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OSPF Configuration

SOLVED
Conversationalist

OSPF Configuration

We are configuring OSPF on new Meraki 425 Core switches tomorrow evening and would like to confirm if the below is an accepted viable configuration.


We have 2 x MPLS links, normally I would configure 2 x L3 point to point connections with associated costs. On this occasion I have been asked to do the following:

Network 10.100.100.X/28


The 2 x CPE's will be configured with 10.100.100.1/28 and 10.100.100.2/28 in OSPF area 0



On the Meraki Core switch stack I have been asked to configure the following:



1. Create a single L3 interface with IP 10.100.100.14/28 in an associated VLAN
2. Enable OSPF area 0 and add the created L3 interface
3. Put 2 x switch ports into the VLAN, 1 switch port physically connected to each of the CPE's.


In the above configuration from the Meraki side the result will be a single L3 interface in associated VLAN with 2 physical switch ports in same VLAN (from the same stack) connected to different CPE's. I have 2 questions around this:


1. Is this configuration viable or likely to cause us problems?

2. Both ports connected to the CPE's would have the same local cost so we would be reliant on the inbound advertised routes to control outbound routing priority. Can you please confirm if this is the case?

 

Does anyone see any major problems with the above proposed configuration, apart from the inability to locally configure costs for each link?

 

Kind Regards,


Karl

1 ACCEPTED SOLUTION

Accepted Solutions
Kind of a big deal

Re: OSPF Configuration

>1. Is this configuration viable or likely to cause us problems?

It will work just fine.  Make sure the MPLS provider is using the "default" broadcast mode of OSPF and not the "point to point" mode.

https://www.cisco.com/c/m/en_us/techdoc/dc/reference/cli/nxos/commands/ospf/ip-ospf-network.html


>2. Both ports connected to the CPE's would have the same local cost so we would be reliant on the inbound advertised routes to control outbound routing priority. Can you please confirm if this is the case?

 

Sounds correct to me.

2 REPLIES 2
Kind of a big deal

Re: OSPF Configuration

>1. Is this configuration viable or likely to cause us problems?

It will work just fine.  Make sure the MPLS provider is using the "default" broadcast mode of OSPF and not the "point to point" mode.

https://www.cisco.com/c/m/en_us/techdoc/dc/reference/cli/nxos/commands/ospf/ip-ospf-network.html


>2. Both ports connected to the CPE's would have the same local cost so we would be reliant on the inbound advertised routes to control outbound routing priority. Can you please confirm if this is the case?

 

Sounds correct to me.

Conversationalist

Re: OSPF Configuration

Perfect thanks @PhilipDAth  🙂

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