RE: summary route

From: Richard Dumoulin (richard.dumoulin@vanco.es)
Date: Tue Jun 01 2004 - 04:59:00 GMT-3


Yasser, can you post your test ? Here is mine:

First I have this:

r2#sh run | b bgp
router bgp 65501
 no synchronization
 bgp router-id 2.2.2.2
 bgp log-neighbor-changes
 bgp confederation identifier 12345
 bgp confederation peers 65505
 neighbor 172.16.30.1 remote-as 65501
 neighbor 172.16.30.18 remote-as 65505
 no auto-summary

r2#sh ip bgp
BGP table version is 34, local router ID is 2.2.2.2
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network Next Hop Metric LocPrf Weight Path
r>i10.1.1.0/24 172.16.30.1 0 100 0 i
r>i10.1.3.0/24 172.16.30.3 0 100 0 i
*>i10.1.6.0/24 172.16.30.34 0 100 0 67 i
*> 10.10.10.0/24 10.1.5.2 0 200 0 (65505) 10 i
r>i10.40.4.0/24 172.16.30.22 0 100 0 (65504) i
r> 10.50.5.0/24 172.16.30.18 0 100 0 (65505) i
*>i10.70.7.0/24 172.16.30.34 0 100 0 67 i

And I am going to summarize 10.0.0.0/8 into bgp:

But first I advertise the classful and see if it appears in the bgp fib:

r2(config)#router bgp 65501
r2(config-router)#netw
r2(config-router)#network 10.0.0.0
r2(config-router)#^Z

But there is no way the network enters the table because the network does
not exist in the local table:

r2#sh ip bgp
BGP table version is 34, local router ID is 2.2.2.2
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network Next Hop Metric LocPrf Weight Path
r>i10.1.1.0/24 172.16.30.1 0 100 0 i
r>i10.1.3.0/24 172.16.30.3 0 100 0 i
*>i10.1.6.0/24 172.16.30.34 0 100 0 67 i
*> 10.10.10.0/24 10.1.5.2 0 200 0 (65505) 10 i
r>i10.40.4.0/24 172.16.30.22 0 100 0 (65504) i
r> 10.50.5.0/24 172.16.30.18 0 100 0 (65505) i
*>i10.70.7.0/24 172.16.30.34 0 100 0 67 i

So I enter auto-summary in the bgp process:

r2#conf t
Enter configuration commands, one per line. End with CNTL/Z.
r2(config)#router bgp 65501
r2(config-router)#auto
r2(config-router)#auto-summary
r2(config-router)#^Z
r2#
r2#
*Mar 1 18:11:33.762: %SYS-5-CONFIG_I: Configured from console by consoles
r2#sh deb
IP routing:
  BGP debugging is on

r2#
*Mar 1 18:12:31.529: BGP: Applying map to find origin for 10.0.0.0/24
r2#sh ip bgp
BGP table version is 35, local router ID is 2.2.2.2
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network Next Hop Metric LocPrf Weight Path
*> 10.0.0.0 0.0.0.0 0 32768 i
r>i10.1.1.0/24 172.16.30.1 0 100 0 i
r>i10.1.3.0/24 172.16.30.3 0 100 0 i
*>i10.1.6.0/24 172.16.30.34 0 100 0 67 i
*> 10.10.10.0/24 10.1.5.2 0 200 0 (65505) 10 i
r>i10.40.4.0/24 172.16.30.22 0 100 0 (65504) i
r> 10.50.5.0/24 172.16.30.18 0 100 0 (65505) i
*>i10.70.7.0/24 172.16.30.34 0 100 0 67 i

I even ran "debug ip bgp" so we can see what happens. I think that I have
confirmed the BGP faq
http://www.cisco.com/en/US/tech/tk365/tk80/technologies_q_and_a_item09186a00
800949e8.shtml#five

Yasser could you please post your test ?

Regards

--Richard

-----Original Message-----
From: Yasser Aly [mailto:blackyeyes00@hotmail.com]
Sent: martes, 01 de junio de 2004 0:37
To: Richard Dumoulin; ahmed.mustafa@sbcglobal.net
Cc: ccielab@groupstudy.com
Subject: RE: summary route

Richard,

  Just tested it before sending my mail to the list. auto-summary only works
with redistributed routes.

Hope to hear others comments about this to confirm.
Yasser

>From: Richard Dumoulin <richard.dumoulin@vanco.es>
>To: Yasser Aly <blackyeyes00@hotmail.com>,
ahmed.mustafa@sbcglobal.net
>CC: ccielab@groupstudy.com
>Subject: RE: summary route
>Date: Mon, 31 May 2004 23:15:53 +0100
>
>Yasser, here I have to disagree. Did you read the BGP faq and did you
test
>it ? I did and auto-summary contrary to what the majority of people
think
>not only works with redistribution,
>
>--Richard
>
>-----Original Message-----
>From: Yasser Aly [mailto:blackyeyes00@hotmail.com]
>Sent: martes, 01 de junio de 2004 0:11
>To: Richard Dumoulin; ahmed.mustafa@sbcglobal.net
>Cc: ccielab@groupstudy.com
>Subject: RE: summary route
>
>
>Hello,
>
>Possibility #2 will not work.
>
>Auto-summary inside BGP acts only on redistributed routes not on routes
>entered in the BGP via the network command. You will need to
redistribute
>the route into BGP and turn on auto-summary. This will summarize it to
its
>classful boundary.
>
>Regards,
>Yasser
>===================
>But I already explained !
>
>Let's say R2 is connected to R1 and they run an igp like RIP. On R2,
>configure "ip summary-address rip 156.1.0.0 255.255.0.0". So
now R1 has the
>network in his routing table right ? You just injected the summary
through
>the igp. Now just redistribute RIP into BGP with filters if you wish and

you
>will be advertising the network.
>
>
>2) Another possibility as explained is :
>
>router bgp 1234
>auto-summary
>network 156.1.0.0
>
>
>And that's it. But it might not be the solution as per the requirements
> >--Richard > > > >-----Original Message-----
>From: Ahmed Mustafa [mailto:ahmed.mustafa@sbcglobal.net]
>Sent: lunes, 31 de mayo de 2004 7:01
>To: Richard Dumoulin
>Subject: Re: summary route
>
>
>Richard,
>
>I have confused you with my question. I completely understand the BGP
rules
>for advertising networks. What i was asking is let say that > >I
have R1 connected to backbone via BGP. on R1 I have subnets of
network
>156.1.0.0 per se
>
>156.1.1.0
>156.1.2.0
>156.1.3.0
>156.1.4.0 and so on.
>
>I know just want to advertise the summary route to B1. The network
between
>BB and R1 is on 204.12.1.0/24.
>
>Is there any other solution besides using aggregate to advertise a
network
>156.1.0.0/16 to BB.
>
>Regards,
>
>Ahmed
>
>----- Original Message -----
>From: Richard Dumoulin <mailto:richard.dumoulin@vanco.es>
>To: Ahmed Mustafa <mailto:ahmed.mustafa@sbcglobal.net>
>Cc: ccielab@groupstudy.com <mailto:ccielab@groupstudy.com>
>Sent: Sunday, May 30, 2004 8:38 PM
>Subject: RE: summary route
>
>Ahmed, auto-summary is not only used when redistributing igp into bgp.
>Suppose you have the subnet 156.1.2.0/24 in your local routing table. If

you
>enable auto-summary and configure network 156.1.0.0 under BGP, you will
>advertise this route as a classful network. > >Attaching a
prefix-list is only policing traffic. This is not a way to >advertise a
network. There 4 ways to advertise: > >redistribute >network
>aggregate >bgp inject-map > >So you solution should come from
one of these four ways, > >HTH, > > >--Richard > > >
>-----Original Message-----
>From: Ahmed Mustafa [mailto:ahmed.mustafa@sbcglobal.net]
>Sent: lunes, 31 de mayo de 2004 4:58
>To: Richard Dumoulin
>Subject: Re: summary route
>
>
>Richard,
>
>I am confused. Under BGP process, the auto-summary keyword is only used

if
>I redistribute the route. CCIE labs don't allow to create a static
route,
>so that option is no permittable.
>
>2nd option to use aggregate address with the summary-only keyword. That

is
>also restricted by the task I am currently doing
>
>3rd option, I thought I could use prefix-list of 156.1.0.0/16 and attach

it
>with the neighbor command under the BGP process, but you are saying it
won't
>work.
>
>Is it because that I have to have a same route 156.1.0.0/16 in my
routing
>table, and then prefix-list can allow only this route to be
advertiseable to
>the backbone, and then implicit deny will deny all the subnets of
156.1.0.0
>network.
>
>Now the question is how to do that.
>
>May be I could just advertise the network 156.1.0.0 under bgp process,
that
>will create a 156.1.0.0 route in a BGP table though, not routing table.
> >I am lost. > >Any clue. > >Ahmed >
>----- Original Message -----
>From: Richard Dumoulin <mailto:richard.dumoulin@vanco.es>
>To: Ahmed Mustafa <mailto:ahmed.mustafa@sbcglobal.net> ;
>ccielab@groupstudy.com <mailto:ccielab@groupstudy.com>
>Sent: Sunday, May 30, 2004 7:04 PM
>Subject: RE: summary route
>
>
>I don't see how you would end up advertising the route. With the
prefix-list
>you are just allowing it. I can see three options: --Aggregate command
>--"auto-summary" + "network 156.1.0.0" under the bgp

process. --you
>summarise in igp and redistribute it into bgp ,
>
>As the first two options use bgp summary features I would do the last
one,
>
>HTH,
>
>--Richard
>
>-----Original Message-----
>From: Ahmed Mustafa [mailto:ahmed.mustafa@sbcglobal.net
><mailto:ahmed.mustafa@sbcglobal.net> ]
>Sent: lunes, 31 de mayo de 2004 3:44
>To: ccielab@groupstudy.com
>Subject: summary route
>
>
>If I want to announce a summary route of my internal network towards the
>Backbone router, and not allowed to use the route-summary in BGP. >
> >Will the following solution work: > > >ip prefix-list TOBB
permit 156.1.0.0/16 ------------------->
Assuming my
>internal network is comprise of 156.1.0.0/16 network, and scattered
>throughout the netowork with /24 bit mask. > > > >router bgp
100 >neighbor 1.1.1.1 remote-as 230 >neighbor 1.1.1.1 prefix-list TOBB
out > > >I didn't use the command aggregate-address. I am assuming
by saying not
use
>route-summary means I can't use aggregation.
>
>
>The implicit deny at the end should block all the longer routes. >
>Please advise >
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