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Congestion Notification Process for Real-Time Traffic. draft-babiarz-tsvwg-rtecn-00.txt. Kwok Ho Chan khchan@nortelnetworks.com. Jozef Babiarz babiarz@nortelnetworks.com. 59 th IETF, March 1, 2004. DiffServ Field & Explicit Congestion Notification.
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Congestion Notification Process for Real-Time Traffic draft-babiarz-tsvwg-rtecn-00.txt Kwok Ho Chan khchan@nortelnetworks.com Jozef Babiarz babiarz@nortelnetworks.com 59th IETF, March 1, 2004
DiffServ Field & Explicit Congestion Notification Explicit Congestion Notification (ECN) reserved for bits 6 & 7 0 1 2 3 4 5 6 7 ECN DSCP 0 15 4 8 31 Version HLen DS field Length Identification Flags Fragment offset IP header TTL Protocol Header checksum Source address Destination address Data The DiffServ (DS) Field is an 8-bit field in the IP header and is defined in RFC 2474. • The first six bits contain the DiffServ Code Points (DSCP). • The two least significant bits (LSBs) of the DiffServ Field (bits 6 & 7) are used for Explicit Congestion Notifications (ECN) RFC 3168 defines method for TCP flows. Congestion Notification Process for Real-Time Traffic 59th IETF
Major Points • ECN marking for real-time non TCP flows • Does not impact ECN for TCP (RFC 3168) • Meter real-time flows • Mark ECN bits if congestion detected • Metering and marking is deploy only where needed • Requires separation of real-time flows • Reaction to ECN marking is the responsibility of end devices / application Congestion Notification Process for Real-Time Traffic 59th IETF
Usage • Flow admission control of real-time traffic • Rate control of established flows • Features • Allows end-to-end control • Based on current network load conditions • Selective deployment of metering and ECN marking in network • End stations need to support ECN capability Congestion Notification Process for Real-Time Traffic 59th IETF
Next Steps • Would like to request that this draft be considered as a workgroup item Congestion Notification Process for Real-Time Traffic 59th IETF