Abstract:
Methods and systems provide an asymmetric Ethernet service. An Ethernet network transports Ethernet frames over an asymmetric connection to a point of service for a subscriber located remotely from the Ethernet network, and the Ethernet connection is asymmetric in that the effective data transfer rates for uploading and downloading of data over the Ethernet connection are different. The subscriber may then have Ethernet capable network devices such as routers and computers linked to the point of service so that data transfer between the network devices of the subscriber and the Ethernet network occurs over the asymmetric Ethernet connection. The Ethernet network allows for communication between the network devices of the subscriber and any desired Ethernet network resources, such as network resources located on the Ethernet network or resources of downstream networks such as the global Internet that are available through the Ethernet network.

Description:
This patent relates to U.S. patent application Ser. No. 10/636,432, now U.S. Pat. No. 7,315,538, filed on Aug. 7, 2003 and issued on Jan. 1, 2008. 
   TECHNICAL FIELD 
   The present invention is related to Ethernet communications. More particularly, the present invention is related to providing an asymmetric Ethernet service from a service provider network to a subscriber point of service. 
   BACKGROUND 
   Ethernet communications are a popular data network protocol used to carry frames of data. Ethernet communications are often used within local area networks to carry data between nearby computers as well as within wide area networks where the Ethernet may be carried through lower layer connections such as an asynchronous transfer mode (“ATM”) link. Ethernet communications allow for the transfer between end points of higher layer data packets such as Internet Protocol packets that are destined for a remote location such as a domain of the global Internet. The original Ethernet standards related to a protocol for accessing a shared communication medium. Over time this has evolved to a suite of protocols that are commonly used on symmetric point-to-point links between Ethernet switching devices. Ethernet protocols can also be encapsulated and transported over other protocols, e.g., Ethernet over ATM per RFC 1483. 
   Typically, an Ethernet network includes many closely located devices interconnected via the Ethernet protocol to form a local area network. Because the devices are located closely, there is a direct Ethernet connection between the devices since the distances are not greater than that possible over a direct Ethernet connection. However, some situations call for a node of an Ethernet network to be located remotely from the Ethernet network itself such that the distance is too great for a direct Ethernet connection to be utilized. 
   Ethernet service has been provided to certain customers having a point of service that is remote from the Ethernet network such that a direct Ethernet connection cannot be utilized. This Ethernet service is symmetrical and provides a relatively high bandwidth to subscribers in both the upload and download directions, but because this data transfer is symmetrical it requires a relatively high amount of bandwidth of a service provider network interconnecting the point of service to the Ethernet network. Thus, this symmetrical Ethernet service is not an economical option for many subscribers. 
   SUMMARY 
   Embodiments of the present invention address these issues and others by providing an asymmetrical Ethernet service to a point of service for subscribers. Thus, the subscribers may connect their Ethernet devices such as routers and/or computers to the asymmetric Ethernet service which provides a difference in the upload and download data transfer speeds when communicating with the remote Ethernet network. 
   One embodiment is a method of providing asymmetric Ethernet service. The method involves providing an Ethernet network remote from a point of service and in communication with the point of service. The method further involves establishing an asymmetric Ethernet communication between the remote Ethernet network and the point of service to allow access to the asymmetric Ethernet service by a subscriber. 
   Another embodiment is a system for providing asymmetric Ethernet service. The system includes an Ethernet network including an Ethernet port and includes a point of service located remotely from the Ethernet port of the Ethernet network. An Ethernet communications connection exists between the subscriber point of service and the Ethernet port of the Ethernet network. The Ethernet communications connection provides for an upload speed from the subscriber point of service to the Ethernet port of the Ethernet network that is a different speed than a download speed from the Ethernet port of the Ethernet network to the point of service. 
   Another embodiment is a system for providing asymmetric Ethernet service to a network device of a subscriber. The system includes an Ethernet network including an Ethernet port and includes a point of service located remotely from the Ethernet network. An Ethernet connection exists between the point of service and the Ethernet port of the Ethernet network. The Ethernet connection provides for an upload speed from the point of service to the Ethernet port of the Ethernet network that is a different speed than a download speed from the Ethernet port of the Ethernet network to the point of service. An Ethernet connection also exists between the point of service and a network device of the subscriber. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a high level view of an asymmetric Ethernet service from an Ethernet network to a point of service of a subscriber according to an embodiment of the present invention. 
       FIG. 2  is a diagram of the connectivity of devices to aggregate Ethernet links, which may be used in embodiments of the present invention. 
   

   DETAILED DESCRIPTION 
   Embodiments of the present invention provide for an asymmetric Ethernet service to be provided between an Ethernet network and a point of service for a subscriber. The asymmetric Ethernet service provides for effective data transfer rates that are greater in one direction of transfer than the other, thereby freeing the data network between the point of service and the Ethernet network from providing a full speed data transfer rate in both directions. The asymmetric Ethernet service may be provided by including the point of service at the network interface device outside the premises of the subscriber where the endpoint communications device is maintained as part of a service provider network to eliminate the requirement of additional communications devices such as DSL or cable data modems within the premises of the subscriber. Alternatively, the asymmetric Ethernet service may be provided through communications devices such as DSL or cable modems of the subscriber rather than including them as endpoint devices of the service provider network. 
     FIG. 1  shows a high level view of an asymmetric Ethernet service. An Ethernet network  102  provides Ethernet data services for subscribers, such as providing access to LAN resources such as email and file servers and/or access to a downstream Internet Service Provider (“ISP”). A service provider may provide the connectivity between the Ethernet network  102  and the point of service where the subscriber gains access to the Ethernet network at a device  122  of the subscriber such as a network interface card (“NIC”) equipped computer, router, or other Ethernet capable device. The service provider, or another service provider, may also provide access to the public switched telephone network (“PSTN”)  104  for subscribers. As shown in  FIG. 1 , the Ethernet network access may be distributed to the subscriber from the Ethernet network  102  in various ways. For example, ADSL modem  106  or set of modems contained within a DSL access multiplexer (“DSLAM”) of a service provider may be used to transport the Ethernet data communications between a central office (“CO”) of the service provider and out to the location of the subscriber. The ADSL communications carrying the Ethernet data are received at a service point by another ADSL modem  108  or set of modems where the ADSL data communications are then converted back to Ethernet layer communications for access by the subscriber at the point of service. 
   The Ethernet communications extend over communication lines  112  to the point of service, such as the NIC  122 . These Ethernet communications are made asymmetric by the ADSL modems  106  and  108  providing the asymmetry between the upload and download data transfer rates while carrying the Ethernet data frames. The upload speed may be faster than the download speed or the download speed may be faster than the upload speed. For example, ADSL modems  106  may be type ATU-C and ADSL modems  108  may be ATU-R so that the download for the subscriber is faster than the upload. Alternatively, the ADSL modems  106  may be type ATU-R while ADSL modems  108  may be ATU-C so that the upload for the subscriber is faster than the download. 
   Providing an upload speed faster than a download speed between the ADSL modems  106  and  108  may not be permitted under a regulatory scheme where copper communications extend from the ADSL modem  106  back to the network  102  and where the upload speed refers to an upload from the subscriber to the service provider network. However, the ADSL modem  106  may be positioned away from a CO to a point that is closer to the point of service where the ADSL modem  108  is positioned. The ADSL modem  108  may be positioned at the point of service where located within the subscriber&#39;s premises, or alternatively very closely to the point of service, such as at a street corner out from the location of the subscriber. Thus, the distance the Ethernet link must travel from the ADSL modem  108  to the point of service for access by the subscriber may be minimized. Communications between the location of the ADSL modem  106  and the network  102  may then occur over fiber to avoid the faster upload speeds from creating copper networking issues. 
   The asymmetric Ethernet service extends from an Ethernet port of the ADSL modem  108  over communications line  112  into the device  122 . Thus, the subscriber can access the Ethernet network over the asymmetric Ethernet connection at the device  122 . The device  122  appears as a node on the Ethernet network  102  even though the device  122  is located remotely from the Ethernet network  102  because the Ethernet frames that are exchanged between the Ethernet network  102  and the device  122  are being carried by the ADSL connectivity. 
   The asymmetric Ethernet service may also utilize aggregated Ethernet connections so as to increase the bandwidths of the data transfer directions while maintaining the asymmetry. For example, an aggregator device  126  such as an Ethernet switch may be positioned between the DSLAM containing modems  106  and the downstream link to the Ethernet network  102 . The aggregator device  126  aggregates the communications of multiple (1-N) ADSL modems  106  that are in communication with multiple (1-N) ADSL modems  108 . The multiple ADSL modems  108  are then aggregated by an aggregator device  124  located between the modems  108  and the point of service. Thus, the single Ethernet link  112  may benefit from the bandwidth of multiple ADSL modem connections to increase the effective bandwidth of the asymmetric Ethernet service being provided to the subscriber. The aggregation of Ethernet links is described below in more detail with reference to  FIG. 2 . 
   The asymmetric Ethernet service shown in  FIG. 1  may also co-exist with other conventional services such as plain old telephone service (“POTS”). The DSLAM housing the ADSL modems  106  provides a splitter function to interconnect the link back to the Ethernet network  102  with the ADSL modems  106  for data communications while interconnecting voice links from subscriber POTS devices  118  to the PSTN  104 . The voice links are passed through a filter-splitter, such as at the service point where the modems  108  are located and also at the splitter function of the DSLAM so that the copper line pairs between the ADSL modems  108  and ADSL modems  106  may carry both the voice signals and the data signals while preventing the data signaling from being heard by the POTS devices. The filtered voice lines  110  extend to the POTS devices  118 . 
   As shown in  FIG. 2 , the Ethernet communications of an Ethernet link, such as the Ethernet link to the point of service may be transferred by multiple communications devices  206 ,  208  such as DSL modems  106  that communicate with distant multiple communications devices  210 ,  212  such as DSL modems  108 . Where the Ethernet service is asymmetric, the upload speed differs from the download speed for the communication devices  206 ,  208 ,  210 , and  212 . 
   The subscriber has a network device  202  that utilizes Ethernet communications, such as a router linked to a personal computer or such as a NIC of the personal computer. The Ethernet communications are exchanged between the network device  202  and an aggregator device, such as an Ethernet switch  204 . The Ethernet switch  204  then communicates with the two communications devices  206 ,  208  using Ethernet communications and aggregates the two devices  206 ,  208  for use by the network device  202 . The Ethernet switch  204  may aggregate communications with the two devices  206 ,  208  in accordance with the link aggregation standard IEEE 802.1 ad. 
   The communications devices  206 ,  208  then exchange communications with the communications devices  210 ,  212  over the copper lines between the two sets of devices. This exchange is asymmetric when providing the asymmetric Ethernet service through application of the asymmetric communications devices on both ends of the connection. The communications devices  210 ,  212  also communicate with an Ethernet switch  214  that aggregates the communications of the communications devices  210 ,  212  when exchanging communications with the Ethernet network and other downstream devices such as an ATM switch  216  or broadband service gateway (“BSG”)  218 . The Ethernet switching that provides for the aggregation of communication devices may alternatively be incorporated into the BSG  218  rather than utilizing an external Ethernet switch  214 . The data communications from the communications devices  210 ,  212  may be exchanged with the Ethernet switch  214  by a direct Ethernet interface for a DSLAM, by ATM interfaces through the ATM switch  216  (e.g., Ethernet over ATM encapsulation), or by interfaces from the BSG  218  (e.g., Ethernet, ATM, or Ethernet encapsulated over an Internet Protocol interface). 
   To optimize the aggregated communications devices, the aggregator devices such as Ethernet switches  204 ,  214  may perform rate shaping and/or load balancing. The aggregator devices may perform rate shaping by directing frames of data according to the upload speed of the communications devices being aggregated by the aggregator device. Thus, the aggregator device  204 ,  214  may store in memory the relative upload speed differential between the two communications devices connected to the ports of the aggregator device. For example, with ADSL the differential may be defined as 8 megabits per second upload for one communication device and 1.5 megabits per second upload for the other communication device, which results in a differential factor of 5.3. The aggregator device may then channel every sixth frame to the communications device with the slow upload speed while the five preceding frames are channeled to the communications device with the fast upload speed. 
   In addition to rate shaping, the aggregator device may load balance between the communications devices being aggregated. The aggregator device communicates status information with the communications devices to detect the amount of data that a communications device has queued to transfer. If one of the communications devices has overly filled its queue relative to the other communications device, such as due to frame retransmissions or other similar reasons, then more frames are temporarily directed to the other communications device until the relative loads of each communications device have become balanced. 
   While the discussion above has described the communications devices for providing the asymmetric Ethernet service as ADSL modems, it will be appreciated that other types of communications devices that have asymmetric data transfer rates may be used as well. Furthermore, while the aggregator device has been described as an Ethernet switch, it will be appreciated that other types of aggregator devices may be used as well, such as routers that perform aggregation at the Internet Protocol level as opposed to the Ethernet level. Such a router may be optimized to rate shape and load balance as discussed above, such as by modifying the equal cost multiple paths (“ECMP”) code to account for the differential in upload speeds of the communications devices that are attached. 
   As discussed above, the subscriber of the asymmetric Ethernet service is provided an Ethernet connection at the point of service. The Ethernet service provided to the subscriber at the point of service is made asymmetric so that the effective upload and downloads speeds available to the subscriber and that are supported in the service provider network differ between the Ethernet network and the point of service. 
   Although the present invention has been described in connection with various illustrative embodiments, those of ordinary skill in the art will understand that many modifications can be made thereto within the scope of the claims that follow. Accordingly, it is not intended that the scope of the invention in any way be limited by the above description, but instead be determined entirely by reference to the claims that follow.