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Connection Routing Schemes for Wireless ATM

Proceedings of the 32nd Hawaii International Conference on System Sciences - 1999

Upkar VarshneyComputer Information Systems DepartmentGeorgia State University

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outlineIntroductionConnection rerouting schemesIssues not addressed by rerouting schemesRerouting for multicast connectionRerouting for multiple connectionsConclusion

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Introduction discuss several rerouting schemes for wireless ATM networks Discuss many issues including multi- connection and multicast connection handoffs propose generic techniques that can be incorporated in rerouting schemes to support such handoffs.

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Connection rerouting schemes(1/10)

Connection reestablishment -- setting up a new connection every time mobile host moves to a new location

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Connection rerouting schemes(2/10)

Connection(path) extension --extended from the previous location to the new location of the mobile user.

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Connection rerouting schemes(3/10)

Anchor routing --connection from the backbone network to anchor switch is fixed and only the connection from anchor switch to new BS is modified

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Connection rerouting schemes(4/10)

Dynamic rerouting --modification of old path to find an optimal or close to optimal new path to the new location of the mobile user

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Connection rerouting schemes(5/10)

Rerouting by advance setup of paths

-- setting up paths in advance. 1. set up a complete tree 2. use prediction to set up a path to the possible location

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Connection rerouting schemes(6/10)

Hybrid schemes --combine the features of some of the above scheme 1.RAC(Rearrange ATM Connection) 2.EAC(Extend ATM Connection) --based on dynamic rerouting through ATM network and connection extension in wireless network

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Connection rerouting schemes(7/10)

Rearrange ATM Connection (RAC) --faster if a single entity can process a connection request and inform the ATM switches about the new connection --this type of signaling arrangement has been termed as centralized signaling system and such an entity is called NCP.

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Connection rerouting schemes(8/10)

Rearrange ATM Connection (RAC) --NCP periodically broadcast information about its loading that can be used by a BS in determining whether to pursue RAC or not, include 1.the queue length at NCP 2.resource unavailability in the new route to support QoS

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Connection rerouting schemes(9/10)Rearrange ATM Connection

(RAC) --If NCP executes RAC, it finds a new route between the fixed user and the current location of the mobile user

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Connection rerouting schemes(10/10)

EAC(Extend ATM Connection) --to extend the connection to the new location of the mobile user --Extending connection through base stations in wireless network may cause triangular or circular

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Issues not addressed by rerouting schemesRerouting for multicast handoffs

Rerouting for multi-connection handoffImpact of heterogeneous environmentInterworking of heterogeneous networksImpact of failure

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Rerouting for multicast connection(1/2)

several issues that are important for multicasting in wireless ATM networks, include --cost of updating/maintaining multicast tree -- impact of admission control -- scalability issues

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Rerouting for multicast connection(2/2) Rerouting with possible tree updat

ing --Find a shortest path to the core connected via a shortest path to the current core. --Find a shortest path to the tree connected to the existing tree using a shortest path. --Find a shortest path to a future core If the new core can be predicted, then mobile user is connected to the new core

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Multicast tree in wireless ATM network(a) connecting to B3 via C6 (shortest

path to the core)(b) connecting to C5 via C6 (shortest path to the tree)(c) extending the existing connection (B3-B4-C7) to C6

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Rerouting for multiple connections(1/3)

Reason: A mobile user may be involved in several simultaneous one-to-one connections, --downloading a file while talking to someone

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Rerouting for multiple connections (2/3)

Handoff delay for real-time traffic --may be possible that real-time traffic may experience more delay than the other traffic types.QoS & admission control In case of multiple connection handoff, the new base station may not have the sufficient bandwidth to support connections

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Rerouting for multiple connections (3/3)

Multi-connection handoff rerouting --which connection should be handoff first include (a) type of traffic, (b) handoff delay history for the connection (c) bandwidth of connection

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Conclusionthe design of connection re-routing schemes has received some consideration in the literature. This paper presents general schemes to support into multi-connection and multicast connection handoffs.