What Are Networking Devices? Can You Explain Bridges And Switches.

Bridges and Switches are discussed in the following paragraphs.A Bridge is a combination of hardware and software. It has its own operating system. It helps to conserve the bandwidth of a network. Bandwidth is the speed of a network. It indicates how many bits can be transmitted across a network in a given time. In case of a bridge, the larger network is physically chopped into smaller segments.

A bridge can read the MAC (Media Access Control) or physical address of a computer on data packets. MAC address is printed on the Network Interface Card. A bridge matches this MAC address with the one stored in its table and judges that which particular segment does a data packet belong to and accordingly sends that packet to such a segment. It does not allow other packets belonging to other segments to spread to a particular segment and hence conserves the bandwidth.

A switch is also a combination of hardware and software having its own operating system. Like bridges, the switches are also used to increase the bandwidth of a network. However, in case of a switch, a network is virtually divided into small segments called Virtual LANs or VLANs. Similar type of users can be grouped into a VLAN despite that they have no physical proximity or closeness. A switch would read the MAC address on a data packet and match it with the list of MAC addresses of the user machines contained in it. It then sends data packets only to that machine on a VLAN to which these packets relate. Packets belonging to other VLANs are not allowed to enter into a particular VLAN, hence bandwidth increases.

Switches

Like a hub, a switch is a device that connects individual devices on an Ethernet network so that
they can communicate with one another. But a switch also has an additional capability; it
momentarily connects the sending and receiving devices so that they can use the entire bandwidth
of the network without interference. If you use switches properly, they can improve the
performance of your network by reducing network interference.
Switches have two benefits: (1) They provide each pair of communicating devices with a fast
connection; and (2) They segregate the communication so that it does not enter other portions of
the network. (Hubs, in contrast, broadcast all data on the network to every other device on the
network.)
These benefits are particularly useful if your network is congested and traffic pools in particular
areas. However, if your network is not congested or if your traffic patterns do not create pools of
local traffic, then switches may cause your network performance to deteriorate. This performance
degradation occurs because switches examine the information inside each signal on your network
(to determine the addresses of the sender and receiver) and therefore process network information
more slowly than hubs (which do not examine the signal contents).
Most switches operate by examining incoming or outgoing signals for information at OSI level 2,
the data link level.

Bridges

A bridge connects two or more networks, or segments of the same network. These networks may
use different physical and data link protocols. For example, you can install a bridge to connect a
small lab of Macintosh computers using LocalTalk to the school's main Ethernet network.
Bridges filter network traffic. They examine each set of data, transmitting only appropriate data to
each connected segment. (Hubs, by contrast, broadcast all information to each connected
computer, whether or not that computer is the intended recipient.) In this manner, bridges help
reduce overall network traffic.
Bridges are relatively simple and efficient traffic regulators. However, in most networks they
have been replaced by their less expensive or more powerful cousins—hubs, switches, and
routers.
Most bridges operate by examining incoming or outgoing signals for information at OSI level 2,
the data link level.