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CCNA, Route Summarization with RIP

I'm studying CCNA. The following setup does actually build RIP routes without problem. All 3 routers I typed following commands;

Config t
Router Rip
Network 172.16.0.0

I'm confused. How does this work when all 3 routers have different subnets, but having same same rip network statements with the same summarized network? I thought summarization is for combining routes of next hop's IP network, not router's for 2 or more hops away.

Can someone clarify it?
rip-sum.jpg
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Cyclops3590
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First off, you didn't specify "version 2" so with RIPv1 there's no summarization, everything is classful.

Second, RIP configuration, no matter version, is always configured with classful network statements.  A network statement just says two things
1) Turn on RIP for any interface with an IP that is in that classful network
2) Announce the connected route for the interface that RIP gets turned on

So while you have three routers and three different subnets, it'll work because of the above.  keep in mind RIPv1 doesn't do mask info which is why its never really used anywhere.  do a "sh ip route" to confirm what all you have.  ripv1 has issues depending on your exact ip scheme you use within your network

summarization is great when you have a nicely designed network with a hierarchical structure as to its IP scheme.

For example.  Let's say you have 10.0.0.0/8 space to assign.  You have 5 sites.  You assign as such.
10.1.0.0/16
10.2.0.0/16
10.3.0.0/16
10.4.0.0/16
10.5.0.0/16

Now you won't have each site be designed with a single subnet that can hold 65534 hosts.  That's just ludicrous and asking for problems.  That /16 space will be in turn divided further at that site as each site pleases.  However, If you're a host on 10.1.200.0/24 and want to get to 10.5.20.0/24.  Your gateway has not need to know the specific route to the /24 as anything in the 10.5.0.0/16 will go to site 5.  As such, you configure summarization so that site 5 only announces that one route.  This help keep the routing table smaller so less memory is used as well as routing decisions can be made faster.

so if you want yours to work type the following in the router rip

version 2
no auto-summary
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"1) Turn on RIP for any interface with an IP that is in that classful network
2) Announce the connected route for the interface that RIP gets turned on"

So, since rip is classful, the summarization network statement is correct for 3 routers having the same network statement.
As long as most distant network is less than max hop 15, then I may assume RIP can deliver frame with its learned routes. So, let's say if 13 routers are all connected horizontally, then with same single statement 'network 172.16.0.0', all 13 routers will populate rip routes correctly. Correct?
Reading your statement again, without 'version 2' statement, the 3 routers populate all routes correctly. PC0 can ping PC2, which means, summarization works with RIPv1. Why?
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It makes sense. So, RIP is always classful, user doesn't have to care about how it collects routes as long as it's inside max hop counts.
Always is a strong word. :-)

It's classful when discussing the network statement in the configuration.

But with RIP version 2, the updates are not technically classful (if auto-summary is disabled).