Cabletron Systems SEHI-22/24 - Manual (Page 40)

Link/Seg Traps
3-2 What is a Link Trap?
What is a Link Trap?
Some Cabletron Ethernet repeater ports — including RJ45 twisted pair and fiber
optic ports — generate a link signal to monitor the status of their connection with
the device at the other end of the cable segment. If the cable is removed or broken,
the port’s link status goes to “No Link” and the repeater generates a
portLinkDown
trap. When a port in a “No Link” condition receives a link signal,
the port goes to a “Link” condition and the repeater generates a portLinkUp trap.
Note that devices at both ends of the disconnected or broken cable will generate
the portLinkDown and portLinkUp traps, even when only one end of the cable
has been removed.
Enabling and Disabling Link/Seg Traps
Although each Cabletron device comes with a number of traps built in to the
firmware, no device will generate these traps unless it is configured to do so. This
can be accomplished via Local Management (by enabling traps and entering your
workstation’s IP address in the Community Names screen), or via the SPMA Trap
Table utility, accessible from the icon menu or from the command line. Once traps
as a whole have been enabled, you can use the Link/Seg Traps feature to
selectively enable and disable link and segmentation traps as required by your
network management needs.
To open the Repeater Link/Seg Traps window:
from the icon:
1. Click on the appropriate SEHI icon to display the icon menu.
2. Drag down to Link/Seg Traps and release.
NOTE
Unterminated BNC (thin coax) ports appear in the Hub View as segmented ports. When
you attach a thin coax cable or a 50
Ω
terminator to a port, the repeater generates a
portUnsegmenting trap; when you remove the cable or terminator, the repeater
generates a portSegmenting trap. Note also that devices at both ends of the cable will
generate the portUnsegmenting and portSegmenting traps, even if only one end of the
cable has been disconnected.
NOTE
BNC (thin coax), AUI, and transceiver ports do not support a link signal. As described
above, BNC ports respond to changes in link status by generating portSegmenting and
portUnsegmenting traps; AUI and transceiver ports do not respond at all to changes in
link status (unless the port has been segmented due to excessive collisions), and will
always display as on, even if no cable is connected.