[c-nsp] Two DS3s Bounced at the Same Time

[John Neiberger]

> So, what sort of alarm are we talking about here? Is there some sort
> of alarm that might clear up within two seconds, so the controller is
> supposed to wait to see if the alarm is cleared before resetting
> itself?

Following up on my own email, I just found this link that explains it
a bit better:

http://www.cisco.com/en/US/products/hw/modules/ps2033/products_field_notice09186a00802ff01d.shtml

<snip>
Problem Description

    The port adapters listed in the Products Affected section above,
bring the T3 controller down immediately after receiving one of the
following alarms on the wire: LOS or AIS.

Background

    Based on the ANSI T1.231 specification a T3 controller should not
react to an alarm (LOF, LOS, AIS) unless the alarm persists for 2
+/-0.5 seconds. The T3 Port Adapters (PAs) listed above in the
Products Affected section do not adhere to the failure declaration
specification threshold.

Problem Symptoms

    Since the T3 PAs listed above in the Products Affected section do
not adhere to the two second holddown timer before reacting to an
alarm as defined in the ANSI T1.231 specification, the controllers
will go down immediately and come back up a few seconds later. This
will result in loss of data and interference with user traffic.

</snip>

Now, if I could just figure out a way to determine if my equipment
received an alarm at that time. It doesn't appear that I have an alarm
history available.

Okay, I just ran into something even stranger. There are two PAs on
the VIP in slot 12. I just tried "show controllers serial 12/1/0" and
I got one page of data and then my SSH session was disconnected. I
logged back in, tried a few other commands and then re-entered the
"show controllers" command, and my session dropped again at exactly
the same point. This really worries me.

John