Label encoding algorithm for MPLS Segment Routing

Abstract

International audienceAbstract: Segment Routing is a new architecture that leverages the source routing mechanism to enhance packet forwarding in networks. It is designed to operate over either an MPLS (SR-MPLS) or an IPv6 control plane. SR-MPLS encodes a path as a stack of labels inserted in the packet header by the ingress node. This overhead may violate the Maximum SID Depth (MSD), the equipment hardware limitation which indicates the maximum number of labels an ingress node can push onto the packet header. Currently, the MSD varies from 3 to 5 depending on the equipment manufacturer. Therefore, the MSD value considerably limits the number of paths that can be implemented with SR-MPLS, leading to an inefficient network resource utilization and possibly to congestion. We propose and analyze SR-LEA, an algorithm for an efficient path label encoding that takes advantage of the existing IGP shortest paths in the network. The output of SR-LEA is the minimum label stack to express SR-MPLS paths according to the MSD constraint. Therefore, SR-LEA substantially slackens the impact of MSD and restores the path diversity that MSD forbids in the network

NetworkAPI: An In-Band Signalling Application-Aware Traffic Engineering Using SRv6 and IP Anycast

“…The maximum number of MPLS labels which a router can handle is referred to as Maximum SID Depth (MSD) [30]. The reason why the maximum number of MPLS label stacks is seven in this evaluation is because the MSD value of current major router implementations is less than seven [31]. Furthermore, according to [31], user's demand can be achieved with less than seven MSD using an optimized MPLS label encoding algorithms (SR-LEA and SR-LEA-A).…”

Failure Recovery In SDN: A Segment Routing Based Link Protection Approach

“…With this approach, a 1000 node graph would result in a new graph of approximately half million links and a significant computing load to the controller. Authors of [42], [43] proposed algorithm to slice the SRP into multiple sub-paths and then if any sub-path contains more than three nodes, all of them is replaced by the tail nodes SID and if a sub-path has only two nodes in it, the adj-SID of the link between those two nodes are inserted.…”

PASR: An Efficient Flow Forwarding Scheme Based on Segment Routing in Software-Defined Networking

“…SDN can obtain a global network view to provide global optimal routing decisions for SR. So far, some studies [15], [16] focus on deploying SR on large-scale SDN networks for achieving efficient flow forwarding schemes. Guedrez et al [15] present and analyze SR-LEA, an efficient path label encoding algorithm to use the least label stack to express the complete routing path.…”

“…So far, some studies [15], [16] focus on deploying SR on large-scale SDN networks for achieving efficient flow forwarding schemes. Guedrez et al [15] present and analyze SR-LEA, an efficient path label encoding algorithm to use the least label stack to express the complete routing path. Huang et al [16] design an architecture of OpenFlow-based Segment Routing and propose a new path encoding scheme to reduce the overhead of additional flow entries and label space.…”