Re: Eigrp SUmmarization

From: Fahad Khan (fahad.khan@gmail.com)
Date: Wed Aug 13 2008 - 09:59:49 ART

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)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
> >>
> >>
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> >>
> >>
> >>
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> >
>
>
> --
> 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.

Blogs and organic groups at http://www.ccie.net

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