hope somebody can help me with my problem. I have a cisco 7206VXR(IOS: C7200-IK9S-M 12.2(15)T1) on one site and cisco 2691(IOS: C2691-IK9S-M 12.3/17b)) on the other site. There are tunnels established on 2691 to 7206VXR through a service provider network where MTU size is 1500. MTU size on 2691 and 7206VXR are ajusted and work fine. Now we installed a cisco 2811(IOS: C2800NM-ADVIPSERVICESK9-M 12.4(9)T1) and we have to downsize the MTU size to lower size than on 2691. Can anybody tell me why? Is it the model or is there a problem with the newer IOS?
Thanks in advance for your help.