Contents

Configuring MPLS OAM·· 1

About MPLS OAM·· 1

Fault management tools· 1

MPLS ping· 1

MPLS tracert 1

Protocols and standards· 1

Verifying LSP connectivity· 1

About LSP connectivity verification· 1

Performing MPLS ping for LSPs· 1

Performing MPLS tracert for LSPs· 2

Configuring MPLS OAM

About MPLS OAM

MPLS Operation, Administration, and Maintenance (OAM) provides fault management tools for the following purposes:

·     MPLS data plane connectivity verification.

·     Data plane and control plane consistency verification.

·     Fault locating.

Fault management tools

MPLS OAM provides on-demand fault management tools, which must be triggered manually, such as MPLS ping and MPLS tracert.

MPLS ping

MPLS ping tests the connectivity of a tunnel. At the ingress node, MPLS ping adds the label associated with a tunnel into an MPLS echo request and sends it to the egress node over the tunnel. The egress node processes the request and returns an MPLS echo reply to the ingress node. An MPLS echo reply with a success notification indicates that the tunnel is available for data forwarding. An MPLS echo reply with an error code indicates that the tunnel has failed.

MPLS tracert

MPLS tracert displays the path that a tunnel travels from the ingress to the egress to locate errors on the tunnel. MPLS tracert consecutively sends MPLS echo requests along the tunnel, with the TTL increasing from 1 to a specific value. Each hop along the tunnel returns an MPLS echo reply to the ingress due to TTL timeout so the ingress can collect information about each hop along the tunnel. This information allows you to locate the failed node or access information for each hop, for example, the label allocated by each downstream hop.

Protocols and standards

·     RFC 4379, Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures

Verifying LSP connectivity

About LSP connectivity verification

To verify LSP connectivity, you can use the ping mpls ipv4 command or the tracert mpls ipv4 command to trigger LSP connectivity verification as needed.

Performing MPLS ping for LSPs

Pinging the LSPs for an IPv4 prefix

To verify MPLS LSP connectivity for an IPv4 prefix, execute the following command in any view:

ping mpls [ -a source-ip | -c count | -exp exp-value | -h ttl-value | -m wait-time | -r reply-mode | -rtos tos-value | -s packet-size | -t time-out | -v ] * ipv4 ipv4-address mask-length [ destination start-address [ end-address [ address-increment ] ] ][ fec-type { generic | ldp } ]

Pinging the LSPs of the specified outgoing labels

To verify MPLS LSP connectivity by specifying the outgoing labels, execute the following command in any view:

ping mpls [ -a source-ip | -c count | -exp exp-value | -h ttl-value | -m wait-time | -r reply-mode | -rtos tos-value | -s packet-size | -t time-out | -v ] * out-labels out-label-value&<1-3> interface interface-type interface-number [ nexthop nexthop-address ]

Performing MPLS tracert for LSPs

Tracing the path of the LSPs for an IPv4 prefix

To trace the path that the LSPs for an IPv4 prefix take from the ingress node to the egress node, execute the following command in any view:

tracert mpls [ -a source-ip | -exp exp-value | -h ttl-value | -r reply-mode | -rtos tos-value | -t time-out | -v | fec-check ] * ipv4 ipv4-address mask-length [ destination start-address [ end-address [ address-increment ] ] ][ fec-type { generic | ldp } ]

Tracing the path of the LSPs of the specified outgoing labels

To trace the path that the LSPs of the specified outgoing labels take from the ingress node to the egress node, execute the following command in any view:

tracert mpls [ -a source-ip | -exp exp-value | -h ttl-value | -r reply-mode | -rtos tos-value | -t time-out | -v | fec-check ]* out-labels out-label-value&<1-3> interface interface-type interface-number [ nexthop nexthop-address ]