From: Venkatesh Palani (kvpalani@gmail.com)
Date: Tue Feb 14 2006 - 11:18:27 GMT-3
Hi Ashok,
I am not sure if I am missing out some thing but I cant find any difference
between your case 1 and case2. probbaly you may want to uses EXIST-MAP key
work instead of the non-exist-map one.
I think it will be an "and" operation when you have more than one ACL to
match so the result will be -ve in both case, thus case 1 will work where as
not the case 2. Meanwhile I am a bit off tracked about the ACl
3.3.3.0doesnt it have a Wild card mask did you mean it to be
0.0.0.255 ?
Anyway I havent labbed this up to verify my answers, so guys please correct
me if I was wrong.
HTH,
Venkatesh
On 2/14/06, Ashok M A <maashok@cyberwerx.com> wrote:
>
> I have a question.
>
> If I have something like this under NON-EXIST or EXIST map is every
> access-list should be matched or only one is fine?
>
> Case 1:
> ~~~~~~
> router bgp 123
> neighbor 1.1.1.1 remote-as 456
> neighbor 1.1.1.1 advertise-map ADVERTISE non-exist-map NON-EXIST
> !
> access-list 2 permit 2.2.2.0 0.0.0.255
> access-list 3 permit 3.3.3.0
> access-list 3 permit 4.4.4.0 0.0.0.255
> access-list 3 permit 5.5.5.0 0.0.0.255
> !
> route-map NON-EXIST permit 10
> match ip address 3
> !
> route-map ADVERTISE permit 10
> match ip address 2
> ~~~~~
> Here what going to happen if I have 3.3.3.0 in the BGP table but not
> 4.4.4.0/24 and 5.5.5.0/24
>
> Will the 2.2.2.0/24 advertised?
>
> Case 2:
>
> router bgp 123
> neighbor 1.1.1.1 remote-as 456
> neighbor 1.1.1.1 advertise-map ADVERTISE non-exist-map EXIST
> !
> access-list 2 permit 2.2.2.0 0.0.0.255
> access-list 3 permit 3.3.3.0
> access-list 3 permit 4.4.4.0 0.0.0.255
> access-list 3 permit 5.5.5.0 0.0.0.255
> !
> route-map EXIST permit 10
> match ip address 3
> !
> route-map ADVERTISE permit 10
> match ip address 2
> ~~~~~
> Here what going to happen if I have 3.3.3.0 in the BGP table but not
> 4.4.4.0/24 or 5.5.5.0/24
>
> Will the 2.2.2.0/24 advertised?
>
> -Ashok
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Mark
> Lasarko
> Sent: Friday, February 10, 2006 7:14 AM
> To: ajayvm@gmail.com; ccielab@groupstudy.com
> Subject: Re: COnditional Advertisement in BGP
>
> AFAIK "Conditional Advertisement" is just that,
> conditional advertisement.
> As in...
>
> router bgp 123
> neighbor 1.1.1.1 remote-as 456
> neighbor 1.1.1.1 advertise-map ADVERTISE non-exist-map NON-EXIST
> !
> access-list 2 permit 2.2.2.0 0.0.0.255
> access-list 3 permit 3.3.3.0
> !
> route-map NON-EXIST permit 10
> match ip address 3
> !
> route-map ADVERTISE permit 10
> match ip address 2
>
> In other words:
> Only advertise routes matched in ADVERTISE
> on the "condition" that the routes in
> NON-EXIST are not in the BGP table.
>
> If 3.3.3.0/24 exists let's not advertise 2.2.2.0/24 and its subnets.
> If 3.3.3.0/24 doesn't exist let's advertise 2.2.2.0/24 and its subnets.
> (I intentionally left out the wildcard on 3.3.3.0/24 for an exact match)
>
> With 12.2T the option for "exist-map" was introduced.
> Just invert the logic.
> "If THIS exists let's advertise THAT"
> "If THIS does not exist don't advertise THAT"
>
> (Somebody please correct me if I have this askew!)
>
> There are other means by which to "conditionally" send a route.
> But if I read "conditional advertisement" I would have to go with the
> above.
>
> There is the aggregate/unsuppress-map on the neighbor approach - that
> could
> work.
> And another "conditional" thing called "Conditional Route Injection".
> If 'injection' were interpreted as 'advertisement'.
> Gives us a different way to do stuff!
>
> Conditional Advertisement has been around for a long time.
> Route Injection is a much newer feature.
> Both work on newer (lab) hardware.
>
> So I would say:
> 1. Conditional advertisement
> 2. Conditional route injection
> 3. Aggregate w/ unsuppress-map
> In that order. 3 ways. That's all I know :-)
>
> Lucky for you there's a lot of folks up on this board who know a heck of a
> lot
> more than me - ladies and gentlemen, thoughts?
>
> BTW - I don't know if the unsuppress-map would be an option if the
> aggregate
> was not there?
> Meaning if you were not asked to create it would it violate the lab
> scenario?
> (Another nod to "ask the proctor")
> Best,
>
> ~M
>
> >>> Ajay V m <ajayvm@gmail.com> 02/09/06 3:25 PM >>>
>
> Can ANyone tell me wat are the possible ways i can do conditional
> Advertisement in bgp
> --
>
> --
> Regards
>
> Ajay
>
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