What exact commands did you add to get the MPLSoGRE working ? If you
remove them do the web traffic issues stop ? Is the traffic narrowed to
being dropped by the 7600 ?
Shimol
On 11/9/10 8:04 PM, Rettke, Brian wrote:
It appears that about half of our web traffic is now being dropped, so problems
continue. I'll have to double check MTU and TCP adjust-mss settings, but other
than that I have no idea. I've heard that there are some issues with MPLS using
some of the 67xx linecards, and apparently this is going to be a huge problem
for us.
________________________________________
From: Shimol Shah [shims...@cisco.com]
Sent: Monday, November 08, 2010 1:19 PM
To: nanog@nanog.org
Subject: Re: GRE Tunnels and MPLS
Good deal. Sounds like a plan.
Shimol
On 11/8/10 2:00 PM, Rettke, Brian wrote:
This seems to be working now with the 'mls mpls tunnel-recir' command entered.
There are some potential downsides, but this should get things up and running
until I create the new backup tunnels (GRE over IPSec) on a connected router
that is not MPLS-enabled. Thanks!
Sincerely,
Brian A . Rettke
RHCT, CCDP, CCNP, CCIP
Network Engineer, CableONE Internet Services
------------------------------
Message: 6
Date: Thu, 04 Nov 2010 16:49:55 -0400
From: Shimol Shah<shims...@cisco.com>
Subject: Re: GRE Tunnels and MPLS
To: nanog@nanog.org
Message-ID:<4cd31c73.80...@cisco.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Do you have recir enabled ? If not, good one to enable and check for
status of issue.
http://www.cisco.com/en/US/docs/ios/mpls/command/reference/mp_m1.html#wp1012208
"If you do not enable tunnel-MPLS recirculation, the IPv4 and
IPv4-tunneled packets that need to be labeled (for example, the packets
that are encapsulated with an MPLS header) will be corrupted when they
are transmitted from the Cisco 7600 series router."
Shimol
On 11/4/10 4:00 PM, Rettke, Brian wrote:
Beginning work on our implementation of MPLS for the backbone network. I've run
into difficulty with our GRE tunnels. The GRE Tunnel sits on our co-lo router
(a Cisco 7600), and it uses a route-map to push our 10.x modem traffic to our
DHCP servers. This is because the backbone is not complete and DHCP traffic
needs to traverse the internet. What I have found is that when I enable basic
MPLS on the co-location interfaces that head back to the individual systems,
DHCP traffic still works, but ICMP and other 10.x traffic dies. There is also
an intermittent problem with DHCP when it is enabled, where not all DISCOVERS
are answered. I've tried everything I can think of, including adjusting MTU and
TCP MSS. It only seems to impact when the co-location router has a GRE tunnel
on one buffer, which it terminates, and then it has to encapsulate traffic with
an MPLS tag before sending out of the other buffer. Theoretically, it should
work, but I can't figure out if there is some pr
o
b
lem with MPLS' interaction with the tunnel. Has anyone encountered something
similar?
Sincerely,
Brian A . Rettke
RHCT, CCDP, CCNP, CCIP
Network Engineer, CableONE Internet Services
