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Question regarding: Routing -> OSPF -> Networks

Posted: Wed Apr 13, 2016 10:04 pm
by rg2
Hello,

I work at a WISP and I am routing the network that is currently in bridge mode.

I have available a /22 network and I managed to aggregate each POP with appropiate network size using best pratices. Each POP have the required network size, like /25, /26, etc depending on quantity of costumers and expected growth rate. Please see the picture below:
example.jpg
All routers and costumers have public addresses (I kept wireless equipment using private addresses).

My question is: When configuring each router's OSPF, should I configure the "Networks" using each POP's network's (/25, /26, etc) or I can use the entire aggregated network (/22) on all routers?

Thanks!

Re: Question regarding: Routing -> OSPF -> Networks

Posted: Wed Apr 13, 2016 10:54 pm
by StubArea51
Using the exact mask length will work and using an aggregate will work. However, it's considered a best practice to only allow the specific mask you need advertised to keep from trying to form neighbors on a misconfigured interface, or advertising a subnet inadvertently.

Re: Question regarding: Routing -> OSPF -> Networks

Posted: Wed Apr 13, 2016 11:02 pm
by rg2
Using the exact mask length will work and using an aggregate will work. However, it's considered a best practice to only allow the specific mask you need advertised to keep from trying to form neighbors on a misconfigured interface, or advertising a subnet inadvertently.
Thanks! So I will configure the exact Networks that are actually being used on each Router. Thanks for the fast reply!

Re: Question regarding: Routing -> OSPF -> Networks

Posted: Thu Apr 14, 2016 4:44 pm
by rg2
Hi,

I was thinking about a problem I could have migrating from bridge to OSPF... please take a look at the topology example I posted in my original post.

All those POPs have Mikrotik Routerboards, where I will apply OSPF. But they currently have all ports attached to a bridge (because currently my network runs on bridge).

If I start to configure OSPF before removing the interfaces from the bridge, all routerboards will be neighbors with each other... right? Do I have to configure the firewall on each routerboard to not forward OSPF discovery packets? Or this will not be an issue?

Thanks!

Re: Question regarding: Routing -> OSPF -> Networks

Posted: Fri Oct 27, 2017 7:35 am
by 43north
What did you end up finding out on this when you switched it to a routed network?