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TeleMIP: Telecommunications-enhanced Mobile IP

Archan Misraarchan@research.telcordia.comApplied Research,Telcordia Technologies

IPCN2000 – 2

TeleMIP Contributors/Goals

Telcordia Technologies University of Texas at Arlington

Archan Misra Sajal K Das Subir Das Ashutosh Dutta Anthony Mcauley Prathima Agrawal

Goals– Develop an IP-based mobility architecture for 3rd/4th generation

cellular networks that is not tied to a single protocol.– Apply general ideas for mobility management in hierarchical dynamic

networks.

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TeleMIP: Telecommunications-enhanced Mobile IP

Goal: Improve the latency of intra-domain location updates.

TechniqueA two-level mobility management solution for intra-domain mobility.

Currently based on extensions/modifications to Mobile IP functionality. – However, two-level architecture is independent of the exact

mobility management algorithm (Mobile IP, SIP).

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Primary Problems with Basic Mobile IP

High latency of location updates– All location updates must travel all the way to Home Agent (HA) or

Correspondent Node (CN).

High frequency of global location update messages– Since address binding changes with change in every subnet, frequent

generation of location updates to HA/CN.

Inefficient use of existing public address space– Since HA (or CN) use the mobile’s current care-of address, we need at

least one global address per subnet (for FA) or one global address per mobile in FA (in co-located mode).

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TeleMIP’s Solution to Problems

Reduce the latency of intra-domain location updates by specifying an intra-domain termination point (Mobility Agent or MA). – Intra-domain updates only up to the MA, which provides a

globally valid COA to MN.

Reduce the frequency of global update messages– Since the MA is located at a higher hierarchy than that of subnets,

global updates (to HA, CNs etc.) only occur for inter-domain mobility.

Reduce the requirement of public addresses – By promoting a two-level addressing scheme, we promote the

use of private (locally-scoped) addresses for handling intra-domain mobility.

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TeleMIP’s Architecture Layout

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Architecture Functional Specification

Foreign Agents/ DHCP(DRCP) Servers at the subnet level– Provide MN with a locally-scoped address which identifies mobile

location within the domain.

Mobility Agents (MA) distributed within the domain– Multiple MAs for load-balancing and redundancy within the domain.– Provides MN with a global care-of address that stays constant

within the domain. MN’s location is globally known only up to the MA-level granularity.

HA/CNs as in conventional Mobile IP (with or without route optimization).

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TeleMIP Operational Overview: 1

Network is divided into domains.

Domain Identifiers broadcast in Agent Advertisement/ Discovery messages.

When MN first moves into a domain, it obtains a global care-of address (Mobility Agent’s (MA) address), as well as a local care-of address. – MA’s global COA sent in the registration message to HA.

In IPv4 optimized mode, HA transmits this global COA to CNs in its binding updates; in IPv6, MN sends the global COA directly to CNs in binding updates.

– MN also registers itself (with its local COA) with its MA.

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TeleMIP Operational Overview: 2

MN retains the same MA (global care-of address) within the same domain

All packets from the global Internet tunneled to the MA, which acts as a single point of enforcement/accounting. – MA forwards packets to MN, using regular IP routing, by using

the local COA (co-located or FA) as the destination.

On subsequent movement within the domain, MN only obtains a new local COA.– No need to update the HA or CNs.– MN updates its MA with its new local COA.

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Initial Domain-Based Registration Procedure

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Subsequent Intra-Domain Registration

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Architectural Choices in TeleMIP…1

Two-level Mobility Management

Judged to be an adequate compromise between the need for fast intra-domain location updates and low network management complexity.

– Single level suffers from the generation of frequent global messages and large update latencies. (common to Mobile IP and SIP-based mobility management)

– Multiple levels (HMIP etc.) introduce additional management (especially security) overhead as well as generate multiple points of failure.

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Architectural Choices in TeleMIP…2

A Domain-Specific Agent for Handling Intra-domain Mobility

MA provides a stable care-of address, as well as a central point for regulating and metering the traffic flow.

Stable care-of address also promotes proper functioning of TCP applications and the establishment of backbone QoS bounds (up to the MA).

Architecture allows flexibility in the choice of either FA-based or co-located local care-of addresses. Thus, traffic sent by MN can proceed directly.

In-bound traffic must arrive via MA. Architecture provides a point (in the wired backbone) to filter traffic before it reaches the expensive wireless link. MA also serves as a natural point for performing local AAA registration.

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Architectural Choices in TeleMIP…3

Global Location Updates are Responsibility of the Mobile Node

By shifting the responsibility of global updates to the MN, we allow the destination of the update message to be a specific node (HA or SIP server) or correspondent nodes (SIP, Mobile IPv6).

Separates the local security and authentication scheme (between MN, HA and FA) from global security and authentication (between MN and HA or between MN and CN).

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Architectural Choices in TeleMIP…4Cellular Domain Nodes Left Unchanged as far as Possible

Avoid requiring host-based routing or protocol upgrades at all nodes.– Use conventional routing algorithms to avoid upgrades at large

number of nodes.– In addition to scaling concerns (which may be important only in the

future), host-based routing leads to high route re-establishment costs in case of intermediate node failures.

Use of explicit locally-scoped address promotes address efficiency and reduces the need for host-specific route management.

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Possible Alternatives for Intra-Domain Mobility

Certainly, TeleMIP shares many of its ideas with several other proposals, including:– Cellular IP (Ericsson, Columbia University)– HAWAII (Lucent Technologies)– Mobile IP Regional Tunnel Management

(Ericsson, Nokia)+ Hierarchical Mobile IP with Fast Handoffs (Ericsson)

– HMMP (Telcordia, Toshiba)– HMIPv6 (INRIA)

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Feature Comparison of Alternative ProtocolsDesiredMobilityFeature

CellularIP

HAWAII Mobile IPRegionalTunnel

HMIP(v6)

TeleMIP

RequiresMinimalChanges toDomain Nodes

2 2 4 1 4

EfficientAddressUtilization

5 2 5 5 5

SeparateSecurity forIntra-Domainand GlobalMobility

- - 3 4 5

Reduces Intra-Domain UpdateLatency

3 3 4/5 (*) 4 5

5 (Most Favorable) -- 1(Least Favorable)

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Comparison of Alternative Protocols…2DesiredMobilityFeature

CellularIP

HAWAII Mobile IPRegionalTunnel

HMIP(v6)

TeleMIP

Reduces GlobalUpdateFrequency

5 5 5 5 5

Reduces LocalUpdateFrequency

5 3 3 3 3

LowEncapsulationand TransportOverhead

4 4 2 5 2

Can Workwithout changesto CN

5 5 5 2 5

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Comparison of Alternative Protocols…3DesiredMobilityFeature

CellularIP

HAWAII Mobile IPRegionalTunnel

HMIP(v6)

TeleMIP

Scalable Intra-DomainRouting

3 3 5 5 5

Well-definedfor Arbitraryand Multi-PeeredNetworks

1 1 5 5 5

Multiple Agentsfor DynamicLoad Balancing

2 2 4 (?) 4 5

Supports Co-located AddressMode

5 3 5 5

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Status of TeleMIP Prototype Linux code to be ready by end-July.

– Use and augment existing publicly available IPv4 code.– Changes involve Agent Advertisements, two care-of-addresses and

small changes to FA (MA) code.

S. Das, A. Misra, P. Agrawal and S. Das, “TeleMIP: Telecommunication Enhanced Mobile IP architecture for Fast Intra-Domain Mobility”, to be published in IEEE PCS Magazine, August 2000.

Develop a Web page to retrieve papers/ implementations etc.

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Additional Features of TeleMIP

Techniques for faster intra-domain handoffs have been developed.

Enhancements to architecture to incorporate QoS considerations inside the mobility management scheme are under consideration.

Specific attention to the security and authentication mechanisms of TeleMIP is the next goal.

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That’s It for Now…..

For more information, please contact– archan@research.telcordia.com– subir@research.telcordia.com

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References RFC 2002, IETF. “IP Mobility Support” A Campbell, J Gomez, C-Y Wan, Z Turanyi and A. Valko, “Cellular IP”, <draft-valko-

cellularip-01.txt>, Work in Progress, October 1999. E. Gustafson, A Jonsson, C. Perkins, “Mobile IP Regional Registration”, draft-ietf-

mobileip-reg-tunnel-02.txt”, Work in Progress, March 2000. R. Ramjee, T. La Porta, S. Thuel, K Varadhan and L. Salgarelli, “IP Micro-Mobility

using HAWAII”, <draft-ietf-mobileip-hawaii-00.txt>, Work in Progress, June 1999. F. Vakil, A. Dutta, J.-C. Chen, S. Baba, and Y. Shobatake, “Host Mobility Management

Protocol: Extending SIP to 3G-IP Networks”, <draft-itsumo-hmmp-00.txt>, Work in Progress, October 1999.

S. Das, A. Misra, P. Agrawal and S. Das, “TeleMIP: Telecommunication Enhanced Mobile IP architecture for Fast Intra-Domain Mobility”, to be published in IEEE PCS Magazine, June 2000.

K Malki and H Soliman, “Hierarchical Mobile IPv4/v6 and Fast Handoffs”, <draft-elmaki-soliman-hmipv4v6-00.txt>, Work in Progress, March 2000.

M. Handley, H. Schulzrinne, E. Schooler, J. Rosenberg, “SIP: Session Initiation Protocol, RFC 2543 (Proposed Standard), IETF

E. Wedlund, and H. Schulzrinne, “Mobility Support using SIP” ACM WOWMOM workshop, Seattle, August 1999

K. el Malki and H Soliman, “Hierarchical Mobile IPv4/v6 and Fast Handoffs”, <draft-elmalki-soliman-hmipv4v6-00.txt”, Woek in Progress, March 2000.