Zyxel IES-5112 [168/1156] Ldm test screen delt

Zyxel IES-6000 [168/1156] Ldm test screen delt
Chapter 7 Diagnostic Screens
Management Switch Card User’s Guide
168
CFM provides two tests to discover connectivity faults.
Loopback test - similar to “pinging” a computer. A loopback test checks if the MEP port receives
its LBR (Loop Back Response) from its target after it sends the LBM (Loop Back Message). If no
response is received, there might be a connectivity fault between them.
Link trace test - similar to the “traceroute” function. A link trace test provides additional
connectivity fault analysis to obtain more information on where the fault is. In the link trace test,
MIP ports also send a LTR (Link Trace Response) in response to the source MEP port’s LTM (Link
Trace Message). If an MIP or MEP port does not respond to the source MEP, this may indicate a
fault. Administrators can take further action to check and resume services from the fault
according to the line connectivity status report.
An example is shown next. A user reports he cannot access the Internet. To check the problem, the
administrator starts the link trace test from the A which is an MEP port to the B which is also an
MEP port. Each aggregation MIP port between aggregated devices response the LTM packets and
also forwards them to the next port. A fault occurs in the port C. A discovers the fault since it just
gets the LTR packets from the ports flowing before the port C.
Figure 90 MIP and MEP Example
7.2 LDM Test Screen (DELT)
Click Diagnostic > LDM in the navigation panel to display this screen. Use this screen to perform
loop diagnostics (LDM stands for Loop Diagnostic Mode) on an ADSL2, ADSL2+ or VDSL port. This
is a Dual End Loop Test (DELT) that acts on a per-tone basis. A DELT provides details about the line
condition. The subscriber device must also support DELT in order to perform this. See ITU-T G933.2
for more information. This feature is applicable for ALC line cards only.
(port 2, MEP)
(port 18, MIP)
(port 8, MEP)
B
C
(port 17, MIP)
A

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