Specifications
Installation and Operation Manual Chapter 5 Monitoring and Diagnostics
ASMi-52 Ver. 2.8 Frequently Asked Questions 5-27
the modems are TDM-based and not ATM-based, the modems should work
together.
Q What is the meaning of Prop Protocol Fail Alarm?
A The "Prop Protocol Fail" Alarm indicates that the local modem has lost
management communication with the remote modem. It is an alarm that
normally appears when there are error bits on the line, since the first thing
affected by this is the EOC (Embeded Operations Channel) which is used for
management communication between both modems.
The alarm may be set off due to a noisy line or a line that is close to the
maximum reach of the modem at the specific data rate selected. To solve the
problem, you can check the configuration of the Power Backoff feature, and
see if it is ON. If Power Backoff is ON, then setting it to OFF will cause the
modems to transmit at their maximum power, which should improve the
Signal to Noise Relation (SNR) and avoid errors with data reception.
Apart from changing the Power Backoff setting, the only other option you
have is to decrease the data rate at which the modems are synchronized, or
to use a better line.
Q Question: In which cases is it not possible to loop the ASMi-52 modem via
the diagnostic screen?
A There are two possible reasons why the loops options do not appear in the
diagnostic screen:
• The modem has an ETH interface, and since there are no loops in ETH,
this option does not exist.
• When two modems are connected back-to-back and one of them is in
loop mode, the other modem cannot access the loop options.
Q What is the ASMi-52 buffer size in the following modes: 1) No QoS is
assigned 2) QoS is assigned to the 4 queues?
A The ASMi-52 buffer size is 64 frames:
• In case no QoS assigned, all the traffic is mapped to class 1 (size of
64 frames).
• In case QoS is assigned, there are 4 classes which are actually 4 buffers
that can contain 64 frames each.
Q What is the ASMi-52 maximum frame length (MTU)?
A The maximum frame length ASMi-52/ETH can forward is 1912 bytes.