From: Yasser Aly (blackyeyes00@hotmail.com)
Date: Mon May 31 2004 - 19:10:59 GMT-3
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
This archive was generated by hypermail 2.1.4 : Wed Jun 02 2004 - 11:12:19 GMT-3