IDMPbased Fast Handoffs and Paging in IPbased Cellular

IDMP-based Fast Handoffs and Paging in IP-based Cellular Networks IEEE 3 G Wireless Conference, 2001 Telcordia 李威廷 11/22/2001

Outline n n n Introduction IDMP Overview Fast Handoff Scheme in IDMP Paging Support in IDMP Conclusions 2

Introduction (1/3) n Disadvantages of Mobile IP n n High update latency Large global signaling load Lack of paging support These problem are also present in various non-hierarchical MIP solutions 3

Introduction (2/3) n The Intra-Domain Mobility Management Protocol (IDMP) is proposed recently to reduce: n n the latency of intra-domain location updates and the mobility signaling traffic. 4

Introduction (3/3) n IDMP is conceptually a two-level generalization of the Mobile IP architecture n n Mobility Agent (MA) provides a mobile node (MN) a domain-wide stable point of packet redirection IDMP can be combined with multiple global binding protocols n With Mobile IP or SIP 5

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IDMP Overview (1/3) n n IDMP is a multi-Co. A intra-domain mobility solution Unlike HAWAII, MIP-RR or HMIPv 6, IDMP is designed as a stand-alone solution for intra-domain mobility and does not assume the use of MIP for global mobility management 7

IDMP Overview (2/3) n Mobility Agent (MA) n n n It is similar to a Mobile IP Regional Registration (MIP-RR) GFA It provides an MN a stable global Co. A Subnet Agent (SA) n n It is similar to a MIP FA It provides subnet-specific mobility services 8

IDMP Overview (3/3) n MN obtains two concurrent Co. As: n Local Care-of Address (LCo. A) n Similar to MIP’s care-of address n Unlikely MIP, it only has local scope n Global Care-of Address (GCo. A) n Domain-level granularity 9

Fast Handoff Scheme in IDMP

Handoff Delay of IP-based BS (1/2) n Radio-channel Establishment Delay (Δ 1) n n IP Subnet Configuration (Δ 2) n n n Establishing new radio-channel for new BS SA mode: obtain an agent beacon and then request a new LCo. A Co-located mode: DHCP and then LCo. A Intra-domain Update Delay (Δ 3) n MN must inform the MA of its new LCo. A 11

Handoff Delay of IP-based BS (2/2) n Δ 1 is expected to be quite low n n n CDMA-based soft handoff: Δ 1 is 0 Old BS is not discontinued until the connection with the new BS is established IDMP’s fast handoff process is designed to eliminate Δ 3 , not eliminate Δ 2 12

The Fast Handoff Procedure (1/2) n n Either MN or old SA generates Movement. Imminent message to the MA Upon reception of this message, the MA multicasts all inbound packets to the entire set of neighboring SAs Each of these SAs buffers such arriving packets After MN performs a subnet-level configuration, new SA forward all buffered packets. 13

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The Fast Handoff Procedure (2/2) n n IDMP’s Movement. Immient message does not specify the IP address of the new BS Multicast forwarding is invoked concurrently with subnet-level IP configuration phase, thereby reducing the Δ 3 The MA decides (network-controlled) the set of target BSs to which in-flight packets are multicast Only the new BS forwards arriving multicast packets to the MN 15

Implementing Fast Handoff n IP multicast n n n The group membership is not dynamic PIM or DVMRP can be used to establish the multicast tree Buffer size n (intra-domain update latency) * (incoming traffic rate) 16

Alternative Fast Handoff Suggestions n Layer-2 trigger is used to cause old FA to establish a transient tunnel to the new FA n n It eliminates Δ 2, but authentication is only at radio layer The MN initiate a new MIP registration with the new FA through the old FA n n HMIPv 4/v 6 Does not provide network any control over handoff process 17

Paging Support in IDMP

Paging Operation for Idle Hosts n n SAs are grouped into Paging Area (PA) The MN in passive/idle mode listens FA Agent Advertisement to know which PA it belongs to MN Moving among the same PA does not update MA about its current LCo. A, and not obtain a new LCo. A The MA multicast a Page. Solcitation packet to all the subnets associated with the MN’s current PA 19

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Paging Implementation n Paging Area Identifier (PAI) is used An SA can be associated with multiple PAs An MN must inform its MA when it switches from the active to the idle state, thereby activating the paging functionality at the MA 21

Comparison with Alternative IP Paging Schemes n IDMP does not need intermediate nodes n n Only SA and MA take part in the paging process localize future upgrades Paging operations are distributed among different MAs (each serving different MNs) n There is no single point of failure for the entire domain 22

Conclusions (1/2) n n IDMP is an IP-based hierarchical mobility management and IP-based BS architecture Although the latency is higher than other schemes that assume some layer-2 coordination, the temporary buffering mechanism provides acceptable latency variation 23

Conclusions (2/2) n n IDMP does not assume a tree-like topology and allows easy configuration of variablesized Pas Implementation of IDMP n n Linux Mobile IP code (Mosquito. Net Proj) MA daemon is modified from HA daemon 24