1. 1 Highlight 1: AER/NCA

2. 2 Active Multicast Repair Services Receiver Sender Conventional Routers Repair latency is a complete round trip time Link causing loss of original message Lost message retransmission request Retransmitted message Traditional Error Recovery (TCP) Base premise: Active Networking can significantly improve latency, efficiency, and scalability of transport protocols Repair latency much less than one round trip Loss detected by nearest router downstream from loss Message retransmitted by nearest router upstream from loss Active Error Recovery (AER) Active Packet ‘ Active Node Active Routers Active Packet

3. 3 AER/NCA AER Repair Servers (RSs) Co-located with routers AER loss handling: rcvrs and RSs unicast NAKs RSs subcast NAKs one level downstream subcast repairs, NAK supression NCA Estimating worst receiver TCP friendliness Decoupled from AER Sender Repair Servers Routers Receivers

4. 4 Team 4 Demonstration Configuration AER/NCA Send Applications (Sun Ultra 5s/Solaris) NIST Net WAN Emulators (200 MHz Pentium Pros/LINUX) CANEs Active Node (Dual Processor Sun Ultra 2/Solaris) NIST Net WAN Emulator (733 MHz Pentium III/LINUX) AER/NCA Receive Apps (Windows NT with HW MPEG2 Decoders)

5. 5 Video Server (Unicast) AER Demo: Enhanced Reliable Transport With repair servers active, dropped packets repaired locally - decreased latency speeds playout With repair servers inactive, dropped packets repaired by video server - increased latency delays playout Emulated bottleneck link Unicast MPEG-2 Video Client

6. 6 Demo Performance Indicators Total AER Packets Received Short-term average “goodput” in packets/sec Short-term average of error recovery ratio -> dropped packets recovered / dropped packets detected Short-term average delay in packet recovery

7. 7 AER Demo: Semi-reliable Multicast With repair servers active, dropped packet repaired before playout time: quality improved With repair servers inactive, dropped packets not repaired before playout time: quality suffers Video Server (Multicast) Emulated bottleneck link Multicast MPEG-2 Video Client

8. 8 AER Demo: Bandwidth Sharing Data Server (Multicast) Emulated bottleneck link Multicast Data Clients Independent sessions share bandwidth fairly as number of sessions is increased