[j-nsp] Aggregate and directly connected routes (route preference)

[Gary Tate]

You could advertise the aggregate if you really want to by using 
advertise-inactive option on the bgp group or neighbor that you wish 
the aggregate to be advertised on.  This is needed because as you have 
mentioned the aggregate will always be inactive in this configuration.

However, if the interfaces which have the actual routes go down the 
route will still be advertised and you will sink traffic to your router 
before it is dropped.

If you advertise the actual routes then they will be withdrawn if the 
interface goes down.

Gary

On Jan 26, 2004, at 6:05 PM, Gary Tate wrote:

> The network statement in Cisco does produce aggregate routes if you 
> have a contributor.
>
> In Juniper the Aggregate route will indeed be inactive.  You can 
> simply advertise the /24 from the interface routes using an 
> appropriate filter:
>
> policy-options policy statement aggeregate {
>     term send-agg-5 {
> 		from route-filter 5.5.5.0/24 exact
> 		then accept;
>         }
>     term send-agg-6 {
> 		from route-filter 6.6.6.0/24 exact
> 		then accept;
>         }
> 	term reject-rest {
>         then reject
> 	}
> }
>
> This will advertise only the 5.5.5.0/24 and reject all other routes.
> Gary
>
> On Jan 26, 2004, at 5:54 PM, Robin Balen wrote:
>
>>
>>
>>> -----Original Message-----
>>> From: Gary Tate [mailto:gtate at juniper.net]
>>> Sent: 27 January 2004 01:49
>>
>> Gary,
>>
>> Thanks for the swift reply!
>>
>>> Why not just advertise the /24 routes via bgp why create an aggregate
>>> when the route already exists?
>>
>> This is the source of the advertisement. The equivalent Cisco IOS 
>> command
>> would be:
>>
>>  network 5.5.5.0
>>  network 6.6.6.0
>>
>> Then set 5.5.5.1 and 6.6.6.1 as addresses on a FE port.
>>
>>> Do you necessarily need this as an aggregate?
>>
>> No - this just seemed like a fairly straightforward way of achieving 
>> what I
>> wanted... If you could give any pointers to a more effective method 
>> please
>> let me know!
>>
>> Regards
>>
>> Robin Balen
>>
>>
>