question about OSPF routing on 3750 & 3550 switches

crtplague

I have a question about ospf routing on Cisco 3750's & 3550's. Two 3750's connected via ether channel over ports G8/G9. I have OSPF configured on the two 3750s and they route across to each other no problem. I also have ports G5/G6 on each 3750 going to a 3550 switch (again via etherchannel). When I do a "sh ip int brief" on the 3750 I can see that both ports G5/G6 are in up - up status. Same results when I run "sh ip int brief" on each of the 3550s. OK, looks like layer 2 is up and running. I'm trying to use OSPF to do the routing between the 3750s & 3550s.

The output of the 1st 3750 shows:

VoIPSwitch1#sh ip int brief
Interface IP-Address OK? Method Status Protocol
Vlan1 unassigned YES NVRAM administratively down down
Vlan10 192.43.169.202 YES NVRAM up up
Vlan20 192.43.169.212 YES NVRAM up up
Vlan21 192.43.169.228 YES NVRAM up up
Vlan22 192.43.169.244 YES NVRAM up up
Vlan23 192.43.170.4 YES NVRAM up up
GigabitEthernet1/0/1 unassigned YES unset up up
GigabitEthernet1/0/2 unassigned YES unset down down
GigabitEthernet1/0/3 unassigned YES unset down down
GigabitEthernet1/0/4 unassigned YES unset down down
GigabitEthernet1/0/5 unassigned YES unset up up
GigabitEthernet1/0/6 unassigned YES unset up up
GigabitEthernet1/0/7 unassigned YES NVRAM down down
GigabitEthernet1/0/8 unassigned YES unset up up
GigabitEthernet1/0/9 unassigned YES unset up up
GigabitEthernet1/0/10 unassigned YES unset down down
GigabitEthernet1/0/11 unassigned YES unset up up
GigabitEthernet1/0/12 unassigned YES unset administratively down down
Port-channel1 unassigned YES unset up up
Port-channel2 10.8.255.253 YES NVRAM down down
Loopback0 10.152.255.1 YES NVRAM up up

_____________________

The output of the 3550 that's connected to it via etherchannel ports G5/G6 show:

3550-switch1#sh ip int brief
Interface IP-Address OK? Method Status Protocol
Vlan1 unassigned YES NVRAM administratively down down
Vlan30 10.8.93.10 YES NVRAM up up
GigabitEthernet0/1 unassigned YES unset down down
GigabitEthernet0/2 unassigned YES unset down down
GigabitEthernet0/3 unassigned YES unset down down
GigabitEthernet0/4 unassigned YES unset down down
GigabitEthernet0/5 unassigned YES unset up up
GigabitEthernet0/6 unassigned YES unset up up
GigabitEthernet0/7 unassigned YES unset down down
GigabitEthernet0/8 unassigned YES unset up up
GigabitEthernet0/9 unassigned YES unset up up
GigabitEthernet0/10 unassigned YES unset down down
GigabitEthernet0/11 unassigned YES unset up up
GigabitEthernet0/12 unassigned YES unset down down
Port-channel1 unassigned YES unset up up
Port-channel2 unassigned YES unset up up
Loopback0 10.8.255.3 YES manual up up


I'm trying to get OSPF to route from the 192.43.169.202/29 network on the 3750 to the 10.9.93.10/24 network on the 3550. Is it possible to do this without adding another vlan on the 3550 in the 192.43.169.x/29 network?

mikej412

Do you have a network in common? Is that Port-channel2 @ 10.8.255.253 on the 3750 pingable from the Loopback0 @ 10.8.255.3

If you don't want to add or change anything on the 3550, how about an SVI and VLAN30 on the 3750?

You could always try ISIS between a couple of the SVIs and route redistribution.

crtplague

Hi, Thanks for your response. No, I could not ping Loopback0 @ 10.8.255.3. I guess my problem was the I did not have both of the port-channel 2 groups on each switches in the same network. I gave them both valid IPs and put them both on a /30 subnet and configured ports G5/G6 for "no switchport" & also configured the port-channel 2 interface for no port-group & no switchport. After this I did a "clear ip ospf process" on both switches and it started routing layer 3. Basically, port-channel 2 was set up for layer 2 and not layer 3.

When first I tried reconfiguring the channel-group 2 mode on the G5 interface it gave me this message:

VoIPSwitch1(config-if)#channel-group 2 mode desirable
Command rejected (Port-channel2, Gi1/0/5): Either port is L2 and port-channel is L3, or vice-versa.

Also, when I was trying to unconfigure ports G5/G6, I was running the "no switchport" command first. I guess I need to do this command AFTER I run "no port-channel" & "no port-group" (in this order). I was not aware I had to do the commands in that order.

I've been working with 2950's & 2924's WAY too long. The 3750's & 3550's are a whole different ball game.