MPLS over GRE, sending but not receiving

Nicholas Peet · ‎04-22-2016

Hi,

Currently trying to setup a layer 2 bridge over the internet between 2 6504's. For testing I have setup a GRE tunnel and then using xconnect with MPLS over this. Show mpls l2 vc, shows up and is showing that it is sending on both ends but is not receiving on either end.

SNBRIDGEMKRT01#show mpls l2 vc detail
Local interface: Gi3/2 up, line protocol up, Ethernet up
Destination address: 10.10.250.1, VC ID: 2222, VC status: up
Tunnel label: imp-null, next hop point2point
Output interface: Tu0, imposed label stack {17}
Create time: 01:03:48, last status change time: 00:53:02
Signaling protocol: LDP, peer 10.10.250.1:0 up
MPLS VC labels: local 16, remote 17
Group ID: local 0, remote 0
MTU: local 1500, remote 1500
Remote interface description:
Sequencing: receive disabled, send disabled
VC statistics:
packet totals: receive 0, send 5450
byte totals: receive 0, send 409612
packet drops: receive 0, send 0

I am confused why this is not working and dont know if I am missing something. Has anyone seen this before and would they be able to give me some pointers

Kind Regards

Nick

Philip D'Ath · ‎04-23-2016

You don't need MPLS to do this, just simple IP.

Here is the jist of a config from one router that I do this with.

l2tp-class hamliton
 hostname l2tp
 password xxx

pseudowire-class pw-ak-hn
  encapsulation l2tpv3
  protocol l2tpv3 hamliton
  ip local interface Tunnel1

interface Tunnel1
 ip address 10.255.255.1 255.255.255.252
 ...

interface GigabitEthernet0/1
 xconnect 10.255.255.2 1 encapsulation l2tpv3 pw-class pw-ak-hn

Nicholas Peet · ‎04-25-2016

Hi,

I have set the L2TPv3 up on some 3845's but they are not quick enough. Unfortunately the 6504's dont have L2TPv3.

Nick

Philip D'Ath · ‎04-25-2016

L2TPv2?

Nicholas Peet · ‎04-25-2016

Just has the mpls encapsulation for xconnect. So have a GRE tunnel over WAN and then establish the mpls xconnect over that, it connects and both ends send but neither if them receive.

Nick

COncrete · ‎11-07-2023

Did you ever figure this out. I've ran into the same thing where if I build an xconnect over physical MPLS interfaces it works. But if I do it over a GRE tunnel I get one way traffic only. Interface stats are like yours where I see have send stats but no receive on one side.

Like you I'd love to use L2TP but it isn't supported on cat9ks.