Liaison statement
Reply LS on port allocation

1. Overall Description:

CT4 thanks RAN3 for the LS on port allocation (R3-202553 / C4-203405).

CT4 recommends CT and RAN to request again IANA/IESG to allocate a port for the
W1 interface, to simplify implementations and comply with Rel-16 timeframe.
When doing so, CT4 also recommends 3GPP to commit towards IANA/IESG that 3GPP
will develop alternative solutions from Rel-17 onwards, i.e. that no further
port allocation requests for use in private networks will be issued towards
IANA in future, in accordance to IANA instructions.

CT4 also discussed the following possible alternatives for port allocation for
new 3GPP applications/interfaces in future but couldn't reach a conclusion.
Each alternative is further described in the attachment:

-       3GPP may specify a port in the Private/Dynamic Port Numbers range
[49152 - 65535] for a new 3GPP application;

-       Operator may specify a port in the Private/Dynamic Port Numbers range
[49152 - 65535] for a new 3GPP application;

-       DNS based solution.

2. Actions:

To RAN3:

ACTION: CT4 kindly asks RAN3 to take the above information into account.

To IESG and IANA:

ACTION: CT4 kindly asks IESG and IANA to take the above information into
account.

To RAN/CT:

ACTION: CT4 kindly asks RAN/CT to take the above information into account and
consider requesting IANA to allocate a port for the W1 interface. CT4 kindly
asks CT/RAN whether CT4 should work on defining possible alternative solutions
for port allocation from Rel-17 onwards, that each 3GPP WG could then rely upon
when they would need to define a port for a new interface.

3. Date of Next TSG-CT WG4 Meetings:
CT4#99e                 2020-08-18      2020-08-28       E-meeting