2.17.1 Feature Overview

A route is a path to a destination. For example, RSP.Routeset is a collection of routes to a destination. With multiple Routes support, vSTP allows up to 6 routes to be established to a single destination or exception route. However, it continues to allow load sharing between only 2 routes. The remaining routes are used for backup.

The Multiple Route support feature considerations:

• The feature allows vSTP to allow load sharing between only 2 routes with same Route Cost, where Route Cost is the cost assigned to a route.
• Only one route can be associated to a linkset to a single destination.
• vSTP can have multiple cost groups or individual cost route for a destination.
• With no network or link failures, routing starts on the normal cost routes. In case of link and network failures, routing switches to a higher cost routes or the route without any traffic loss.

  Where, Normal Cost Route is the route with minimum route cost to a destination. and Higher Cost Routs is the route with the cost more than the minimum route cost to a destination.

vSTP provides four different options for route set:

1. Three Combined Routes

   Where, Combined Routing is having more than one routes with same cost to a destination (vSTP allows only two routes of same route cost).

2. Two combined routes and two individual routes with different costs
3. One combined route and four individual routes with different costs
4. Six individual routes with different cost

In case of combined routing the traffic will loadshare between two equal cost active routes.

Note:

• vSTP broadcasts TFP messages, if all the routes to a destination goes down.
• Route to any destination will be restricted if associated linkset is restricted.
• vSTP broadcasts TFR, if higher cost route to a destination becomes restricted.
• vSTP broadcasts TFA, if any configured route to a destination becomes available.