Ethernet Repeaters and Hubs
Ethernet hubs and repeaters operate at the Physical Layer of the OSI Reference model and are defined by IEEE 802.3c/d. They are used to connect together one or more Ethernet cable segments of any media type. If an Ethernet segment were allowed to exceed the maximum length or the maximum number of attached systems to the segment, the signal quality would deteriorate. (If unchecked this would ultimately lead to errors in the data.)
Hubs and repeaters may be used between a pair of segments (see below) to provide signal amplification and regeneration to restore a good signal level before sending it from one cable segment to another. By allowing two or more LAN segments to be connected, they allow the network to span a larger distance. They also provide electrical isolation from failures in the cable or attached systems, protecting equipment on other LAN segments from the effect of the fault.
A very important fact about hubs and repeaters is that they allow users to share an Ethernet LAN. A network of repeaters and hubs is therefore called a "Shared Ethernet" or a "Collision Domain". The various systems sharing the Ethernet all compete for access using the CSMA/CD access protocol. This means that only one system is allowed to proceed with a transmission of a frame within a Collision Domain at any one time. Each system has to share a proportion of the available network bandwidth.
Ethernet hubs and repeaters operate at the Physical Layer of the OSI Reference model and are defined by IEEE 802.3c/d. They are used to connect together one or more Ethernet cable segments of any media type. If an Ethernet segment were allowed to exceed the maximum length or the maximum number of attached systems to the segment, the signal quality would deteriorate. (If unchecked this would ultimately lead to errors in the data.)
Hubs and repeaters may be used between a pair of segments (see below) to provide signal amplification and regeneration to restore a good signal level before sending it from one cable segment to another. By allowing two or more LAN segments to be connected, they allow the network to span a larger distance. They also provide electrical isolation from failures in the cable or attached systems, protecting equipment on other LAN segments from the effect of the fault.
A very important fact about hubs and repeaters is that they allow users to share an Ethernet LAN. A network of repeaters and hubs is therefore called a "Shared Ethernet" or a "Collision Domain". The various systems sharing the Ethernet all compete for access using the CSMA/CD access protocol. This means that only one system is allowed to proceed with a transmission of a frame within a Collision Domain at any one time. Each system has to share a proportion of the available network bandwidth.
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