Mapping Differentiated Service Classes to User Priorities Month Year doc.: IEEE 802.11-yy/xxxxr0 November 2008 Mapping Differentiated Service Classes to User Priorities Date: 2008-10-10 Authors: Osama Aboul-Magd, Nortel Networks John Doe, Some Company

Month Year doc.: IEEE 802.11-yy/xxxxr0 November 2008 Abstract This contribution considers issues related to CID 4006, LB 137. In particular it considers the mapping between the IP Diffserv code points (DSCP) and the IEEE 802.11 UP code points Osama Aboul-Magd, Nortel Networks John Doe, Some Company

November 2008 Background The current revision of the IEEE 802.11u draft (D4.0) provides two methods for mapping IP DSCP to IEEE 802.11 UP. Explicit mapping using one or more DSCP Exception field By range This contribution argues that the explicit mapping should be retained and the by-range mapping should be removed from the draft. Osama Aboul-Magd, Nortel Networks

IP Diffserv Code Points November 2008 000000 CS 0 001000 CS 1 010000 CS 2 011000 CS 3 100000 CS 4 101000 CS 5 110000 CS 6 111000 CS 7 000001 001001 010001 011001 100001 101001 110001 111001 000010 001010 AF11 010010 AF21 011010 AF31 100010 AF41 101010 110010 111010 000011 001011 010011 011011 100011 101011 110011 111011 000100 001100 AF12 010100 AF22 011100 AF32 100100 AF42 101100 110100 111100 000101 001101 010101 011101 100101 101101 110101 111101 000110 001110 AF13 010110 AF23 011110 AF33 100110 AF43 101110 EF 110110 111110 000111 001111 010111 011111 100111 101111 110111 111111 The IETF defines 21 different PHB with their related definitions There is no expected behaviour based on the numerical values of the DSCP Osama Aboul-Magd, Nortel Networks

IP Diffserv PHB Definitions November 2008 IP Diffserv PHB Definitions Class Selector (CS): introduced for backward compatibility and provides 8 levels of priority Expedited Forwarding (EF): forwarding treatment aimed at providing services with low loss, low delay, and low delay variation. A rate R is configured for EF PHB and the delay of the EF packets is expected to be bounded. Assured Forwarding (AF) PHB Group: defines four possible AF Classes. Each Class is assigned three discard levels for selective discard of incoming packets. Each class offers different forwarding assurances (discard precedence) to IP Packets. A configurable minimum amount of resources is needed for each AF class. AFi2 AFi3 AFi1 Incoming packets Up to four AF classes Osama Aboul-Magd, Nortel Networks

November 2008 IEEE 802.11 UP IEEE 802.11 UP are based on those defined in IEEE 802.1D. Each priority has a designated traffic type (informative) Priority UP IEEE 802.1D AC Designation 1 BK AC_BK Background 2 - BE AC_BE Best Effort 3 EE 4 CL AC_VI Video 5 VI 6 VO AC_VO Voice 7 NC Lowest Highest Osama Aboul-Magd, Nortel Networks

Mapping Issues Both IP DSCP and Ethernet PCP imply certain behavior. November 2008 Mapping Issues Both IP DSCP and Ethernet PCP imply certain behavior. For example IP packets marked as EF expects low delay and should be mapped to IEEE 802.11 UP that provides similar behavior. Mapping by range may result in inconsistent behavior between IP and IEEE 802.11. E.g. packets marked as EF are treated at low priority. On the other hand explicit mapping ensures consistent treatment of packets and frames. Osama Aboul-Magd, Nortel Networks

Possible Mapping based on RFC 4594 November 2008 Possible Mapping based on RFC 4594 Recommended DSCP Mapping Recommend using RFC4594 Application Class Definitions and Mappings (Summarized Above) Arrows Show Possible Alignment Of 802.11u Application Classes To RFC4594 Application Classes Additional Concerns with Current 802.11u DSCP Mapping Bulk Data uses AF1. AF class is intended for applications with assured bandwidth allocation and it does not allow possible starvation, characteristic of “below BE” application classes (REF RFC 2597). Recommend aligning Bulk Data to RFC4594 High Throughput Data. Controlled Load is a behavior, not an application class (RFC 2211). It can be applied to many application classes. Signaling should use CS not AF. AF has drop precedence which is not applicable to signaling. CS also helps ensure better end-user responsiveness. Osama Aboul-Magd, Nortel Networks

November 2008 Straw Poll Do you agree that the by-range mapping may lead to inconsistent mapping between DSCP and UP Yes: No: Don’t care: Do you support the removal of the by-range mapping from IEEE 802.11u draft Do you support updating the table T-2 in Annex T to align it with RFC 4594 applications Osama Aboul-Magd, Nortel Networks

November 2008 References [1] IETF RFC 2474, “Definition of the Differentiated Service field (DS filed) in the IPv4 and IPv6 Headers”, December 1999. [2] IETF RFC 2597, “Assured Forwarding PHB Group”, June 1999. [3] IETF RFC 3246, “An Expedited Forwarding PHB (per Hop Behavior), March 2002. [4] IETF RFC 4594, “Configuration Guidelines for Diffserv Service Classes”, August 2006. Osama Aboul-Magd, Nortel Networks