Telescope LAN Loading calculations

The Tables presented here are made from an analysis of the traffic to be generated by each computer in the GBT that is attached to the Telescope LAN. All figures use a Maximum throughput figure of 800K Bytes per Second for Ethernet, and 8000K Bytes per Second for Fast Ethernet and FDDI.

FDDI Ring backbone

The figures in the first table are based on using a ring type FDDI backbone, and Switched Ehternet for the Ethernet segments.

`Machine`	`Destination Equipment`	`Link Speed, Mb/s`	`KB/s`	`Percent utilization`
`Equipment/Control Rooms`			`@80%`
`IF SBC, Weather SBC, SCRB`	`Equipment Room Lan Switch`	`10`	`1.5`	`0.1875`
`DCR`	`Equipment Room Lan Switch`	`10`	`64`	`8`
`Spectrometer`	`Equipment Room Lan Switch`	`10`	`0.4`	`0.05`
`Spectral Processor`	`Equipment Room Lan Switch`	`10`	`0.4`	`0.05`
`VLBA Station Computer`	`Equipment Room Lan Switch`	`10`	`0`	`0`
`Equipment Room Switch`	`Backbone`	`100`	`66.3`	`0.82875`
`Operator Consoles`	`Backbone`	`100`	`2000`	`25`
`Data W.S.`	`Backbone`	`100`	`2000`	`25`
`Engineering/Server W.S.`	`Control Room LAN Switch`	`100`	`1000`	`12.5`
`Observer W.S. 1`	`Control Room LAN Switch`	`100`	`1000`	`12.5`
`Observer W.S. 2`	`Control Room LAN Switch`	`100`	`1000`	`12.5`

`Alidade Room`

`Laser SBC`	`Backplane Network`	`10`	`8`	`1`
`Antenna SBC`	`Backplane Network`	`10`	`8`	`1`
`Servo Monitor SBC`	`Backplane Network`	`10`	`0`	`0`
`Antenna SBC`	`Alidade Room LAN Switch`	`10`	`15`	`1.875`
`Servo Monitor SBC`	`Alidade Room LAN Switch`	`10`	`20`	`2.5`
`Laser SBC`	`Alidade Room LAN Switch`	`10`	`40`	`5`
`Telescope I/O SBC 1&2`	`Alidade Room LAN Switch`	`10`	`2`	`0.25`
`Laser LAN Repeater`	`Alidade Room LAN Switch`	`10`	`50`	`6.25`
`Receiver Room LAN,SCRB`	`Alidade Room LAN Switch`	`10`	`0`	`0`
`Actuator Control Room LAN`	`Alidade Room LAN Switch`	`10`	`3`	`0.375`
`Pointing W.S.`	`Alidade Room LAN Switch`	`100`	`110`	`1.375`
`Alidade Room LAN Switch`	`Backbone`	`100`	`150`	`1.875`

`Total Backbone Traffic`		`100`	`4216.3`	`52.70375`
`Total Control Room Switch Traffic`		`1000`	`4000`	`5`
`Total Equipment Room Switch Traffic`		`1000`	`502.3`	`0.627875`
`Total Alidade Room Switch Traffic`		`1000`	`150`	`0.1875`

Fast Ethernet Star Topology backbone

The figures in this table are based upon using an Ethernet switch in the Equipment Room that can handle multiple Fast Ethernet segments. The Data Acquisition Machine and the Operator Consoles are connected to this switch, while the FDDI link goes only to the Alidade Room switch. This topology is under consideration because it will reduce costs, while providing good performance, and allowing the network to scale even more.

Machine Destination Equipment Link Speed, Mb/s KB/s Percent utilization

Equipment/Control Rooms @80%

IF SBC, Weather SBC, SCRB Equipment Room Lan Switch 10 1.5 0.1875

DCR Equipment Room Lan Switch 10 64 8

Spectrometer Equipment Room Lan Switch 10 0.4 0.05

Spectral Processor Equipment Room Lan Switch 10 0.4 0.05

VLBA Station Computer Equipment Room Lan Switch 10 0 0

Operator Consoles Equipment Room Lan Switch 100 2000 25

Data W.S. Equipment Room Lan Switch 100 2000 25

Equipment Room Switch Backbone 100 150 1.875

Engineering/Server W.S. Control Room LAN Switch 100 1000 12.5

Observer W.S. 1 Control Room LAN Switch 100 1000 12.5

Observer W.S. 2 Control Room LAN Switch 100 1000 12.5

Alidade Room

Laser SBC Backplane Network 10 8 1

Antenna SBC Backplane Network 10 8 1

Servo Monitor SBC Backplane Network 10 0 0

Antenna SBC Alidade Room LAN Switch 10 15 1.875

Servo Monitor SBC Alidade Room LAN Switch 10 20 2.5

Laser SBC Alidade Room LAN Switch 10 40 5

Telescope I/O SBC 1&2 Alidade Room LAN Switch 10 2 0.25

Laser LAN Repeater Alidade Room LAN Switch 10 50 6.25

Receiver Room LAN,SCRB Alidade Room LAN Switch 10 0 0

Actuator Control Room LAN Alidade Room LAN Switch 10 3 0.375

Pointing W.S. Alidade Room LAN Switch 100 110 1.375

Alidade Room LAN Switch Backbone 100 150 1.875

Total Backbone Traffic 100 150 1.875

Total Control Room Switch Traffic 1000 4000 5

Total Equipment Room Switch Traffic 1000 4066.3 5.082875

Total Alidade Room Switch Traffic 1000 150 0.1875