What does the RIP Subnet Summary DO??

[mroberts]

Can anyone tell me what the RIP Subnet Summary does? I see where you may enable and disable it but what does it accomplish exactly??

MRoberts

http://www.a1teletronics.com

 

[3Sixty]

RIP stands for routing internet protocol. If you want more info have a look at the cisco website.It works a bit like this the BCM or router sends a request out to the network. Providing all the other routers are using RIP the routers will reply with there IP address and the BCM or router will populate the routing tables. It saves you having to configure static routes.

Marshall

 

[mroberts]

Thanks for the reply.... I know what RIP routing is.... what I was curious about is the RIP Subnet Summary Page. Being able to disable it and re-enable it... What does it accomplish?



MRoberts

http://www.a1teletronics.com

 

[mroberts]

So in order for you to configure Static Routes (if you wanted to) you would have to disable the RIP Routing?

MRoberts

http://www.a1teletronics.com

 

[3Sixty]

You can use RIP and still configure static routes.

Marshall

 

[biv343]

Subnet summary can be used to keep the routing tables smaller, should you have multiple networks that can be "summarized" to the next host. Let's say you have two buildings connected via a WAN. Building A has 1 subnets - 10.10.1.0/255.255.255.0. Building B has four subnets, 192.168.1.0/255.255.255.252, 192.168.1.4/255.255.255.252, and 192.168.1.8/255.255.255.252 (we'll say those are WAN links), and 192.168.2.0/255.255.255.0, which is their LAN. Route summarization can advertise 192.168.1.0 and 192.168.2.0 in the routing table and RIP updates instead of sending 192.168.1.0, 192.168.1.4, 192.168.1.8 and 192.168.2.0 in the RIP updates. In theory, this helps keep the amount of traffic for the RIP updates to a minimum.

It can also come into play if using CIDR (classless interdomain routing, I think thats what it stands for) or supernetted networks.

Typically I leave summarization turned off (in both the Cisco and Nortel worlds), unless you are lucky enough to have totally different networks on both sides of the WAN. If you have 192.168 stuff everywhere, summarization can make life a bit more difficult.

Hope this helps, and more importantly I hope I got my facts right and didn't butcher this too badly.