Access Router Identifier (ARID) for supporting L3 mobility

1. Access Router Identifier (ARID) for supporting L3 mobility Soohong Daniel Park soohong.park@samsung.com Samsung Electronics. Jaehwan Lee tasmea@kt.co.kr Korea Telecom Soohong Daniel Park & Jaehwan Lee

2. AR AR AP AP AP MN1 MN2 L3 Handover ? L3 Handover ? Miscellaneous Handover in WLAN • Typically, STA doesn’t know whether it changes AP(MN1) or AR(MN2) when moving to another domain without IP layer operations or even more layers. Soohong Daniel Park & Jaehwan Lee

3. Problem Statement • #3 There is no standardized mechanism in 802 for information exchange between mobile terminals and network attachment points. This impacts the ability to make informed decisions to select between disparate network attachment points or to initiate handoffs between heterogeneous network types or between administrative domains within a single network type. Thus there is a need to develop a standard that permits mobile terminals and network attachment points to access information on which to base effective handoff decisions. Soohong Daniel Park & Jaehwan Lee

4. Current drawback of FMIP6 • After discovering a new nearby AP, MN sends RtSolPr in order to resolve AP identifiers to subnet router information. • If the new AP is connected to the PAR’s current interface itself, PAR MUST respond indicating that the point of attachment is known, but is connected to current interface. • Handover doesn’t need a new CoA. • Similar drawback happens on IPv4. PrRtAdv (Code=2, LLA Sub-type=5) AR RtSolPr AP AP MN1 RtSolPr: Router Solicitation for Proxy Advertisement PrRtAdv: Proxy Router Advertisement Soohong Daniel Park & Jaehwan Lee

5. Proposal • AP (means network attachment points) lets MN know the handover either L2 or L3 when moving to a new attachment point. • Reduced the redundant message exchanges between MN and AR when doing L2 handover. • Supporting effective handover decision to MN for doing a fast handover. Soohong Daniel Park & Jaehwan Lee

6. Potential Solution -1 • ARID in the MAC Management Frame. • Capability Information in the Beacon (and Probe response) can be used for letting MN know its movement whether it occurs on L2 or L3. • Just let STA knows what handover tends to occur when moving to another link. • Simply managed and configured by admin. • ARID (Access Router Identifier) can be simply configured in conjunction with the SSID on the AP (network attachment points). Soohong Daniel Park & Jaehwan Lee

7. Potential Solution -1 Beacon Probe response 0 7 15 ARID So far, the length of ARID is not fixed because several amendments are using this area. Soohong Daniel Park & Jaehwan Lee

8. Potential Solution -2 • ARID in conjunction with 802.11k-D1.0 • Section 7.3.2.26 Neighbor Report element (Fig. k18,k19) • It contains pertinent information on a collection of AP’s that are candidates to which STAs can roam to. Octets: Bit: • ARID bit, if different from the current ARID, indicates that the AP represented by this ARID • is a different subnet, so that L3 handover must be performed when attaching to this AP. Soohong Daniel Park & Jaehwan Lee

9. Proposed Operation - I Solution-1: Extended Beacon IETF is working on this area (CAPWAP WG) AR AR aaaa aaaa bbbb AP AP AP Scanning Scanning Beacon or Probe response with ARID (aaaa) Beacon or Probe response with ARID (bbbb) MN1 MN2 aaaa ? L2 Handoff bbbb ? L3 Handoff Soohong Daniel Park & Jaehwan Lee

10. Proposed Operation - II Solution-2: Extended Site Report element of 802.11k AR AR aaaa aaaa bbbb AP AP AP Site Report Request Site Report Request L3 Handover Site Report response with ARID (aaaa) Site Report response with ARID (bbbb) MN1 MN2 aaaa ? L2 Handoff bbbb ? L3 Handoff Soohong Daniel Park & Jaehwan Lee

11. Use case – I (hotspot) • When MN tries to roam, first MN searches near APs. • If near APs have different IP subnet due to different AR, selecting the AP which does not need to L3 roaming is beneficial • In this case, MN should roam to AP2, not to AP3, because AP3 does not share the AR even though SSID is the same. MN AP1 T1 or E1 Router 1 MN Ethernet Internet AP2 T1 or E1 Router 2 (NAS) AP3 xDSL xDSL Modem DSLAM Soohong Daniel Park & Jaehwan Lee

12. Use case – II (University) • When MN moves to next building, MN should roams to other AP located in next building. • In university, generally IP subnet can be different according to building. • In this case, MN must renew IP address due to different AR. • ARID can reduce handover time if MN associate with AP and renew IP address simultaneously. Internet Building 1 Ethernet Ethernet Building 2 AP2 AP1 MN MN Soohong Daniel Park & Jaehwan Lee

13. Conclusion • Develop a standard that permits mobile terminals and network attachment points to access information on which to base effective handover decisions. • Suggest to work on the solution for distinguishing either L2 or L3 handover on the 802.11 as well as heterogeneous networks. • Today, ISP is requiring for this solution. Soohong Daniel Park & Jaehwan Lee

14. Open Issue • The length of ARID is not definitely fixed so far in this proposal. • Several amendments are likely to use this area. • At least 4-bits are available at this stage. Soohong Daniel Park & Jaehwan Lee

15. Motion • Move to request that the IEEE 802.11 WIEN SG accepts that the Access Router ID (ARID) is regarded as work to be done within the PAR Soohong Daniel Park & Jaehwan Lee