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RE: Requirements
Snip from James' response.
> One useful thing would be to try to get a handle on what makes
> a "good" L2 for IP. We have tried to do that for handoff in
> draft-manyfolks-mobilereq-ipv6-00.txt, which includes requirements
> for an L2 trigger API or protocol.
The Performance Implications
of Link Characterists (pilc) working
group has spent alot of time describing the impact of various
layer 2 techniques on TCP/IP.
The pilc web page,
http://www.ietf.org/html.charters/pilc-charter.html,
contains some interesting drafts. There is even
one about TCP over 2.5G and 3G wireless networks. I have
not read all of these, but I know the slow links and
links with errors drafts has some good info for link
layer designers.
End-to-end Performance Implications of Slow Links (41881 bytes)
End-to-end Performance Implications of Links with Errors (38504 bytes)
Advice for Internet Subnetwork Designers (92940 bytes)
TCP Performance Implications of Network Asymmetry (103539 bytes)
Link ARQ issues for IP traffic (47793 bytes)
TCP over 2.5G and 3G Wireless Networks (33785 bytes)
Request For Comments:
Performance Enhancing Proxies Intended to Mitigate Link-Related Degradations
(RFC 3135) (114825 bytes)
thanks,
Dana
> -----Original Message-----
> From: James Kempf [mailto:James.Kempf@Sun.COM]
> Sent: Friday, July 20, 2001 7:28 PM
> To: RRobin01@sprintspectrum.com; jgw@cisco.com; dblair@cisco.com
> Cc: more@ops.ietf.org
> Subject: RE: Requirements
>
>
> Dana,
>
> While I agree with you in principle, I think a case can be made that
> some wireless L2 protocols are better engineered for IP than others,
> handoff not included.
>
> In particular, I think the 3G wireless protocols like wCDMA, which were
> not originally designed for IP (but rather primarily for ATM-like
> voice) are not as optimally designed as, say, 802.11.
>
> One useful thing would be to try to get a handle on what makes
> a "good" L2 for IP. We have tried to do that for handoff in
> draft-manyfolks-mobilereq-ipv6-00.txt, which includes requirements
> for an L2 trigger API or protocol.
>
> jak
>
> >From: "Dana L. Blair" <dblair@cisco.com>
> >To: "Robinson, Richard" <RRobin01@sprintspectrum.com>, "John
> G. Waclawsky"
> <jgw@cisco.com>
> >Cc: <more@ops.ietf.org>
> >Subject: RE: Requirements
> >Date: Fri, 20 Jul 2001 17:42:59 -0400
> >X-Priority: 3 (Normal)
> >X-MSMail-Priority: Normal
> >X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2615.200
> >Importance: Normal
> >
> >My comments below.
> >
> >...
> >
> >> > it is just that the mobility of wireless subscribers as
> well as some
> >> unique
> >> > performance requirements/problems in the air interface may
> >> indeed bring
> >> out
> >> > special requirements - perhaps more so in the macro cell
> >> environment of
> >> > wireless operators than in controlled micro/pico cell links
> >
> >For the past 2.5 years I have been asking the question is
> >there anything special about wireless that impacts application,
> >transport, or IP protocols that is different than wired.
> >
> >Up til now, the only exception for wireless than wired that
> >I have discovered is handoff. I believe that we SHOULD
> >view the wireless access network as just another Layer 2.
> >
> >Here are some examples of suggested differences.
> >
> >1. Wireless links are special because they have low bandwidth
> and large
> >latency.
> >
> > Some wired links are slow and have large latency too.
> >
> > V.22 modems run over the PSTN and are slow with large latency.
> TCP was
> >designed to optimize bandwidth on slow and fast links.
> > V.42bis, MNP compression, and Header compression were
> invented several
> >years ago to improve performance n
> > wired links.
> >
> >2. Wireless links are special because they are error prone.
> >
> > Some wired links are error prone too.
> >
> > Many PSTN connections are error prone depending on wiring.
> > MNP and V.42 error correction protocols were created
> several years
> ago to
> >fix errors in the link layer.
> >
> > The RLP layer of cellular standards provides the same
> > function.
> >
> >3. Wireless devices are special because they move.
> >
> > Roaming:
> > Wired devices roam too.
> > My laptop roams because it plugs into an ethernet at
> > home or in the office depending on where I want to
> > work.
> >
> > Handoff:
> > One possible exception for wireless is handoff. There is
> > really no need that I can think of for handoff in
> > the wired world, but the Mobile IP WG seems to getting
> > the right idea of Internet Handoff for wireless devices.
> >
> >4. Wireless devices are special because they need to know
> where they are
> -
> >Location services.
> >
> > Wired elements devices can benefit from location services
> > too, and be supported with a small inexpensive GPS chip.
> >
> >thanks,
> >Dana
> >
> >> >
> >> > some of these come through in Paul Reynolds draft - as
> >> wireless operators
> >> > get engaged in these requirements some of the things that
> >> make wireless
> >> > different may be highlighted - i'm reviewing the draft now
> >> >
> >> > Richard Robinson
> >> > Sprint PCS
> >> > 15405 College Boulevard
> >> > Lenexa, Kansas 66219
> >> > 913.890.4242 (fax 4100)
> >> > MS - KSLNXZ0201
> >> > rrobin01@sprintspectrum.com
> >> >
> >> > -----Original Message-----
> >> > From: tim clifford [mailto:tjc@lacunanet.net]
> >> > Sent: Monday, July 16, 2001 11:23 AM
> >> > To: James Kempf; more@ops.ietf.org; jgw@cisco.com
> >> > Subject: RE: Requirements
> >> >
> >> > which would seem to imply that we need to try to convince
> >> people at the
> >> ietf
> >> > (i think its a misnomer to say "convince the ietf") that
> we're talking
> >> about
> >> > more than a link layer, maybe the right term is
> mobility, or roaming
> >> > services, or disadvantaged user devices, or large populations
> >> of always on
> >> > subscribers ;-)
> >> >
> >> > tc
> >> >
> >> > > -----Original Message-----
> >> > > From: owner-more@ops.ietf.org
> >> [mailto:owner-more@ops.ietf.org]On Behalf
> >> > > Of James Kempf
> >> > > Sent: Monday, July 16, 2001 11:47 AM
> >> > > To: more@ops.ietf.org; jgw@cisco.com
> >> > > Subject: Re: Requirements
> >> > >
> >> > >
> >> > > John,
> >> > >
> >> > > There is no such catalog. In general, IETF has been
> resistent to
> >> > > making wireless a special category. It is viewed as just
> >> another link
> >> > > layer.
> >> > >
> >> > > jak
> >> > >
> >> > > >Date: Sat, 14 Jul 2001 11:15:34 -0400
> >> > > >From: "John G. Waclawsky" <jgw@cisco.com>
> >> > > >To: more@ops.ietf.org
> >> > > >Subject: Re: Requirements
> >> > > >
> >> > > >Does anyone know if the IETF does an cataloguing of activities
> >> > > with regards to
> >> > > wireless?
> >> > > >For example is there a cross reference anywhere that
> >> describes wireless
> >> > > activities going
> >> > > >on in the IETF? This information would probably be
> very uesful
> >> > > for the mobile
> >> > > >operators. Regards John
> >> > > >
> >> > > >
> >> > >
> >>
> >
> >
>