4x4 Optimization4x4 Optimization

Alkesh Patel Alkesh Patel

& &

Hemant PatelHemant Patel

BackgroundBackground

IP address – identify computer on the networkIP address – identify computer on the network

Mobile domain - mobile host Mobile domain - mobile host IP address is not restricted to regionIP address is not restricted to region

Problem : Identifying computer on mobile domainProblem : Identifying computer on mobile domain

Solution: Solution: Change IP address when the host moves to other subnetChange IP address when the host moves to other subnet Use same IP address and add special routing entries to Use same IP address and add special routing entries to

track the current location of the user – good for small track the current location of the user – good for small groupgroup

ChallengeChallenge

Following challenges should be solved before Following challenges should be solved before considering solutionconsidering solution

Compatibility: Should work with current wired internet Compatibility: Should work with current wired internet infrastructureinfrastructure

Scalability: Should be able to support large number of Scalability: Should be able to support large number of user to meet future demandsuser to meet future demands

Transparency: User should not feel difference between Transparency: User should not feel difference between wireless and wired networkwireless and wired network

OptimizationOptimization

Optimization scheme should ensureOptimization scheme should ensure

Guaranteed deliveryGuaranteed delivery

Low latencyLow latency

Low overheadLow overhead

4x4 Approach 4x4 Approach

Four options for packets directionFour options for packets direction

IN approaches CN to MNIN approaches CN to MN OUT approaches MN to CNOUT approaches MN to CN s – outer source in the encapsulated packets – outer source in the encapsulated packet d – outer destination in the encapsulated packetd – outer destination in the encapsulated packet S – inner source of the packetS – inner source of the packet D – inner destination of the packetD – inner destination of the packet

The IN strategies in 4x4 approachThe IN strategies in 4x4 approach

IN Strategy s d S D Notes Acceptable Combinations

Incoming IndirectEncapsulated (IN-IE)

IP address of HA

COA ofthe MN

IP addressof the CN

Home IP addressof the MN

1. Highest overhead2. Guaranteed deliveryUses tunnelingCN need not be mobility aware

OUT-IEOUT-DEOUT-DH

Incoming DirectEncapsulated(IN-DE)

IP address of CN

COA ofthe MN

IP addressof the CN

Home IP addressof the MN

1. CN is mobility aware2. No tunneling

OUT-DEOUT-DH

Incoming Uses HomeAddress(IN-DH)

Notapplicable

Notapplicable IP address

of the CNHome IP addressof the MN

1. No encapsulation2. Usable when there are no security constraintsat intervening routers3. MN and CN on same subnet

OUT-DH only

Incoming DirectUses Temporary address(IN-DT)

Notapplicable

Notapplicable IP address

of the CN COA of MN

1. MN cannot receive packets addressd to its orginal IP address2. Useful for short-term communication

OUT-DT only

The OUT strategies in 4x4 approachThe OUT strategies in 4x4 approachOUT Strategy s d S D Notes Acceptable

Combinations

Outgoing IndirectEncapsulated(OUT-IE)

COA of the MN

IP addressof HA

Home IP addressof the MN

IP addressof the CN

1. Highest overhead2. Guaranteed delivery3. No ingress filtering4. CN need not be mobility aware

IN-IE only

Outging DirectEncapsulated(OUT-DE)

COA of the MN

IP addressof CN

Home IP addressof the MN

IP addressof the CN

1. CB is mobility aware2. No tunneling

IN-IEIN-DE

Outgoing DirectHome Address(OUT-DH)

NotApplicable

Not Applicable

Home IP addressof the MN

IP addressof the CN

1. No encapsulation2. Usable when there are no security constrains at the interven-ing routers3. MN and CN on the same subject

IN-IEIN-DEIN-DH

Outgoing Direct uses TermporaryAddress (OUT-DT)

NotApplicable

Not Applicable

COA of MN IP addressof the CN

1. MN cannot receiverpackets addressed to its original IP address2. Useful for short-term communication

IN-DT only

Comparison & Evaluation Comparison & Evaluation

16 different strategies for transmission16 different strategies for transmission Four approaches for each of the two directionsFour approaches for each of the two directions Different advantages & disadvantages Different advantages & disadvantages

Choice based on session basis or packet-to-packet Choice based on session basis or packet-to-packet basisbasis