2.3.3 Conclusion: Network Properties

Packet Switched Networks present certain fundamental problems to the distributed systems programmer:

• Whilst switches converge on a consistent set of routes, packets will bounce around in the network, and suffer delays or get dropped.
• Switches shared with other packets, therefore get queues.
• Total latency is therefore variable.
• Loss rate is variable (noise, available switch buffers).
• Queue size management (aka congestion control) changes the bandwidth available to machines. Therefore bandwidth is variable.