XCAST explicit Multi-Unicast. Presented By Mahesh Gupta

Transcription

1 XCAST explicit Multi-Unicast Presented By Mahesh Gupta

2 Category of Multicast Applications Focus! Broadcast-like (one-to-many) Multicast of IETF meetings Broadcast of TV programs Narrowcast-like (a few-to-a few) IP Telephony with conferencing Video conferencing Real-time collaborative applications Multiparty networked games Existing Multicast (scales with number of receivers) Small Group Multicast (scales with number of sessions)

3 Goal: Narrowcast like multicast TV conference Multi-player game To deliver for limited small number of nodes Network must support very huge number of small groups. Anybody can transmit from anywhere on the Internet

4 Main idea of XCAST Instead of a group address, an explicit list of unicast destination addresses is stored in an extra header. IPv6 header SRC=Tokyo DST=N.Y. Hop-byHop header TAIL=Paris IPv6 header SRC=Tokyo DST=XCAST. ROUTING header [N.Y., London, Paris] [ 1, 1, 0 ] UDP header Example: XCAST for IPv6 Tokyo N.Y. Internet Paris London

5 Routing procedure S B receiver-b sender-s S B C payload S C S A B S A payload payload receiver-c C payload payload receiver-a

6 Routing procedure (detailed) Tokyo [NY, London, Paris] [ 1, 1, 1 ] [NY, London, Paris] [ 0, 1, 1 ] Paris N.Y. [NY, London, Paris] [ 1, 0, 0 ] London a. Look-up the next-hop for each address using a unicast routing table. a. Bundle up destinations which have same next-hop

7 Advantages XCAST can be delivered using only unicast routing information. No need for a multicast specific routing protocol maintaining multicast status on intermediate routers group address allocation sender location advertisement Unlimited Scalability with respect to the number of groups

8 Advantages(Cont d) Explicit end-to-end control of multicast group membership. Senders can start transmission anytime without any preparation (MLD, IGMP, PIM...). With existing multicast, receiver must join before transmission. Sender can change the group membership (destinations) per packet basis. With existing multicast schemes, membership change is done by join/prune process, a complex process.

9 SICC ( Sender Initiated Congestion Control ) Feature ( SICC is intended to provide) TCP Fairness Fast Congestion Avoidance Intra Session Fairness ( not limited by slowest receiver ) Method Progress Multiple predefined CBR associated with a different XCAST6 group containing receivers with similar acceptable sending rates. The acceptable sending rate of each receiver is estimated at the sender using TCP-friendly Rate Control (TFRC:RFC3448) in response to feedback generated by the receiver. Panasonic implemented SICC on XCAST6 and installed on the prototype of Network camera, Linux xcast6-patch, windows viewer under X2U router. Internet Conference 2005 ( ) Demonstration in WIDE camp March on 2006 Future plan Field experiment on AI3 network in Autumn kbps IPv6 internet PHS 128kbps 2fps 1Mbps Hotspot 11Mbps 18fps FTTH 100Mbps 18fps

10 Deployment of existing multicast Connecting XCAST islands by tunneling. Tokyo Paris N.Y. London negotiation between network operators complicated management encapsulation/peeling cost Big obstacle for deployment

11 Semi-permeable capsule of XCAST6 The intermediate router which does not support XCAST6 treats a XCAST6 datagram as a regular unicast datagram. IPv6 header SRC=Tokyo DST=N.Y. Hop-byHop header TAIL=Paris IPv6 header SRC=Tokyo DST=XCAST. ROUTING header [N.Y., London, Paris] [ 1, 1, 0 ] UDP header Temporal destination Type prefix has 01 that means ignore this option and forward if router doesn t know this option.

12 Semi-permeable capsule(cont d) Even if non-xcast6 routers are on the way, XCAST6 datagrams pass them once and turn back to next destination at next XCAST6 node. Tokyo N.Y. Paris London i. End node can transmit XCAST6 in any environment. ii. Installing more XCAST6 routers, path become optimized gradually.

13 Implementations XCAST fan club/wide project/fujitsu Lab. OS: NetBSD 3.0, FreeBSD VIC (Video Conference) & RAT (Robust Audio Tool) XCAST fan club/etri/soongsil University OS: Linux 2.6.x VIC & RAT

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