RE: on the point of mobility & multihoming

["Kanchei Loa" <loa@ieee.org>]

>> Kanchei Loa wrote:

> > Well, a connection between exit router and ISP using "100 base T with
500m
> > UTP-3 cables and 10 dumb hubs" is out of the specification of  IEEE
standard.
> > The user won't expect M6 solution would work on an out-of-spec
connection
> > nor should this WG. But the same user would expect M6 solution maintains
> > reasonable performance (or degrade gracefully) with his "within-spec"
> > wireless link to ISP independent of the weather condition.
>
> Masataka Ohta wrote:

> What, do you mean, "within-spec" of, say, 11b.
>
> With some definition of "within-spec", what performance
> is expected by the standard?
>
> To answer the questions, quote the standard, please.
>

Quote from IEEE 802.11 1999 edition
----------

5.1.1 How wireless LAN systems are different

Wireless networks have fundamental characteristics that make them
significantly different from traditional
wired LANs. Some countries impose specific requirements for radio equipment
in addition to those specified in this standard.

5.1.1.1 Destination address does not equal destination location

In wired LANs, an address is equivalent to a physical location. This is
implicitly assumed in the design of
wired LANs. In IEEE 802.11, the addressable unit is a station (STA). The STA
is a message destination, but not (in general) a fixed location.

5.1.1.2 The media impact the design

The physical layers used in IEEE 802.11 are fundamentally different from
wired media. Thus IEEE 802.11 PHYs
a) Use a medium that has neither absolute nor readily observable boundaries
outside of which stations with conformant PHY transceivers are known to be
unable to receive network frames.
b) Are unprotected from outside signals.
c) Communicate over a medium significantly less reliable than wired PHYs.
d) Have dynamic topologies.
e) Lack full connectivity, and therefore the assumption normally made that
every STA can hear every other STA is invalid (i.e., STAs may be "hidden"
from each other).
f) Have time-varying and asymmetric propagation properties.

Because of limitations on wireless PHY ranges, wireless LANs intended to
cover reasonable geographic distances may be built from basic coverage
building blocks.

---------------- end quote --------

The limitations on  802.11b PHY range vary with antenna configuration and
local environment factors, which is the information provided by the ISP to
subscribed users.

I believe we are off-topic here. If you want to discuss what the 802.11b
coverage is under various configurations, we should take it off-line.

------------
Kanchei Loa
loa@ieee.org