Hey buddy,
I feel like this question deserves some further explanation,
First, “TE metric” is used solely by the cSFP in order to route the TE trunk (tunnel/LSPs) to a destination.
It is used in cases where standard SPF (LDP LSPs) should route traffic using different path compared to LSPs routed by cSPF (TE LSPs).
And as you have found out, TE metric has nothing to do with the actual forwarding of traffic down the TE LSPs.
In order to forward traffic via TE LSPs there’s a plethora of options to choose from:
Auto-route (announce / destination)
Policy Based Routing
Pseudowire Tunnel Selection
Static routes
Forward Adjacency
Policy / Class Based Tunnel Selection
Autoroute Announce
It allows IGP to treat TE Tunnel as a regular interface.
However with Autoroute Announce the tunnel is used by IGP only on the tunnel head-end router.
That means the tunnel head-end router will not advertise this “shortcut” via IGP to anyone else and will keep it to itself as a secret.
Autoroute Destination
Static version of Autoroute Anounce
To install one/multiple static routes into the RIB and FIB pointing to an MPLS TE tunnel as next-hop interface.
You can tell the RIB to use a given TE Tunnel to reach one or multiple destination IPs
It’s like a static route, but configuration is done under the TE
Static routes
Same as Autoroute Destination
To install one/multiple static routes into the RIB and FIB pointing to an MPLS TE tunnel as next-hop interface.
You can tell the RIB to use a given TE Tunnel to reach one or multiple destination IPs
Configuration is done under static routes config stanza
Forwarding Adjacency or IGP shortcuts
It allows IGP to treat TE Tunnel as a regular interface.
And IGP can advertise the TE Tunnel as a link to the tunnel tail-end (a shortcut to a particular node)
So other nodes in the network can use this newly advertised link/shortcut in their SPF calculations
Use with caution as it affects routing decision on other routers in the network
Policy-Based-Tunnel-Selection
Static in nature
To install one/multiple static rules into the FIB, that can be used to direct traffic into an MPLS TE tunnel as next-hop interface.
You can tell the FIB to use a given TE Tunnel to reach one or multiple destination IPs
Configuration is done in policy and that is then applied on an ingress interface or on a VRF(all ingress interfaces in the VRF are affected by the policy).
Class-Based-Tunnel-Selection CBTS
CBTS supports tunnel selection based on the value of the EXP field that the headend router imposes on the packet.
Before imposing this value, the router considers the input QoS config. If the input QoS modifies the EXP field value, CBTS uses the modified value for its tunnel selection.
Packets may enter the headend from multiple incoming interfaces. These ingress interfaces can belong to different customers that have different DiffServ policies. In such cases, service providers generally use input QoS to apply their own DiffServ policies and mark imposed EXP values accordingly. Thus, CBTS can operate consistently for all customers by considering the EXP values marked by the service provider on ingress to the ISP network.
Pseudowire/AToM Tunnel Selection
The Any Transport over MPLS (AT0M) Tunnel Selection feature allows you to specify the path that a particular PW traffic uses. In other words you can map a Virtual Circuit (VC) to a defined TE LSP.
Attachment circuits are cross-connected to specific MPLS traffic engineering tunnel interfaces instead of remote PE router IP addresses (reachable using IGP or LDP)
This is configured under the PW config section using “preferred-path”.
adam
netconsultings.com
::carrier-class solutions for the telecommunications industry::
adam
