EE 6951 term project Columbia University The Fu Foundation School of Engineering and Applied Science 2002 Spring

Cellular IP project: Cellular IP with Multiple Gateways Group members: Adrija Biswas, Charalampos Mantelis, Naoya Seta, Nil Unerdem, Will Jenkins

Overview Objectives Benefits Load balancing Fault Tolerance Gateway Module Foreign Agent Implementation Gateway Broadcast Beacon Base-Station Module Base-Station Topology  Root Base-Station  Mesh Base-Station Mobile-Host Task allocation Demo timeline

Objectives Modify the current Cellular IP implementation, so as to support multiple gateways Verify the modified protocol using the ns simulator

Benefits A multiple gateway network is more robust in terms of load balancing, so traffic can be redirected when the load for a gateway becomes unbearable (uplink). A multiple gateway network is less susceptible to gateway failures, as there is always an alternative gateway (re-register at HA’s).

Modifications in the CIP In the Gateway functionality (FA, beacon) In the Base-station functionality (routing tables, load balancing decisions, beacons to MH’s) The Mobile Host is currently unchanged

The Gateway Module The FA will be implemented inside each gateway. If a gateway fails, traffic will be re-directed to another gateway, and nodes will be re-registered with HA’s. The gateway broadcast beacon will be modified to carry load information. The beacon will be broadcast to all base stations. The format of the beacon will include the Cellular IP Network Identifier, the IP address of the gateway, a sequence number, and a paging area ID field. The beacons will be used in set- up and also in uplink routing to balance load.

Base-Station Module Initialization Creation of routing tables used to determine the shortest path to each gateway. The base-stations receive the broadcast gateway beacons and store the interface they received it from The base-stations forward the gateway beacons to their downlink neighbors Duplicated gateway beacons should be ignored to prevent looping Beacon Base-Station send out periodic beacon with Layer2 parameters, cellular IP network Identifier, IP gateway address, ID of paging area Load Balancing Base-stations use gateway load value of gateway beacon to determine, the optimal path for packets to traverse. According to the decision based on load information, the Base-station advertises the selected gateway’s address to the mobile host in the beacon message

Topology Root Base-Station Topology Load Balancing  Root Base-Stations in the root base-station topology are the only base-station that make route decisions Gateway Route Management  Root Base-Stations maintain gateway state information Mesh Base-Station Topology Load Balancing  In the Mesh Base-Station Topology all base-station make route decisions. Gateway Route Management  All base-stations maintain gateway state information

The Mobile Host module Currently there is no need to change the mobile host module, since the load balancing and routing decisions are made in the base- stations. There is no need to change the hand-off procedure too. Proposal for future work: gateway beacons are forwarded to mobile hosts and they decide which gateway to use

Task allocation Simulator Code: Adrija Biswas, Naoya Seta, Nil Unerdem, Will Jenkins Protocol Design & Implementation: Adrija Biswas, Charalampos Mantelis, Naoya Seta, Nil Unerdem, Will Jenkins Presentation and Final Draft: Adrija Biswas, Charalampos Mantelis

Timeline Obtain NS-2 simulator documentation and installation 3/25 Review NS-2 simulator tutorials and documentation 4/2 Complete learning of NS-2 simulator 4/18 Obtain NS-2 simulator code 4/18 Compile existing cellular IP code in NS-2 4/19 Reproduce NS-2 simulator results presented with this code 4/20 Create modification to gateway broadcast beacons (Load information) 4/22 Create Root base-station structure (Maintaining state information of gateway) 4/23 Create intermediate base-station code 4/24 Create mobile host code 4/25 Establish traffic patterns 4/25 Cellular IP component evaluation 4/27 Component code revisions 4/29 Cellular IP component evaluation 5/1 Mesh topology assessment 5/1 Demo and presentation 5/2 Final Write-up and Code 5/4