[RPRWG] Corrections in Table 10.13, 10.15 ?

[Mohit Sood <msood@xxxxxxxxxxxxxx>]

Hi everyone,

 

I came across lots of statements in Tables 10.13 and 10.15 in the standard, which I think are erroneous. I was wondering if somebody who understands these can reflect on them. I would really appreciate that.

 

(1) Table 10.13-line 9: the condition "myWrappingMethod == CENTER_WRAP" should be "myWrappingMethod == EDGE_WRAP" ? I used Fig.10.4 as reference. Rationale behind this - A ringlet's datapath in a 'center-wrapped' station can receive data/control frames only from the ringlet to which it belongs. (e.g. datapath D0 can receive frames from RI = 0 only). Since, FROM EDGE means that the span on the Rx side of the relevant datapath is broken, it is not possible for this datapath to receive any frames (and in a way it rendered useless). If there are no frames received by this datapath then this condition becomes irrelevant !

The condition is relevant while doing EDGE_WRAP.

 

(2) Table 10.15-lines 13,15, an 16: I think in most of the assignments 'myRi' and 'otherRi' have been mixed up - first, when getting 'lrtt' values from 'topoEntry' and second, when getting 'totalHops' to calculate wrapPoints. I donot want to describe all of those here but here is an example - line 16: 'WrapPoint' should be = totalHopsRx[<myRi>]' or 'totalHops<Tx>[otherRi]'. 'lrttToTail' should be = '2*topoEntry[<otherRi>][wrapPoint].lrtt + topoEntry[<myRi>][tailIndex].lrtt;'. (NOTE: variables inside <> are the corrected ones). The equations on page 274 and 275 seem to be calculating lrttToTail correctly, than the ones in this Table.

Thanks,

Mohit