IP Address Strategy for Serial Interfaces

[Iota]

Greetings, I'm in the process of linking up remote sites via T1s and was curious how I should number the Serial Interfaces. Currently, there are 3 routers, but more are coming.

Our core router is a 3640 and its connecting to a 1700 and a 2600 series router. I've decided to allocate 10.0.0.0/24 as network for my serial interfaces on the routers. The question is, should the serial interfaces in the same Area be on the same logical network, or should I subnet them into /32s so there is a private network between each serial interfaces.

I'm going to enable OSPF and will also need to setup DHCP relays on the end routers. All the example I've seen show the Serials in the same Class C, but that seems like unnecessary broadcast traffic would hit the T1s.

Any thoughts, suggestions?

 

[ccie9545]

if you are going to be using OSPF then you could set them up as /30. /30 will allow two valid IP host addresses per subnet, perfect for a point-to-point link.

One reason that you might use /24 on serial point-to-point link would be to ensure routing updates are properly advertised if using a protocol that doesn't support VLSM....(i.e. RIPv1, IGRP). Erik Rudnick, CCIE No. 9545
mailto:erik@kuriosity.com