From: Mark Lasarko (mlasarko@co.ba.md.us)
Date: Thu Feb 09 2006 - 22:43:30 GMT-3
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
This archive was generated by hypermail 2.1.4 : Wed Mar 01 2006 - 11:28:17 GMT-3