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typesh wrote: » See Page 218 - 221 in your ICND2 Book (and Page 215 "Route Summarization Strategies"). It's explained quite well in that section. Autosummarization happens at the classfull boundary. For example (on P. 219 of the Odom Book), Seville is connected to 10.3.4.0 10.3.5.0 10.3.6.0 10.3.7.0 When Seville advertises these routes to Albuquerque over their common 172.16.3.0 link, Seville advertises 10.0.0.0, meaning the entire 10.0.0.0 /8 range. With manual summarization you can create a summary route that more closely fits the subnets that are actually connected to Seville. Seville does not have the entire 10.0.0.0 /8 network behind it- just the subnets mentioned above. With manual summarization you can choose the summary to be advertised instead of having the router summarize at the classfull boundary. For example, the same subnets can be advertised as 10.3.4.0 255.255.252.0 which really means 10.3.4.0 - 10.3.7.255. With Autosummary, Seville tells Albuquerque "I know of the entire 10.0.0.0 network." However when using manual summarization, Seville says "I know about 10.3.4.0 /22."
DerekAustin26 wrote: » Very nicely explained! Now that chapter explains how to configure/enable Route Summarization but it doesnt show us how to configure/enable Autosummarization.... How do you configure Autosummarization?
typesh wrote: » Autosummary is on by default for RIPv2 and EIGRP.
DerekAustin26 wrote: » And RIPv1
typesh wrote: » Correct. However you cannot manually summarize with v1.
typesh wrote: » For RIPv2: Cisco IOS IP Command*Reference, Volume 2*of 3: Routing Protocols, Release*12.2 - RIP Commands [Cisco IOS Software Releases 12.2 Mainline] - Cisco Systems For EIGRP: Cisco IOS Release 12.0 Network Protocols Command Reference, Part 1 - EIGRP Commands - Cisco Systems Autosummary is on by default for RIPv2 and EIGRP.
DerekAustin26 wrote: » Okay so I tested this out on my virtual lab. I setup 2 routers On the 1st router I had 2 subnets. 10.2.1.0 & 10.2.2.0 (both with 255.255.255.0 as the mask) I configured rip on both the routers and setup the serial line and everything. When i was done, I went to Router 2 and entered "sho ip route" instead of showing the default autosummarization of "10.2.0.0" via the s 0/0 port it learned the routes from.. It showed both routes learned from Router 1's IP address.. Now if autosummarization were on by default with RIPv1, why didnt it show just 10.2.0.0 instead? I dont understand...
alan2308 wrote: » Even though RIPv1 is a classful protocol, if you have any connected networks within the classful boundary (10.0.0.0/8 in this case), the router will assume that same subnet mask for all routes within that classful boundary. Does router 2 have anything directly connected to a network within 10.x.x.x? And the summarization would be 10.0.0.0, not 10.2.0.0. The 10.x.x.x network is Class A.
typesh wrote: » What is the subnet of the link between the 2 Routers? Is it 10.x.x.x /24?
typesh wrote: » You wont see the Autosummarization because you have set it up as a Contiguous Network. Since the link between R1 and R2 are of 10.x.x.x /24, R1 will advertise the individual subnets. R2 assumes that the subnets described in R1s updates use the same /24 mask since R2 has an interface in the same classfull (10.x.x.x) network. Set the link between R1 and R2 to be 172.16.1.0/24. Also turn on debug ip rip and have a look at the entries.
alan2308 wrote: » And the summarization would be 10.0.0.0, not 10.2.0.0. The 10.x.x.x network is Class A.
typesh wrote: » This is what you're looking for: What is your output for debug ip rip on R2? Post your config for R1 and R2.
typesh wrote: » Post your debug output. Did you try running clear ip route * on R2?
DerekAustin26 wrote: » It's 10.1.1.0 - Router 1 is 10.1.1.1 & Router 2 is 10.1.1.2 Mask is 255.255.255.0
alan2308 wrote: » But your configs and debug say the link is 172.16.1.0. Did you change them? Then you may need to restart the RIP processes. Reloading both routers will do the trick. Then you should see something more in tune with what you're expecting.
DerekAustin26 wrote: » Router 2 Debug Router>en Router#debug ip rip RIP protocol debugging is on Router# *Jun 27 22:01:08.078: RIP: sending v1 update to 255.255.255.255 via Serial0/0 (172.16.1.2) *Jun 27 22:01:08.078: RIP: build update entries *Jun 27 22:01:08.078: subnet 10.2.1.0 metric 2 *Jun 27 22:01:08.078: subnet 10.2.2.0 metric 2
alan2308 wrote: » Something just isn't right here. Here's what I just labbed up. RIPv1 with 10.0.0.0 and 192.168.1.0 in the process for R1: R1: eth0/0 10.1.0.1/24 eth0/1 10.2.0.1/24 s0/0/0 192.168.1.1/24 R2: s0/0/0 192.168.1.2/24on R2: Router2#sh ip route <snip> R 10.0.0.0/8 [120/1] via 192.168.1.1, 00:00:08, Serial0/0/0 C 192.168.1.0/24 is directly connected, Serial0/0/0 Router2#debug ip rip received v1 update from 192.168.1.1 on Serial0/0/0 10.0.0.0 in 1 hopson R1: Router1#debug ip rip RIP: sending v1 update to 255.255.255.255 via Serial0/0/0 (192.168.1.1) RIP: build update entries network 10.0.0.0 metric 1 This is roughly what you should be seeing. In cases like this, I usually just wipe the routers and start over again.
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