[AG-TECH] Access Grid vs. Wireless LAN

Michael Robson Michael.Robson at man.ac.uk
Fri Nov 30 04:20:55 CST 2001

Wireless currently only runs at 11Mbps, although the real maximum throughput
is actually around 7.5Mbps after overheads of the 802.11b protocol are taken
into account. In addition,
the 11Mbps wireless uplink into the access point is shared with all the
wireless devices using that access point. This all means that wireless is
not a good way to connect computers that need to send/receive multicast
traffic: A 100Mb/s would be more appropriate.

If the intention is simply to provide convenient networking for laptops,
PDAs, etc. in the AG node (e.g.. for general internet access or to take
control of an AG Power Point presentation) then this would be a reasonable
use (we have such a wireless network set-up in the AG node at the University
of Manchester). For this, it is probably better to have the wireless network
as a separate segment to the AG node network; With the 802.1x standard not
yet 'released into the wild' the security side of wireless is inadequate
(and sadly very often ignored) and so could be 'tightened up' somewhat at
the gateway router for the wireless segment (ACLs etc). I haven't yet come
across IGMP (or the Cisco flavour, CGMP) support on an 802.11b access point
yet, but if the wireless network was in on a separate segment (i.e. a
separate broadcast domain), then this would no longer be an issue).

Michael Robson,     | Tel:   +44 161 275 6113
Room G100A,         | Fax:   +44 161 275 6040
Kilburn Building,   | Email: Michael.Robson at man.ac.uk
Manchester Computing,
University of Manchester,
Oxford Road, Manchester,
M13 9PL, U.K.

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