[Last-Call] Re: [EXTERNAL] [Pals] Re: Genart last call review of draft-ietf-pals-ple-08

[Joel Halpern <jmh.direct@xxxxxxxxxxxxxxx>]

Sasha, I am no expert on this work, but section 7.2.2 of the draft seems to deal with the filling issues quite clearly.

Yours,

Joel

On 10/20/2024 4:04 AM, Alexander Vainshtein wrote:

Joel, Christian and all,

Regarding the marked question from Joel:

 

IMHO and FWIW the receiver always sends all the bits in all the bytes in has received: the transmitter simply slices the (potentially, infinite) bitstream it has received into chunks, and the number of bits in each chunk is a multiple of 8.

 

A more interesting question is what happens if a packet that carries one of the chunks is lost in transit.

Of course, the receiver detects a lost packet  (this is why the sequence numbers are MUST), and it also knows how many bits have been lost (this is why all chunks MUST be of the same size), so that it can play out some predefined patter (e.g., all ones) replacing the lost chunk in the outgoing bitstream. But how does the receiving CE react to such a replacement?

 

In the case of traditional TDM streams, a pattern of all ones could be used to make the receiving CE to detect, report and handle a suitable alarm (AIS).

But here we are dealing with Ethernet and Fober Channel…

 

My 2c,

Sasha

 

From: Joel Halpern <jmh@xxxxxxxxxxxxxxx>
Sent: Friday, October 18, 2024 9:33 PM
To: Christian Schmutzer (cschmutz) <cschmutz@xxxxxxxxx>
Cc: gen-art@xxxxxxxx; draft-ietf-pals-ple.all@xxxxxxxx; last-call@xxxxxxxx; pals@xxxxxxxx
Subject: [EXTERNAL] [Pals] Re: Genart last call review of draft-ietf-pals-ple-08

 

Thanks.  With regard to the non-byte-aligned payload, I am still slightly confused.  I can well believe this is clear to those working in the area.  But... If the payload is not byte aligned, and bytes are sent, how does the receiver know how many bits in the last byte to ignore?

Thanks,

Joel

On 10/18/2024 1:44 PM, Christian Schmutzer (cschmutz) wrote:

Hi Joel,

 

Thank you for your review! Let me try to comment/answer here

 

1) RSV/FRG:

 

Good catch. We indeed forgot to mention explicitly that payload fragmentation is not used by PLE. I changed the text for FRG to 

 

    These bits MUST be set to zero by the sender and ignored by the receiver as PLE does not use payload fragmentation

 

And similar to RFC4553 (https://datatracker.ietf.org/doc/html/rfc4553#section-4.2) I also added the following sentence to the PW demultiplexing section

 

    The total size of a PLE packet for a specific PW MUST NOT exceed the path MTU between the pair of PEs terminating this PW.

 

 

2) byte aligned payload

 

For Ethernet and Fibre Channel services, PLE is carrying 66B/64B encoded data for example. So the payload carried by PLE is not always in bytes. The basic payload of PLE is designed to be completely structure agnostic without any need to align the PLE packet generation with the incoming payload data.

 

For OTN services (https://datatracker.ietf.org/doc/html/draft-ietf-pals-ple-08#section-4.5) the CE-bound IWF function must extract the extended ODUk frames from the received PLE payloads. Based on our discussions with leading OTN technology vendors, this "search function" is easier to implement under the assumption that the PLE payload is byte aligned hence we defined this dedicated PLE payload type which is byte aligned for OTN services.

 

 

I hope this addresses your comments. The changes with respect to 1) are included in the -09 version I just uploaded to data tracker

 

Regards

Christian 

On 11.10.2024, at 16:34, Joel Halpern via Datatracker <noreply@xxxxxxxx> wrote:

 

Reviewer: Joel Halpern
Review result: Ready with Nits

I am the assigned Gen-ART reviewer for this draft. The General Area
Review Team (Gen-ART) reviews all IETF documents being processed
by the IESG for the IETF Chair.  Please treat these comments just
like any other last call comments.

For more information, please see the FAQ at

<https://wiki.ietf.org/en/group/gen/GenArtFAQ>.

Document: draft-ietf-pals-ple-08
Reviewer: Joel Halpern
Review Date: 2024-10-11
IETF LC End Date: 2024-10-23
IESG Telechat date: Not scheduled for a telechat

Summary: This draft is ready for publication as a Proposed Standard

Major issues: N/A

Minor issues: N/A

Nits/editorial comments:
   Section 5.2.1 defining the PLEA Control Word describes two pairs of bits,
   one pair called RSSV and described in the usual way for describing reserved
   bits.  A second pair is called FRG and is described more teresely but
   appears to be simply more reserved bits.   It is unclear why these two
   fields are separated, and why the wording is slightly different between
   them.

   Section 6 desccribes the basic payload and the byte aligned payload.  The
   description makes it look like there are two different forms.  Thinking
   about it, the payload is always in bytes, so the sender will fill bits from
   the source until it has filled the fixed number of bytes.  SO what is the
   difference between 6.1 and 6.2?

 

Disclaimer

This e-mail together with any attachments may contain information of Ribbon Communications Inc. and its Affiliates that is confidential and/or proprietary for the sole use of the intended recipient. Any review, disclosure, reliance or distribution by others or forwarding without express permission is strictly prohibited. If you are not the intended recipient, please notify the sender immediately and then delete all copies, including any attachments.

-- 
last-call mailing list -- last-call@xxxxxxxx
To unsubscribe send an email to last-call-leave@xxxxxxxx