[j-nsp] L3VPN: Pinging CE from PE with larger packet size

[Harry Reynolds]

What's the mtu and encap on the ce facing interfaces?  If the default
1514 frame/1500 data, then a PE ping with size 1472, when combined with
IP and ICMP (28 bytes), yields the largest packet supported w/o frag.

You mention that you have enabled rsvp PMTU signaling and frag. Its not
clear what you mean by "solves problem but causes L2 packet drops". Are
these drops for the CE's described below, or for some other L2 service
that touches these PEs?

Thinking out loud, as RSVP is not enabled on the PE-CE facing
interfaces, its possible that RSVP PMTU signaling it not discovering the
1500 byte MTU on the CE links, and this prevents ingress PR frag, which
then causes loss. Not clear how enabling could/would break an L2
service.
 

 HTHs



> -----Original Message-----
> From: juniper-nsp-bounces at puck.nether.net 
> [mailto:juniper-nsp-bounces at puck.nether.net] On Behalf Of Salik Mobin
> Sent: Monday, March 05, 2007 2:31 AM
> To: juniper-nsp at puck.nether.net
> Subject: [j-nsp] L3VPN: Pinging CE from PE with larger packet size
> 
> 
> Dear All,
> 
> We have configured an l3vpn b/w two sites in the following topology:
> 
> [CE-A]----FE----[PE-A(M10i)]------E3------[PE-B(<10i)]----FE----[CE-B]
> 
> Although everything b/w CEs works well, we are unable to ping 
> CE-B from PE-A above packet size of 1472 Bytes. It is the 
> case with CE-A from PE-B also. We are not using PMTUD (rsvp 
> mtu-signalling) and even enabling it does not make change in 
> problem. Enabling "allow-fragmentation" under "path-mtu" 
> though solve this problem but it causes packet drops for l2circuits.
> 
> Do we need to re-confgure MTU some where? Default MTU for E3 
> interface is 4474.
> 
> Please suggest.
> 
> Regards,
> Mobin 
> 
> 
> _______________________________________________
> juniper-nsp mailing list juniper-nsp at puck.nether.net 
> https://puck.nether.net/mailman/listinfo/juniper-nsp
>