From: Bob Chahal (bob.chahal@xxxxxxxxxxxx)
Date: Thu Aug 09 2001 - 06:24:54 GMT-3
I agree with that. I can't get my head around that. What it's saying is if a
bgp peer can't pass at least 100 routes then I don't want any routes at
all?????
Also I'm no expert on prefix-lists and we can safely say that it's not
relevant to this question but some of the suggestions below are not accurate
anyway.
----- Original Message -----
From: "Devender Singh" <devender.singh@cmc.cwo.net.au>
To: "Karelis, Pete (2507)" <Pete.Karelis@esavio.com>; "'Sal Nathoo'"
<snathoo2001@yahoo.com>; "Jason Gardiner" <gardiner@sprint.net>; "Jon
Carmichael" <jonc@pacbell.net>
Cc: <ccielab@groupstudy.com>
Sent: Thursday, August 09, 2001 9:05 AM
Subject: RE: BGP filtering
> Minimum routes does not make much sense when I think about it. Because if
> the routes are not there router can't learn them.
>
> Devender Singh
> BE(Hons), CCNP
> IP Solution Specialist
>
>
> -----Original Message-----
> From: Karelis, Pete (2507) [mailto:Pete.Karelis@esavio.com]
> Sent: Thursday, 9 August 2001 1:48
> To: 'Sal Nathoo'; Jason Gardiner; Jon Carmichael
> Cc: ccielab@groupstudy.com
> Subject: RE: BGP filtering
>
>
> Here's how you set the maximum number of learned routes on an ebgp peer:
>
> conf t
> router bgp xxxx
> neighbor a.b.c.d maximum-prefix 500
>
> I don't know of a way to set the minimum number of learned routes....
>
> -Pete Karelis
>
>
> -----Original Message-----
> From: Sal Nathoo [mailto:snathoo2001@yahoo.com]
> Sent: Wednesday, August 08, 2001 11:27 AM
> To: Jason Gardiner; Jon Carmichael
> Cc: Sal Nathoo; ccielab@groupstudy.com
> Subject: Re: BGP filtering
>
>
> Hi Guys,
>
> Sorry for not being clear.
>
> I wanted to know the bgp commands to allow only a
> minimum 100 and maximum 500 routes in the routing
> table from my EBGP neighbor. Not using prefix lists or
> access lists. These routes that are coming into my
> topology are from different networks and subnets.
>
> Thanks,
> Saleem
>
> --- Jason Gardiner <gardiner@sprint.net> wrote:
> > This is just off the top of my head; I haven't run
> > through it, yet. But
> > you show:
> >
> > > ip prefix-list NAMEONE {permit|deny}
> > 192.168.160.0/16 le 19
> >
> > Isn't 192.168.160.0/16 a part of 192.168.0.0?
> >
> >
> > It should be ip prefix-list NAMEONE {permit|deny}
> > 192.168.160.0/19 le 19
> >
> >
> > The number after the le only indicates the length of
> > the subnets allowed
> > to be announced out of the aggregate block. It
> > would only allow the /19
> > to get through, not, say 192.168.161.0/24. This is
> > how many of the
> > larger providers work to reduce the size of the
> > global routing table.
> >
> >
> >
> >
> >
> > Jon Carmichael wrote:
> > >
> > > It sounds as if you are asking for a filter of a
> > range of NLRI when you say
> > > "range of routes." In all cases, when I'm
> > thinking of a "range" I must go
> > > back to the binary, --frequently I draw two
> > numbers in binary on a scratch
> > > paper and a line where I think the mask would go,
> > and then I can see the
> > > range. -And why? Because I'm going to write a
> > access-list and I need to
> > > figure out the proper wildcard mask. --So I
> > would take your example, --of
> > > say 100 to 500, --but 500 does not fit in
> > anybody's eight bit octet. How
> > > about 160 to 192, because it's easy to see... So
> > draw both numbers on a
> > > piece of paper like this....
> > >
> > > 1010000 --binary 160
> > > 1100000 --binary 192
> > >
> > > and then I draw a vertical line with my simulated
> > pencil here, this line is
> > > where the mask would go, --say..
> > >
> > > |
> > > 101|00000
> > > 110|00000
> > > |
> > > 000|11111
> > >
> > > And then I invert that as 00011111, which is
> > decimal 31, and for a range of
> > > NLRI of say 192.168.160.0 thru 192.168.192.0 I can
> > write my access list for
> > > a route filter as ..
> > >
> > > access-list 1 {permit|deny} 192.168.160.0
> > 0.0.31.255
> > >
> > > I think I do this almost once every day.
> > >
> > > Prefix lists are still a little elusive to me tho,
> > --so I play with those a
> > > little more lately, --where if I wanted to do
> > exactly the same
> > > thing, --perhaps someone will jump in and help us
> > out here....
> > >
> > > ip prefix-list NAMEONE {permit|deny}
> > 192.168.160.0/16 le 19
> > >
> > > That does not work, --when you go back and do a
> > "show ip prefix-list" it
> > > looks like 192.168.0.0/16 le 19. Can anybody
> > tell us how to do the same
> > > thing with a prefix-list?
> > >
> > > JONC
> > >
> > > -----Original Message-----
> > > From: nobody@groupstudy.com
> > [mailto:nobody@groupstudy.com]On Behalf Of
> > > Sal Nathoo
> > > Sent: Tuesday, August 07, 2001 2:56 PM
> > > To: ccielab@groupstudy.com
> > > Subject: BGP filtering
> > >
> > > Hi Guys,
> > >
> > > Can someone tell me commands are used to filter a
> > > range of routes (ex. between 100 to 500) from EBGP
> > > neighbors?
> > >
> > > Thanks in advance
> > >
> > > Saleem
> > >
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