🚀 go-pugleaf

I have put together the following list of "rules" from DEC literature
on Ethernet networks.  Please send me any comments.


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		ThinWire Rules
1) Maximum segment length = 185m
2) Stations attach using DESTA and 'T' connector
3) Minimum distance between 'T' connectors = 0.5m
4) Maximum stations on segment regularly = 30
5) Maximum stations on segment with DEMPR = 29
6) Maximum stations on segment with SER and faceplate = 28


		Standard Ethernet Cable rules
1) Stations attach using transceiver
2) Maximum segment length regularly = 500m
3) Maximum segment length with DELNI/DEMPR combination = 300m
4) Maximum transceivers on segment = 100
5) Connect DELNI to segment using transceiver, no heartbeat
6) Connect DEMPR to segment using transceiver, <45m of transceiver cable
7) Minimum distance between transceivers = 2.5m


		DELNI rules
1) DELNI allows 8 devices to share transceiver
2) Stand-alone cascading DELNI network interconnects 8 DELNIs and 64 stations 
   using transceiver cable
3) Connect DELNI to standard Ethernet cable using transceiver 
4) DEMPR connects to DELNI using < 45m of transceiver cable
5) Main DELNI in stand-alone cascading DELNI network must be in 'global' mode
6) Non-Main DELNIs in stand-alone cascading DELNI network must be in 'local'
   mode
7) A DELNI is not a network addressable unit


		DEMPR rules
1) Connect DEMPR to DELNI using <45m of transceiver cable 
2) Connect DEMPR to standard Ethernet cable using transceiver
3) Segments attached to DEMPRs can have 29 stations
4) Main DEMPR in stand-alone cascading DEMPR network uses ThinWire
5) Only one segment attached to main DEMPR in stand-alone cascading 
   DEMPR network can have DEMPRs on it
6) The cascading segment in the stand-alone cascading DEMPR network
   can have up to 29 DEMPRs on it
7) DEMPRs on cascading segment of a stand-alone cascading DEMPR network
   are attached using DESTAs
8) A DEMPR grounds an Ethernet segment
9) A DEMPR provides a termination end to a segment
10) A DEMPR is not a network addressable unit

		General Ethernet Network Rules
1) Maximum cable length between stations = 2800m (all media)
2) All segments must be grounded
3) All segments must be terminated on each of the two ends
4) Maximum stations on a single Ethernet network = 1024
5) A station = network addressable unit
6) Maximum stations on an extended network = 8000
7) Maximum length of low loss transceiver cable = 50m
8) Maximum length of high loss transceiver cable = 12.5m
9) Stand-alone networks cannot be attached to Ethernet networks


		Repeater Rules
1) Local repeaters join segments < 100m apart
2) Remote repeaters join segments <1000m apart
3) No more than 2 repeaters between any two stations
4) A DEREP cannot be connected to a DELNI


		Bridge Rules
1) No more than 7 bridges between any 2 stations
2) Local bridges are connected using <100m of transceiver cable
3) Remote bridges are connected using <2000m of fiber cable
4) Each remote bridge half counts as a bridge for the "7 bridge" rule


		Questions
1) Is a bridge considered to be a station
2) what about the remote bridge/repeater configuration
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Earl Shaffer - University of Pennsylvania - Data Communications Department
"Time was invented so that everything wouldn't happen at once." Steven Wright
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