H3C S3610-28F, Operation Manual

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Operation Manual – IPv4 Routing
H3C S3610&S5510 Series Ethernet Switches
Chapter 4 IS-IS Configuration
4-5
Note:
z
The Level-1 routers in different areas can not establish the neighbor relationship.
z
The neighbor relationship establishment of Level-2 routers has nothing to do with
area.
Figure 4-2 shows a network topology running the IS-IS protocol. Area 1 is a set of
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 shows another network topology running the IS-IS protocol. The Level-1-2
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.