Routing

Hello all,

I am having an issue with certain vlans not routing across my OSPF area. I have inherited 2 stacks of EX switches: My core is EX4300 and the other two stacks are EX4200. OSPF area 0.0.0.0 is shared across all stacks and the switches are connected via fiber. For the most part everything is routing fine but I have 1 vlan (16) that originates on the core that I cannot get to route across OSPF, please see attachment.

I need to be able to have clients in vlan 16 on stack 2 route back to stack 1 to communicate with clients attached to that stack. Any help would be greatly appreciated and please let me know if any further information is needed.

Attachment(s)

OSPF.txt   1 KB 1 version

Hello,

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@cole0424 wrote:

Hello all,

 

For the most part everything is routing fine but I have 1 vlan (16) that originates on the core that I cannot get to route across OSPF, please see attachment.

 

I need to be able to have clients in vlan 16 on stack 2 route back to stack 1 

 

 

 

 

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You don't have any L3 interfaces on "Stack 2" in VLAN 16:

> show configuration vlans
Voice {
    vlan-id 16;
}

You'd need to have:

> show configuration vlans
Voice {
    vlan-id 16;
l3-interface vlan.16;
}

HTH

Thx

Alex

I can ping vlan 16 hosts froom the cli of stack 2 but when I add the l3 interface the connectivity drops. What could be causing that to happen?

Currently the Vlan 16 subnet is showing in the routing table and in the ospf route. I do not understand why the hosts on stack 2 cannot communicate with the hosts on stack 1. Please let me know what other information I can provide.

It seems that you have layer 3 separation between your 2 switch stacks. Is that correct? If so are the hosts on VLAN 16 on STACK1 on different subnet to those on STACK2?

Yes there is l3 separation between the stacks. The Stacks are connected via redundant fiber ports that have their own subnet and are a part of ospf area 0.0.0.0. The links connecting the stacks are not memebers of any vlans and are not configured as trunk ports. This confused me when I came aboard because all previous expirence utlized trunk links to connect switches. I am assuming it is not necessary because of ospf. All of the hosts in Vlan 16 share are in the same subnet.

If I understand this correctly you have the 172.40.1/24 network on both switches, separated by a layer 3 network, 192.168.30.16/29. This means you have the same network in two places which means at least one of them will not work. You will either need to connect the two switches at layer 2 to extend the 172.40.1/24 network from one switch to another, or change the prefix for VLAN 16 on one of the switches. 

VLANs are only locally significant unless you are connecting with trunk links.

There is nothing wrong with setting a point to point link to connect two switches together provided they are not expected to share layer 2 dowmains. This would be considered a routed network rather than a switched network.

Thank you for this. I was thinking that this would be the case but hoping I was missing something that might enable the 172.40 vlan to be routed across without trunk links or a physical connection.