Let A, B, C routers... and the interface IPs start with "198.30.30."
--[A]"78"-----"79"[B]"77"------"76"[C]---
I think 76,77,78,79 should all belong to the same subnet. How can they assign IPs like this?
One thing that came to my mind is that, this could be an ethernet conn. and all interfaces face the same switched network. Is that a correct approach? Is there a way to these 2 links in different networks?? There is no such thing as "/31" prefix... right?
Thanks in advance...
Yes, I believe Cisco does support /31 prefixes for point-to-point links. There's no need for broadcast addresses on these subnets.
I believe there was an RFC a few years ago that made this officially OK.
I don't know if that one is true. Cisco supports address-less p-to-p's. You assign no address and when you reference the serial interface for a route is automatically sends to other side with no need for IP routing/switching.
Since Cisco support no-ip-address on a link I'm not sure why they would bother supporting a /31 scheme, unless the no-ip-address isn't ratified beyond cisco.
Even without an RFC, I think with the right statics it could be made to work with no problems. Networking can be very broken and still work--not work well, but it will appear to pass SOME traffic.
DiGiTAL_ViNYL (no email)
Cisco does support /31. Check it out:
There are benefits to having unique IPs for each interface, rather than using "ip unnumbered". For instance, in a traceroute you can translate the IP to an interface, and you can ping specific interfaces to tell if they're up.
/31 addressing was created because many ISPs were using /30 for this, thus wasting half the addresses.
Guys, thank you very much...
Cabling-Design.com Forums website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.