Subject: Comments/Contribution to PEP draft

From: Zach Shelby <[email-masked]>
Date: Wed, 17 May 2000 15:44:20 +0300

I have not been active before, but I hope these comments on the PEP
draft can be useful.

-----------------------------------------------------------------
Section 2.3: Some PEP implementations could operate both
symmetrically and asymmetrically if a combination of techniques are
used. For instanceimplementing extra ARQ protection in some instances,
SNOOP in others,  and IP header compression when appropriate.

Chapter 3:
----------
Recommended addition: Forward Error Control
In some cases wireless links may not provide sufficient protection against errors.
These errors will either cause a packet to be dropped, or passed on
with errors.  One method for extra protection against errors is for a
link layer PEP to add FEC on all outgoing packets, correcting more
errors. The processing power for extra FEC may be questionable for
high speed links or slow host machines. The protocol booster project
has implemented this mehtod.

- J.D.Bakker and R.Prasad, Efficient Protocols for a Radio Link in a
Wireless Multimedia Environment. Proceedings IEEE fifth Symposium
on Communications and Vehicular Technology in the Benelux, Enschede,
The Netherlands, October 14-15, 1997.

- Michele Zorzi, Prformance of FEC and ARQ Error Control on Bursty
Channel under Delay Constraints. VTC Ottawa 1998.

Recommended addition: Link layer ARQ
For wireless links which do not provide the service of automatic
retransmission it is possible for a PEP to add a symmetrical ARQ
method for improving this type of link.

- Same references as above.

Possibly link layer ARQ and FEC could be considered in one section.

Recommended addition: QoS Mapping
(Section 3.5 does talk about supporting some QoS  through multiplexing,
this goes a step further) Many modern wireless protocols are beginning to
support different QoS levels over the wireless medium.  However the
protocols available for use over these mediums do not automatically
make use of this capability.  Either the Integrated services or
Diffserv methods could be supported for mapping packets to the
appropriate underlying QoS levels of the wireless medium.  This type
of service can be provided by a PEP which IP packets marked with a
type of service and makes appropriate configurations with an
underlying interface.

Section 4.4.3: Could someone clarify the term QoS transparency?

Section 5.3.1: We recommend mentioning IEEE 802.11, HomeRF, Bluetooth,
and Hiperlan as the best WLAN examples.

Hope these are helpful,
Zach Shelby

----------------------------------------------------------------------
   Zach Shelby - Researcher         [email-masked]
   VTT Elektroncs                   Puh.    +358 8 551 2164 (Office)
   Kaitoväylä 1, PL 1100            Fax     +358 8 551 2320
   90571 Oulu, Finland              Mobile  +358 40 7796297 
----------------------------------------------------------------------
                    http://paula.oulu.fi/~zdshelby
       Home:   Yliopistokatu 14-707  90570 Oulu, Finland