The MPLS-OPS Archive[Date Prev][Date Next][Thread Prev][Thread Next] [Date Index][Thread Index][Author Index][Subject Index] Re: MPLS & Path MTU problems
Check what MTU size is advertised by your LDP protocol (show mpls forwarding-table X.X.X.X. detail) Regards, Krzysztof Szarkowicz ----- Original Message ----- From: "Donn Lasher" <dlasher@clearskynet.net> To: <mpls-ops@mplsrc.com> Sent: Thursday, February 21, 2002 8:26 PM Subject: MPLS & Path MTU problems > > I've read all the MPLS-OPS archives on this issue, and tried the fixes, and > I'm still seeing a problem. > > two 3620's running 12.2.6, hooked to a 3524 switch. Multiple MPLS/Dot1Q > vlan's off both routers. When traffic passing through these routers from a > customer to a site blocking PMTU discovery(nice long list any more), it all > the traffice appears to the customer to be blackholed. > > ip icmp debug shows: > > Feb 20 22:39:11 X.X.X.X 5813: 3w5d: ICMP: dst (X.X.X.X) frag. needed and DF > set unreachable sent to 216.221.138.92 > Feb 20 22:39:12 X.X.X.X 5815: 3w5d: ICMP: dst (X.X.X.X) frag. needed and DF > set unreachable sent to 216.221.138.92 > > At the moment I'm applying a route-map to clear df bit on my NSP connected > router, but that's a hack. I'd really like to find and solve the real issue. > > Ethernet MTU is 1500. tag-switching MTU unset (defaulting to 1500) > tag-switching ip set on all interfaces > > I've tried setting the tag-switching mtu to 1540, making sure the switch > was set mtu 2018, didn't make any difference. > > Thanks in advance for any help. > > > > ------- > The MPLS-OPS Mailing List > Subscribe/Unsubscribe: http://www.mplsrc.com/mplsops.shtml > Archive: http://www.mplsrc.com/mpls-ops_archive.shtml > > > ------- The MPLS-OPS Mailing List Subscribe/Unsubscribe: http://www.mplsrc.com/mplsops.shtml Archive: http://www.mplsrc.com/mpls-ops_archive.shtml
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