Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

Dial backup to central router

I am trying to provide dial-backup facility for 150 remote branches at the central router using NM-30DM modem module.

Since the modem module has 30 lines, I can have a pool of 30 IP addresses

at the central site for dial backup.

As the remote branches are devided in to 4 OSPF areas, I have to devide the central IP pool for dial backup also in to 4 groups and has to be dedicated one pool for each area. So a pool can have only 7 IP addresses to support 40 branches.

Is there any way that I can still have one single IP pool for dial backup and to support 4 OSPF areas ?

2 REPLIES
New Member

Re: Dial backup to central router

Two things you might want to try:

Allocate 4 subnets, one to each OSPF area. Each subnet will have enough host addresses to allocate one address per box in that area. This way you will not need to setup a pool at all. make one dialer interface per area.

or

Setup a few loopback interfaces, one per area and get your branches to connect using IP unnumbered. This method may break any summarising you may be doing only during dial-backup. Alternatively if you use loopbacks in Area 0, you won't have the above issue.

have fun...

New Member

Re: Dial backup to central router

Many thnaks for the reply.

I just need to clarify on the second method. ( I actually do not understand the

first method).

I believe that the config for the second method would look like this;

!

Interface group asynch 1

IP unnumbered loopback 0

no peer defalut IP address

group range 1 30

!

Here I have to assign entire range of lines ( 30 lines for 30 modems) in to a single asynch interface. Then I can only assign one loopback address for the interface. Therefor eI will not be able make use of more than one loopbacl addresses ?

83
Views
0
Helpful
2
Replies