RE: [RPRWG] What rcvdFairRate should be used if SC-FCM are not being received?

["Michael Allen" <michael_allen@xxxxxxxxxxxxxxx>]

John:

Thanks for your answers. I must admit, I missed the Clause 11 statement
about missing SC-FCM messages. Shouldn't the Fairness state machines have
some states that reflect the missing messages and generate a failure
indication to the protection state machine?

It looks like the initial value of rcvdFairRate has proponents for two
values:
    FULL_RATE
    unreservedRate

Also, some extra questions...

1) In Table 9.2, "wrappedRing" is not defined. Is this meant to mean "I am
wrapped", or "the ring is wrapped somewhere"?

2) In Table 9.2, for the wrapped congested case, shouldn't the formula be:
hopsToCongestion = hopsToWrappedDownstreamStation + (256 - rcvdTTL);
Assuming hops are not decremented on the "wrong" ring ID.

3) In Table 9.5, Row 2, Line 26 (msg.TTL = rcvdTTL), shouldn't this be
replaced with:
if (rcvdRI == ringId)
{
    msg.TTL = rcvdTTL - 1;
}
else
{
    msg.TTL = rcvdTTL;
}

Regards,

Michael Allen

-----Original Message-----
From: owner-stds-802-17@xxxxxxxxxxxxxxxxxx
[mailto:owner-stds-802-17@xxxxxxxxxxxxxxxxxx]On Behalf Of John Lemon
Sent: Monday, January 20, 2003 11:21 AM
To: Michael Allen; stds-802-17@xxxxxxxx
Subject: RE: [RPRWG] What rcvdFairRate should be used if SC-FCM are not
being received?



Michael,

My answers:

1) Good catch. It is not stated, and therefore needs to be. (I'll expect a
comment from you against D2.1 to address this issue.) My recommendation
would be to initialize the last rcvdFairRate with the same value the
localFairRate is initialized with.

2) From a fairness control unit point of view, it does not time out. (See
(3) for why it doesn't need to.) Whatever the last one was, is the one used.

3) Yes. Note that this is already specified in Clause 11.

John Lemon

-----Original Message-----
From: Michael Allen [mailto:michael_allen@xxxxxxxxxxxxxxx]
Sent: Sunday, January 19, 2003 2:05 PM
To: stds-802-17@xxxxxxxx
Subject: [RPRWG] What rcvdFairRate should be used if SC-FCM are not
being received?



In section 9.3.1 of D2.0, it indicates that the most recently received
rcvdFairRate value should be used in the aging interval calculations.

My questions relate to this.

1) What rcvdFairRate should be assumed if a rcvdFairRate has *never* been
received. Should a rcvdFairRate of FFFFh be assumed initially?

2) What rcvdFairRate should be assumed if a rcvdFairRate has not been
received for "a while" (like 10 or N intervals), but has been received at
least once. Should a rcvdFairRate of FFFFh be assumed after this period?

3) Should a Signal Fail indication be sent to the Protection Machine if 2)
occurs?

Regards,

Michael Allen
Chip Engines, Inc