  for a telephony node to provide telephony services.  FIG.  9    is a flowchart of an example of a technique  900  for telephony load balancing. 
     The techniques  700 ,  800 , and  900  can be executed using computing devices, such as the systems, hardware, and software described with respect to  FIGS.  1 - 6   . The techniques  700 ,  800 , and  900  can be performed, for example, by executing a machine-readable program or other computer-executable instructions, such as routines, instructions, programs, or other code. The steps, or operations, of the techniques  700 ,  800 ,  900  or another technique, method, process, or algorithm described in connection with the implementations disclosed herein can be implemented directly in hardware, firmware, software executed by hardware, circuitry, or a combination thereof. 
     For simplicity of explanation, the technique  700  is depicted and described herein as a series of steps or operations. However, the steps or operations in accordance with this disclosure can occur in various orders and/or concurrently. Additionally, other steps or operations not presented and described herein may be used. Furthermore, not all illustrated steps or operations may be required to implement a technique in accordance with the disclosed subject matter. 
     Referring first to  FIG.  7   , the technique  700  is shown. At block  702 , a client device (e.g., the client device  408  or  608 ) and/or a telephony node (e.g., the telephony node  410  or  610 ) at a customer premises  406  or  606  determines that a telephony outage is occurring. For example, the client device and/or the telephony node may determine that the client device and/or the telephony node is incapable of connecting to a server (e.g., the server  404  or  604 ) at the datacenter (e.g., the datacenter  402  or  602 ). In some implementations, this occurs when the client device attempts to access telephony services via the server but is unable to do so. At approximately the same time (e.g., within 5 seconds) the telephony node attempts to access telephony services via the server but is unable to do so. 
     At block  704 , the client device connects to the telephony node using an encrypted password at a client device. In some implementations, the client device connects to the telephony node in response to an attempt to access telephony services at the client device and a determination at the client device that a telephony outage is ongoing (e.g., due to failure to connect to the server). The client device may transmit the encrypted password to the telephony node for decryption and authentication thereat, for example, as described in conjunction with  FIG.  8   . The password may be an SSO password of the client device for connecting to the telephony node and/or the datacenter. Based on the telephony node determining that the telephony outage is ongoing (in addition to the similar determination at the client device), the telephony node decodes the password and authenticates the password to allow the client device to access the telephony services through the telephony node. 
     At block  706 , the client device accesses a set of telephony services via the telephony node. While using the telephony node as the intermediary, the client device may be able to use all or a subset of the services provided by the datacenter when the telephony outage is not occurring. The services provided while using the telephony node may depend on the configuration of the client device or the telephony node. In some examples, the telephony node is a “thin” telephony node that provides a subset of the services provided by the datacenter. The subset may include, for example, intra-office calling functionality and access to the PSTN (e.g., PSTN  412 ). Other services, such as call recording, online meeting creation, and automated receptionist service might not be available until the client device is able to reconnect to the datacenter. Alternatively, in a “thick” telephony node implementation, the telephony node may include similar software to the datacenter. All of the services typically provided by the datacenter may then be provided by software residing at the telephony node and/or software residing locally at the client device. In one implementation, the set of telephony services provided by the telephony node includes intra-office calling and access to the PSTN and does not include at least one of call recording, online meeting creation, or automated receptionist service. 
     In some implementations, upon connection to the telephony node, the telephony node transmits a message notifying a user of the client device of unavailability of a collection of telephony services. The telephony node may provide a replacement telephony service for one or more services in the collection of telephony services. 
     Referring next to  FIG.  8   , the technique  800  is shown. At block  802 , the telephony node receives an encrypted password from a client device (e.g., client device  408  or  608 ). In some cases, the client device attempts to access telephony services and, upon failing to connect to the datacenter, attempts to connect to the telephony node using the password. 
     At block  804 , the telephony node decrypts the password. Multiple different decryption techniques may be used to decrypt the password. For example, the Diffie-Hellman encryption algorithm may be used. Alternatively, Rivest-Shamir-Adleman (RSA) encryption or elliptic curve cryptography may be used. 
     At block  806 , the telephony node authenticates the decrypted password. For example, the telephony node verifies that the client device attempting to connect to the telephony node has permission to access telephony services via the telephony node. The telephony node may store a data structure indicating client devices that are permitted to access telephony services through the telephony node. 
     At block  808 , the telephony node provides telephony services to the client device. The available telephony services may be determined based on a configuration of the telephony node and/or a configuration of the client device. In some examples, the available telephony services may include access to the PSTN. If the client device is configured for video calling, the available services may include intra-premises video calling. 
     Referring last to  FIG.  9   , the technique  900  is shown. At block  902 , a load balancer (e.g., load balancer  614 , load balancer  616  or a combination of load balancers  614  and  616 ) receives a request to access telephony services. The request to access telephony services may be from a client device (e.g., client device  608 ). The request may be generated by a user attempting to access a telephony service via the client device. Alternatively, the client device may access telephony services without input from a user of the client device, for example, in response to an incoming telephone call or audio/video conferencing request. 
     At block  904 , the load balancer determines a load at telephony servers (e.g., the servers  604  at the datacenter  602 ). The load may be determined using any load measuring technique. For example, the load balancer may send, to the telephony servers, messages to determine what percentages of their processors and cache memory are being used. 
     At block  906 , the load balancer determines a load at the telephony node(s). Various known load determination techniques may be used. For example, the load balancer may send, to the telephony nodes, messages to determine what percentages of their processors and cache memory are being used. 
     At block  908 , the load balancer assigns the request (received at the block  902 ) to access telephony services to a telephony node or a telephony server. The request may be assigned based on technical capability to fulfill the request and/or a current load of the telephony node or the telephony server fulfilling the request. The load balancer may ensure that the load is below a threshold, where the threshold is determined based on loads on other telephony nodes or telephony servers. The load balancer may ensure that the telephony node or the telephony server includes software or hardware for fulfilling the request. For example, if the request is associated with a video conference with parties outside the premises, the load balancer may ensure that the telephony node or the telephony server is capable of handling such a video conference. 
     The techniques  700 ,  800 , and  900  are described as being implemented in series and in a given order. Alternatively, two or more of the operations in the techniques  700 ,  800  or  900  may be performed in parallel. In some cases, the operations of the techniques  700 ,  800  or  900  may be performed in a different order from the specified order. 
     The techniques  700 ,  800 , and  900  may be used separately from one another and/or in conjunction with one another. For example, the technique  700  relates to a client device detecting a telephony outage (due to the client device&#39;s inability to connect to the server) and, in response to detecting the telephony outage, connecting to telephony services via the telephony node. The technique  800  relates to the telephony node receiving a password from the client device and, based on the password, authenticating the client device for accessing telephony services via the telephony node. The technique  900  relates to load balancing between servers at the datacenter and telephony nodes at the customer premises when both are available for providing telephony services. 
     Combinations of the techniques  700 ,  800 , and  900  describe the processes for delivering telephony services over a telephony node (e.g., located on-premises at a customer premises) based on a telephony outage. In particular, at some point after a telephony outage affecting telephony services delivered by a datacenter begins, a client device of a user attempts to connect to the datacenter to use a subject telephony service. The client device is unable to connect to the datacenter based on that attempt. The telephony node also attempts to connect to the datacenter and is unable to. Based on the client device being unable to connect to the datacenter, the client device pushes an encrypted password, usable to authenticate access to telephony services at the telephony node by the client device, to the telephony node. Based on the telephony node being unable to connect to the datacenter, the telephony node decrypts and uses the password pushed from the client device to authenticate access to the telephony services at the telephony node by the client device. The client device thus accesses the telephony services via the telephony node. 
     Some implementations are described below as numbered examples (Example 1, 2, 3, etc.). These examples are provided as exampled only and do not limit the disclosed implementations. 
     Example 1 is a method comprising: determining that a telephony outage is occurring; connecting to an on-premises telephony node using an encrypted password at a client device; and accessing a set of telephony services at the client device via the on-premises telephony node. 
     In Example 2, the subject matter of Example 1 includes, wherein determining that the telephony outage is occurring comprises: determining that the client device is incapable of connecting to a server; and determining that the on-premises telephony node is incapable of connecting to the server. 
     In Example 3, the subject matter of Examples 1-2 includes, wherein connecting to the on-premises telephony node comprises: transmitting the encrypted password from the client device to the on-premises telephony node; and receiving a response from the on-premises telephony node indicating that access to the telephony services is granted. 
     In Example 4, the subject matter of Examples 1-3 includes, wherein the set of telephony services comprises a portion of telephony services accessible when the telephony outage is not occurring. 
     In Example 5, the subject matter of Examples 1-4 includes, wherein the set of telephony services includes intra-office calling and access to a public switched telephone network and does not include at least one of call recording, online meeting creation, or automated receptionist service. 
     In Example 6, the subject matter of Examples 1-5 includes, receiving a notification of unavailability of a second set of telephony services at the client device; and preventing access to the second set of telephony services at the client device. 
     In Example 7, the subject matter of Examples 1-6 includes, wherein connecting to the on-premises telephony node using the encrypted password at the client device comprises: pushing the encrypted password from the client device to the on-premises telephony node. 
     Example 8 is an apparatus comprising: a memory; and a processor configured to execute instructions stored in the memory to: determine that a telephony outage is occurring; connect to an on-premises telephony node using an encrypted password at a client device; and access a set of telephony services at the client device via the on-premises telephony node. 
     In Example 9, the subject matter of Example 8 includes, wherein determining that the telephony outage is occurring comprises: determining that the client device is incapable of connecting to a server; and determining that the on-premises telephony node is incapable of connecting to the server. 
     In Example 10, the subject matter of Examples 8-9 includes, wherein connecting to the on-premises telephony node comprises: transmitting the encrypted password from the client device to the on-premises telephony node; and receiving a response from the on-premises telephony node indicating that access to the telephony services is granted. 
     In Example 11, the subject matter of Examples 8-10 includes, wherein the set of telephony services comprises telephony services accessible when the telephony outage is not occurring. 
     In Example 12, the subject matter of Examples 8-11 includes, wherein the set of telephony services includes access to a public switched telephone network. 
     In Example 13, the subject matter of Examples 8-12 includes, wherein the client device determines that the telephony outage is occurring by failing to connect to a server. 
     In Example 14, the subject matter of Examples 8-13 includes, wherein connecting to the on-premises telephony node is in response to an attempt to access the set of telephony services at the client device. 
     Example 15 is a computer-readable medium storing instructions operable to cause one or more processors to perform operations comprising: determining that a telephony outage is occurring; connecting to an on-premises telephony node using an encrypted password at a client device; and accessing a set of telephony services at the client device via the on-premises telephony node. 
     In Example 16, the subject matter of Example 15 includes, wherein determining that the telephony outage is occurring comprises: determining that the client device is incapable of connecting to a server; and determining that the on-premises telephony node is incapable of connecting to the server. 
     In Example 17, the subject matter of Examples 15-16 includes, wherein connecting to the on-premises telephony node comprises: transmitting the encrypted password from the client device to the on-premises telephony node; and receiving a response from the on-premises telephony node indicating that access to the telephony services is granted. 
     In Example 18, the subject matter of Examples 15-17 includes, wherein the on-premises telephony node is connected to the client device via a local network of a premises. 
     In Example 19, the subject matter of Examples 15-18 includes, wherein the set of telephony services includes intra-office calling. 
     In Example 20, the subject matter of Examples 15-19 includes, wherein the client device stores the encrypted password for accessing the set of telephony services via the on-premises telephony node and an additional password for accessing a second set of telephony services via a datacenter. 
     Example 21 is at least one machine-readable medium including instructions that, when executed by processing circuitry, cause the processing circuitry to perform operations to implement of any of Examples 1-20. 
     Example 22 is an apparatus comprising means to implement of any of Examples 1-20. 
     Example 23 is a system to implement of any of Examples 1-20. 
     Example 24 is a method to implement of any of Examples 1-20. 
     The implementations of this disclosure can be described in terms of functional block components and various processing operations. Such functional block components can be realized by a number of hardware or software components that perform the specified functions. For example, the disclosed implementations can employ various integrated circuit components (e.g., memory elements, processing elements, logic elements, look-up tables, and the like), which can carry out a variety of functions under the control of one or more microprocessors or other control devices. Similarly, where the elements of the disclosed implementations are implemented using software programming or software elements, the systems and techniques can be implemented with a programming or scripting language, such as C, C++, Java, JavaScript, assembler, or the like, with the various algorithms being implemented with a combination of data structures, objects, processes, routines, or other programming elements. 
     Functional aspects can be implemented in algorithms that execute on one or more processors. Furthermore, the implementations of the systems and techniques disclosed herein could employ a number of conventional techniques for electronics configuration, signal processing or control, data processing, and the like. The words “mechanism” and “component” are used broadly and are not limited to mechanical or physical implementations, but can include software routines in conjunction with processors, etc. Likewise, the terms “system” or “tool” as used herein and in the figures, but in any event based on their context, may be understood as corresponding to a functional unit implemented using software, hardware (e.g., an integrated circuit, such as an ASIC), or a combination of software and hardware. In certain contexts, such systems or mechanisms may be understood to be a processor-implemented software system or processor-implemented software mechanism that is part of or callable by an executable program, which may itself be wholly or partly composed of such linked systems or mechanisms. 
     Implementations or portions of implementations of the above disclosure can take the form of a computer program product accessible from, for example, a computer-usable or computer-readable medium. A computer-usable or computer-readable medium can be a device that can, for example, tangibly contain, store, communicate, or transport a program or data structure for use by or in connection with a processor. The medium can be, for example, an electronic, magnetic, optical, electromagnetic, or semiconductor device. 
     Other suitable mediums are also available. Such computer-usable or computer-readable media can be referred to as non-transitory memory or media, and can include volatile memory or non-volatile memory that can change over time. The quality of memory or media being non-transitory refers to such memory or media storing data for some period of time or otherwise based on device power or a device power cycle. A memory of an apparatus described herein, unless otherwise specified, does not have to be physically contained by the apparatus, but is one that can be accessed remotely by the apparatus, and does not have to be contiguous with other memory that might be physically contained by the apparatus. 
     While the disclosure has been described in connection with certain implementations, it is to be understood that the disclosure is not to be limited to the disclosed implementations but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.