[c-nsp] MPLS xconnect with a WS-C3850 switch?

[Shawn L]

I have an interesting one that I'm trying to figure out.  I have TAC case
open, but they've been slow to respond to say the least.  Wondering if
anyone else has ever run into this.  I have a simple MPLS xconnect between
2 ASR-920 routers running EIGRP.  When I insert the 3850 in between them,
the xconnect comes up, but doesn't actually pass data.  The 3850 has MPLS
enabled and sees the routes, etc.  but doesn't seem to actually be passing
the traffic.

Feed --- 920_1 ----- 3850 ------ 920_2 ----- destination

920_1# sh mpls l2transport vc

Local intf     Local circuit              Dest address    VC ID      Status
-------------  -------------------------- --------------- ----------
----------
Te0/0/1        Ethernet:1                 10.10.0.6       10         UP


If I pull the 3850 out of the mix and connect the ASR920 routers together,
the xconnect comes up and passes traffic as I would expect.  All of the
routes look fine, the 2 ASRs can ping each other, etc.  But when I look at
the traffic counters, I see both sides transmitting, but never receiving
packets.  According to the docs, the 3850 does support MPLS, and I do have
(or at least should have) the appropriate license.  It seems like I'm
missing something, but I can't seem to figure out what that is.


Important parts of the config

920_1 (other side is the same, with different IPs).
interface TenGigabitEthernet0/0/0
  description Uplink to 3850
  mtu 9198
  ip address 10.10.0.2 255.255.255.252
  mpls ip
interface TenGigabitEthernet0/0/1
  description Text Crossconnect
  service instance 1 ethernet
    encapsulation untagged
    xconnect 10.10.0.6 10 encapsulation mpls

3850
ip routing
mpls label protocol ldp
system mtu 9198
interface TenGigabitEthernet1/0/1
   description Asr920_1
   no switchport
   ip address 10.10.0.1 255.255.255.252
   mpls ip
   mpls label protocol ldp
interface TenGigabitEthernet1/0/2
  description Asr920_2
   no switchport
   ip address 10.10.0.5 255.255.255.252
   mpls ip
   mpls label protocol ldp