The dot1q header adds 4 bytes to the frame, making a frame of 1522 possible. If you set that incoming L3 interface MTU to 1496, that should do it. Assuming PMTUD is working right.
Chuck -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Comm-AG Sent: Tuesday, October 09, 2007 6:55 AM To: 'Brian Turnbow'; [email protected] Subject: Re: [c-nsp] Catalyst6506 w/ sup1amsfc2 & 6148-ge-tx large packetsaredropped Brian, Thanks for your input. Can you suggest a work-around for the problem that I am having....should I set the MTU lower on the incoming L3 interface ? At this point, all applications which send large packets (1500 bytes) are failing Rgds, Anthony -----Original Message----- From: Brian Turnbow [mailto:[EMAIL PROTECTED] Sent: Tuesday, October 09, 2007 5:56 PM To: Comm-AG; [email protected] Subject: RE: [c-nsp] Catalyst6506 w/ sup1amsfc2 & 6148-ge-tx large packets aredropped The 6148 supports up to 1518 frame size , the 6148A does 9216. This may be your problem Regards Brian -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Comm-AG Sent: martedì 9 ottobre 2007 9.22 To: [email protected] Subject: [c-nsp] Catalyst6506 w/ sup1amsfc2 & 6148-ge-tx large packets aredropped Hi, I have a problem isolated to 6148-ge-tx line-card. The line-card connects a number of service provider connections. When large packets are switched between different ports on the same card, large packets are dropped. The problem has become apparent since our international service provider (call it T-Systems) upgraded their CE router and required us to run dot1q on the 6148-ge-tx interface. Since then, all traffic switched from other sources to the T-Systems port has this problem where large packets are dropped. If we move services to another card leaving the T-Systems connection as it was, the problem goes away. Any help would be appreciated. Thanks Anthony _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/ _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/ _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
