Loopback0 advertise between neigbors

[alex_comms]

Hello everyone!

This is my first topic in this forum. First of all, thank you everyone for your time answering to our doubts.

The explanation about the project:

I have to modify the configuration between 5 facilities connected trough 10 switches, 2 switches in each facility. At this moment these are working using OSPF, but due to some changes in the topology this configuration (OSPF) will be deprecated.

These facilities are not close between them, several kilometers between each. I need to deploy a way to be connected remotely with the switches, without losing connectivity while I turn off the OSPF and re-configure the switches.

My idea is to configure a Loopback0 in each switch and use this to connect from one of the switchs to the other ones. But, I have serious doubts about this. I have read the CLI reference guide to understand what I should do, but It is not clear for me.

Here the question:

What should I do to have connectivity between the switches using the Loopback0? Have I to configure RIP to be able to connect between them or It is not necessary? The LLDP will advertise automatically the management IPs between the switch without configure anything else?

Finally:

I do not have the possibility to do a test in a laboratory. I have to do that over the production systems so I need to have this absolutely clear to avoid unnecesary disconnections.

I would really appreciate your help.

Thank you.

Regards,

[silvio]

Loopback0 is very useful if OSPF or RIP etc. is active. If there are f.e. two ways to a remote switch OSPF will automaticly send the way to the Loopback0 interface via one of them. It is good - but not your best solution during the re-configuration.
If the ip connectivity (transfer networks) between the switches are all the time active and only OSPF will be deactivated, than you only need another routed way: static (or RIP). When OSPF is successfull running after your work you can delete f.e. the static routes.
But also there are other ideas: if possible (depends from the connection between the facilities) you can setup an overlay vlan (tagged) with extra ip interfaces. You should configure than only one way to (no redundance) to avoid loops.
Also you can ssh f.e. to the last possible switch and start from there a ssh session to the neighbor (no routing necessary).
best regards
Silvio

[alex_comms]

Hello Silvio,

Thank you for your answer. To create a new VLAN ID was my first option, but I guess that Loopback0 will be more easy.

So, I will create a new VLAN same ID on each SW, these are sequentially connected without stack or physicall redundancy. I will configure a new "ip interface", with a network quite different of local networks inside the OSPF, on each switch involved. Finally, I will add the VLAN tagged to the interconnection interfaces between the switches.

I suppose that with this configuration, as you have said, I can configure "quietly" the switches without loosing connectivity.

Let me know If I forget something.

Best regards,

[silvio]

sounds correct. You can test all the connections before disabling of OSPF.
BR Silvio