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billyr wrote: » They both perform a similar function one being a bit more granular than the other. If you were to leave the auto-summary command turned on, any subnets you had would be summarized back to their nearest classful address. The ip summary address command applied on an interface allows you to summarize more accurately on a per interface basis. Lets say for example you had a router with the following 4 subnets directly attached: 172.16.0.0 /24 172.16.1.0 /24 172.16.2.0 /24 172.16.3.0 /24 If you were to leave auto-summary applied, these 4 subnets would be summarized back to the nearest classful network, or if you like the parent network that they all came from = the 172.16.0.0 /16 network. This advertisement would be sent through all your interfaces taking part in EIGRP by default. Workable but a very lazy way of subnetting as you are now unable to use any other subnet from the 172.16.0.0 network anywhere else in your organization apart from behind that particular router. What you could do instead is to use the no auto-summary command as recommended and to summarize your subnets manually grouping together only the 4 that you actually own. A manually summary for the 4 subnets above would work out as 172.16.0.0 /22. The IP Summary-Address command will allow you to apply the above manual summarization and to advertise this summary out on a per interface basis. e.g. int f0/0 ip summary-address eigrp 50 172.16.0.0 255.255.252.0
pham0329 wrote: » I'm confused...you're trying to summarize a /29 into a /30? Do you have anything connected to this router? If not, that's why the summary route isn't showing up.
solnsusie wrote: » yes!! I do know exactly what subneting means, I know it in middle of my sleep!!! and about summary, I do know what it is and how to configure it, but as I’m trying it out with this 2 commands, I’m getting confused!!! As you see it does the same with no auto-summary without ip summary-address then with ip summary-address, and it is connected to another router, and the configuration from above is from the networks connected to that router, does it look like i don’t know what I’m talking????
pham0329 wrote: » You should see it on both. The router sending the summary route will have an entry in its routing table for the summary route, pointing to Null0. The router receiving the summary route will have the summary router installed in its routing table, pointing to the originating router as the next hop. Can you explain your reasoning behind the ip summary-address eigrp 1 192.168.2.0 255.255.255.252 command? Why are you taking a /29 and "summarizing" it as a /30? Also, I'm assuming the other router is connected on the S0/0 interface, via the 11.1.1.0/30 subnet? In that case, there's no need for the 11.1.1.0 summary route.
pham0329 wrote: » Because you're summary route is the exact same route as what's already in the routing table. The summary address will only be used if you have more specific routes in the routing table. As I said, you may want to read up on route summarization because you seem a bit confused. If you want a summary route that would capture the 192.168.2.0 and 192.168.2.8, you would use ip summary-route eigrp 1 192.168.2.0 255.255.255.240 (not 248 )
solnsusie wrote: » that’s why I’m here, if i know exactly how it works i wouldn’t post my question here!!! so now i understand better the concept and i changed it to a /28, and my routing table looks like this, D 192.168.2.0/28 is a summary, 00:07:42, Null0 C 192.168.2.0/29 is directly connected, FastEthernet0/0.2 C 192.168.2.8/29 is directly connected, FastEthernet0/0.3 is it now correct?
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