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Lect No-36

Date : 13-04-16
Topics :
•Networking and internetworking devices

Networking and Internetworking devices: Repeater: It connects segments of a LAN It forwards every frame after regeneration. It operates in physical layer . It has no filtering capacity.

If it gets a data packet. it just forwards it to everybody and hopes someone will pick it up. Switch: A switch is just barely smarter. it will try and find the device . . but the device MUST reside on the same subnet. A hub is a totally dumb device. and then send it to that device only. A switch wont send data packets to computers on different subnets.HUB: It is a multiport repeater used to connect stations in physical star topology. If it gets a data signal.

Bridge: It regenerates and takes filtering decisions. Transparent Bridge: .It operates both in physical layer and data link layer.

It floods the frame on all ports except the one on which the frame was received. .Transparent Bridges S1 S2 S3 LAN1 LAN2 LAN3 B1 Port 1 Address Port S5 S4 B2 Port 2 Port 1 Port 2 Address Port If the bridge does not find the match it adds to the forwarding table the source address with the port number on which the frame was received.

S1→S5 S1 S2 S1 to S5 S3 S1 to S5 LAN1 S1 to S5 S1 to S5 LAN2 LAN3 B1 B2 Port 1 Port 2 Address Port S1 1 S5 S4 Port 1 Port 2 Address Port S1 1 .

S3→S2 S1 S2 S3 S3S2 S3S2 S3S2 S3S2 S3S2 LAN1 LAN2 LAN3 B1 B2 Port 1 Port 2 Address Port S1 S3 1 2 S5 S4 Port 1 Port 2 Address Port S1 S3 1 1 .

S4S3 S1 S2 S3 S4 LAN1 S4S3 B1 Port 1 Port 2 Address Port S1 S3 S4 1 2 2 S5 S4 S4S3 S4S3 LAN2 LAN3 B2 Port 1 Port 2 Address Port S1 S3 S4 1 1 2 S3 .

S2S1 S1 S2 S3 S5 S4 S2S1 LAN1 LAN2 S2S1 LAN3 B1 B2 Port 1 Port 2 Address Port S1 S3 S4 S2 1 2 2 1 Port 1 Port 2 Address Port S1 S3 S4 1 1 2 .

Router: It connects two LANs provided both working in same network protocol. The router then figures out where in the world that computer is located and then sends it in the right direction. .It works at link and network layer. A router is just barely smarter than a switch. It only gets a data packet if the destination computer is not on the same subnet or LAN.

It works at at application layer .Gate way: Connects two LANs which are working in different protocol.It performs protocol conversion.

The mostly used architectures are: Bus backbone and Star backbone. . Bus backbone: Used to connect different buildings in an organization or different floors of a building. The backbone is itself a LAN that uses a LAN protocol such as Ethernet.Application of Networking and internetworking devices Backbone Networks: Back bone network allows several LANs to be connected.

Star backbone: .

Need of VLAN? .Virtual LAN: VLAN creates broadcast domain.

. instead of physical segments. This is done by software.VLAN divides a LAN into logical.


Parameters used grouping: Port address MAC address IP address Combination of these. Configuration: Manual Automatic EX: Administrator can define the project number as the criterion for being a member of a group. .