PE-based IPv6 multicast transition for mesh problem Yong Cui @ CERNET
Jan 14, 2016
PE-based IPv6 multicast transition for mesh
problem
Yong Cui @ CERNET
2
Why we need multicast transition? From CERNET
Existing multicast applications are in IPv4
Native IPv6 CERNET2 is expected to support IPv4 multicast applications
IPv4 multicast traffic is low
3
What’s multicast transition problem
IPv6 backbone
I Pv4 Customer
I Pv4 Customer I Pv4 Customer
CECE
PE
PE
CE
PE
Source
Receiver Receiver
How to setup a multicast tree in IPv6 backbone where edge of tree should be PE?
4
Auto-discovery members in mesh framework Auto-discovery of PEs (N PEs totally)
Mesh framework or 4over6 based on MP-BGP
CE
Ipv4 customer
CEPE1 PE4
PE2
IPv6 backbone
P
MP-B
GP
MP-BGP
MP
-B
GP
Ipv4 customer
Ipv4 customer
PE3CE
Ipv4 customer
CE
MP-BGP
5
Potential solution Construct multicast tree in IPv6 backbon
eDynamic mapped IPv6 tree (M trees)
Dynamically mapping IPv4 mgroup to IPv6 mgroup
Single static tree by PIM-SM IPv6 RP in IPv6 backbone
PE-based static tree by PIM-SM (N trees totally)
One tree rooted by each PE SPT rooted by each PE to all other PE
6
IPv4/v6 group mapping
CE
Ipv4 customer
CEPE1 PE4
PE2
IPv6 backbone
P
Ipv4 customer
Ipv4 customer
PE3CE
Ipv4 customer
CE
RPv4
(S,G)v4 <->(S’,G’)v6(S,G)v4 <->(S’,G’)v6
(S,G)v4 <->(S’,G’)v6 ,S’ is IPv6 address of the PE of S G’ is ff18:ssss:ssss:gggg:gggg::x
s and g are the (S,G) P maintains M IPv6 group states if there are M IPv4
groups
7
Construct a single tree in IPv6 backbone PE4 members table
PE IPv6 addr
PE1 IFv AFy
PE2 IFv AFy
be joined join
OK OK
OK OK
PE3 IFv AFy OK OK
CE
Ipv4 customer
CEPE1 PE4
PE2
IPv6 backbone
RPv6
Ipv4 customer
Ipv4 customer
PE3CE
Ipv4 customer
CEPE1 members table
PE IPv6 addr
PE2 IFv AFy
PE3 IFv AFy
be joined join
OK OK
OK OK
PE4 IFv AFy OK OK
•A single IPv6 group address is configure on RPv6 and PEs•Egress PE initiates a single join procedure to RPv6•SPT rooted by RPv6, IPv6 tree optimization is a problem•The number of IPv6 multicast groups is 1
8
Construct one tree rooted by each PE in IPv6 backbonePE4 members table
PE IPv6 addr
PE1 IFv AFy
PE2 IFv AFy
be joined join
OK OK
OK OK
PE3 IFv AFy OK OK
CE
Ipv4 customer
CEPE1 PE4
PE2
IPv6 backbone
P
Ipv4 customer
Ipv4 customer
PE3CE
Ipv4 customer
CEPE1 members table
PE IPv6 addr
PE2 IFv AFy
PE3 IFv AFy
be joined join
OK OK
OK OK
PE4 IFv AFy OK OK
•Each ingress PE has its own IPv6 group address •ingress PE sends its IPv6 group address to all other PEs by Softwire extensions•Egress PE initiates a join procedure to each ingress PE (SPT rooted by each PE)•The number of IPv6 multicast groups is N
9
IPv4 PIM-SM Sender/receiver Registration over IPv6 backbone
CE
Ipv4 customer
CEPE1 PE4
PE2
IPv6 backbone
P
Ipv4 customer
Ipv4 customer
PE3CE
Ipv4 customer
CE
RPv4
S tree
S register
Source
10
Multicast Forwarding
CE
Ipv4 customer
CEPE1 PE4
PE2
IPv6 backbone
P
Ipv4 customer
Ipv4 customer
PE3CE
Ipv4 customer
CE
RPv4
Source
11
Construct multicast tree in IPv6 backbone Dynamic mapped IPv6 tree (M trees)
Dynamically mapping IPv4 mgroup to IPv6 mgroup Scalability problem in IPv6 core
Single static tree rooted by IPv6 RP IPv6 tree optimization is a problem
PE-based static tree by PIM-SM (N trees totally) One tree rooted by each PE SPT rooted by each PE to all other PE Scalability: Keep less states in the backbone Efficiency: PE may receive some packets they do not requi
re Future work
Comments & co-authors are welcome To be a WG document
Conclusion and future work