Cisco Systems 8600 Series Cost-Based Connection Routing, Major Features of Cost-Based AutoRoute

Switch Software Description

Table 1-1	Routing Group Configuration Example
Routing	Connection
group	cell loading
0	0-59
1	60-69
2	70-79
3	80-89
4	90-99
5	101-109
6	110-119
7	120-129
8	130-139
9	140 and up

Cost-Based Connection Routing

Release 9.1 includes a cost-based route selection method to Cisco StrataCom’s standard AutoRoute. This feature is referred to as cost-based AutoRoute. In standard AutoRoute, the path with the fewest number of hops to the destination node is chosen as the best route. The new cost-based route selection uses an administrative trunk cost routing metric. The path with the lowest total trunk cost is chosen as the best route. Cost-based route selection is based on Dijkstra’s Shortest Path Algorithm, which is widely used in network routing environments. You can use cost-based route selection (that is, cost-based AutoRoute) to give preference to slower privately owned trunks over faster public trunks which charge based on usage time. This gives network operators more control over the usability of their network trunks, while providing a more standard algorithm for route selection.

Major Features of Cost-Based AutoRoute

The following list gives a short description of the major functional elements of Cost-Based Route

Selection.

•Enabling Cost-Based Route Selection–cost-based route selection is selectively enabled by the user as the route selection algorithm per node. The feature is not a chargeable feature and does not require special password access. The default algorithm is the hop-based algorithm. cost-based route selection can be enabled or disabled at any time.

•Configuring Trunk Cost–A trunk cost is assigned by the user to each trunk (physical and virtual) in the network. One cost is assigned per trunk - no separate costs are used for different connection or service types. The valid range of trunk costs is 1 (lowest cost) to 50 (highest cost). A trunk has a default cost of 10 upon activation. The cost of a trunk can be changed before or after the trunk has been added to the network topology.

The cost can also be changed after connections have been routed over the trunk. Such a change does not initiate automatic connection rerouting, nor does it cause any outage to the routed connections. If the new trunk cost causes the allowable route cost for any connections to be exceeded, the connections must be manually rerouted to avoid the trunk. This avoids large-scale simultaneous network-wide rerouting and gives the user control over the connection reroute outage.

Introduction 1-21