Re: [tsvwg] FW: New Version Notification for draft-johansson-cc-for-4g-5g-00.txt

["Smith, Kevin, (R&D) Vodafone Group" <[e-mail]>]

HI Ingemar,

Thanks for drafting this, I found it useful. Here follows some feedback which I hope is of help. 

All best,
Kevin

Kevin Smith, Vodafone R&D

===========

2.1. PDCP

s/cell to terminal/cell-to-terminal

s/packets will be ensured to be delivered/packets are guaranteed to be delivered 

Bufferbloat [REF]
> missing REF..?

Clarifications:
Depending on the available link throughput after the handover, an increased RTT may be experienced at a handover event.
> the RTT may also decrease - is that equally likely? 

In addition, a small temporal delay increase can occur as packet transmission is inhibited at the handover event.
> that (should) not be the case for soft handover, in the LTE intra-RAT scenario

Because of the above it is a good practice to keep the amount of data in flight as small as possible, without sacrificing throughput.
> amount of data means number of packets (per text in following paragraph) - maybe worth changing to 'number of packets in flight'

2.2 RLC

s/in order/in-order

s/resources is allocated/resources are allocated

Clarification: 
higher terminal mobility means faster changing channel fading
> should be 'faster changing channel conditions', because the channel can get weaker or stronger during mobility.

2.3 MAC

s/that decreased only/that decreases only

Clarification:
soft decoding is utilized and the softbits of the first transmission and the retransmission are combined, hopefully with a successful result
> Please can you explain 'soft decoding' and 'softbits' here? 

2.3.1 Downlink scheduling

Addition:
Suggest to note that each UE provides Channel Quality Input to downlink scheduling

2.3.2 Uplink scheduling

Addition:
CQIs are sent here too, so worth noting.

Clarification:
HARQ RTT
> worth adding a reference to HARQ

s/ACK traffic in uplink can also be delayed due to for instance lack of
   signaling channel resources for instance if many terminals generate
   ACK traffic that is so sparse that scheduling requests need to be
   generated with high frequency./ACK traffic in uplink can also be delayed, due to for instance lack of
   signaling channel resources. This could arise if many terminals generate
   ACK traffic that is so sparse that scheduling requests need to be
   generated with high frequency.

3 4G and 5G evoluton

Clarification:
Carrier aggregation means that additional carriers (possibly in very high
frequency bands) are added.  Dual connectivity can combine two
similar or different radio access technologies on lower layers
(below IP).  
> these could be read as being identical ('aggregation' and 'combine'), please can you detail the difference?

The shorter TTI feature is part of the 5G standardization, it should
   however be stated that the
> sentence cut short


4. Requirements for improved performance

Clarifications:
The above considerations lead to a few things to consider when
   congestion control is designed for optimal performance in 4G and 5G
   networks:
> is this section intended as advice for the origin server and the network operator? Because the network operator wants to ensure fair throughput for all connections in the cell, especially under congestion. So both actors are valid; If network operator 'holistic' congestion control is out of scope then that should be explicit.

Also a general point: it may be obvious, but worth mentioning/referring to a means to detect that the client is on a 4G/5G network as opposed to WiFi.


===========

-----Original Message-----
From: tsvwg [mailto:[e-mail]] On Behalf Of Ingemar Johansson S
Sent: 15 October 2015 06:08
To: [e-mail]; [e-mail]; [e-mail]
Subject: [tsvwg] FW: New Version Notification for draft-johansson-cc-for-4g-5g-00.txt

Hi

A new IETF draft is submitted in response to general discussion that for instance TCP Cubic is not an appropriate congestion control algorithm for LTE. 
The draft briefly outlines typical 4G access behavior on the PDCP, RLC and MAC  layers that can have an impact on transport protocol performance. The draft also outlines two relatively simple modifications to the Cubic congestion control.

/Ingemar  

-----Original Message-----
From: [e-mail] [mailto:[e-mail]] 
Sent: den 14 oktober 2015 20:17
To: Ingemar Johansson S
Subject: New Version Notification for draft-johansson-cc-for-4g-5g-00.txt


A new version of I-D, draft-johansson-cc-for-4g-5g-00.txt
has been successfully submitted by Ingemar Johansson and posted to the IETF repository.

Name:		draft-johansson-cc-for-4g-5g
Revision:	00
Title:		Congestion control for 4G and 5G access
Document date:	2015-10-14
Group:		Individual Submission
Pages:		14
URL:            https://www.ietf.org/internet-drafts/draft-johansson-cc-for-4g-5g-00.txt
Status:         https://datatracker.ietf.org/doc/draft-johansson-cc-for-4g-5g/
Htmlized:       https://tools.ietf.org/html/draft-johansson-cc-for-4g-5g-00


Abstract:
   This memo outlines the challenge that 4G and 5G access brings for
   transport protocol congestion control and also outlines a few simple
   examples that can improve transport protocol congestion control
   performance in 4G and 5G access.


                                                                                  


Please note that it may take a couple of minutes from the time of submission until the htmlized version and diff are available at tools.ietf.org.

The IETF Secretariat