ospf over te tunnel

[paratrooper]

hello

there is a simple topology 

TE tunnels 10 and 14 are build to betwean IOU 10 and IOU14 

interface Tunnel10
ip unnumbered Loopback0
tunnel mode mpls traffic-eng
tunnel destination 14.14.14.14
tunnel mpls traffic-eng forwarding-adjacency
tunnel mpls traffic-eng path-option 1 explicit name R10-R14
no routing dynamic
router ospf 1
mpls traffic-eng router-id Loopback0
mpls traffic-eng area 0
router-id 10.10.10.10
network 10.10.10.10 0.0.0.0 area 0
network 10.11.0.0 0.0.0.255 area 0
network 10.12.0.0 0.0.0.255 area 0

interface Tunnel14
ip unnumbered Loopback0
tunnel mode mpls traffic-eng
tunnel destination 10.10.10.10
tunnel mpls traffic-eng forwarding-adjacency
tunnel mpls traffic-eng path-option 10 dynamic
no routing dynamic
router ospf 1
mpls traffic-eng router-id Loopback0
mpls traffic-eng area 0
router-id 14.14.14.14
network 11.14.0.0 0.0.0.255 area 0
network 13.14.0.0 0.0.0.255 area 0
network 14.14.14.14 0.0.0.0 area 0

Tunnels works well and is able to forward traffic from PC-1 to PC-2 and vise versa using staic route or policy map.

But i want to do the folowing 

let say 

create router ospf 5 process on both IOU10 and IOU14

since this two are directly conneted over TE Tunels i need to for OSPF adjasency over TE tunnels betwean IOU10 and IOU14 using ospf 5 process 

and then advetise PC-1 network which is 192.168.10.0/24 to IOU14 and advertise PC-2 network which is 192.168.14.0/24 to IOU10 so that this two can be routed using ospf over TE tunnels.

Thanks 

[Peter Paluch]

Hello Arkadiy,

It is not possible to force OSPF to start creating adjacencies over MPLS TE tunnels. However, I do not believe it is necessary for what you want to achieve - I believe that what you are looking for is the tunnel mpls traffic-eng autoroute announce command instead of forwarding-adjacency. Here is a document providing a glimpse into the workings of this feature:

https://www.cisco.com/c/en/us/products/collateral/ios-nx-os-software/multiprotocol-label-switching-traffic-engineering/whitepaper_c11-551235.html

Can you try replacing the forwarding-adjacency with autoroute announce and let us know?

Thank you!

Best regards,
Peter

[paratrooper]

Hello Peter
Thank you for your reply.
You are defenetly right about Autorute shortcat, and it works as you said.
But as i remember for example if we usr GRE tunnel betwean two nodes we can form ospf or eigrp adjacency over GRE tunnel just in the same way as we do over phisical p2p interface.
I wonder if the same is true for TE tunnel ?

[Peter Paluch · Accepted solution]

Hello Arkadiy,

You are defenetly right about Autorute shortcat, and it works as you said.

Thank you! It's good to know.

if we usr GRE tunnel betwean two nodes we can form ospf or eigrp adjacency over GRE tunnel just in the same way as we do over phisical p2p interface

Yes, this is completely true and correct.

I wonder if the same is true for TE tunnel ?

It is not. MPLS TE tunnels are an exception to this rule for a couple of reasons.

First, MPLS TE tunnels are uni-directional. You can set up an MPLS TE tunnel from router A (headend) to router B (tailend), but this tunnel only transports packets from router A to router B, not in the opposite direction, and this is perfectly expected and by design. For opposite direction, you will need a separate MPLS TE tunnel configured on router B (headend) to router A (tailend), and there may be applications in which you only need a tunnel from A to B, not vice versa. Routing protocols, on the other hand, are not designed to operate over unidirectional links such as MPLS TE tunnels - they always expect that a link is bidirectional which is not the case with MPLS TE tunnels.

Second, and this is more in-depth, establishing an IGP adjacency over an MPLS TE tunnels is not really necessary. Think of this: With common physical links, they exist beforehand, and only then you run an IGP through these links to make these links known to the routing protocol so they can be used for transit traffic. With MPLS TE tunnels, the knowledge that such a path between two routers exists is already present in the IGP link-state databases - in fact, that information has been used to construct the tunnel in the first place. Running an IGP adjacency over the MPLS TE tunnel would not bring any additional significant knowledge to the routing protocol that was not there already. Hence, we do not run IGP adjacencies over MPLS TE tunnels.

Please feel welcome to ask further!

Best regards,
Peter