That is not the only option but is one of three.
In the 3560 you can apply the command Mtu system routing 1500 On a 3550 and 3560 you can say Int svi X Mtu 1500 Either of those options can also be used. Regards, Tyson Scott - CCIE #13513 R&S and Security Technical Instructor - IPexpert, Inc. Telephone: +1.810.326.1444 Cell: +1.248.504.7309 Fax: +1.810.454.0130 Mailto: [EMAIL PROTECTED] Join our free online support and peer group communities: http://www.IPexpert.com/communities IPexpert - The Global Leader in Self-Study, Classroom-Based, Video On Demand and Audio Certification Training Tools for the Cisco CCIE R&S Lab, CCIE Security Lab, CCIE Service Provider Lab , CCIE Voice Lab and CCIE Storage Lab Certifications. _____ From: Meraz, Richard [mailto:[EMAIL PROTECTED] Sent: Wednesday, July 16, 2008 11:02 AM To: Tyson Scott; [email protected] Subject: RE: [OSL | CCIE_RS] Vol Sect 5 Layer 2 Tunneling Protocol Thanks Tyson. So to be sure I got this correct (and to add on to a latter lab), if I do increase the MTU to say 1504, then my SVI will also be 1504, and therefore a router's interface, while running OSPF, will go down. If I'm correct in that statement, is my only option to fix my router to use ip ospf mtu-ignore if my MTU must stay at 1504 to support either L2 Tunneling or QinQ? _____ From: Tyson Scott [mailto:[EMAIL PROTECTED] Sent: Wednesday, July 16, 2008 7:53 AM To: Meraz, Richard; [email protected] Subject: RE: [OSL | CCIE_RS] Vol Sect 5 Layer 2 Tunneling Protocol It isn't required. You will notice the l2-tunnel will probably work without doing it. But it is best practice to increase the MTU to account for the extra header. Regards, Tyson Scott - CCIE #13513 R&S and Security Technical Instructor - IPexpert, Inc. Telephone: +1.810.326.1444 Cell: +1.248.504.7309 Fax: +1.810.454.0130 Mailto: [EMAIL PROTECTED] Join our free online support and peer group communities: http://www.IPexpert.com/communities IPexpert - The Global Leader in Self-Study, Classroom-Based, Video On Demand and Audio Certification Training Tools for the Cisco CCIE R&S Lab, CCIE Security Lab, CCIE Service Provider Lab , CCIE Voice Lab and CCIE Storage Lab Certifications. _____ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Meraz, Richard Sent: Tuesday, July 15, 2008 4:55 PM To: [email protected] Subject: [OSL | CCIE_RS] Vol Sect 5 Layer 2 Tunneling Protocol When we configure the switchport with the command l2protocol-tunnel to support CDP between BB1 and R1, do we also need to change the MTU size, or rephrased, does L2 tunneling between switches require an MTU change from 1500 to 1504? Thanks, Rich
