[RPRWG] RPR Perf: simulation models
Hi Adisak,
I have some questions about the posted simulation models. Since the
source code is not available, and there is no documentation I need help
to figure out a few things.
Assuming other people may ask the same questions, anyone interested in
these models may read on.
Thanks,
Pinar
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1) Packet formats are different from the draft proposal. Can you
provide descriptions for the fields in the data and RCM packet formats?
Particularly, what is "CFI", "Stack Bit", and "crr"? Where is RCF value
stored?
2) Other than the packet formats, are there any other issues that are
different from the write-ups in zz_draft_01.zip files?
3) Why are there 0-bit fields in packet format? Is this somehow an
out-of-band communication mechanism between nodes on the ring?
4) Backpressure mechanism between VoQ MAC and MAC Client uses a
single-field packet whose only field is a 0-bit Pause field. Does the
pause message have any additional parameters such as class and/or
destination? If not, is the functionality equivalent to XON/XOFF
signaling between MAC and MAC client?
5) It looks like Pause signal is generated in the MAC by a queue module.
This queue module appears to be part of the transit path and has 4
sub-queues which are 128KB each. What is the functionality of these
queues? How is the pause message generated? Does the policer module have
a role in this?
6) Can you describe the functionality of the statistics below?
What do the indices refer to? What are the reference points for delay
collection?
VoQ MAC->stat collection->Traffic->delay (seconds) [0,1,2,3]
VoQ MAC->stat collection->Traffic->throughput (bits/sec) [0,1,2,3]
7) How does RPR config node work? In the "Traffic configuration
parameters" for this node, is "reserved rates" configured for
RPRMAC<->RPRMAC conversations based on dest-src ring nodes? What is the
unit of reserved rate? What happens if the reserved rates are not
specified (or specified as 0)?
8) Is there a plan to provide models that use raw packet generators?
If not, how can I connect raw packet generators? To the VoQ MAC or MAC
client? It looks like the MAC client does not accept non-Ethernet
packets?
9) Does the model have topology discovery capabilities? How is it
configured? How is topology information communicated between VoQ MAC and
MAC Client?
10) VoQ MAC has an attribute called "ID". What is its significance? Is
it used as the MAC address on the ring? It looks like MAC client has an
auto-assigned Ethernet MAC address. Alternatively, does that become the
address of the VoQ MAC to be locally significant on the ring?