R3303-HP HSR6800 Routers MPLS Configuration Guide

information about the GR restarter and keep sending Hello packets periodically to the GR restarter until

the restart timer expires.

If a GR helper and the GR restarter reestablish a Hello session before the restart timer expires, the

recovery timer is started and signaling packet exchanging is triggered to restore the original soft state.

Otherwise, all RSVP soft state information and forwarding entries relevant to the neighbor are removed.

If the recovery timer expires, soft state information and forwarding entries that are not restored during the

GR restarting process are removed.

An HSR6802/HSR6804/HSR6808 router that supports primary-secondary switchover, if configured

with RSVP-TE GR, can act as a GR restarter and a GR helper at the same time.

HSR6802/HSR6804/HSR6808 routers without secondary MPUs can act as only GR helpers when they

are configured with RSVP-TE GR.

Traffic forwarding

For traffic to travel along an LSP tunnel, you must perform the configuration after creating the MPLS TE

tunnel. Otherwise, traffic is IP routed.

Even when an MPLS TE tunnel is available, traffic is IP routed if you do not configure it to travel the tunnel.

For traffic to be routed along an MPLS TE tunnel, you can use static routing, policy-based routing, or

automatic route advertisement.

Static routing

Static routing is the easiest way to route traffic along an MPLS TE tunnel. You only need to manually

create a route that reaches the destination through the tunnel interface.

For more information about static routing, see Layer 3—IP Routing Configuration Guide.

Policy-based routing

You can also use policy-based routing to route traffic over an MPLS TE tunnel. In this method, you create

a policy that specifies the MPLS TE tunnel interface as the output interface for traffic that matches certain

criteria defined in the referenced ACL.

This policy should be applied to the incoming interface.

For more information about policy-based routing, see Layer 3—IP Routing Configuration Guide.

Automatic route advertisement

You can use automatic route advertisement to advertise MPLS TE tunnel interface routes to IGPs, allowing

traffic to be routed down MPLS TE tunnels.

Two methods are available to automatic route advertisement: IGP shortcut and forwarding adjacency.

OSPF and IS-IS support both methods where TE tunnels are considered point-to-point links and TE tunnel

interfaces can be set as outgoing interfaces.

IGP shortcut, also known as autoroute announce, considers a TE tunnel as a logical interface directly

connected to the destination when computing IGP routes on the ingress of the TE tunnel.

IGP shortcut and forwarding adjacency are different in that in the forwarding adjacency method, routes

with TE tunnel interfaces as outgoing interfaces are advertised to neighboring devices but not in the IGP

shortcut method. Therefore, TE tunnels are visible to other devices in the forwarding adjacencymethod

but not in the IGP shortcut method.