Tim Donahue wrote:
recv_dd_description: invalid MTU 1500 sent by neighbor ID 10.4.64.3, expected 1496
This is your problem. Your physical interface driver doesn't understand frames that are 'slightly' larger than 1500 (baby giant). Frames are increased by 4 bytes when they have 802.1q tags prepended to them. Since the driver/card doesn't understand them, the vlan(4) driver creates itself with a reduced MTU so that it is able to function. If memory serves, there is a warning at the time it is created. MTUs must match for OSPF for form adjacencies. Easiest thing is to use a card/driver that knows about baby giants. Your vlan interfaces will then be created with MTUs of 1500 and that will match the other devices on your network. If you are unsure, you can grep around for 'IFCAP_VLAN_MTU' in the driver source code. Most fxp/bge/nge/em/sk cards should be good. Some vr/rl will work as well. What is the other interface on the box? You could reduce the MTU on the other routers, but that is a hack. Get a real card/driver and you will be set. cheers, -- jason
