Forwarding Traffic onto MPLS TE Tunnels

[Parves Ataev]

Hoping that someone here is going to help me. I have a very simple topology, please see the diagram attached. I have LDP running and currently have pseudowire configured (on diagram marked as Pseudowire1) and no problems with it. So, now I have backup link between PE2 and P routers  and want to set up RSVP TE tunnel between my PE's  and map specific pseudowire to configured TE tunnel (on diagram marked as Pseudowire2). So, in the end i want my Pseudowire1 traffic over main link and Pseudowire2 traffic over backup link. So far I am able to setup bidirectional tunnels between PE routers but I am not sure how to direct the traffic over tunnel . I was able to find this document http://www.cisco.com/c/en/us/td/docs/ios/12_2sr/12_2sra/feature/guide/srtunsel.html but it for 7600 platform. Also I found out that it is possible to forward traffic by configuring one of these methods: Static Routing, Policy-Based Routing, Autoroute Announce, Forwarding Adjacency and Class-Based Forwarding.  I have Cisco 2921 router as PE’s and wondering what will be the best way of Forwarding Traffic onto MPLS TE Tunnel.

Please see the related config of my PE2 router:

ip explicit-path name Via_Backup_Link enable
 next-address 10.1.1.1

interface Tunnel10
 ip unnumbered Loopback777
 tunnel source Loopback777
 tunnel mode mpls traffic-eng
 tunnel destination 1.1.1.1
 tunnel mpls traffic-eng path-option 5 explicit name Via_Backup_Link
 tunnel mpls traffic-eng path-option 10 dynamic
 no routing dynamic

CE facing interface
interface GigabitEthernet0/0.1273
 description Customer2
 encapsulation dot1Q 1273
 xconnect 1.1.1.1 1273 encapsulation mpls

So, I have a figured out that I can forward traffic using Policy-Based Routing. Can you tell me if I configure something like below that it is going to do the trick:

route-map Customer2 permit 10
match interface GigabitEthernet0/0.1273
set interface Tunnel10

interface GigabitEthernet0/0.1273
 description Customer2
ip policy route-map Customer2
 encapsulation dot1Q 1273
 xconnect 1.1.1.1 1273 encapsulation mpls

Many Thanks in advance.

[aqeel ahmed]

Hi

interface Tunnel10
 ip unnumbered Loopback777
 tunnel source Loopback777
 tunnel mode mpls traffic-eng
 tunnel destination 1.1.1.1

"tunnel mpls traffic-eng autoroute announce" will make this tunnel next hop for 1.1.1.1 so all traffic destined to 1.1.1.1 will go on this tunnel.

[Parves Ataev]

Hi,

Thanks for your input. I forgot to mention that Pseudowire1 has the same destination which is 1.1.1.1.

interface GigabitEthernet0/0.123
 description Customer1
 encapsulation dot1Q 123
 xconnect 1.1.1.1 123 encapsulation mpls

So as far as I understand if I configure tunnel mpls traffic-eng autoroute announce it will make all pseudowires use TE tunnel which has destination 1.1.1.1. In my case both pseudowires has the same destination. My goal is to have Pseudiwire1 to be forwarded via main link (LDP) and Pseudowire2 via backup link (TE Tunnel).

[Nagendra Kumar Nainar]

Jeronimo,

If I understood the requirement, you need to have 1 PW traffic over LDP based LSP while the other PW to same destination 1.1.1.1 over TE tunnel.

You can remove the "autoroute announce" from the tunnel. This way, all pseudowire traffic will follow the LDP based LSP. Now include "preferred-path" under respective pseudowire with TE tunnel as preferred path.

Something like below,

pseudowire-class <name>
 encapsulation mpls
 preferred-path interface <TE-Interface>

Now apply the pseudowire-class to the respective xconnect.

-Nagendra

[Parves Ataev]

Hello Nagendra,

Thanks for reply. Yes that is correct. I want my 1 PW traffic over LDP based LSP while the other PW to same destination 1.1.1.1 over TE tunnel. Please note that I have Cisco 2921 router as PE and it seems that it does not support  "preferred-path interface" feature.

Please see the output from my router:

PE2(config)#pseudowire-class test1
PE2(config-pw-class)#encapsulation mpls
PE2(config-pw-class)#?
Pseudowire-class configuration commands:
  default        Set a command to its defaults
  encapsulation  Data encapsulation method
  exit           Exit from Pseudowire-class configuration mode
  interworking   Interworking options for pseudowire
  no             Negate a command or set its defaults
  protocol       Signaling protocol to use
  status         Enable pseudowire status extensions in label advertisement and label notification messages. This is not advised unless your
                 peer router also supports this functionality as it may lead to premature enabling of the dataplane on that peer.

In my question I have posted a link to this document  http://www.cisco.com/c/en/us/td/docs/ios/12_2sr/12_2sra/feature/guide/srtunsel.html where  "preferred-path interface" feature is explained but it is for 7600 platform.  That is why I took a different approach to forward the traffic with route-map. Please advise.

[paolo_carbone]

Hi,

Did you ever get this resolved?

I have the same problem and not have the preferred-path feature available on our ME3600s.

Thanks

Paolo

[Riccardo Romani]

hello , i have a similar situation with my asr9010 , i have put preferred path tunnel x under pseudowires to reach e remote pseudowire loopback. how can i check that effectively the mac address to destination PE are taking the wanted physical links configured under my tunnel (with explicit path configured)?

if i traceroute from PE1-DC1 to PE1-DC2 look it is using shortest path (direct lnk) selected by IGP but this is something i don't want , i want to use links defined into tunnel (explicit path).

can somebody help me?

maybe i do not have to consider IGP routing table for the remote pw loopback when TE is configured?

[Deivid85_]

Hello,

Which IGP do you use? I think you can use Forwarding Adjacency to achieve that behavior if it's supported on your platform. The idea behind it it's to include your tunnel as a new link inside your IGP. The metric for your tunnel (New virtual link) would be higher than the one over the Main link (You can manually set it). Considering a normal condition, the PWE will flow through the Main link; if this LSP fails, the PWE would turn to the LSP formed by RSVP-TE. Take also into account that the tunnel is unidirectional.

I found this link about this topic:

https://www.cisco.com/c/en/us/td/docs/ios/12_0s/feature/guide/fs_tefa.html

Hope it helps.