Patent Application
20070233885
Assuring that information is transported from one point to another with a certain quality-of-service (“QoS”), especially when the points are located in different domains (i.e., inter-domain) operated by different service providers, is important to the success of existing services as well as to enable the spread and growth of relatively new services, such as voice-over-Internet protocol (“VoIP”), multimedia and mission-critical services.
The de facto standard for inter-domain routing in today's Internet is Border Gateway Protocol (BGP), which uses so-called BGP speakers to advertise and select paths to destination prefixes (i.e., destinations). BGP is “QoS-agnostic”. That is, in BGP no QoS path related information is exchanged between speakers and all traffic, independent of its QoS requirements, is forwarded along the same selected path. As such, it can be fairly stated that there is no explicit support for the transport of QoS sensitive traffic using the Internet's current infrastructure.
As evidenced by the ‘Infranet’ effort, there is an increasing realization that this is inadequate to support high-revenue, commercial-grade services that require some degree of reliability and quality assurance (i.e., QoS guarantees). Recently, some have attempted to modify BGP to make it less QoS agnostic. Unfortunately, the disadvantages discovered outweigh the advantages.
It is noteworthy that the co-pending Application referenced above sets forth methods (and devices to carry out the methods) that assures QoS sensitive information can be transported over different domains without the disadvantages inherent in BGP just described.
What is yet to be addressed is the architecture of a given domain. That is, what are the architecture(s) that assure the transport of QoS sensitive information over different domains?
The present inventors have discovered architectures that assure the transport of QoS sensitive information over multiple, different domains.
In one embodiment of the invention, one such architecture comprises separate control and forwarding “planes”. More specifically, the control plane may comprise one or more devices called “speakers”, each located in a different domain. In accordance with the present invention, each speaker's control plane computes and identifies best paths before QoS sensitive information is forwarded and reserves paths in response to trunk requests and the like. The forwarding plane may comprise one or more other devices, such as border routers, which are responsible for forwarding QoS sensitive information between different domains along best paths computed and identified by the speakers.
In a further embodiment of the invention, the speakers are operable to exchange messages with one another over their control planes. The messages may include information related to possible best paths which may be used to route QoS sensitive information, and/or, may be related to the reservation of one or more best paths. Upon receiving a message, a speaker may use information in these messages to compute and/or reserve best paths.
In accordance with additional embodiments of the invention, the speakers may comprise AQUA (an abbreviation for Assured Quality) speakers.
The embodiments described above are just some examples of the present invention. Other examples are set forth in the drawings and detailed description of the invention which follow.
The inventors believe that the architectures provided by the present invention may be deployed by service providers that need to cooperate with each other in order to deliver QoS-sensitive services to their customers.
Referring now to
It should be understood that within each domain there is typically a single speaker. Though shown as a separate element within each of the domains in
The architecture 1, as well as other architectures provided by the present invention, comprises two separate layers or “planes”; a (1) control plane and (2) a forwarding plane.
More specifically, the speakers S1, S2, S3 and S4 connected via pathway 2 comprise a control plane. In accordance with the present invention, the control plane computes and identifies best paths before QoS sensitive information is forwarded and is used to reserve paths in response to trunk requests and the like. In contrast, the Border Routers comprise a forwarding plane that forwards QoS sensitive information over AS1, AS2, AS3 and AS4 via one or more best paths identified by the control plane.
In order to compute the best paths for routing QoS sensitive information, each of the speakers S1, S2, S3 and S4 is operable to exchange messages with one another via their respective control planes. Based on information contained in this messages, each speaker S1, S2, S3 and S4 may compute and identify one or more best paths that may be used to route QoS sensitive information via the separate forwarding planes. The co-pending Application mentioned above sets forth some examples of how speakers S1, S2, S3 and S4 may compute the best paths using, for example, a stored information base of best paths or an on-demand method of determining best paths. The examples set forth in the co-pending Application are just some of the methods which may be used by the speakers S1, S2, S3 and S4 to compute and identify possible best paths.
As mentioned above, in one embodiment of the invention, the forwarding plane comprises those elements of the architecture 1 which are responsible for actually forwarding QoS sensitive information from one point to another, such as the border routers mentioned above as well as network elements (“ne”) within each domain to give just a few examples. In accordance with the present invention, the paths used by the forwarding planes (e.g., border routers) to route QoS sensitive information over domains AS1, AS2, AS3 and AS4 are those best paths computed and identified by the separate control plane of architecture 1. An example of a best path is path 3 shown in
Thus, while no traffic is routed through a speaker S1, S2, S3, S4, it is the speakers S1, S2, S3, S4, that: (i) determine which paths are to be used by the forwarding plane to route QoS sensitive information over AS1, AS2, AS3 and AS4 (i.e., which paths have the bandwidth and delay characteristics required to route the information); (ii) guarantee that the so-selected paths will be reserved; and (iii) reserve best paths in response to trunk requests and the like.
In accordance with embodiments of the present invention, the features and functions of the present invention may be carried out completely independent of any BGP functions, thus assuring that critical BGP functions are not adversely impacted.
The discussion above has set forth some examples of the present invention. However, the true scope of the present invention is better represented by the claims that follow.
The present application is related to co-pending U.S. patent application Ser. No. ______, entitled “Methods and Devices For Computing Paths To Assure The Inter-Domain Transport of QoS Sensitive Information”, the disclosure of which is incorporated by reference herein in full as if set forth in full herein.
