[j-nsp] RR and VPN on PE L3VPN

Olivier Benghozi olivier.benghozi at wifirst.fr
Sat Nov 21 18:44:22 EST 2015

Hi Tim,

About sessions flaps:

Yes, other i-MP-BGP will flap on PE1 once the group with cluster-id configured has a first established neighbor (and will also flap once the last established neighbor goes down in this group).

The solution documented in the link you wrote works (a passive pseudo session with a clusterid), but is an old one. You would better use advertise-from-main-vpn-tables (available since 12.3).

Basically, add advertise-from-main-vpn-tables on the RR, it will make sessions flap once and only once.
http://www.juniper.net/documentation/en_US/junos14.2/topics/reference/configuration-statement/advertise-from-main-vpn-table-edit-protocols-bgp.html <http://www.juniper.net/documentation/en_US/junos14.2/topics/reference/configuration-statement/advertise-from-main-vpn-table-edit-protocols-bgp.html>

Note: if you use GRES+NSR, this doc:
http://www.juniper.net/documentation/en_US/junos14.2/topics/reference/requirements/nsr-system-requirements.html#nsr-bgp <http://www.juniper.net/documentation/en_US/junos14.2/topics/reference/requirements/nsr-system-requirements.html#nsr-bgp>
requests to add advertise-from-main-vpn-tables in bgp config, by the way. Maybe you already have it ?

Note 2: when you configure a cluster id in a group, I guess that all neighbors in this group flap anyway.

Note 3: RR with 3 routers looks overkill :)


> Le 21 nov. 2015 à 14:05, Dragan Jovicic <draganj84 at gmail.com> a écrit :
> Hi,
> By default PE1 will not have those routes. Once you make it a route
> reflector, it keeps and reflects all bgp.l3vpn.0 it can resolve, regardless
> of local vpns.
> If your router in EUROPE is in different AS, an eBGP session with inet-vpn
> family between PE1 and PE3 will also make PE1 keep and reflect all routes
> to PE3.
> Finally an option is to dismiss RR and keep full mesh between 3 routers.
> Regards
> On Sat, Nov 21, 2015 at 7:05 AM, tim tiriche <tim.tiriche at gmail.com> wrote:
>> Hi,
>> I have the following:
>> PE1 router (VRF A and VRF B) - USA
>> PE2 router (VRFA, VRFB, VRFC, VRFD) - USA
>> I currently have full mesh iBGP between PE1 and PE2.
>> I am adding a PE3 in EUROPE and would like to have PE1 act as an RR for
>> PE3.
>> I will add full mesh MPLS LSP for all PE's.
>> How will PE3 get VRFC and VRFD, since PE1 currently does not have VRFC and
>> VRFD in its bgp.l3vpn.0 table?
>> Is it true, i will loose all my BGP sessions if configure cluster-id on
>> PE1?
>> http://www.juniper.net/documentation/en_US/junos13.3/topics/topic-map/bgp-sessions.html
>> Any advice would be appreciated.

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