RE: mpls l2vpn between 2 asr901's

Hey guess what, I got a very sharp cisco tac engineer on the phone and he
was able to find a fix

The other day I couldn't get ospf to work between the asr901 and
9k...actually it worked for a moment then stopped...it was sort of weird.
So I resorted to a static default route.

The tac eng didn't think that mpls would work with a static default, as he
mentioned that labels will need to bind to specific underlying igp
prefixes...(I wondered what the global command "mpls ip default-route" was
for but not sure I got a good answer out of that) so he proceeded to do what
I did the other day...turn up ospf. We did enable ospf and we got neighbor
state up and routes and labels in lfib (sho mpls for) but all labels said
"no label" . strangely, the 9k didn't have a route to the loopback address
of the 901. The asr9k when doing "sh ip ospf dat router (ipaddress of
asr901) it should at top of display something about "router not
reachable"....he added ip ospf net point to point to the gige interface of
the asr9k and the svi of the asr901 and BAM it worked.

The link between 9k and 901 is a /30. I didn't know you had to use ip ospf
point-to-point on Ethernet links addressed as /30's ?! anybody ever seen
that before?

This 9k was running xr 4.1.2

However the other side of the l2vpn (9k_b and 901_b)I had same hardware BUT
that 9k was running xr 4.0.1...I DIDN'T have to do that ip ospf net p-to-p
trick and it just worked on this side. Why the different behavior? Xr
version ?

Ce_a-----901_a-----/30----9k_a----/30-----9k_b-----/30-----901_b-----ce_b

Aaron

p.s. I did see that YOU MUST have link up/up on AC (attchement circuit)
going from pe to ce or the PW will NOT come up. I read it online last night
and saw it first-hand today....after it all got working I shutdown ce_b gig
interface and the pw between asr9k's went down.

-----Original Message-----
From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
Aaron
Sent: Tuesday, March 27, 2012 10:29 AM
To: ccielab_at_groupstudy.com
Subject: mpls l2vpn between 2 asr901's

I'm not able to get the pw to come up between 2 different asr901's. anybody
know how?

I have the xconnects on the g0/0 interfaces that I wish to emulate L2
between on each side. I can ping the xconnect endpoint on each side. I
have an mpls (asr9k) network in the middle between the two 901's..the 901's
and 9k's do see each other as ldp neighbors..also after the xconnect is
config'd on the 901's I do see the targeted ldp session fireup between the
901's.

But "sho mpls l2 vc" and "sh xcon all" both show the pw portion ("segment2")
as DN (down)..the ac (segment1) on both sides is up.

Aaron

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Received on Tue Mar 27 2012 - 18:19:17 ART