[c-nsp] 12.2(18)SXF5 to SXF6++ change in AToM back2back PE

[Rene Avi]

Hi,

anyone else stumbled into a changed behavior for a point2point Eth-AToM
starting with 12.2(18)SXF6++ and exactly the same configuration on both
sides?

The scenario is a MAC-address bypass EoMPLS setup with back2back PEs on
SUP32s:

Router1  <---- switched VLAN2 network with MAC-address-limit ----> Router2

Router1 @ SXF5:
Router1#sh mpls l2transport vc

Local intf     Local circuit        Dest address    VC ID      Status
-------------  -------------------- --------------- ---------- ----------
Vl15           Eth VLAN 15          172.16.16.102   140        UP
Router1#
Router1#sh mpls l2transport vc 140 detail
Local interface: Vl15 up, line protocol up, Eth VLAN 15 up
  Destination address: 172.16.16.102, VC ID: 140, VC status: up
    Tunnel label: imp-null, next hop 81.94.63.253
    Output interface: Vl2, imposed label stack {41}
  Create time: 03:43:36, last status change time: 03:35:35
  Signaling protocol: LDP, peer 172.16.16.102:0 up
    MPLS VC labels: local 43, remote 41
    Group ID: local 0, remote 0
    MTU: local 1500, remote 1500
    Remote interface description:
  Sequencing: receive disabled, send disabled
  VC statistics:
    packet totals: receive 10, send 505
    byte totals:   receive 1160, send 58580
    packet drops:  receive 0, send 0

Router1#

Router2 @ SXF6 or higher:
Router2#sh mpls l2transport vc

Local intf     Local circuit        Dest address    VC ID      Status
-------------  -------------------- --------------- ---------- ----------
Vl15           Eth VLAN 15          172.16.16.101   140        DOWN
Router2#sh mpls l2transport vc 140 detail
Local interface: Vl15 up, line protocol up, Eth VLAN 15 up
  MPLS VC type is Eth VLAN, interworking type is Ethernet
  Destination address: 172.16.16.101, VC ID: 140, VC status: down
    Output interface: none, imposed label stack {43}
    Preferred path: not configured
    Default path: active
    Next hop: Invalid ADDR    <----
  Create time: 03:34:08, last status change time: 03:33:52
  Signaling protocol: LDP, peer 172.16.16.101:0 up
    MPLS VC labels: local 41, remote 43
    Group ID: local 0, remote 0
    MTU: local 1500, remote 1500
    Remote interface description:
  Sequencing: receive disabled, send disabled
  VC statistics:
    packet totals: receive 500, send 10
    byte totals:   receive 56000, send 1820
    packet drops:  receive 0, send 0

Router2#

Strangely enough - the pseudowire still works with the VC down:

Router2#ping mpls pseudowire 172.16.16.101 140
Sending 5, 100-byte MPLS Echos to 172.16.16.101,
     timeout is 2 seconds, send interval is 0 msec:

Codes: '!' - success, 'Q' - request not transmitted,
       '.' - timeout, 'U' - unreachable,
       'R' - downstream router but not target,
       'M' - malformed request

Type escape sequence to abort.
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms
Router2#

Nothing found in the release-notes. Hints are appreciated.

Cheers, /Rene