| Here's the formula for Ethernet Contention:
Ethernet Contention = Bytes Sent,initially deferred + Bytes sent,Single collision + Bytes sent multiple collisions
------------------------------------------------------------------------------------------
data blocks sent
We will update the Use Manual.
|
| .re 4
>Here's the formula for Ethernet Contention:
>
> Ethernet Contention = Bytes Sent,initially deferred
> + Bytes sent,Single collision
> + Bytes sent multiple collision
> ----------------------------------------
> data blocks sent
>
>
>We will update the Use Manual.
We have some problems to understand the formula, although we made the same
guess some days ago:
1) You divide "Bytes Sent, ... + .. + .." by "Data Blocks Sent". Bytes and
Blocks! But I think this a documentation error for the variables BSID, BSM,
BSMC and BSSC on page A-2 Peformance Analyzer Function Module Use (V1.1).
Please, compare the corresponding NCL output:
Line Counters as of 20-MAY-1992 14:35:48
Line = MNA-0
31034 Seconds since last zeroed
2980945 Data blocks received
1078645 Multicast blocks received
1 Receive failure, including:
Frame too long
417836874 Bytes received
108680418 Multicast bytes received
0 Data overrun
1835245 Data blocks sent
15688 Multicast blocks sent
32089 Blocks sent, multiple collisions
27040 Blocks sent, single collision
67020 Blocks sent, initially deferred
1022748545 Bytes sent
2109405 Multicast bytes sent
0 Send failure
0 Collision detect check failure
0 Unrecognized frame destination
29 System buffer unavailable
0 User buffer unavailable
2) If you compare the values from a statistics output you observe a too small
percent(!) value for the Ethernet Contention:
Node4 bern03 Line mna-0
AT 20-MAY-1992 14:13:47 Statistics
Examination of Attributes shows:
Duration = 300 Seconds
Outbound Utilization = 4.92 Percent
Inbound Utilization = 1.6 Percent
Average Outbound Block Size = 651.6 Bytes/Block
Average Inbound Block Size = 141.13 Bytes/Block
Outbound Block Rate = 90.73 Blocks/Sec
Inbound Block Rate = 119.57 Blocks/Sec
Deferred Percent = 4.64
Single Collision Percent = 1.91
Multiple Collision Percent = 2.43
Inbound Multicast Percent = 28.67
Error Percent = 0
Count of Data Overrun Blocks = 0
Count of System Buffers Unavailable = 0
Count of User Buffers Unavailable = 0
Count of Collision Detect Failures = 0
Count of Unrecognized Frame Destination = 0
Count of Frame Send Failures = 0
Count of Frame Receive Failures = 0
Ethernet Contention = 9.000000E-02 Percent
Outbound Bytes = 1.773526E+07 Bytes
Inbound Bytes = 5.062306E+06 Bytes
Outbound Data Blocks = 27218 Blocks
Inbound Data Blocks = 35870 Blocks
|
| The error 2), reported in the note .6, is corrected in a newer SSB release
of DECmcc V1.1. I have noticed this during a test at a customer site with
the PA FM:
MCC_PA_FM.EXE;3 18-JUL-1991 18:11:07.00
The computation of the Ethernet Contention is here correctly performed.
Edgar
|