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Lect No-36

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

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

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

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

.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. It floods the frame on all ports except the one 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 .

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

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

Application of Networking and internetworking devices Backbone Networks: Back bone network allows several LANs to be connected. The backbone is itself a LAN that uses a LAN protocol such as Ethernet. 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.

Star backbone: .

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

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

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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.