Rockwell Automation Ethernet Design Considerations Reference Manual - Manual (Page 25)

Rockwell Automation Publication ENET-RM002C-EN-P - May 2013 25
Ethernet Infrastructure Components Chapter 2
Hubs Hubs are multiport repeaters. They are based on older technology, which has
been largely replaced by network switches at Layer 2, but they are still used as
network diagnostic tools to analyze network traffic:
• A hub is at the center of a star topology.
• Hubs can connect together with a variety of media as a backbone between
hubs.
• A hub broadcasts everything it receives on any channel out all other
channels.
Repeaters A repeater recreates the incoming signal and re-transmits it without noise or
distortion that can have affected the signal as it was transmitted down the cable.
Repeaters are generally used in older networks to increase the network length.
More modern networks use fiber media or switches to increase network length.
Hub
HMI
1756 Controller
1734 POINT I/O
PowerFlex
1738 ArmorPOINT® I/O
Personal computer
Repeater