140 likes | 265 Views
doc: IEEE 802.11-04/1052r0. 802.21 and TGr. Marian Rudolf, Alan Carlton - InterDigital. Summary. 802.21 and TGr seem to address complementary mobility scenarios 802.21 – Across 802 networks and 802.11 Inter-ESS mobility 802.11r – Intra-ESS mobility for 802.11
E N D
doc: IEEE 802.11-04/1052r0 802.21 and TGr Marian Rudolf, Alan Carlton - InterDigital Rudolf, Carlton
Summary • 802.21 and TGr seem to address complementary mobility scenarios • 802.21 – Across 802 networks and 802.11 Inter-ESS mobility • 802.11r – Intra-ESS mobility for 802.11 • But expect partial overlap between 802.21 and TGr mobility solutions, • ESS definition is too broad and unclear and does not allow to draw a clear boundary line between 802.21 and TGr • When addressing L2 mobility handling across different 802 technologies, 802.21 will automatically come up with a solution that implies L2 mobility handling for the same 802 technology • Two different mobility solutions for 802.11 are not an attractive option, 802.21 and TGr mobility solutions should, • either be fully complementary • or TGr solution should be forwards-compatible with future 802.21 framework • Many good reasons speak in favor of a quickly available TGr standards supplement, but need to anticipate on 802.21 development Rudolf, Carlton
Introduction • From 802.21 and TGr PARs and 802.21 requirements, • TGr scope “… This PAR will apply only to the STA-AP state within the same ESS,…” • 802.21 scope “… extensible 802 media access independent mechanisms that enable the optimization of handover between heterogeneous 802 systems and may facilitate handover between 802 systems and cellular systems” • 802.21 draft requirements – Handover Scenarios IEEE 802 Family, … Handover between 802.3 and 802.11 networks Handover between 802.11 and 802.11 networks, across ESSs … • 802.21 Media-Independent Handover addresses 802.xx to 802.yy and 802.11 inter-ESS mobility cases • 802.11r Fast BSS Transition addresses 802.11 intra-ESS mobility cases Rudolf, Carlton
802.11 ESS definition • ESS definition in 802.11-1999 Clause 3.25 “A set of one or more interconnected basic service sets (BSSs) and integrated local area networks (LANs) that appears as a single BSS to the logical link control layer at any station associated with one of those BSSs.” • ESS definition in 802.11-1999 Clause 5 “5.2.2.1 The key concept is that the ESS network appears the same to an LLC layer as an IBSS network. Stations within an ESS may communicate and mobile stations may move from one BSS to another (within the same ESS) transparently to LLC.” • Key points, • L2 connectivity inside ESS • SSID does not define the ESS • STAs within ESS may communicate and move transparently to LLC Rudolf, Carlton
AP + DS + Portal 802.11 ESS – logical definition HOST Router 802.3 network 802.11-1999 Clause 5.2.2.1 “The key concept is that the ESS network appears the same to an LLC layer as an IBSS network. Stations within an ESS may communicate and mobile stations may move from one BSS to another (within the same ESS) transparently to LLC.” Portal Distribution System AP AP AP STA Source: 11-04-0629-01 by Nortel, Airespace Rudolf, Carlton
Portal Portal Integration Integration AP Device AP Device Distribution System Distribution System WM WM 802.11 ESS definition / L2 connectivity with VLAN HOST Router 802.3 network Portal Portal 802.3 L2 Hub or Switch 802.3 L2 Hub or Switch Distribution System STA STA STA ESS with a logical DS and Portal using a Router ESS L2 link ESS L2 link Source: 11-04-0629-01 by Nortel, Airespace Rudolf, Carlton
Internet Internet L2 link L2 link Scenario 1 – L3 versus L2 mobility R1 R2 FA FA No L2 connectivity between two DS Clear separation between L2 and L3 mobility handling 802.21 and 802.11r complementary AP1 AP2 AP3 AP4 ESS2 ESS1 TGr L2 mobility TGr L2 mobility 802.21 L3 assisted mobility (Mobile IP) Rudolf, Carlton
Internet Internet Scenario 2 – Complex network setups R1 R2 L2 connectivity with Router Both L3 and L2 mobility handling apply 802.21 (L3 assisted) and 802.11r (L2) conflicting mobility handling procedures ? Need to ensure some degree of cooperation between 802.21 and TGr mobility solutions FA R FA VLAN AP1 AP2 AP3 AP4 ESS L2 link TGr L2 mobility 802.21 L3 assisted mobility (Mobile IP) Rudolf, Carlton
Internet Internet L2 link L2 link Scenario 3 – In case 802.21 and TGr don’t have the same understanding what an ESS is R1 If 802.21 don’t agree on “ESS” definition Both come up with a L2 mobility solution, but addressing the same scenario 802.21 and 802.11r conflicting mobility handling procedures ? Need to define mobility scenarios to avoid solving the same problem twice R FA VLAN AP1 AP2 AP3 AP4 ESS2 ESS1 802.21 perspective 802.21 L2 mobility ESS TGr perspective TGr L2 mobility Rudolf, Carlton
Internet Internet Scenario 4 – 802.21 L2 mobility part 802.21 handover scenariofrom 802.3 to 802.11 To be seamless, 802.21 will need features such as pre-authentication and neighbor discovery – same functionality needed in TGr for 802.11 ESS From 802.21 perspective, the 802.3 ports could be replaced by 802.11 AP, it would very likely not change the L2 mobility procedure ! Both 802.21 and 802.11r duplicate functionality to allow seamless handover ? R1 R FA VLAN AP1 AP2 802.3 802.3 ESS L2 link TGr L2 mobility 802.21 L2 mobility Rudolf, Carlton
Scenario 4 – 802.21 L2 mobility (cont’d) 802.21 802.11r Pre-authentication Network discovery Management information … In MAC Pre-authentication Network discovery Management information … In L2.5 Rudolf, Carlton
Conclusions • Expect partial overlap between 802.21 and TGr mobility solutions, • ESS definition is too broad and unclear and does not allow to draw a clear boundary line between 802.21 and TGr without agreeing on specific mobility scenarios • When addressing L2 mobility handling across different 802 technologies, 802.21 will automatically come up with a solution that implies L2 mobility handling for the same 802 technology • Two different mobility solutions for 802.11 are not an attractive option, 802.21 and TGr mobility solutions should, • either be fully complementary • or TGr solution should be forwards-compatible with future 802.21 framework Rudolf, Carlton
Conclusions (cont) • We favor quickly available solutions that address 802.11 mobility but recognize that evolution towards 802 inter-technology solutions (802.21) is of great importance Rudolf, Carlton
Recommendations • Harmonization • Valuable worked conducted within the group shall provide solid ground for further development within 802.21 (Forward Compatibility) • Joined meeting slot with 802.21 is required as soon as 11r starts proposal evaluation • Existing ESS logical concept needs to be translated into tangible implementation scenarios • Either define mobility scenarios or • Bring the issue up to 802.1 Rudolf, Carlton