3com 8807 User Guide
Introduction to Integrated IS-IS
341
Figure 87 IS-IS topology
NSAP Structure of IS-IS
Routing Protocol
Address structure
Figure 88 NSAP structure
ES
Routing Domain Boundary
IS-IS Area
End system
Subnetwork Path
Level 1 IS-IS Routing
Level 2 IS-IS Routing
Interdomain Routing
Intermediate system
ES
IS
Area 1
Area 2
Area 3
Routing Domain 1
Routing Domain 2
ES
ES
IS
IS
IS
IS
IS
IS
IS
ES
ES
ES
ES
ES
IS
IS
AFI
IDI
High Order DSP
SyStem ID
SEL
(1 octet)
DSP
IDP
Area Address