CANOGA PERKINS N525 Ethernet Termination Service Unit - Manual (Page 87)

N525 Ethernet Termination Service Unit 4-11
Connectivity Loss Detection
The Connectivity Loss Detection (CLD) feature enables you to detect loss of connectivity to
a remote N525 in a point-to-point circuit, and to detect undesired link performance. In
conjunction with CLD you can use Connection Loss Forwarding (CLF), which will shut down
the User port if there is a loss of connectivity to the remote N525. CLD and CLF are disabled
by default.
Note: Before enabling Connection Loss Forwarding, you should disable Link Loss
Forwarding.
Note: You should configure the settings for CLD before enabling CLD.
Note: You can use CLD to detect loss of connectivity in point-to-point circuits only. Multipoint
CLD is not supported.
When you enable CLD, the N525 sends Ping packets continuously to the remote N525.
Loss of connectivity is determined based on a certain number of consecutive lost pings.
Recovery of connectivity is determined based on a number of consecutive successful pings.
Link performance is determined by round trip time (RTT) of the pings. All of these factors are
configurable.
The N525 uses hardware timestamps in the Ping packets in order to measure RTT. The
hardware timestamps are inserted into the Ping packets by both the local and remote N525.
This allows the local N525 to exclude ICMP packet processing time when calculating RTT,
which makes for highly accurate measurements.
You enable CLD on each N525 individually. Typically two N525s are configured to use CLD
on the link between them. Each N525 pings the Extension port of the other N525. However,
if one N525 does not have CLD enabled, that N525 will still respond to the CLD pings from
the other N525.
There are SNMP traps for CLD and CLF events.