06-04-2010 09:17 PM
It's been mentioned in Juniper documentation and IETF drafts that NG MVPN provides different data plane options; one of them is PIM/GRE.
However, as I know the main purpose for NG MVPN is to provide PIM free core due to the huge number of PIM adjacencies,and yet JUNOS allows PIM to be configured on the core network when you choose NG-MVPN mGRE.
Now, my question is that only to allow for smoother migration to P2MP LSPs or because PIM/GRE has some advantages over P2MP? if not, then what are scalability and/or performance issues when PIM/GRE is used?
I will be very glad if anyone can answer my questions.
06-22-2010 04:25 AM
As far as I can see, the PIM/GRE data plane option is for interoperability only. Most vendors only support mVPN defined in Draft Rosen which uses PIM/GRE. The data plane options for NG mVPN defined by IETF include PIM/GRE, RSVP p2mp, mLDP p2mp. With JUNOS, mLDP is still roadmap feature. Thus RSVP-signaled p2mp LSPs are the preferred solution. However, if you want to connect to routers not capable of doing this ... PIM/GRE might be an option.