Cisco and their inconsistencies

Cisco is known for the inconsistencies between platforms and different IOS versions. I came across another that was rather annoying. Now between linecards.

Trying to configuring the following standard sub-interface Ethernet AToM tunnel on a Cisco 7606 with a ES+ linecard:

pseudowire-class CISCO
 encapsulation mpls
!
interface Te2/2.2
 encapsulation dot1Q 2
 no ip redirects
 no ip directed-broadcast
 no ip proxy-arp
 xconnect 10.5.0.99 12345 encap mpls pw-class CISCO

Yields the following misleading error…

7606(config)#int te2/2.2
7606(config-subif)# xconnect 10.5.0.99 12345 encap mpls pw-class CISCO
MPLS encap is not supported on this circuit

This is enough to annoy you for some time. If you have a look at the supported capability on CLI or using Cisco Feature Navigator you will see the AToM is indeed supported.

7606#sh mpls l2transport hw-capability interface te2/2 | section Eth VLAN
Transport type Eth VLAN
  Core functionality:
    MPLS label disposition supported
    Distributed processing supported
    Control word processing supported
    Sequence number processing not supported
    VCCV CC Type CW [1] processing not supported
  Edge functionality:
    MPLS label imposition supported
    Distributed processing supported
    Control word processing supported
    Sequence number processing not supported
    Fast backup switchover is supported
    Standby RP forwarding is not supported

The next step would generally be to consult the DOC-CD to confirm you didn’t messed up the really simple config. But this only adds to the head scratching.

Cisco Feature Navigator says AToM is supported, the DOC-CD shows the correct config used, CLI says it is supported, so what gives.

Cisco’s dumb sense of humor.

The ES+ Linecard has its own way of taking certain commands, which includes AToM.
On the 7600 ES+ linecard the configuration happens below a instance instead of a sub-interface configuration:

interface TenGigabitEthernet2/2
 no ip address
 no ip redirects
 no ip proxy-arp
 service instance 2 ethernet
  description atom on a ES_plus
  encapsulation dot1q 2
   xconnect 10.5.0.99 12345 encap mpls pw-class CISCO

For more information read this link at Cisco.

Trust that was helpful :)

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2 thoughts on “Cisco and their inconsistencies

    1. Hmm, yip its listed under the ES+ linecard page, but not in the general IOS page unless I missed it. The annoyance is that now you have to check linecard page in addition for IOS differences :(

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