xconnect wont come up – Mor-Pah.net

Following on from my previous post I found that in some instances it was either not practical or not possible down to the feature set of the IOS being run to successfully terminate xconnects on subinterfaces and have them actually pass traffic despite coming up.

Another workaround if you do want to achieve an alternative to terminating an xconnect on an SVI is to use portchannels (etherchannel). By terminating an xconnect on a port channel you can then place up to 8 ports into a channel group for example:

#interface Port-channel100
#no ip address
#xconnect 92.60.104.41 1003 encapsulation mpls
#!

#interface GigabitEthernet3/3
#description XC: Backup servers
#no ip address
#channel-group 100 mode on
#!

Ensuring that your ports are ‘no shut’ then you should find that running the following will show the link as up and you should be passing traffic:

#do sh mpls l2t vc

Local intf Local circuit Dest address VC ID Status
------------- -------------------- --------------- ---------- ----------
Gi3/2 Ethernet 92.60.104.34 1002 UP
Gi3/1 Ethernet 92.60.104.37 1001 UP
Po100 Ethernet 92.60.104.41 1003 UP

Now time to call it a day:)

James Greig

Ever gone to try and terminate a cisco L2TPv3 xconnect on an SVI on Cisco 6500 and wondered why the hell it wouldn’t come up? You run the following:

switch# sh mpl l2transport vc

and find that the output is always down no matter what. Well, cleverly Cisco decided you’re not allowed to do that. A useful technology introduced to improve things actually ends up making things a little more difficult. It *is* possible if you have a SIP line card (ES20) for example, but if you’re reading this it’s doubtful you have one of these.

There is a possible workaround to achieve what you’re probably after. Although you cannot terminate the xconnect on an SVI you can, however, terminate the xconnect on a sub interface and in turn sub interface’s can be placed into a vlan. It’s not an ideal work around and in some cases it’s probably not very practical – nonetheless it is a sometimes feasible workaround if required. All that you should need to do is create a sub interface on the upstream facing link with the xconnect configuration and place the sub interface into a dot1q vlan – et voila

Hope this helps people:)

Also see the follow up article for another workaround: Xconnects on SVIs Part 2

James Greig

Mor-Pah.net

Tag Archives: xconnect wont come up

Xconnects on SVIs part 2

Xconnects on SVIs