Flexible OTN / fractional 100GbE
lists.nanog at monmotha.net
Thu May 30 01:46:28 UTC 2019
On 5/29/19 3:53 PM, Mitcheltree, Harold B wrote:
I'm not sure I see how this particular product resolves the concern I
Yes, it will aggregate native subrate services at 10Gbps or 40Gbps
native line rate up onto 100G OTN (on OTU4), and it can (presumably) do
that without packet switching using either 1:1 frame mapping using GFP-F
or straight cut-through stream mapping with GFP-T or similar.
What it doesn't appear to do, and where my concern lies with the OP's
desires surrounding OTN, is take a "fractional" 100Gb service and
aggregate it up with other services onto an OTU4. "Fractional" here
means that the committed/available throughput is something less than the
native line rate which is what OP appeared to be asking for
("'fractional 100GbE' e.g. starting with 30-60Gbps commit").
The only way I know to do this is to packet switch, as either Ethernet
or GFP-F OTN traffic, the subscriber data onto a FlexODU at the desired
subscriber rate within the OTU4. Other traffic could then be placed
within the same OTU4 using the normal OTN TDM mechanisms including
subrate (e.g. 10Gbps) traffic that might NOT require packet switching
since it could be re-framed/re-transmitted onto the OTU4 at its native
I don't see any reason you can't do this, though I know of no equipment
that will off hand, and it will incur some latency and jitter due to the
packet switching which OP seemed to want to avoid. You'd still get the
benefits of FEC, enhanced monitoring, etc. from the OTN side of things,
and the latency and jitter should be generally better than switching it
onto a higher-rate native Ethernet even if the high-rate side is not
oversubscribed. It should certainly be no worse.
The crux of this is what happens when you have a subscriber service
who's native line rate exceeds the provisioned OTN throughput which is a
scenario OP alluded exactly to.
More information about the NANOG