Presentation is loading. Please wait.

Presentation is loading. Please wait.

BGP based Multi-homing in Virtual Private LAN Service Wim Henderickx Florin Balus.

Similar presentations


Presentation on theme: "BGP based Multi-homing in Virtual Private LAN Service Wim Henderickx Florin Balus."— Presentation transcript:

1 BGP based Multi-homing in Virtual Private LAN Service Wim Henderickx Florin Balus

2 Problem Statement CE1 VPLS PE1 PE2 PE3 PE4 CE1 is multi-homed to PE1 and PE2; CE1 wants a resilient connectivity Simple dual connectivity leads to loops and duplicate packets. Proposal provides a complementary solution next to STP, MC- LAG, etc leveraging BGP CE3 CE4

3 Goal Address both PE and access link failure Provides fast convergence times Only the traffic transiting the affected network elements should be impacted Decouple the Multi-Homing mechanism from the PW signaling Minimize the traffic load on the network; ideally just the local PEs should be involved in the selection process Re-use existing BGP procedures while minimizing the network migration to ease operation

4 Solution Let PE1 and PE2 know that they are connected to the same site using BGP-AD AFI/SAFI, procedures –Add to BGP-AD NLRI an identifier for the Multi-homed Site –Site ID to be the same between peer PEs PW infrastructure can be built using either LDP or BGP signaling Local Multi-homed PE(s) decide which PE is the designated forwarder for a given site/CE using BGP attributes –LPREF e.g. –VSI ID is the tie-breaker If none of the attached CE(s) is elected as designated forwarder for a given VSI, PW status can be used to minimize the BUM traffic in the network

5 Solution Designated PE forwards packets from and to CE Non-designated PEs (losing PEs) drop packets from CE as well as from other PEs The effect is as if CE was single-homed to just the designated PE

6 Proposal BGP AD MH NLRI to carry the VSI-ID identifying the base VSI and 2 byte Site ID

7 Operation CE2 VPLS PE1 PE2 PE3 PE4 Site1 LPREF=200 CE3 CE4 CE1 Site2 LPREF=200 Site1 LPREF=100 Site2 LPREF=100 PE1 is elected as designated forwarder

8 Operation: link failure CE2 VPLS PE1 PE2 PE3 PE4 Site1 LPREF=200 CE3 CE4 CE1 Site2 LPREF=200 Site1 LPREF=100 Site2 LPREF=100 PE1 withdraws the MH NLRI, send a MAC flush PE2 becomes designated forwarder for CE1

9 Operation: PE failure CE2 VPLS PE1 PE2 PE3 PE4 Site1 LPREF=200 CE3 CE4 CE1 Site2 LPREF=200 Site1 LPREF=100 Site2 LPREF=100 PE2 becomes designated forwarder for CE1/CE2 upon BGP neighbor failure detection or upon reception of MH-NLRI withdraw for CE1/CE2

10 Operation continued RR usage does not impact the operation since the VSI-ID is unique No impact in Inter-AS scenarios since the designated forwarding decisions are local multi-homed PE(s) No impact on H-VPLS operation

11 Next steps Minimize BGP flooding through the usage of ORF Add startup procedures and procedures for re-configuration Do we use this framework for both LDP VPLS and BGP VPLS?

12 Questions?


Download ppt "BGP based Multi-homing in Virtual Private LAN Service Wim Henderickx Florin Balus."

Similar presentations


Ads by Google