Configuring Ldp Loop Detection - HP MSR2000 Configuration Manual

Figure 16 Label acceptance control diagram
A label advertisement policy on an LSR and a label acceptance policy on its upstream LSR can achieve
the same purpose. HP recommends using the label advertisement policy to reduce network load.
You must create an IP prefix list before you configure a label acceptance policy. For information about IP
prefix list configuration, see Layer 3—IP Routing Configuration Guide.
To configure a label acceptance policy:
Step
1. Enter system view.
2. Enter LDP view or enter
LDP-VPN instance view.
3. Configure
acceptance policy.

Configuring LDP loop detection

LDP detects and terminate LSP loops in the following ways:
Maximum hop count—LDP adds a hop count in a label request or label mapping message. The
•
hop count value increments by 1 on each LSR. When the maximum hop count is reached, LDP
considers that a loop has occurred and terminates the establishment of the LSP.
• Path vector—LDP adds LSR ID information in a label request or label mapping message. Each LSR
checks whether its LSR ID is contained in the message. If it is not, the LSR adds its own LSR ID into
the message. If it is, the LSR considers that a loop has occurred and terminates LSP establishment.
In addition, when the number of LSR IDs in the message reaches the path vector limit, LDP also
considers that a loop has occurred and terminates LSP establishment.
To configure LDP loop detection:
Step
1. Enter system view.
Command
system-view
•
Enter LDP view:
mpls ldp
•
Enter LDP-VPN instance view:
a. mpls ldp
b. vpn-instance vpn-instance-name
a label
accept-label peer peer-lsr-id prefix-list
prefix-list-name
Command
system-view
31
Remarks
N/A
N/A
By default, LDP accepts all label
mappings.
Remarks
N/A