[netconf] Re: WGLC for udp-client-server

[[e-mail]]

Dear Andy,

Andy> 2) local-port use of 'default 0'

I agree with your assessment that the IANA Service Name and Transport Protocol Port Number Registry (https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml) with the reference to RFC 6335 does not specify the semantics for port 0. However looking at
https://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers, it appears under Unix to be well known that port 0 is being used to assign a dynamic port.

However this has been discussed and commented already in the AD review of "tcp-client-grouping":  https://mailarchive.ietf.org/arch/msg/netconf/LzVLgbk_FU3FZqi9MCoTMLGAGbs/

This let then to

The "tcp-client-grouping" Grouping
https://datatracker.ietf.org/doc/html/rfc9643#section-3.1.2.1
---
The "local-port" node, which is enabled by the "local-binding-supported" feature (Section 3.1.1), is not mandatory. Its default value is "0", indicating that the operating system can pick an arbitrary port number.

And is being mirrored in udp-client-server where Mahesh as AD asked for consistency: https://mailarchive.ietf.org/arch/msg/netconf/JD8NNDPmhoLCFM0PZKKzQUokDYk/, which I support.


What I suggest is to open for RFC 6335 an errata. Default port 0 use should be described clearly. Otherwise the IANA reference has no value.

Would you and other on the mailing list agree? Shall I go ahead and open the errata?

Best wishes
Thomas

From: Andy Bierman <[e-mail]>
Sent: Wednesday, February 12, 2025 9:50 PM
To: Per Andersson <[e-mail]>
Cc: [e-mail]
Subject: [netconf] Re: WGLC for udp-client-server

Hi,

This document is ready with the following minor issues:

1) leaf remote-port is optional


   leaf remote-port {

      type inet:port-number;

      description

        "The port number of the remote UDP server.";

    }


Our implementation will reject a missing remote-port leaf in a receiver-instance.
There is no standard port assignment in this case.
The description should specify that it depends on the context whether this leaf
can be absent or not.

2) local-port use of 'default 0'


    leaf local-port {

      if-feature "local-binding";

      type inet:port-number;

      default "0";

      description

        "The local port number to bind to when sending UDP

        messages to the remote server. The port number '0',

        which is the default value, indicates that any available

        local port number may be used.";

    }


This usage does not appear to be consistent with the typedef description for port-number:


      Note that the port number value zero is reserved by IANA.  In

      situations where the value zero does not make sense, it can

      be excluded by subtyping the port-number type.


Is the IANA text supposed to mean "make up any semantics you want for value zero"?
Not the cleansest modeling I've seen but consistent with coding hacks.


Andy

On Thu, Feb 6, 2025 at 7:51 AM Per Andersson <[e-mail]<mailto:[e-mail]>> wrote:
Hi!

This email begins a two-week WGLC on:

YANG Groupings for UDP Clients and UDP Servers
https://datatracker.ietf.org/doc/html/draft-ietf-netconf-udp-client-server-05

Please take time to review this draft and post comments by February
20. Favorable comments are especially welcomed.

None of the authors or contributors have declared IPR:

https://mailarchive.ietf.org/arch/msg/netconf/NncA8JHqZH14wCptMhktgGcngyM/


--
Per, co-chair

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