Routing

The Problem

Assumptions

• Hosts
• Subnets
• Routers

High Level Solution

• Addresses
• Prefixes
• Routing Tables
• Router Behavior

IPv4 Addressing

• What Gets Addressed?
• Address Format


• Expressing Prefixes

ex. 255.255.0.0 = 16 bit prefix = /16

Example Network

Filling the Table

• Loopback Address
• Interface Address & Netmask
• Default Route
• Manual
• Router Discovery
• ICMP Redirects
• Static Routes

Routing Protocols

• Static Routing
• Internal

- optimize a metric
• Distance Vector
• Link State
• External

- enforce a policy

Addressing/Routing Dynamics

• Routing Protocol Traffic
• Stability
• Table Size
• Shortest Path Computation
• Address Availability

Hierarchical Addressing

• Aggregates
• Implementation
• Requirements
• Results
• Classfull Addressing...