HP 600 Series, Services And Applications

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Load Balancing Limitations
First, the circuit assignment algorithms ignore such obvious parameters as
delay and throughput. This means that circuits placed in a circuit group must
be of the same capacity. Otherwise, low-capacity circuits (56 Kbit/s) will
have to handle the same networking load as high-
capacity circuits (1.544 Mbit/s).
Second, the circuit assignment algorithms do not necessarily provide
balanced link utilization. Large packets may be sent on circuit 1 while small
packets may be sent on circuit 2. Additionally, the indexed circuit-assign-
ment algorithm relies on a large enough population of users (actually,
summed addresses) to achieve a measure of balanced circuit utilization.
As a final note, it is generally a good practice when designing a network with
coterminous circuits to purchase the circuits from different carriers to
insulate your network from multiple simultaneous circuit failures.
Packet-Switching Networks
Packet-switching networks (PSNs) based on technologies that include X.25,
frame relay, and Switched Multimegabit Data Service (SMDS) are designed
to be very reliable. Reliability is achieved through a highly redundant
network architecture with many interconnected, parallel switching nodes;
see figure 3. The relatively recent deployment of frame relay and SMDS,
which offer high throughput and low latency, have added to the desirability
of these networks for interconnecting LANs.
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Improving Network Availability
Load Balancing Limitations
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