ROUTING

ROUTING

          Routing is a process of transferring the packets to one logical network to another logical network.

Ø      Routing process is done by layer 3 device (network layer)

Ø      Routing process is done with the help of routing protocols.

Routing Protocols:

          It is used to construct routing table dynamically. Routing protocol are used to select best path to reach the destination.

RTP version 1:

          It will not send subnet mask to another router.

RTP version 2:

          Routing protocols are RIP, IGRP, OSPF, EIGRP, in real narrow we are using OSPF routing protocol.

Routed Protocols

          It is used to carry IP address packet from one logical network to another logical network ex: IP, IPx, Apple talk.

R1

Destination	Gateway	Interface
5.0	5.100	eo
6.0	6.1	so
7.0	6.2	so
8.0	7.2	so

R2

Destination	Gateway	Interface
6.0	6.2	S1
7.0	7.1	S0
5.0	6.1	S1
8.0	7.2	S0

R3

Destination	Gateway	Interface
8.0	8.100	e0
7.0	7.2	S1
6.0	7.1	S1
5.0	7.1	S1

Default Routing

R1

Destination	Gateway	Interface
192.168.1.0	192.168.1.100	e0
2.0	2.1	S0
3.0	3.1	S1
4.0	4.1	S2
5.0	5.1	S3
6.0	2.2	S0
7.0	3.2	S1
8.0	4.2	S2
9.0	5.2	S3

R3

Destination	Gateway	Interface
192.168.6.0	192.168.6.100	e0
2.0	2.2	S1
0.0	2.1	S1

Default Routing

R3

Destination	Gateway	Interface
7.0	8.100	e0
3.0	4.2	S0
0.0.0.0	4.1	S0

R4

Destination	Gateway	Interface
8.0	8.100	e0
4.0	4.2	S0
0.0.0.0	4.1	S0

R5

Destination	Gateway	Interface
9.0	9.100	e0
5.0	5.2	S0
0.0.0.0	5.1	S0

Ø      It can be configured it reduced routing table size.

Ø      Default routing is configured only for the stub routers.

Ø      Stub routers: The routers which is having 1 entry and 1 exit.

Note:

          In real cenarrow there will be 1000’s of network in that case we can’t keep all the network information in the routing table.