Advanced IP Network Design (CCIE Professional Development)

Summary

Hierarchical routing is the most efficient basis for large scale network designs because it:

• Breaks one large problem into several smaller problems that can be solved separately

• Reduces the size of the area through which topology change information must be propagated

• Reduces the amount of information routers must store and process

• Provides natural points of route summarization and traffic aggregation

The three layers of a hierarchical network design are described in Table 1-1.

Table 1-1. Summary of Goals and Strategies of Layers and Hierarchical Network Design

Layers	Goals	Strategies
Core	Switching speed	Full reachability: No default routes to internal destinations and reduction of suboptimal routing No policy implementation: Access control, ...