BGP Aggregate Address question

[vyas.nilay]

Topology

LAN AS 11(192.168.x.x) ---- DMZ AS 12  |------- MPLS 13 (172.16.x.x)
                                                                  |------- MPLS 14 ( 10.x.x.x)

LAN AS 21 (192.168.x.x) ---- WAN AS 22  |------- MPLS 13 ( 172.16.x.x)
                                                                    |------- MPLS 14 (10.x.x.x)

AS 11 and AS 21 is connected vai ebgp. 

all other AS is conencted via Ebgp.

AS 12 and As 22 router has aggregate command for Private IP address range going towards MPLS 14.

It also has the prefix list allowing aggregate address well.

I would like to achive following.

From AS 14,

All AS 11  network should come to as 12 path

all AS 21 network should come to AS 22 Path

all communication between AS 13 and AS 14 should happen only via AS 11.

I have tried the route map and filter the traffic originate from AS 11 and AS 21 but still it is not advertising. It only advertise aggregate address. 

There is no aggreegate summary command only aggreegate command.

aggregate-address 10.0.0.0 255.0.0.0
aggregate-address 172.16.0.0 255.240.0.0
aggregate-address 192.168.0.0 255.255.255.0

Routem map

route-map rm permit 10
match as-path 1

route-map rm permit 20
match ip address prefix-list so

route-map rm deny 99

Please help me out.

[Giuseppe Larosa]

Hello @vyas.nilay 

we are lost here ...

>> all communication between AS 13 and AS 14 should happen only via AS 11.

But in your description AS 13 and AS 14 connects to AS 22

>> LAN AS 21 (192.168.x.x) ---- WAN AS 22 |------- MPLS 13 ( 172.16.x.x)
                                                                         |------- MPLS 14 (10.x.x.x)

so AS13 and AS14 will communicate via AS 22 as it provides the best path ( shortest AS path )

Or they would use AS 12

>> LAN AS 11(192.168.x.x) ---- DMZ AS 12 |------- MPLS 13 (172.16.x.x)
                                                                       |------- MPLS 14 ( 10.x.x.x)

For the same reason (shortest AS path)

You need to provide network commands under router bgp  that match at least one component route in order to have an aggregate-address to work = to be advertised

BGP is now classless by default

no summary is the new default and you need an exact match with the component route/prefix to have it in the BGP table . when at least one component route is in the BGP table the aggregate is triggered and advertised ( if allowed by your route filters)

I would suggest to remove route filters , add the necessary network commands under BGP with exact match to existing IP prefixes in the IP routing table ( whatever they are connected, static routes or learned via an IGP)

Hope to help

Giuseppe