Requested revision
Standard: | 802.1Qbg-2012 | Clause: | 41.5.5 |
Clause title: | VDP state machine variables and parameters |
Rationale for revision
1) In 41.5.5.9, respWaitDelay is defined as follows:
respWaitDelay = 1.5 x (2^urpVdpResourceWaitDelay + (2 x ecpOperMaxTries + 1) x 2^ecpOperAckTimerInit)
and the default value of respWaitDelay is stated as about 11.6s.
But, the ecpOperAckTimerInit is the operational value of ackTimerInit (D.2.13.6) which is defined as 10 x 2^RTE
microsec, so it cannot be a exponent value. Actually, no system varaible is defined for operational RTE.
The original intent of the respWaitDelay definition seems to be as follows:
respWaitDelay = 1.5 x (resourceWaitDelay + (2 x ecpOperMaxTries + 1) x ecpOperAckTimerInit)
And, resourceWaitDelay = 10 x 2^urpVdpResourceWaitDelay (D.2.13.8), not 2^urpVdpResourceWaitDelay
The above corrected definition of respWaitDelay yields the default value of 17.4s, not 11.6s in original text.
Another one is that respWaitDelay is only used at EVB station, but the original text states that this is used by both station and Bridge.
2) Same mistakes exist at 41.5.5.13 toutKeepAlive definition
toutKeepAlive is defined as
toutKeepAlive = 1.5 x (2^sbpVdpOperReinitKeepAlive + (2 x ecpOperMaxTries + 1) x 2^ecpOperAckTimerInit
but, the original intent of the toutKeepAlive definition seems to be as follows:
toutKeepAlive = 1.5 x ( reinitKeepAlive + (2 x ecpOperMaxTries + 1) x ecpOperAckTimerInit.
And, reinitKeepAlive = 10 x 2^sbpVdpOperReinitKeepAlive (D.2.13.9), not 2^sbpVdpOperReinitKeepAlive.
This corrected definition of toutKeepAlive yields the default values of 17.4s, not 11.6s in original text.
The toutKeepAlive variable is only used at EVB Bridge, but the original text states that this is used by both station and Bridge.
Proposed text
1) In 41.5.5.9,
REPLACE the definition equation of respWaitDelay,
respWaitDelay = 1.5 x (2^urpVdpResourceWaitDelay + (2 x ecpOperMaxTries + 1) x 2^ecpOperAckTimerInit)
with the following equation:
respWaitDelay = 1.5 x (10 x 2^urpVdpResourceWaitDelay + (2 x ecpOperMaxTries + 1) x ecpOperAckTimerInit)
CHANGE the following original text :
"The default value used by the station and Bridge is about 11.6 s. The default value for urpVdpResourceWaitDelay is an exponent of 20 representing a timer interval of about 10.5 s and for ecpOperAckTimerInit is an exponent of 14 representing a timer interval of about 164ms."
with
"The default value of respWaitDelay used by the station is about 17.4 s. The default value for
urpVdpResourceWaitDelay is an exponent of 20 representing a timer interval of about 10.5 s and default value of
ecpOperAckTimerInit is about 164 ms with the default value of RTE, 14."
2) In 41.5.5.13,
REPLACE the definition equation of toutKeepAlive,
toutKeepAlive = 1.5 x (2^sbpVdpOperReinitKeepAlive + (2 x ecpOperMaxTries + 1) x 2^ecpOperAckTimerInit
with the following equation:
toutKeepAlive = 1.5 x (10 x 2^sbpVdpOperReinitKeepAlive + (2 x ecpOperMaxTries + 1) x ecpOperAckTimerInit)
CHANGE the following original text :
"The default value used by the station and Bridge is about 11.6 s. The default for sbpVdpOperReinitKeepAlive is an exponent of 20 representing a timer interval of about 10.5 s and for ecpOperAckTimerInit is an exponent of 14 representing a timer interval of about 164 ms."
with
"The default value used by the Bridge is about 17.4 s. The default for sbpVdpOperReinitKeepAlive is an exponent of 20 representing a timer interval of about 10.5 s and default value of ecpOperAckTimerInit is about 164 ms with the default value of RTE, 14."
Impact on existing networks
The respWaitDelay and toutKeepAlive are wrongly defined, so any EVB implementator can't know how to calculate the variables without this corrections.
Originator
Name: | Sung Hyuk Byun | Email: | shbyun@etri.re.kr<mailto:shbyun@etri.re.kr> |
Affiliation: | ETRI | ||
Submitted: | 2012-12-26 |