H3C S3610-28P Operation Manual page 438

Operation Manual – IPv4 Routing
H3C S3610&S5510 Series Ethernet Switches
Note:
The Level-1 routers in different areas can not establish the neighbor relationship.
The neighbor relationship establishment of Level-2 routers has nothing to do with
area.
Figure 4-2
Level-2 routers, called backbone network. The other four areas are non-backbone
networks connected to the backbone through Level-1-2 routers.
Figure 4-2 IS-IS topology
Figure 4-3
routers connect the Level-1 and Level-2 routers, and also form the IS-IS backbone
together with the Level-2 routers. There is no area defined as the backbone in this
topology. The backbone is composed of all contiguous Level-2 and Level-1-2 routers
which can reside in different areas.
shows a network topology running the IS-IS protocol. Area 1 is a set of
shows another network topology running the IS-IS protocol. The Level-1-2
4-5
Chapter 4 IS-IS Configuration