Traffic engineering in frame-based carrier networks

Abstract

The invention relates to enabling traffic engineering in frame-based networks such as Ethernet networks. There is described a method of and connection controller for establishing connections (76, 77) in a frame-based communications network comprising nodes (71-75 and 78) such as Ethernet switches. The connections are established by configuring, in various of the nodes, mappings for forwarding data frames, such as Ethernet frames. The mappings are from a combination of a) a destination address corresponding to a destination node (73) of the connection and b) an identifier, such as a VLAN tag. The mappings are to selected output ports of the various nodes. By using the combination of destination address AND identifier, the mappings enable data frames belonging to different connections (76, 77) to be forwarded differentially (ie forwarded on different output ports) at a node (75) despite the different connections having the same destination node. This enables flexibility in routing connections—ie the ability to perform traffic engineering.

Description

FIELD OF THE INVENTION [0001] The present invention relates to methods of, software for and apparatus for enabling traffic engineering in carrier networks. BACKGROUND TO THE INVENTION [0002] For many years now, telecommunications carriers have been deploying packet-switched networks in place of circuit-switched networks for reasons of efficiency and economy. Packet-switched networks such as Internet Protocol (IP) or Ethernet networks are intrinsically connectionless in nature and as a result suffer from Quality of Service (QoS) problems. Customers value services which are guaranteed in terms of bandwidth and QoS. [0003] Carriers may use Multi-Protocol Label Switching (MPLS) over a layer 2 network to create connection-oriented label switched paths (or tunnels) across the intrinsically connectionless network, and thereby to provide guaranteed QoS and bandwidth services to customers. However, MPLS is a relatively unstable standard and carriers desire an alternative. [0004] It is desire...

AI Technical Summary

Benefits of technology

"The present invention relates to enabling traffic engineering in frame-based networks, such as Ethernet networks. The invention provides methods for configuring network nodes with mappings that allow for flexible routing of data frames. These mappings enable differential forwarding of data frames despite the same destination node. The invention also provides a connection controller for establishing connections in a frame-based network and a method of data traffic engineering in a frame-based network. The technical effects of the invention include improved traffic engineering, efficient network utilization, and flexibility in setting up connections."

Problems solved by technology

Packet-switched networks such as Internet Protocol (IP) or Ethernet networks are intrinsically connectionless in nature and as a result suffer from Quality of Service (QoS) problems.

However, MPLS is a relatively unstable standard and carriers desire an alternative.

However, the behaviour of conventional switched Ethernet networks is incompatible with carriers' requirements for providing guaranteed services to customers.

As a consequence, conventional Ethernet networks do not have support for network-wide load balancing, suffer from resiliency problems and cannot support traffic engineering.

One problem with the method proposed in draft-kawakami-mpls-lsp-vlan-00.txt is that a maximum of 4094 unique VLAN tags are definable in 802.1Q compliant equipment.

This limits the flexibility in and increases the complexity of provisioning connections across the network.

Another problem is that connections may not easily be re-routed once provisioned without creating transitory loops.

Another problem is that the Frame Check Sequence (FCS) in Ethernet frames is computed over both the payload and header portions of the frame.

Moreover, during the interval from when the original FCS is removed and the new FCS added, the frame is vulnerable to corruption without the protection of any FCS.

Another problem with the ‘label-swapping’ approach proposed in draft-kawakami-mpls-lsp-vlan-00.txt is that it requires a “chain of correctness” in that forwarding relies on each local label-forwarded link on the LSP being correct, whereas conventional Ethernet which uses globally unique address information to perform forwarding.

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