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Trying to get more minds on this subject: I’m looking at the new descriptive language that describes the aging of claims: “Soft claims are removed from the claim table, txop_claim_table, if they are older than soft_aging_cycles. Similarly, stale hard claims are removed every hard_aging_cycles.” This appears to be the function desired. When I look at the D-PLCA Aging state diagram, this appears to occur in the state TXOP_END. However, if I am right, this isn’t what TXOP_END does. What it looks like TXOP_END does is clear the soft claims from the claims table every soft_aging_cycles transmit opportunities (irrespective of when during the past soft_aging_cycles Tos the soft claim was
set). Hard claims are more difficult to describe. If I look at the state diagram, the txop_claim_table and txop_claim_table_new are kept synchronized in that they are initialized clear at the same time (DISABLED state), updated each at the same time (in the
UPDATE_SOFT and UPDATE_HARD states, and have soft claims cleared out at the same time (TXOP_END state). However, the clearing that happens at hard_aging cycles seems the relevant part: First the txop_claim_table_new is moved into the txop_claim_table (this is the one that gets used in the D-PLCA Control state diagram).
THEN, the txop_claim_table_new gets completely cleared (both hard and soft claims). At this point it is out of sync with the txop_claim_table being used – in terms of soft claims, until the next soft claiming
cycle, but that doesn’t seem to matter… In terms of hard claims, what I think this means is that the claims transferred to txop_claim_table (and therefore used by D-PLCA Control) are those that have been hard claimed during the previous hard_aging_cycle
transmit opportunities. First, IS THIS THE FUNCTION WE WANT? (or do we want something more like each claim, hard or soft, having it’s own age – something I don’t think is in the state diagram as written). IF MY UNDERSTANDING IS CORRECT, I would suggest replacing “Soft claims are removed from the claim table, txop_claim_table, if they are older than soft_aging_cycles. Similarly, stale hard claims are removed
every hard_aging_cycles.” With “All soft claims are cleared from the txop_claim_table every soft_aging_cycles. Similarly, only those hard claims detected within the previous hard_aging_cycles transmit opportunities are loaded into the
txop_claim_table used by the D-PLCA Control state diagram.” Second, for this to work properly, it is a requirement that hard_aging_cycles be greater than soft_aging_cycles – or the algorithm won’t work… Ideally it is greater than several cycles of soft aging cycles
(but not necessarily a multiple of soft aging cycles). If my understanding above is correct, I would go further and replace the final sentence of the paragraph: “The value of hard_aging_cycles should be sufficiently greater than the value of soft_aging_cycles
to maintain stability of the D-PLCA process as well as interoperability with statically configured PLCA nodes.” With “The values of both hard_aging_cycles and soft_aging_cycles should be greater than several than the maximum number of transmit opportunities expected to be on a mixing segment. Additionally, the value of
hard_aging_cycles should be sufficiently greater than soft_aging_cycles, preferably several times greater, to maintain stability of the D-PLCA process as well as interoperability with statically configured PLCA nodes.” This seems to suggest that our default for soft_aging_cycles might be too low… 50 nodes seems to be within the scenarios many have considered. We may wish to consider changing this to 100. I do NOT plan
to submit that comment this round, but want people to think about it. The default for hard_aging_cycles (1000) seems perfectly fine, even if we change soft_aging_cycles to 100…. I haven’t submitted comments yet, so input is appreciated. George Zimmerman, Ph.D. President & Principal CME Consulting, Inc. Experts in Advanced PHYsical Communications 310-920-3860 To unsubscribe from the STDS-802-3-SPMD list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=STDS-802-3-SPMD&A=1 |