July 2006 doc IEEE 802 11 06841 r

July 2006 doc. : IEEE 802. 11 -06/841 r 4 6 -Address Scheme for TGs Mesh Authors: Date: 2006 -07 -19 Notice: This document has been prepared to assist IEEE 802. 11. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802. 11. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures <http: // ieee 802. org/guides/bylaws/sb-bylaws. pdf>, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard. " Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair <stuart. kerry@philips. com> as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802. 11 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at <patcom@ieee. org>. Submission 1 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 Outline • Background • Review of 4 -Address Scheme and WDS in 802. 11 • 6 -Address Scheme • Addressing Examples – MP to MP – STA to STA – Interworking: STA to External STA • Summary and Discussions – Straw Poll Submission 2 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 Background • This proposal is to resolve several major comments including – CID #183: Rules for handling legacy STAs – CID #205: Encapsulation format to transmit frames via a root MP in HWMP • The current 4 -address scheme cannot support all cases of routing & forwarding in mesh networks where frames between legacy STAs associated with MAPs are delivered through multiple MPs, including redirecting MPPs ( Examples). – Use of proxy tables (e. g. , [1, 2]) is neither able to solve the problem of redirecting MPPs, nor a scalable solution for frame forwarding at intermediate MPs. – The encapsulation proposal in [3] incurs rather large overhead due to unnecessary duplication of several header fields. • The 6 -address scheme (e. g. , [1]) would be desirable not only for TGs mesh networks but also for other applications in the future. – However, MP to MP end-to-end traffic does not need the 6 -address scheme – selective use is possible. Submission 3 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 Review of 4 -Address Scheme and WDS in 802. 11 (1) • What is the (W)DS in existing 802. 11 standards? – No notion of true multihopping through nodes. • A kind of shared media/hub/L 2 switching implicitly assumed. • At most 1 hop from each other node • See the example on the right (given in [4]). – Hence not a proper model for the 802. 11 s wireless mesh networks. Submission 4 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 Review of 4 -Address Scheme and WDS in 802. 11 (2) • TGs mesh networks are different from the WDS described in the current 802. 11 standard. – Multi-hopping through MPs (i. e. , more than one hops from a source to a destination in general) – Existence of MPPs that can redirect incoming frames to other MPPs or destination MPs/MAPs by remapping of address fields • In tree-based routing in HWMP • In interworking with outside mesh • Tunneling between portals (e. g. , for wireless bridging) Submission 5 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 6 -Address Scheme (1) Octets: 2 2 6 6 6 2 4 Frame Control Dur Address 1 Address 2 Address 3 Address 4 RA TA DA Seq Control Qos Control Mesh Forwarding Control SA 0 -tbd 12 Mesh Addressing Field Payload FCS Bits: 0 -7 Bits: 8 -23 Bits: 0 -7 Octets: 6 Mesh Flags Mesh E 2 E Seq Number Time To Live Address 5 (If AE flag = 1) Address 6 (If AE flag = 1) Bit 0: Address Extension (AE) Bits 1 -7: Reserved for future use 4 These fields are always present in mesh frames. Mesh Forwarding Header Submission 6 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 6 -Address Scheme (2) To DS From DS AE Flag Address 1 Address 2 Address 3 Address 4 Address 5 Address 6 0 0 0 RA=DA TA=SA BSSID N/A N/P* N/P 0 1 0 RA=DA TA=BSSID SA N/P N/P 1 0 0 RA=BSSID TA=SA DA N/P N/P 1 1 0 RA TA DA SA N/P 1 1 1 RA TA Mesh DA Mesh SA DA SA * N/P = Not Present 11 s MAC Header (w/ modified field) Address 5 6 Frame Body FCS When the AE flag = 0, all fields have their existing meaning, and there exist no “Address 5” and “Address 6” fields – this assures compatibility with existing hardware and/or firmware. Submission 7 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 6 -Address Scheme – Address Mapping Principle • The ordering of the addresses should be from the innermost to the outermost “connections” ( More examples) – Address 1 & 2 for endpoints of a link between RX and TX – Address 3 & 4 for endpoints of a mesh path between a destination and a source MP • Including MPPs and MAPs – Address 5 & 6 for endpoints of an (end-to-end) 802 communication • A series of mesh paths connected at MPPs (e. g. , TBR in HWMP) or • An 802 path between legacy STAs (including nodes outside the mesh) or • Any mixture of them (e. g. , an MP to an STA or vice versa). MP MP link MP MPP link mesh path MP link mesh path 802 communication Submission 8 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 Addressing Examples: Network Configuration STA 3 • Wired L 2 Network MPP (Root) Consider the following three cases for different types of path selection modes/protocols: – STA 1 → STA 2 • Through MP 2 and MP 3 for HWMP on-demand routing and RA-OLSR • Through MPP for HWMP TBR Mesh Network MP 3 MP 2 – MP 1 → MP 4 • Only for HWMP TBR MP 1 MAP 1 – STA 1 → STA 3 MAP 2 • For all three protocols/modes STA 1 Submission STA 2 9 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 Addressing Examples: Operational Assumptions • Maintenance of STA association information* – HWMP • In on-demand routing**, each MAP/MPP locally maintains its STA association and responds to an RREQ message if any of destination addresses matches one of its associated STAs. • In TBR, the Root maintains a global mapping table for all MPs and STAs in the mesh (i. e. , Registration assumed; see 11 A. 4. 3. 1. 5. 4 of [5]). – RA-OLSR • Each MAP/MPP broadcasts its associated STAs to other MAPs/MPPs using LABA (see 11 A. 4. 3. 2. 13 of [5]). • Each MAP/MPP maintains LAB & GAB for mapping STAs to their associated MAPs (see 11 A. 4. 3. 2. 4. 7 of [5]). * External STA (i. e. , in wired networks) association at MPPs can be treated same way as wireless STAs. ** RREQ/RREP messages need to be modified as in slide #9 of [2]. Submission 10 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 Example 1 a: STA to STA not via Root Portal STA 1 MAP 1 Address 2 Address 3 Address 4 MAP 1 STA 2 N/A Address 1 Address 2 Address 3 Address 4 Address 5 Address 6 MP 2 MAP 1 MAP 2 MAP 1 STA 2 STA 1 Address 2 Address 3 Address 4 Address 5 Address 6 MP 3 MP 2 MAP 1 STA 2 STA 1 Address 2 Address 3 Address 4 Address 5 Address 6 MAP 2 MP 3 MAP 2 MAP 1 STA 2 STA 1 Address 2 Address 3 Address 4 STA 2 MAP 2 STA 1 N/A MP 2 MP 3 MAP 2 STA 2 Submission 11 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 Example 1 b: STA to STA via Root Portal STA 1 Address 2 Address 3 Address 4 MAP 1 STA 2 N/A Address 1 Address 2 Address 3 Address 4 Address 5 Address 6 MP 2 MAP 1 ROOT MAP 1 STA 2 STA 1 Address 2 Address 3 Address 4 Address 5 Address 6 ROOT MP 2 ROOT MAP 1 STA 2 STA 1 Address 2 Address 3 Address 4 Address 5 Address 6 MP 3 ROOT MAP 2 ROOT STA 2 STA 1 Address 2 Address 3 Address 4 Address 5 Address 6 MAP 2 MP 3 MAP 2 ROOT STA 2 STA 1 Address 2 Address 3 Address 4 STA 2 MAP 2 STA 1 N/A MAP 1 MP 2 Root MP 3 MAP 2 STA 2 Submission 12 Root maps STA 2 to MAP 2 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 Example 2: STA to External STA 1 Address 2 Address 3 Address 4 MAP 1 STA 3 N/A Address 1 Address 2 Address 3 Address 4 Address 5* Address 6* MP 2 MAP 1 MPP MAP 1 STA 3 STA 1 Address 2 Address 3 Address 4 Address 5 Address 6 MPP MP 2 MPP MAP 1 STA 3 STA 1 DA SA STA 3 MPP** MAP 1 MP 2 MPP STA 3 Submission Non-802. 11 (i. e. , Ethernet) frame * Intermediate MPs (here MP 2) don’t have to process these fields. ** Ethernet address of MPP’s interface to a wired network 13 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 Example 3: MP to MP Via Root Portal MP 1 Address 2 Address 3 Address 4 Address 5 Address 6 MP 2 MP 1 ROOT MP 1 MP 4 MP 1 Address 2 Address 3 Address 4 Address 5 Address 6 Root MP 2 ROOT MP 1 MP 4 MP 1 Address 2 Address 3 Address 4 MP 3 ROOT MP 4 MP 1 Address 2 Address 3 Address 4 MP 3 MP 4 MP 1 MP 2 Root MP 3 MP 4 Submission 14 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 Summary and Discussions • A number of open comments depend on the proposed scheme. – CID #183, #205, #207, #58, #217, #155, . . • Considered both intra-mesh communications and interworking with external wired networks. • The 6 -address scheme protects the origin and destination fields with encryption and thus increases the security of the overall approach. • The use of two additional address fields (i. e. , “Address 5/6”) is optional, and their existence is indicated by the AE flag 0. • The 6 -address scheme may have applications beyond TGs. – That suggests this feature should be documented as a delta on the baseline standard rather than a mesh specific feature. – Regarding frame aggregation/encapsulation, this proposal is compatible with TGn’s MPDU aggregation scheme ( Details). Submission 15 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 6 -Address Scheme: Frame Format Consideration Encrypted Octets: 2 2 6 6 6 2 4 Frame Control Dur Address 1 Address 2 Address 3 Address 4 RA TA DA Seq Control Qos Control Mesh Forwarding Control SA 0 -tbd 12 Mesh Addressing Payload FCS Field Bits: 0 -7 Bits: 8 -23 Bits: 0 -7 Octets: 6 Mesh Flags Mesh E 2 E Seq Number Time To Live Address 5 (If AE flag = 1) Address 6 (If AE flag = 1) Bit 0: Address Extension (AE) Bits 1 -7: Reserved for future use 4 These fields are always present in mesh frames. Mesh Forwarding Header Submission 16 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 6 -Address Scheme Straw Poll • Shall we accept the 6 -address scheme and prepare texts based on it for approval during the September TGs meeting? – Yes – No – Abstain Submission 17 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 References 1. L. Chu et al. , “ST+UCLA TGs Mesh Network Proposal, ” IEEE 802. 11 -05/0379 r 0. 2. H. Gossain et al. , “Packet Forwarding for Non-routable Devices in Multi-hop Wireless Mesh, ” IEEE 802. 11 -06/0661 r 0. 3. J. Kruys and S. Rahman, “Mesh Encapsulation”, Rev. 3. 4. D. Engwer, “’WDS’ Clarifications, ” IEEE 802. 11 -05/0710 r 0. 5. IEEE P 802. 11 s/D 0. 01 Submission 18 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 Backup Slides Submission 19 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 6 -Address Scheme – Examples for Link/Mesh Path/Connection (1) MP MP link (= mesh path) MP MP link MP link mesh path MAP STA link MP MP link MAP link STA link mesh path 802 communication Submission 20 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 6 -Address Scheme – Examples for Link/Mesh Path/Connection (2) MP MP link MP MPP link mesh path MP link mesh path 802 communication MAP STA link MP MPP link mesh path MAP link STA link mesh path 802 communication Submission 21 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 6 -Address Scheme – Examples for Link/Mesh Path/Connection (3) MP MPP link mesh path MAP link STA link mesh path 802 communication MAP 1 STA link MP MPP link mesh path link MPP link Wired Networ k External STA mesh path 802 communication Submission 22 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 A-MPDU Aggregation • Robust Structure • A purely-MAC function – – PHY has no knowledge of MPDU boundaries Simplest MAC-PHY interface • Control and data MPDUs can be aggregated • Limited to a single rate Submission 23 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 A-MSDU • Efficient Structure • MSDUs of the same TID can be aggregated • Error recovery is expensive Submission 24 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 Bursting No idle gap Np Ns PSDU Ns Normal ACK policy PSDU x. IFS Np Ns PSDU Non-normal ACK Last PSDU bit Np • • = N-Preamble Ns = N-Signal field @ robust encoding rate Sequence of MPDUs or PSDUs from same transmitter on-the-fly aggregation Reduced inter-frame spacing – – 0 usec if at same Tx power level and PHY configuration 2 usec otherwise (with preamble) Multiple RAs allowed within the burst multiple rates within burst allows varying TX power within burst Block Ack Request and Block Ack frames allowed within the burst • Does not support multiple responses from multiple receivers Submission 25 K. Kim et al.

July 2006 doc. : IEEE 802. 11 -06/841 r 4 On the Use of TGn Frame Aggregation Schemes in TGs • The A-MPDU structure seems simplest and best suited for Mesh applications • The A-MSDU structure requires overhead that seems to add no value • Bursting is something that happens “below the horizon” • Considering that TGn does work on features that TGs can leverage, there is no need for TGs to spend (more) time on aggregation, other than encouraging TGn to make sure the AMSDU makes it to the TGN amendment Submission 26 K. Kim et al.