From: Tharaka Kariyawasam (tharakak@dini.net)
Date: Wed Apr 11 2007 - 19:29:42 ART
Hi,
You can also use "system mtu routing 1500" , see the following sample
config. This will only effect "routed" traffic, so I believe dot1q tunnels
can still forward large packets (=1500) with the "metro" tag.
Rack1SW1#show ip ospf nei
Neighbor ID Pri State Dead Time Address Interface
150.1.1.1 1 EXSTART/BDR 00:00:37 192.10.1.1
FastEthernet0/1
Rack1SW1#
Rack1SW1#sh run int fa0/1
Building configuration...
Current configuration : 109 bytes
!
interface FastEthernet0/1
no switchport
ip address 192.10.1.2 255.255.255.0
spanning-tree portfast
end
Rack1SW1#
20:05:55: %OSPF-5-ADJCHG: Process 1, Nbr 150.1.1.1 on FastEthernet0/1 from
EXSTART to DOWN, Neighbor Down: Too many retransmissions
Rack1SW1#
Rack1SW1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
Rack1SW1(config)#system mtu routing 1500
Rack1SW1(config)#
20:06:55: %OSPF-5-ADJCHG: Process 1, Nbr 150.1.1.1 on FastEthernet0/1 from
DOWN to DOWN, Neighbor Down: Ignore timer expired
Rack1SW1(config)#
20:07:04: %OSPF-5-ADJCHG: Process 1, Nbr 150.1.1.1 on FastEthernet0/1 from
LOADING to FULL, Loading Done
Rack1SW1(config)#
Rack1SW1(config)#do sh ip ospf nei
Neighbor ID Pri State Dead Time Address Interface
150.1.1.1 1 FULL/BDR 00:00:36 192.10.1.1
FastEthernet0/1
Still the system MTU is 1504,
Rack1SW1(config)#do sh int fa0/1 | in MTU
MTU 1504 bytes, BW 100000 Kbit, DLY 100 usec,
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Mohamed Radwan
Sent: Sunday, April 08, 2007 9:09 AM
To: ccielab@groupstudy.com
Subject: OSPF stuck in Exstart phase -- due to MTU mismatch --
Hello everybody,
I am facing a problem with ospf neighbor to established the neighborship is
stuck in Exstart phase and when I debug it . if found the problem with MTU
between a router and switch here is the ropology SW1 --- R1
r1(config-if)#mtu 1504
% Interface FastEthernet0/0 does not support user settable mtu.
SW1#sh int fa0/1 | in MTU
MTU 1504 bytes, BW 100000 Kbit, DLY 100 usec
R1#sh int fa0/0 | in MTU
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
any ideas?
Thanks
This archive was generated by hypermail 2.1.4 : Tue May 01 2007 - 08:28:35 ART