Load Balancing - 3Com CoreBuilder 9000 User Manual

Table 43 shows a typical routing table.
Table 43 Routing Table
Connection #

Load Balancing

As mentioned in the previous section, one reason for providing alternate
routes is to divide or balance the load between the alternate links. Load
balancing ensures that calls are distributed equally among the available
links between source and destination nodes.
The CoreBuilder 9000 ATM Enterprise Switch is designed to automatically
distribute calls equally over alternate links, provided that these links have
the appropriate addressing.
The routing algorithm distinguishes between different types of address
matching among the NNI neighbors: exact match, best match, and partial
match. (For more information, see "E-IISP Hierarchic Routing Algorithm"
on page 368.) If two or more NNI neighbors have the same match type,
the CoreBuilder 9000 ATM Enterprise Switch uses its routing table to
assign a connection to each of the links in a round robin algorithm; the
first connection to the first link, the second connection to the second link,
and so on. In this way, the calls are distributed and the load is balanced.
To effect load balancing, the addressing of the alternate routes needs to
be planned with the match types in mind. For example, in the network of
Figure 15, link-1 and link-2 are used for load balancing because they both
have the same match type (exact match); link-3 is not used because it is
the only one with its type (best match).
Current Link
1 1
2 2
3 3
4 1
E-IISP Hierarchic Routing Algorithm
Optional Link(s)
2 3
3 1
2 1
2 3
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