From what I know RIPv1 is a classful protocol and RIPv2 is a classless protocol.
I have become confused though as I was using RIPv1 on my 2811 router and when I input the command, show running-config it states;
<**Lots of info**>
<**Lots of info**>
I noticed this line "ip classless", now why would this line be included in the readout? when I am using Ripv1?
I asked my tutor at uni and he was also unsure, does anyone have any ideas or theories?
Re: Classless and Classful, RIPv1 and RIPv2
10 years 5 months ago #28438
It can be quite confusing at the beginning. But it eventually sinks in. ip classless has a totally different job than what RIP or RIPv2 does.
ip classless affects the way routes are searched for when a packet arrives at a router. If ip classless is not configured (using the no ip classless command) then a packet will NOT be routed using a route that has a subnet mask less than the classfull mask of the packet's destination IP. For example, a packet with a destination IP address 126.96.36.199 (Class C, /24). Will be routed by a route like 188.8.131.52/28 and will be routed by a route like 184.108.40.206/24 BUT it will not be routed by a route like 220.127.116.11/22 or by 18.104.22.168/16. Since /22 and /16 are less than the classfull mask /24 (i.e super nets).
RIP and RIPv2 has no relation to this. RIP does not send subnet-masks during updates. It always assumes classful masks. RIPv2 sends subnet-masks. Thats why RIP is said to be classfull and RIPv2 is classless.
Thats as far as I know, any one, please correct me if I'm wrong.
It says that:
- It doesn't interfere with the way the routing table is built - the routing table is filled in the same way with or without this command: routing protocols supply routes with administrative distances/metrics, and the routing table chooses among them the routes with the best administrative distance/metric, to be used in the routing table
- It *does* interfere in the way the routing table is "read" to decide where to forward a packet, as explained by SOlo.