Subject: Switchover traps in draft-ietf-atommib-sonetaps-mib-05.txt

From: Mickey Spiegel <[email-masked]>
Date: Thu, 07 Feb 2002 19:10:54 -0800

We realize that last call for this MIB ended a while ago, but we would
like to raise an issue with regard to the switchover trap defined in
draft-ietf-atommib-sonetaps-mib-05.txt.

The relevant definitions from the current draft are:

   apsChanStatusSwitchovers OBJECT-TYPE
       SYNTAX     Counter32
       MAX-ACCESS read-only
       STATUS     current
       DESCRIPTION
           "The number of times this channel has switched to the protection
            line. When queried with index value apsChanConfigNumber set to 0,
            which is the protection line, this object will return 0."
       ::= { apsChanStatusEntry 4 }

   apsChanStatusLastSwitchover OBJECT-TYPE
       SYNTAX     TimeStamp
       MAX-ACCESS read-only
       STATUS     current
       DESCRIPTION
           "The value of sysUpTime when this channel last completed a switch
            to the protection line. If this channel has never switched to the
            protection line, or this channel is the protection line, the value
            0  will be returned."
       ::= { apsChanStatusEntry 5 }

   <snip>

   apsEventSwitchover NOTIFICATION-TYPE
       OBJECTS { apsChanStatusSwitchovers, apsChanStatusCurrent }
       STATUS  current
       DESCRIPTION
               "An apsEventSwitchover notification is sent when the
               value of an instance of apsChanStatusSwitchovers increments."
                  ::= { apsNotificationsPrefix 1 }

With these definitions, a trap is issued whenever a switchover occurs
from the working channel to the protection line.  However, no trap is
issued if a switchover occurs from the protection line to the working
channel.  We believe this is a serious limitation, particularly when
1+1 non-revertive APS is used.

Why was it decided that apsChanStatusSwitchovers should not apply to
the protection line?

We would like to propose the following modifications:

   apsChanStatusSwitchovers OBJECT-TYPE
       SYNTAX     Counter32
       MAX-ACCESS read-only
       STATUS     current
       DESCRIPTION
           "When queried with index value apsChanConfigNumber other than 0,
            this object will return the number of times this channel has
            switched to the protection line.

            When queried with index value apsChanConfigNumber set to 0,
            which is the protection line, this object will return the
            number of times that any working channel has been switched
            back to the working line from this protection line."
       ::= { apsChanStatusEntry 4 }

   apsChanStatusLastSwitchover OBJECT-TYPE
       SYNTAX     TimeStamp
       MAX-ACCESS read-only
       STATUS     current
       DESCRIPTION
           "When queried with index value apsChanConfigNumber other than 0,
            this object will return the value of sysUpTime when this
            channel last completed a switch to the protection line. If this
            channel has never switched to the protection line, the value
            0 will be returned.

            When queried with index value apsChanConfigNumber set to 0,
            which is the protection line, this object will return the
            value of sysUpTime the last time that a working channel was
            switched back to the working line from this protection line.
            If no working channel has ever switched back to the working
            line from this protection line, the value 0 will be returned."
       ::= { apsChanStatusEntry 5 }

With these definitions, the apsEventSwitchover trap is issued whenever
a switchover occurs, either from a working channel to the protection
line, or from the protection line back to a working channel.

We also suggest that a global MIB object be added to enable or disable
generation of the traps defined in this MIB.

Mickey

---

From: "C. M. Heard" <[email-masked]>
Date: Sun, 10 Feb 2002 14:36:31 -0800 (PST)

> The relevant definitions from the current draft are:
<details snipped>
> 1+1 non-revertive APS is used.

I agree.

> We would like to propose the following modifications:
<details snipped>
> line, or from the protection line back to a working channel.

The APS MIB module has not yet been published;  it is listed on the
OPS area web site (http://www.ops.ietf.org) as In Status Revision
(last changed 09 Jan 2002).  Since the omission Mickey points out is
a serious technical flaw, these changes should be made.

Mike