Usage

java -jar RIP-1.0-jar-with-dependencies.jar [router_id] [mode]

router_id:

• defined in config file
• 1 by default

mode:

• 0: normal (default value)
• 1: split horizon
• 2: split horizon with poison reverse

The files below have to be in the same folder:

- RIP-1.0-jar-with-dependencies.jar
- log4j.properties
- config.txt

Configuration

{
    "regular_timer": 10,
    "shutdown_timer": 120,
    "protocol_port": 5200,
    "routers": {
        "1": {
            "id": 1,
            "ip": "ip1",
            "neighbors": [2],
            "actions": {
                "1": "DISCONNECT"
            }
        },
        "2": {
            "id": 2,
            "ip": "ip2",
            "neighbors": [1, 3]
        },
        "3": {
            "id": 3,
            "ip": "ip3",
            "neighbors": [2, 4]
        },
        "4": {
            "id": 4,
            "ip": "ip4",
            "neighbors": [3, 5]
        },
        "5": {
            "id": 5,
            "ip": "ip5",
            "neighbors": [4]
        }
    }
}

Main Idea

This RIP implementation is base on UDP. Packets are encoded by Protobuf.

• Every config.regular_timer seconds, a router sends RIP.REQUEST to its neighbors.
• When a router receives a RIP.REQUEST, response with its Routing Table.
• When a router receives a RIP.RESPONSE:
  • if destination is the router itself, pass it.
  • if destination is not exist in the routing table, and metric is not infinite, insert into the routing table.
  • if next hop is the sender of the response message, force a update of metric.
  • if new metric is smaller, update routing table.
• To simulate disconnection:
  • DISCONNECT action is configured in config.txt, will be triggerd in certain round.
  • When DISCONNECT action is triggered, a router sends RIP.DISCONNECT to its neighbors.
  • When a router receives a RIP.DISCONNECT, it updates the metric of corresponding destination to infinite.

Depedencies

• Netty: network application framework
• Protobuf: binary packet serialization/deserialization
• asciitable: format table string
• Gson: json serialization/deserialization

Analyses

All 3 modes are running with the same config file in which router_1 will disconnect with router_2 at round 1.

Below shows how metric of Destination_1 changes in each routing table.

Normal Mode

Cause the "Count To Infinity" problem.

router_2	router_3	router_4	router_5
1	2	3	4
3	4	5	6
5	6	7	8
7	8	9	10
9	10	11	12
11	12	13	14
13	14	15	16
15	16	16	16
16	16	16	16

Split Horizon Mode

router_2	router_3	router_4	router_5
1	2	3	4
16	2	3	4
16	16	3	4
16	16	16	4
16	16	16	16

Split Horizon wIth Poison Reverse Mode

router_2	router_3	router_4	router_5
1	2	3	4
16	2	3	4
16	16	3	4
16	16	16	4
16	16	16	16