3.8.c Describe network types, levels and router types

■ Level 0 routing: Routing between two ES nodes on the same link, or between an ES
node and its nearest IS
■ Level 1 routing: Routing between ES nodes in a single area of a domain
■ Level 2 routing: Routing between ES nodes in different areas of a domain
■ Level 3 routing: Routing between ES nodes in different domains

is-is_levels