157 
                         Level-2 IPv4 Forwarding Table 
                         ----------------------------- 
 
 IPv4 Destination     IntCost    ExtCost ExitInterface   NextHop         Flags 
------------------------------------------------------------------------------- 
 192.168.0.0/24       10         NULL    Eth1/2          Direct          D/L/- 
 10.1.1.0/24          20         NULL    Eth1/2          192.168.0.1     R/-/- 
 10.1.2.0/24          20         NULL    Eth1/2          192.168.0.1     R/-/- 
 172.16.0.0/16        10         NULL    Eth1/1          Direct          D/L/- 
 
      Flags: D-Direct, R-Added to Rib, L-Advertised in LSPs, U-Up/Down Bit Set 
The output shows that the routing table of Level-1 routers contains a default route with the next hop as the 
Level-1-2 router, and the routing table of Level-2 router contains all Level-1 and Level-2 routes. 
DIS election configuration example 
Network requirements 
As shown in Figure 41, on a broadcast network (Ethernet), Router A, Router B, Router C, and Router D 
reside in IS-IS Area 10. Router A and Router B are Level-1-2 routers, Router C is a Level-1 router, and Router 
D is a Level-2 router. 
Change the DIS priority of Router A to make it elected as the Level-1-2 DIS router. 
Figure 41 Network diagram 
 
 
Configuration procedure 
1.  Configure IP addresses for interfaces. (Details not shown.) 
2.  Enable IS-IS: 
# Configure Router A. 
<RouterA> system-view 
[RouterA] isis 1 
[RouterA-isis-1] network-entity 10.0000.0000.0001.00 
[RouterA-isis-1] quit