Cisco Systems A9014CFD manual Configuring Mpls OAM, Understanding Mpls OAM, LSP Ping, 17-1

C H A P T E R 17

Configuring MPLS OAM

This chapter describes how to configure multiprotocol label switching (MPLS) operations, administration and maintenance (OAM) in the Cisco ASR 901 router.

Contents

•Understanding MPLS OAM, page 17-1

•Configuring MPLS OAM, page 17-2

Understanding MPLS OAM

MPLS OAM helps service providers monitor label-switched paths (LSPs) and quickly isolate MPLS forwarding problems to assist with fault detection and troubleshooting in an MPLS network. The Cisco ASR 901 router supports the following MPLS OAM features:

•LSP Ping

•LSP Traceroute

•LSP Ping over Pseudowire

LSP Ping

MPLS LSP ping uses MPLS echo request and reply packets, similar to Internet Control Message Protocol (ICMP) echo request and reply messages, to validate an LSP. ICMP echo request and reply messages validate IP networks; MPLS OAM echo and reply messages validate MPLS LDP networks. The LSP ping and trace functions use IPv4 UDP packets with UDP port number 3503. You can use MPLS LSP ping to validate IPv4 LDP or Forwarding Equivalence Classes (FECs) by using the ping mpls privileged EXEC command. The MPLS echo request packet is sent to a target router by using the label stack associated with the FEC to be validated.

The source address of the LSP echo request is the IP address of the LDP router generating the LSP request. The destination IP address is a 127.x.y.z/8 address, which prevents the IP packet from being switched to its destination if the LSP is broken. The 127.0.0.x destination address range prevents the OAM packets from exiting the egress provider-edge router, which keeps them from leaking from the service-provider network to the customer network.

	Cisco ASR 901 Series Aggregation Services Router Software Configuration Guide
OL-23826-09		17-1