1. MVPN/MSDP SA Interoperation
draft-zzhang-bess-mvpn-msdp-sa-interoperation
Zhaohui Zhang
Lenny Giuliano
Juniper Networks
IETF 100
BESS WG

2. MSDP Source Active
FHR
RP1 discover ASM sources via PIM register mechanism in its local domain and distribute (s,g, rp1) information via SA message to other RPs
PIM (*,g) joins terminate at one of the RPs
RP6 learns (s,g) via the SA and sends PIM (s,g) join towards the FHR
MSDP sessions must be continuous among all RPs
RP1
(s,g) register
RP2
RP3
(s,g) join
RP4
RP5
RP6
LHR
(*,g) join
MSDP session
MSDP (s,g, rp1) SA
PIM join
IETF 100
BESS WG

3. MVPN Source Active Inter-site source-tree-only mode
C-RP discovers ASM sources via PIM register mechanism and distribute (s,g,c-rp) information via MSDP SA message to its MSDP peers PE1
PE1 advertise MVPN (s,g) SA routes to all PEs
Note there is no RP information
All PEs learns (s,g) via the SA and PE3 sends (s,g) C-multicast route towards its UMH PE2
PE3 gets (*,g) join from CE but does not send (*,g) C-multicast route
PEs are just like RPs in the previous slide, and MVPN/MSDP SAs are similar – except one caveat
FHR
C-RP
(s,g) register
PE1
PE2
PE3
PE4
(*,g) join CE
LHR
(*,g) join
MSDP session
MSDP (s,g, rp1) SA
PIM join
MVPN C-multicast route
MVPN (s,g) SA
IETF 100
BESS WG

4. MVPN + MSDP
A PE does NOT advertise MSDP SAs when it receives MVPN SAs!
RFC 6513/6514 does not specify the MVPN SA -> MSDP SA conversion
C-RP2 will not get MSDP SAs on its MSDP session with PE3
PE3 will not get (*,g) joins (as they stop at C-RP2), and will not send (s,g) C- multicast route
There must be an MSDP session between PE1/PE3, or PE1/C-RP2, or C-RP1/PE3, or C-RP1/C-RP2
To ensure MSDP session continuity
These are per-customer MSDP sessions
These additional MSDP sessions will cause multiple PEs to advertise excessive MVPN SA routes
FHR
C-RP1
(s,g) register
PE1
PE2
PE3
PE4 X
MSDP session
C-RP2
LHR
MSDP (s,g, rp1) SA
(*,g) join
MVPN (s,g) SA
IETF 100
BESS WG

5. Solution
FHR
Treat incoming MVPN SAs as MSDP SAs and trigger outgoing MSDP SAs to peers
MVPN SA routes additionally carry an "MVPN SA RP-address Extended Community“
To mimic MSDP (S,A,RP)
C-RP1
(s,g) register
PE1
PE2
PE3
PE4
PIM (s,g join)
MSDP session
C-RP2
LHR
MSDP (s,g, rp1) SA
(*,g) join
MVPN (s,g,rp1) SA
PIM join
MVPN C-multicast route
IETF 100
BESS WG

6. Aren’t we “deprecating MSDP”?
Ongoing Mboned discussion about deprecating inter-domain ASM
Not about deprecating MSDP
Recommendation not mandation
MSDP is actually widely used for intra- domain as well
This document is for real deployment scenarios that need interoperation between MVPN and customer MSDP infrastructure
IETF 100
BESS WG

7. Next Steps
Seeking WG comments
Seeking WG adoption
IETF 100
BESS WG