Extending an ethernet with bridges

Extending an ethernet with bridges
Adaptive bridge

• Connecting 2 Ethernet with bridges in superoir to connecting them in repeater a hub because bridges operate on packet rather than electrical signal
• bridges
• do not replicate noise
• do not replicate error
• donot replicate malformed frames
• validates the frame before transmitting to other the other network
• hides the details of interconnections : set of bridges segmentsact as like a single ethernet
• and Ethernet follow CSMNCD rules
• make intelligent decisions about frame to forward

Collision and propagation delays on one segment remain isolated from those on the other

Bridges network are  classified as transparent

Adaptive bridge/learning bridge
Bridges makes intelligent decision about frame to forward
An adaptive bridge consist of a computer with two Ethernet interfaces software in adaptive bridge keep two address stack

when a frame srrives from ethernet \(E_1\), the adaptive bridge add a 48 bit Ethernet source address to list associated with \(E_1\)
similiarly
when a frame arrive from \(E_2 \) to bridge adds the source address to list associated with \(E_2\)
Thus adaptive bridge will learn which machine lie on \(E_1\) and which lie on \(E_2\)

In bridge packet forwarding is used by softwares
bridge work only for half duplex mode
Switch
In this packet forwarding using by ASIC(Application Specified Integrated Circuits)
Operates in comparatively higher speed than bridge
superior than bridge
Method of switching in switching is store and forward ,cut through switching or fragment free
Normally switches has more ports than a bridge
Switches operates in half duplex mode or full duplex mode