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 pro 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 >> >> >
