Multiplex communications – Pathfinding or routing – Switching a message which includes an address header
Reexamination Certificate
1999-06-18
2003-08-26
Ton, Dang (Department: 2661)
Multiplex communications
Pathfinding or routing
Switching a message which includes an address header
C370S395420, C370S395500, C370S469000, C709S245000, C709S230000, C709S238000
Reexamination Certificate
active
06611522
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to communication nodes and more particularly to Quality of Service (QoS) features in a single communication node for performing IP forwarding and ATM switching.
BACKGROUND OF THE INVENTION
QoS covers a broad range of issues in computer networks. QoS features can take the form of preferred service for particular data flows. QoS features can also include congestion control. As used herein, the term “QoS features” refers to those features in a digital communication network that provide a capability to differentiate between data flows so that network service providers some traffic differently than other traffic. The need for QoS features arises from different types of network traffic having different transmission requirements. By way of example, to avoid echoes, voice traffic typically requires a 64 kbs bandwidth, with less than 100 ms of delay. Alternatively, non-interactive broadcast video typically requires a 271 Mbs bandwidth, but does not have a strict delay requirement. To be competitive, network service providers need to provide differentiated classes of service.
In conventional systems, ATM networks have been viewed as separate universes from IP networks. ATM networks work well for a subset of services, and IP networks work well for a different subset of services. Traditionally, ATM networks have been viewed as preferential for applications requiring more sophisticated QoS features. For example, the ATM Forum has defined five service categories for ATM: Constant Bit Rate (CBR); real-time Variable Bit Rate (rtVBR); non-real-time Variable Bit Rate (nrtVBR); Unspecified Bit Rate (UBR); and Available Bit Rate (ABR). When a service provider sets up an ATM virtual circuit (VC), the service provider and the user contract for one of the service categories. With each service category, comes a set of transmission priority parameters that are specific to the category.
However, as multimedia applications have infiltrated computer networking, IP QoS features have improved. Today, IP QoS features include the ReSerVation Protocol (RSVP); the Integrated Services models (IntServ); and the Integrated Services over Specific Link Layers (ISSLL). Together, these components provide comprehensive QoS features for end-to-end flows, but still do not provide all of the QoS features available from ATM. Additionally, this type of end-to-end flow regulation lacks the flexibility required for adapting to emerging technologies.
Given that neither IP nor ATM offer a complete multiservice solution, many service providers choose to operate dual networks. IP networks support applications such as Internet access and virtual private networks (VPNs), whereas ATM networks support Frame Relay (FR), VPNs, circuit emulation, private branch exchanges (PBX) and other applications where reliability and more rigorous QoS are a priority. These dual networks can be a complex and expensive aggregation of core routers connecting smaller Access Points of Presence (PoPs) to the core transport capacity. These structures are fragile, with frequent service outages due to performance limitations and equipment failures. Enterprises cannot afford to be exposed to significant down time due to failures or updates associated with conventional technology.
Accordingly, an object of the invention is to provide enhanced QoS features in a single communication node for performing IP forwarding and ATM switching.
A further object of the invention is to provide QoS features, which are capable of accommodating emerging technologies, in a single communication node.
Another object of the invention is to provide QoS features, which are capable of accommodating a variety of communication protocols, without requiring the maintenance of costly parallel networks.
These and other objects of the invention will be apparent with respect to the following description of the invention.
SUMMARY OF THE INVENTION
The invention is directed to a facility and related methods for providing Asynchronous Transfer Mode (ATM) and Internet Protocol (IP) Quality of Service (QoS) features in a digital communication node. Optionally, the QoS facility of the invention also provides Frame Relay (FR) QoS features. According to one embodiment of the invention, the facility comprises a plurality of logical input ports, a plurality of logical output ports, switching elements, routing elements and QoS elements.
The logical input ports are adapted for receiving input data flows from external data sources. Similarly, the logical output ports are adapted for transmitting output data flows to a plurality of external data destinations. According to the invention, the input and output data flows can be ATM-based data flows or IP-based data flows. The input and output data flows can also be IP over ATM. That is, IP packets can be carried in ATM cells. In a further embodiment of the invention, the logical input ports are included in a common physical interface. According to a further aspect, the input data flows through the common physical interface include Synchronous Optical Network (SONET) frames.
The switching elements are adapted for switching ATM data cells from one of the logical input ports toward at least one of the logical output ports, along a selected forwarding path. According to a further feature of the invention, the switching elements include ATM lookup elements for identifying toward which of the logical output ports particular ATM data cells should be switched.
The routing elements are adapted for routing IP data packets from one of the logical input ports toward at least one of the logical output ports along a selected forwarding path. According to a further embodiment of the invention, the routing elements include IP lookup elements for identifying toward which of the logical output ports to rout a particular IP data packet, in response to information contained in the particular IP data packet.
The QoS elements are common to the switching elements and the routing elements and provide ATM QoS features to the ATM data cells and IP QoS features to the to the IP data packets. Optionally, the ATM lookup elements are further adapted for determining which of the ATM QoS features should be applied to a particular ATM data cell. According to a time saving feature, the lookup elements identify a forwarding path and determine the applicable ATM QoS features in a single lookup operation.
The ATM QoS features include one or more of, Constant Bit Rate (CBR), Unspecified Bit Rate (UBR), non-real-time Variable Bit Rate (nrtVBR), real-time Variable Bit Rate (rtVBR) and Available Bit Rate (ABR), and the IP QoS features include one or more of, Provisional QoS, Differentiated Services, and Integrated Services.
In another embodiment of the invention, the facility for providing ATM and IP QoS features includes a mechanical housing that contains both the switching, routing and QoS elements. In this way, a facility according to one embodiment of the invention, provides an integrated system for switching ATM data cells, routing IP data packets and providing ATM and IP QoS features. Thus, a facility according to this embodiment of the invention enables service providers to avoid maintaining costly parallel networks; one for switching ATM data cells and one for routing IP data packets. The facility of the invention also enables service providers to provide different classes of service (e.g. coach, business and first class) for both ATM-based and IP-based data flows; thus, providing an additional source of revenue from clients willing to pay for enhanced bandwidth guarantees.
In alternative embodiments, the QoS facility provides call control elements. The call control elements enable the facility to form service contracts with client networks. The service contracts typically specify QoS features, such as bandwidth guarantees, that the communication node agrees to provide to data flows received from or transmitted to a client network. Optionally, the call control elements determine the available bandwidth of the communication node, and a
Crawley Eric
Kastenholz Frank
Willis Steven R.
Zheng Qin
Harrity & Snyder LLP
Juniper Networks, Inc.
Phan Tri H.
Ton Dang
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