Priority-based Route Convergence
Priority-based route convergence, which provides faster convergence of routes for key services, is an important technology to improve network reliability.
Definition
Routes can be set with different convergence priorities, such as critical, high, medium, and low. The system performs route convergence based on the convergence priorities and a convergence rule. In other words, the system schedules the convergence of routes with different convergence priorities in proportion to a weighting scheme.
Purpose
With the integration of network services, the services must be differentiated. As required by operators, the routes for key services, such as Voice over IP (VoIP), video conferences, should converge as fast as possible, while the routes for common services can be converged relatively slowly. To improve network reliability, the system converges routes in a manner based on their convergence priorities.
Principle
Table 1 shows the default convergence priorities of public routes. The routing protocols first compute and deliver routes of high convergence priorities to the system. By default, the system converges routes according to the scheduling weight values assigned to the convergence priorities in the proportions of critical:high:medium:low = 8:4:2:1. You can re-configure the scheduling weight values as required.
Routing Protocol or Route Type |
Convergence Priority |
|---|---|
Direct |
High |
Static |
Medium |
32-bit host routes of OSPF and IS-IS |
Medium |
OSPF route (except 32-bit host routes) |
Low |
IS-IS route (except 32-bit host routes) |
Low |
RIP |
Low |
BGP |
Low |
For private routes, only 32-bit host routes of OSPF and IS-IS can be identified as medium and all other routes are identifies as low.