XCAST eXplicit Multi-Unicast Yuji IMAI (UG) xcast-fan-club/WIDE XCAST WG Eiichi Muramoto Panasonic/WIDE XCAST WG

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 (Source Dirk Ooms in Alcatel.com) Category of Multicast Applications Existing Multicast (scales with number of receivers) Small Group Multicast (scales with number of sessions) Focus!

Goal: Narrowcast like multicast 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 TV conference Multi-player game

Tokyo London N.Y. Paris Internet 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 ROUTING header [ N.Y., London, Paris ] [ 1, 1, 0 ] UDP header IPv6 header SRC=Tokyo DST=XCAST. Example: XCAST for IPv6

Routing procedure sender-S receiver-A receiver-C receiver-B payload C B A S A S C B S C S B S

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

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

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.

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  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. Progress  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 2006 IP ｖ６ internet PHS 128kbps FTTH 100Mbps 1Mbps 128kbps 18 ｆｐｓ 2 ｆｐｓ Hotspot 11Mbps Contact: Takahiro Yoneda, Eiichi Muramoto, Kazunobu

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

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

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

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 

14 X6Bone project NoBUG CBUG IRISA (fr) WIDE xgate /40 EBUG BayBUG /40 v6/v4 tunnel ADSL For WIDE 6Bone /48 NBUG2 KNOPPIX Siz-PUG UMD (MY) WakHok Univ.