MPLS TE Tunnel priority

[k.hariharan1]

Hi ,

I have a doubt on MPLS TE tunnel selection for LSP.  I understood that by using the TE tunnels , suppose if have 3 different path to reach the next hop router. we can set a priority by using the command tunnel mpls traffic-eng priority (set priority) (hold priority).

if i have configured tunnel 1 and i have given tunnel mpls traffic-eng priority 1 1 and the back up tunnel for this is tunnel 2 and the relevant priority is tunnel mpls traffic-eng priority 2 2 , so now the first tunnel is the first best path to reach the desired next hop Ldp ID  and if the link associated with that tunnel is down the automatically the back up tunnel with the priority 2 2 should come up.

and i need in rare case if  both the links associated with the Tunnel 1 and tunnel are down then the 3rd tunnel should come up. For achieving this is it enough if i create another one tunnel 3 and give the command tunnel mpls traffic-eng priority 3 3.

Or since i have 3 seperate path to reach the next hop router , is it possible to do the load balancing between LSP. if its good to do the load balancing how can we achieve this.

Regards,

Hariharan k

[shivjain · Accepted solution]

yes, you can configure load balancing, all tunnels toward the same destination appear as equal-cost paths, even when their TE bandwidths are not the same.

config is given below

interface Tunnel0
ip unnumbered Loopback0
tunnel destination a.b.c.d
tunnel mode mpls traffic-eng
tunnel mpls traffic-eng autoroute announce
tunnel mpls traffic-eng priority 7 7
tunnel mpls traffic-eng path-option 1 explicit path1
!
interface Tunnel1
ip unnumbered Loopback0
tunnel destination 172.16.0.21
tunnel mode mpls traffic-eng
tunnel mpls traffic-eng autoroute announce
tunnel mpls traffic-eng priority 7 7
tunnel mpls traffic-eng path-option 1 explicit path2

after this if you run the show ip route command, you will see the two paths listed in routing table.

regards

shivlu jain

[k.hariharan1]

Hi shivlu,

Thanks for the reply.

So the priority value which we are setting under the tunnel configuration define which is the preffered link for LSP. and as per your configuration both the tunnel priority values are identical so the per destination load balancing will happen   automatically.

Regards,

Hariharan k 

[shivjain]

yes you are right.

regards

shivlu jain