The dynamic address assignment allows one to create IP networks in which the number of nodes exceeds the number of the IP addresses administrator has.
4.2.3 Bridging of local networks
Bridges are the simplest devices for logical network structuring. They divide the transmission network medium into segments (logical segments), forwarding data from one segment to another, if such a transmission is necessary, i.e. if the destination address belongs to another subnet.
Bridges are data communication devices that operate at the data link layer of the OSI reference model. They use addresses of computers and other devices. Bridges control data flow, handles transmission errors, provides physical (as opposed to logical) addressing and manage access to the physical medium. Bridges provide these functions by using various
The primary advantage of bridging is the
By dividing large networks into
Types of bridges
Bridges can be either local or remote. Local bridges provide a direct connection of subnet segments in the same area. Remote bridges connect subnet segments in different areas, usually over telecommunication lines. The
Remote bridging represents several unique internetworking challenges. One of them is the difference between LAN and WAN speeds. Vastly different LAN and WAN speeds sometimes prevent users from running
Remote bridges cannot increase WAN speeds, but they can compensate for the speed discrepancies by using buffering capacities. If a LAN device capable of a
The
The “transparent bridge” is called so because its presence and operation is transparent to all network hosts.
A bridge builds its own address table while passively monitoring the traffic. At this stage it extracts the information about source addresses of data frames. The source address shows that it belongs to a certain node of this or that network segment. Fig. 2 shows the creation of an
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