This soft copy for use by IBM employees only.
6.1.4 Planning for Availability
The 8285 switch is designated as a customer setup device. If you choose not to have the switch covered under an IBM maintenance plan, you may choose to provision one or more spares for key components to improve network availability. For your convenience, a
6.2 Logical Planning
The following sections contain information about various aspects of IBM 8285 logical planning:
•Capacity planning:
−Switching capacity
−ATM bandwidth capacity
−Integrated LES/BUS capacity
−SSI connection (TRS capacity)
−NNI connection
•Other Planning:
−Compliance to the standards
6.2.1Capacity Planning
The following sections describe several aspects of capacity planning for the 8285 switch, such as:
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Switching Capacity
Bandwidth Capacity
LES/BUS Capacity
ATM Topology Management Limitations
Note that the values described in the following sections are theoretical maximums and may be different from the practical maximums that apply to your network.
6.2.1.1 Switching Capacity
•Maximum Number of Connections
In most cases, the maximum number of connections per switch would be constrained by storage, such as the number of control blocks, rather than by the switch component capacity itself. Consequently, it may be possible to attain the maximum number of connections supported by the switch on an actual network if the traffic volume is not too much.
•Transmit Delay (Latency per Port)
This value is sometimes used as a measure of the switch′s capacity. However, care should be used in using this value as a proxy for overall throughput in a
Chapter 6. IBM 8285 Planning and Installing 97
