MPLS PATH RESTORATION

• Main Authors: Chieh-Min Hsieh, 謝界民
• Other Authors: Yen-Chieh Ouyang
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/14344511920423342611

碩士 === 國立中興大學 === 電機工程學系 === 92 === Today’s communication networks and services are migrating to a converged paradigm centered on IP (Internet Protocol). MPLS (Multiprotocol Label Switching) has recently been accepted as a new approach for integrating IP layer 3 routing with layer 2 switching technology. It is estimated that in the near future, MPLS will be chosen as bearer of IP large backbone networks. MPLS technology has proven its value for delivering new services while at the same time allowing migration from old to new networks. The path recovery in MPLS is the technique to reroute traffic around a failure or congestion in a LSP(Label Switched Path). In Haskin’s proposal the authors present a fast rerouting protection mechanism for setting up an alternative LSP to handle fast rerouting of traffic upon a failure in primary/protected LSP in MPLS network. This proposal provides a quick restoration time nearly to the 50 milliseconds. But this proposal with the two problem: One is while the ingress LSR detects traffic in the reverse direction it switches the traffic directly to the alternative LSP. These packets will with a two-way delay while traversing the backwards loop from the ingress LSR to the last LSR at the point of failure. Another problem of this scheme is that as packets arriving from the reverse direction are mixed with incoming packets, this results in packet disordering through the alternative LSP during the restoration period. In Makam’s proposal the authors use a fault notification mechanism to convey information about the occurrence of a fault to a responsible node in order to let ingress LSR redirects the traffic over a pre-established alternative LSP. This method provides better resource utilization the Haskin’s scheme. But the the traffic that is in transit during the interval of time between the detection of the fault detected and the time the fault notification signal reaches the ingress LSR will be droped by the alert LSR. My proposal improve Haskin’s protection switching and combined with Makam’s scheme proposes an efficient rerouting scheme can decrease the packets reordered prolem , support MPLS path restoration failure types such as link failures, node failures. Through simulation, the performance of the proposed scheme is measured and compared with the existing schemes. Keyword: MPLS, MPLS path restoration.