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Community Member

NM-30DM with OSPF

I have NM-30DM at central router, to use as a dial backup device for lased lien connected branch routers ( about 150 branches).

Here I have pool of modems to share with all the branches assuming maximum of 30 concurrent link failures.

These branch routers are divided in to several ospf areas for better profomance.

Is there any example of assigning addresses for the backup line pool at central site to share these lines by all of the OSPF areas ?

Cisco Employee

Re: NM-30DM with OSPF

There are no specific examples like that. But you can configure the static ip addresses to be allocated for the branches during dialin and include them accordingly under ospf to maintain the routing connectivity.

Community Member

Re: NM-30DM with OSPF

Thanks for the answer.

My question is, when I am assigning static routes to the backup links, the ip addresses at the ends of the backup link need to be in the same subnet. But I do not have 1:1 mapping of the number of the modems at the head office.

for example I may have 30 modems at head office to serve 120 branches. Then the approach that I can see is to group the modems so that one modem is serving 4-5 branches. Once a modem is allocated to a set of branches, it allocated for exclusive use of those branches. It cannot be used by a branch belongs to another group.

Q1.Is there any other way that I can efficiently make use the pool of modes ?

Q2.Can I use IP unnumbered on backup links ?

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