Appendix
34
Appendix 2 Switching Hubs and Hubs
(Shared Hubs)
There are two types of hubs: switching hubs (also called simply "switches") and shared hubs (also called simply
"hubs").
-
Switching Hub:
It is called a Multiport Bridge in IEEE802.3u. It has a MAC address table for stations connected between
ports. The destination address of a frame is used to switch between ports for output (switching).
The following figure illustrates the data flow when data is sent from Station A to Station B if a switching hub
is used.
c
Data is sent from Station A to Switching Hub First Port.
d
In the Switching Hub, data received from the first port is temporarily stored in the buffer memory.
e
According to the destination address of the frame, the port for output is determined, and data is passed to
the 4th port.
f
Data is sent from the Switching Hub 4th Port to Station B.
1
2
3
4
5
6
7
8
E
E
E
E
E
E
E
E
Buffer
Memory
LAN Control LSI
RJ-45Connector
Station A
Station B
c
d
e
f
Switching Hub
High-speed
Internal Bus
Station C
Station D
Figure A2.1 Operations of a Switching Hub
