Lucent Meeting on WaveLAN 5/11/00
Rough notes by Les Cottrell, SLAC
May 11, 2000
Anita Warren - account executive; Mark Benoit - engineer. Attendees: Marty Breidenbach, Hector Prado, Ken Martell, Stefan Luitz, Tony Zele, Davide Salomoni, Charley Granieri, Gary Buhrmaster, Dave Nelson, Bob Cowles.
SLAC interests varied from wireless for SPEAR tunnels, next generation accelerator, conference rooms and general LAN deployment.
Recently big surge of interest in 802.11b 11Mbps standard for home "wiring". Mac comes standard with Airport built in aerial and chips. 11Mbps gives enterprise customers a reason for small offices to by pass cabling. There are drivers for most OS'. DFSS (Direct Frequency Spread Spectrum) uses a common Harris chip technology so complete interoperability and power management features. Differences are in interfaces to other devices. Doze mode is 9mA, ~300mA for transmit. They use a Mac layer bridge to bring signals into network. Lucent uses a type 2 PCMCIA card in the access point (AP), new cards will negotiate with old. Next gen 22Mbps, then 55Mbps. Hope for 100Mbps soon, AP has 10Base2 and 10BaseT. Airport cards use Lucent internals. Each card has a sub minimal coax connector that allows one to connect a cable to a larger grid and get 1Mbps throughput up to 30km away. There is product under development for the 5GHz band, the leader is a small company in the Bay Area. This allows opportunity for expansion, but need higher power output, transceivers are larger. The power requirements is bad for hand held devices.
Bluetooth is some way away from having an integrated network. Wireless industry is embracing (e.g. Ericson dropped a lot of CDPD to pursue Bluetooth). Bluetooth is positioned for lower thruput, but more extensive (e.g. in the middle of nowhere). CDPD was rolled out with big charges which hurt deployment. Bluetooth is more at a nacsent engineering stage.
Security is a concern. There is 128bit encryption cards which cost extra. The DFSS is impossible to pick out of air and is very secure. However, if everyone is using the same DFSS compatible radio equipment, then the DFSS does not work for security. So add encryption. But each physical client has to be equipped with a key which will be the same in every host so info will get out when have hundreds of people. How to secure a network with thousands of users and hundreds of building and want roaming (i.e. 1 subnet on same VLAN) with no intervention. So cannot access internal core subnets (on visitor network). To access internal network have to use a VPN with access to specific parts of Apple's core network. Another problem is the MAC address filtering in the bridge, switch when one has a large number of MAC address on a single subnet. Another security concern is for customers who have secure network and users plug and Aironet AP into the net and can access from their laptop. Then engineer can sit in parking lot and access company data.
Placement of AP depends on thruput requirements. 150-200 feet for 11Mbps, will auto reduce thruput as distance increases. Automatically switch to another AP as its signal exceeds that of the other station. The AP looks like a 24 port shared 100Mbps hub. This is OK for light users. The 2.4-2.483.5 GHz range is divided into 11 channels. Only use 3 frequencies in a given area. If 6 neighbours in a residential block and each has an AP then one runs into too many channels overlapping. So skip every other frequency and don't have frequencies sides by side.
Interference may come from an AP placed on top of a microwave. There is no problem with a cordless phone running at 2.4GHz. Klystrons at SLAC have 2.4GHz which Dave Nelson has tested and has not been a problem.
Site survey can be done with a laptop, more difficult between building since may be time dependent. Number of walls one can penetrate depends on type of walls. One has to make tests and decide also on throughput required. Should get seamless handoffs when roaming despite different manufacturers. To transparently roam need APs to be on same subnet.
Most OS' are supported for PCMCIA cards, W95/98/2000/NT fully supported, Linux drivers are available. Others get on the web and look around. Need to ensure have latest driver software to go with the card. Can download from ftp://wavelan.com/ If have already installed driver for one card, then get a new card need to either load its driver from its CD ROM or install latest from WaveLAN. Note a Cisco driver won't properly work with a Lucent card and vice versa.
Lucent using separate PCMCIA cards in AP means easier to upgrade APs. Typical max realistic users on an AP is 75 light users, more likely to limit to 25 users. AP is SNMP manageable, do it by WaveManager tool which is downloadable. Standard MIB, can use OpenView. It has NVRAM to save the configurations.Software for site configurations, tests etc. is all free.
Market directed to ISPs. 13-14 airports are equipped. Many conferences and shows have the arena set up. Working with Gates building (robots roaming with 15 APs) on campus.
Prices are $179 for 40 bit security PCMCIA cards, and $199 for 128bit. AP is about $1000 without PCMCIA cards. No wireless USB cards yet available.
Cisco same range & coverage, superior web based application (vs special from Lucent). Form factor on AP is smaller but radio integrated so harder to upgrade. 100% interoperability if both boxes similarly configured. Have site with 50% of each (done by floor). Lucent chaires IEEE committee and WECA.
Need to sweet talk Kim Navarette of Corsa Network Topologies (408)341-8602 email@example.com for demo. Stanford Gates building contact is Tom Deanspear 650-723-1767. Apple in Cupertino has about 150 APs in use.