IBM SG24-4817-00 User Manual
Page 96
This soft copy for use by IBM employees only.
Note:
1
In this case assuming an even distribution of three workstations per
segment on each of 16 available Ethernet segments.
2
Calculated by dividing the total bandwidth available after the change
by the original bandwidth available per device, which was calculated by
dividing the total bandwidth available by the number of devices sharing it.
In this case, the original bandwidth calculation is: 10,000 Kbps/segment *
1 segment / (40 users + 4 servers) = 227 Kbps/device. To be fair, this is
a nominal value: in reality, the available bandwidth on a shared Ethernet
segment rarely exceeds 40-50% of the rated bandwidth because of
collisions and re-transmissions.
3
This is an average value. The four segments with one device would
actually receive 10,000 Kbps/device, while the remaining 12 segments
would have two devices a piece, each receiving 5,000 Kbps.
Table 11 (Page 2 of 2). Bandwidth Improvement with Ethernet LAN Switch M o d u l e
Device
Maximum Bandwidth Available (Kbps)
Bandwidth
Improvement
Ratio
2
Server
Offload
ATM
Server
Micro-
segment
-ation
1
ATM25
Offload
Ethernet Desktop
250
250
4000
5714
3
25x
A T M Desktop
250
250
4000
25000
110x
80
ATM Workgroup Solutions: Implementing the 8285 ATM Switch