From: Bob Sinclair (bsin@cox.net)
Date: Tue Jun 01 2004 - 10:38:53 GMT-3
Georg,
I can second Richard's findings. Auto-summary will summarize to classful
boundary. I am sure this is version-dependent. As Richard suggested, check
out the BGP faq at this link:
http://www.cisco.com/en/US/tech/tk365/tk80/technologies_q_and_a_item09186a00800949e8.shtml
Here is my version: (C2500-JK8S-L), Version 12.2(1d)
Here is the output:
router bgp 700
no synchronization
bgp log-neighbor-changes
network 70.0.0.0
neighbor 172.16.17.1 remote-as 100
!
ip kerberos source-interface any
ip classless
no ip http server
!
route-map LOOP1 permit 10
match interface Loopback1
!
!
alias exec srb show run | begin
FRS#sh ip b
BGP table version is 3, local router ID is 70.70.70.70
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 10.10.10.0/24 172.16.17.1 0 100 300 1000 i
*> 70.0.0.0 0.0.0.0 0 32768 i
FRS#sh ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter
area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is not set
70.0.0.0/24 is subnetted, 1 subnets
C 70.70.70.0 is directly connected, Loopback1
172.16.0.0/16 is variably subnetted, 18 subnets, 4 masks
C 172.16.204.0/27 is directly connected, Tunnel11
C 172.16.200.0/22 is directly connected, Tunnel10
R 172.16.25.32/27 [120/2] via 172.16.204.1, 00:00:01, Tunnel11
R 172.16.36.0/22 [120/2] via 172.16.200.1, 00:00:01, Tunnel10
R 172.16.32.0/22 [120/2] via 172.16.200.1, 00:00:01, Tunnel10
R 172.16.25.0/27 [120/2] via 172.16.204.1, 00:00:02, Tunnel11
R 172.16.16.0/24 [120/1] via 172.16.17.1, 00:00:02, Ethernet0
C 172.16.17.0/24 is directly connected, Ethernet0
R 172.16.12.0/24 [120/1] via 172.16.17.1, 00:00:02, Ethernet0
R 172.16.13.0/24 [120/1] via 172.16.17.1, 00:00:02, Ethernet0
R 172.16.124.0/24 [120/1] via 172.16.17.1, 00:00:03, Ethernet0
R 172.16.124.4/32 [120/1] via 172.16.17.1, 00:00:03, Ethernet0
R 172.16.120.0/24 [120/1] via 172.16.17.1, 00:00:03, Ethernet0
R 172.16.124.5/32 [120/1] via 172.16.17.1, 00:00:03, Ethernet0
R 172.16.104.0/24 [120/1] via 172.16.17.1, 00:00:03, Ethernet0
R 172.16.105.0/27 [120/2] via 172.16.204.1, 00:00:03, Tunnel11
R 172.16.106.0/24 [120/1] via 172.16.17.1, 00:00:03, Ethernet0
R 172.16.103.0/24 [120/1] via 172.16.17.1, 00:00:03, Ethernet0
10.0.0.0/24 is subnetted, 1 subnets
B 10.10.10.0 [20/0] via 172.16.17.1, 00:01:21
Bob Sinclair
CCIE #10427, CISSP, MCSE
www.netmasterclass.net
----- Original Message -----
From: "Georg Pauwen" <pauwen@hotmail.com>
To: <richard.dumoulin@vanco.es>; <blackyeyes00@hotmail.com>;
<ahmed.mustafa@sbcglobal.net>
Cc: <ccielab@groupstudy.com>
Sent: Tuesday, June 01, 2004 3:51 AM
Subject: RE: summary route
> Hello Richard,
>
> BGP would need the summary route in the routing table, and just turning on
> auto-summary will not put it there. You could put a static route to null
in
> your config for the summarized network...
> Can you post your test configuration and the output of show ip route from
> the router where you have tested this ?
>
> Regards,
>
> Georg
>
> >From: Richard Dumoulin <richard.dumoulin@vanco.es>
> >Reply-To: 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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