Application Layer Virtual Routing

• A cartoon demostration application is good.

Main Reference:Route Information Protocol

• DV routing:
  • Bellman-Ford algorithm
• RIP hop count metric
• split horizon, route poisoning, holddown
• Timers
  • Update
  • Invaild
  • Flush
  • Holddown
• RIPv2 message
  • request
  • response

4 threads:

• listenUDPThread

  event driven

• routerWatchThread

  determine whether to remove a router

• updateThread

• mainThread

1. How to send and receive data? check the buffer regularly.
2. Is it necessary to maintain the route table?

No explicit status

Package: Hello, LSU, broadcast, normal, traceRoute, echo

Broadcast: RPF

features:

1. multi-path
2. tackle with routing loops, using md5

Timers:

1. hello
2. dead

• connect with routers
• receive the LS from routers
• execute the Floyd algorithm
• send the corresponding forwarding table to each router

How to connect the routers?

1. routers send LS packet periodically
2. set a dead interval How to store the map?

How to send the forwarding table?

• Triggered update and periodically

Using Twisted!

• connect with the server
• connecting with the neighbours
• send the LS to the server
• receive the forwarding from the server

How to connect to the server?

• periodically and at the beginning

How to connect to the neighbours?

• send hello to the neighbours at the beginning and periodically

• Overview
• Algorithm
• Protocol Specification
  • Flow
  • Timer
• Message Format
• Protocol Extension
  • Deal with the disadvantages of origin DV and LS
    • DV: infinite count
    • LS: multi-path, looping
  • TraceRoute
• Implementation
• Result
• Conclusion