Re: BGP: suppress-map vs unsuppress-map and logic

From: Narbik Kocharians (narbikk@gmail.com)
Date: Sat Jan 17 2009 - 14:04:29 ARST

Suppress-map can be part of the aggreagte-address and it can deny or allow
suppression of a specific route of a summary (Aggregate in BGP), and it will
globally effect all neighbors. Whereas, unsuppress-map can be configured to
effect only a specific neighbor and this keyword can not be part of the
aggregate-address command, its on a per neighbor, using the neighbor x.x.x.x
unsuppress-map yyyy.

Let's say you need to advertise the summary + one of the specific routes:
aggregate-address 10.1.0.0 255.255.252.0 summary-only suppress-map TST

roue-map TST permit 10
match ip addr 1

Access-list 1 deny 10.1.1.0 0.0.0.255
access-list 1 permit any

You see in the above configuration you are advertising the aggregate address
of 10.1.0.0/22 + the 10.1.1.0/24 which is one of the specific routes of that
aggregate, and you are advertising it to all neighbors; in this command you
are denying 10.1.1.0/24 from getting suppressed.

Now with unsuppress-map:

Aggregate-address 10.1.0.0 255.255.252.0 summary-only
Neighbor 200.1.1.1 unsuppress-map TST

Route-map TST permit 10
match ip addr 1

access-list 1 permit 10.1.1.0 0.0.0.255

Note now ONLY neighbor 200.1.1.1 gets the specific route, which is the
10.1.1.0/24 and every one else get the aggregate.

I hope this helped, i still need my coffee.

On Sat, Jan 17, 2009 at 4:28 AM, GAURAV MADAN <gauravmadan1177@gmail.com>wrote:

> i guess answer to ur question in in CLI itself .
>
> aggregate-address -----> supress map
> neighbor --------> unsupress-map
> give it a thought
>
> Gaurav Madan
> On Sat, Jan 17, 2009 at 5:28 PM, Wouter Prins <wp@null0.nl> wrote:
>
> > hi group,
> >
> > I was wondering why the unsuppress-map feature exists if you can use
> > matching logic in combination with a suppress-map?
> > Is the unsuppress-map giving other possibilities then the suppress-map
> > option, i cannot find which one that would be?
> >
> > What i mean is the following to unsuppress routes using the suppress-map:
> >
> > <snippet>
> > aggregate-address 10.0.0.0 255.252.0.0 suppress-map UNSUPPRESS
> > !
> > ip prefix-list 10.3.0.0 seq 5 permit 10.3.0.0/16
> > !
> > route-map UNSUPPRESS deny 10
> > match ip address prefix-list 10.3.0.0
> > route-map UNSUPPRESS permit 20
> > </snippet>
> >
> > Thanks!
> > --
> > Wouter Prins
> >
> >
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-- 
Narbik Kocharians
CCSI#30832, CCIE# 12410 (R&S, SP, Security)
www.MicronicsTraining.com
www.Net-Workbooks.com
Sr. Technical Instructor

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

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