From: Hobbs (deadheadblues@gmail.com)
Date: Fri Aug 15 2008 - 23:43:28 ART
Hi Mark, I think another example might explain. This time we want to remove
the null route completely. I also don't think you can generate a summary you
already have learned, it doesn't work for me just like it doesn't work for
you.
We can work with different prefix-lengths. Suppose I have the following
topology:
R5---->R2---->R1<----R4
|
R3
R5 has a loopback 192.168.1.1/32.
R4 has two loopbacks: 192.168.1.2/32 and 192.168.1.3/32.
R2 sends summary to R1 192.168.0.0/22
R1 wants to send a summary for these R4 routes to R3 of 192.168.168.1.0/30.
R1 now has null route with a longer match than the summary from R2:
R1#show ip route | inc 192.168.1|192.168.0.0
192.168.1.0/24 is variably subnetted, 4 subnets, 2 masks
D 192.168.1.0/30 is a summary, 00:06:33, Null0
D 192.168.1.3/32 [90/2297856] via 172.12.14.4, 00:06:33, Serial1/1
D 192.168.1.2/32 [90/2297856] via 172.12.14.4, 00:06:33, Serial1/1
D 192.168.1.4/32 [90/2297856] via 172.12.14.4, 00:06:33, Serial1/1
D 192.168.0.0/22 [90/2809856] via 172.12.123.2, 00:06:33, Serial1/0
R3#ping 192.168.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.1, timeout is 2 seconds:
U.U.U
Now when R3 sends a packet to 192.168.1.1 it matches the null route not the
summary from R2. Even in this case we can't change the AD to just be higher
than 90 because longer match still rules over AD. So we need to change the
AD to 255 to make it disappear completely.
R1(config)#int s1/0
R1(config-if)#ip summary-address eigrp 1 192.168.1.0 255.255.255.252 255
R1#clear ip route *
R1#show ip route | inc 192.168.1|192.168.0.0
192.168.1.0/32 is subnetted, 3 subnets
D 192.168.1.3 [90/2297856] via 172.12.14.4, 00:00:02, Serial1/1
D 192.168.1.2 [90/2297856] via 172.12.14.4, 00:00:02, Serial1/1
D 192.168.1.4 [90/2297856] via 172.12.14.4, 00:00:02, Serial1/1
D 192.168.0.0/22 [90/2809856] via 172.12.123.2, 00:00:02, Serial1/0
R1#
R3#ping 192.168.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 20/53/168 ms
does that explain it?
On Thu, Aug 14, 2008 at 7:33 PM, Mark Stephanus Chandra <
mark.chandra@gmail.com> wrote:
> Sorry Fahad,
>
>
>
> But even I Do with ip summar address AD of 5, the summary route form R1
> won't dissapear either.
>
>
>
>
>
>
>
> Regards
>
>
>
> *Mark Stephanus Chandra
> *IT Consultant
>
>
>
>
>
> *From:* Fahad Khan [mailto:fahad.khan@gmail.com]
> *Sent:* Thursday, August 14, 2008 1:47 PM
>
> *To:* Mark Stephanus Chandra
> *Cc:* Hong Chan; Hobbs; ccielab@groupstudy.com
> *Subject:* Re: Eigrp SUmmarization
>
>
>
> Yeah , thats wat exacty u want to achieve. The discard route in R3 routing
> table disappears when you increase the AD value in "ip summary-address" on
> R3.
>
>
>
> regards,
>
>
>
> On 8/13/08, *Mark Stephanus Chandra* <mark.chandra@gmail.com> wrote:
>
> Hi Fahad,
>
>
>
> I have tried what you told me to do, but summary address from R1 still
> installed on R3 and it's not defeated by discard route with AD 5.
>
>
>
> Somehow the discard route AD5 doesn't appear in the routing table.
>
>
>
> R3 route :
>
>
>
> D 212.18.0.0/16 [90/8234010] via 162.1.13.1, 00:46:06, Serial1/1
>
> C 212.18.5.0/24 is directly connected, Loopback2
>
> C 212.18.4.0/24 is directly connected, Loopback1
>
>
>
> interface FastEthernet0/0
>
> ip address 162.1.38.3 255.255.255.0
>
> ip summary-address eigrp 200 212.18.0.0 255.255.0.0 91
>
> duplex half
>
> end
>
>
>
>
>
> and r3 still be able to ping loopback on R1 since Summary address not
> defeated and stil in the routing table.
>
>
>
> Sw2 also can ping all the loopback since R3 loopback have specific route
> and route to R1 is a summary
>
>
>
> Regards
>
>
>
> *Mark Stephanus Chandra
> *IT Consultant
>
>
>
> *From:* Fahad Khan [mailto:fahad.khan@gmail.com]
> *Sent:* Wednesday, August 13, 2008 8:00 PM
>
>
> *To:* Mark Stephanus Chandra
> *Cc:* Hong Chan; Hobbs; ccielab@groupstudy.com
> *Subject:* Re: Eigrp SUmmarization
>
>
>
> OK e.g,R1 is having loopbacks as 212.18.0.1/24,
> 212.18.1.1/24....212.18.10.1/24 and u created the summary address as
> 212.18.0.0/16 and R3 is having loopbacks as
> 212.18.11.1/24,212.18.12.1/24....212.18.20.1/24 and u send the summary as
> 212.18.0.0/16 towards SW2 , now you wont ping 212.18.0.1 or any of the
> loopbacks configured on R1 since a discard route (having AD of 5) would be
> there on R3 suppressing the summary(AD 90) got from R1. I hope you are
> getting me now. Now inorder to prevent this situation you need to increase
> the AD of discard route from 90 so that R3 can have summary form R1. that
> why u have the keyword in this "ip summary-add" command.SW2 would be able to
> ping all the loopbacks on R3 and R1.
>
>
>
> HTH
>
>
>
>
>
> what i am saying , the summary which R3 is getting from R1 is actually a
> simple EIGRP update for SW2 which R3 is sending to SW2. But if R3 will
> generate its own summary (of specific routes that are on R3 other then that
> on R1 but having the same major net i.e 212.18) to SW2 but "ip-summary add"
> command on R3, then R3 will create a discard route Ok i will try to
> make an exmaple for you later.
>
>
>
> On 8/13/08, *Mark Stephanus Chandra* <mark.chandra@gmail.com> wrote:
>
> Yes Fahad
>
>
>
> The SW 2 getting the summary address from R3 which R3 getting this from R1.
>
>
>
> I still don't understand what this distance going to effect.
>
>
>
> COuld you give me live example ?
>
>
>
> Sorry to bother you like this.
>
>
>
> Regards
>
>
>
> *Mark Stephanus Chandra
> *IT Consultant
>
>
>
>
>
> *From:* Fahad Khan [mailto:fahad.khan@gmail.com]
> *Sent:* Wednesday, August 13, 2008 6:56 PM
>
>
> *To:* Mark Stephanus Chandra
> *Cc:* Hong Chan; Hobbs; ccielab@groupstudy.com
> *Subject:* Re: Eigrp SUmmarization
>
>
>
> Remeber! this route is not due to the "ip-summary address eigrp" command
> used on R3. just do one thing, delete the "ip summary-add" commnad on R3 for
> SW2, then check whether are u getting the same route in SW2?
>
> On 8/13/08, *Mark Stephanus Chandra* <mark.chandra@gmail.com> wrote:
>
> I'm Getting summary route with internal AD
>
>
>
> D 212.18.0.0/16 [90/8236570] via 162.1.38.3, 00:00:33, FastEthernet0/0
>
>
>
> Regards
>
>
>
> *Mark Stephanus Chandra
> *IT Consultant
>
>
>
> *From:* Fahad Khan [mailto:fahad.khan@gmail.com]
> *Sent:* Wednesday, August 13, 2008 6:23 PM
>
>
> *To:* Mark Stephanus Chandra
> *Cc:* Hong Chan; Hobbs; ccielab@groupstudy.com
> *Subject:* Re: Eigrp SUmmarization
>
>
>
> Dear Mark,
>
>
>
> First tell me quickly, are u getting summary route installed in SW2's
> routing table? and what is that route?
>
>
>
> On 8/13/08, *Mark Stephanus Chandra* <mark.chandra@gmail.com> wrote:
>
> HI Fahad,
>
>
>
> Thanks for your Input,
>
>
>
> I immediately test on my lab environment, but the result is not what We
> Expect, please correct me if I'm Wrong.
>
>
>
> The topology is like this :
>
>
>
> R1 ------ R3 ----- SW2
>
>
>
> 1. R1 summary Route 212.18.0.0 255.255.0.0 distance 5
>
> and get this route : D 212.18.0.0/16 is a summary, 00:11:41, Null0 (As
> we agree that this route AD should be 5 right ? How to verify this ?)
>
> 2. R3 get the summary route with AD 90
>
> D 212.18.0.0/16 [90/8234010] via 162.1.13.1, 00:17:40, Serial1/1
>
> 3. And I summary this route to SW2 with this command :
>
> ip summary-address eigrp 200 212.18.0.0 255.255.0.0 5
>
> IF I get you right, this command will over rule the summary address D
> 212.18.0.0/16 [90/8234010] via 162.1.13.1, 00:17:40, Serial1/1
>
> as this summary will install in the routing table with AD 5 right ? The
> route in R3 should be D 212.18.0.0/16 is a summary, 00:11:41, Null0
>
>
>
> but As I see, the route is not change :
>
>
>
> D 212.18.0.0/16 [90/8234010] via 162.1.13.1, 00:17:40, Serial1/1
>
>
>
> DO I Miss something here ?
>
>
>
>
>
> Thanks a lot for looking into this.
>
>
>
>
>
> Regards
>
>
>
> *Mark Stephanus Chandra
> *IT Consultant
>
>
>
>
>
> *From:* Fahad Khan [mailto:fahad.khan@gmail.com]
> *Sent:* Wednesday, August 13, 2008 3:16 PM
> *To:* Mark Stephanus Chandra
> *Cc:* Hong Chan; Hobbs; ccielab@groupstudy.com
> *Subject:* Re: Eigrp SUmmarization
>
>
>
>
> Dear Mark,
>
>
>
> I posted regarding this query on19th july,08. This "distance" keyword in
> "ip summary-address eigrp" command is used to modify the AD of the discard
> route populated in the routing table when a router sends a summary route to
> its neighbour and absolutely not for modifying the AD of the routes in
> neighbour's routing table. consider this scenario,
>
>
>
> 1.1.1.1/24----(lo0) <http://1.1.1.1/24----%28lo0%29>R1(s1/0)10.0.0.1-------10.0.0.2(s1/0)R2(s1/1)11.0.0.1-----11.0.0.2(s1/0)R3
>
> |
>
>
> (lo0)
> 1.1.2.1/24
>
>
>
> -R1 is sending summary (1.0.0.0/8) to R2 through "ip summ-add" command
>
>
>
> -R1 will have discard route to null0 in its routing table
>
>
>
> -R2 gets this summary with AD of 90 from R1 ( as its normal eigrp update
> for R2's perception)
>
>
>
> -if R2 needs to generate summary route(1.0.0.0/8) towards R3 through "ip
> summ-add" command, then here comes a conflit, R2 will create discard route
> entry in its routing table for 1.0.0.0/8 since it has deafilt AD of 5 and
> that will suppress the summary update got from R1. In order to prevent this
> behaivour , increase the AD of summary route more than 90 when configuring
> on R2 for R3. Then , R2 wont be having any discard route in its routing
> table and R3 will be having a summary in its routing table as 1.0.0.0/8and will be able to ping
> 1.1.2.1 and 1.1.1.1.
>
> -This is how we can play with discard route through modifing AD.
>
>
>
> HTH
>
>
>
>
> On 8/13/08, *Mark Stephanus Chandra* <mark.chandra@gmail.com> wrote:
>
> Hi Hong,
>
> The problem is, The Distance is not propagated to the neighbor router.
>
> Just like I said, whatever your distance is, the AD on your neighbor would
> still the same, which is 90
>
> On Wed, Aug 13, 2008 at 12:54 PM, Hong Chan <howard.chan34@gmail.com>
> wrote:
>
> > For my understanding, the distance is used if you 2 router doing
> > summarization and you don't want to load balance them. you can adjust 1
> of
> > the summary route to be larger than 90 on 1 of the routers which perform
> the
> > summarization. Then the router should only have 1 summary route, which is
> > learned from another summary router.
> > Please correct me if I am wrong
> > 2008/8/13 Mark Stephanus Chandra <mark.chandra@gmail.com>
> >
> >> Hi expert,
> >>
> >>
> >>
> >> I'm wondering about EIGRP summarization,
> >>
> >>
> >>
> >> IP summary address eigrp 200 192.168.10.0 255.255.255.0 160
> >>
> >>
> >>
> >> The distance value seems don't do anything.
> >>
> >>
> >>
> >> I check in my neighboring router, I have the eigrp summarization route
> >> with
> >> AD 90 (Internal).
> >>
> >>
> >>
> >> So what the distance is for in eigrp summarization
> >>
> >>
> >>
> >> Thanks
> >>
> >>
> >>
> >> Regards
> >>
> >>
> >>
> >> Mark Stephanus Chandra
> >> IT Consultant
> >>
> >>
> >> Blogs and organic groups at http://www.ccie.net
> >>
> >> _______________________________________________________________________
> >> Subscription information may be found at:
> >> http://www.groupstudy.com/list/CCIELab.html
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >
>
>
> --
> Mark Stephanus Chandra
> IT Consultant
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
>
>
>
>
>
> --
> *FAHAD KHAN**
>
> BE Computer Systems NED,
>
> CCNA,CCDA,CCNP,FOUNDFE,CLSE,QOS,JNCIA,JNCIS,MCP,CCIE (Written)
>
> Systems Support Engineer, Premier Systems (Pvt) limited,
>
> Karachi, Pakistan
>
> 92-321-2370510.*
>
>
>
>
> --
> *FAHAD KHAN**
>
> BE Computer Systems NED,
>
> CCNA,CCDA,CCNP,FOUNDFE,CLSE,QOS,JNCIA,JNCIS,MCP,CCIE (Written)
>
> Systems Support Engineer, Premier Systems (Pvt) limited,
>
> Karachi, Pakistan
>
> 92-321-2370510.*
>
>
>
>
> --
> *FAHAD KHAN**
>
> BE Computer Systems NED,
>
> CCNA,CCDA,CCNP,FOUNDFE,CLSE,QOS,JNCIA,JNCIS,MCP,CCIE (Written)
>
> Systems Support Engineer, Premier Systems (Pvt) limited,
>
> Karachi, Pakistan
>
> 92-321-2370510.*
>
>
>
>
> --
> FAHAD KHAN
>
> BE Computer Systems NED,
>
> CCNA,CCDA,CCNP,FOUNDFE,CLSE,QOS,JNCIA,JNCIS,MCP,CCIE (Written)
>
> Systems Support Engineer, Premier Systems (Pvt) limited,
>
> Karachi, Pakistan
>
> 92-321-2370510.
>
>
>
>
> --
> *FAHAD KHAN**
>
> BE Computer Systems NED,
>
> CCNA,CCDA,CCNP,FOUNDFE,CLSE,QOS,JNCIA,JNCIS,MCP,CCIE (Written)
>
> Systems Support Engineer, Premier Systems (Pvt) limited,
>
> Karachi, Pakistan
>
> 92-321-2370510.*
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