Huawei Quidway NetEngine80E Configuration Manual page 559

HUAWEI NetEngine80E/40E Router
Configuration Guide - IP Routing
along the default route. If neither the default route nor the destination address of the packet exists
in the routing table, the device discards the packet and informs the source end that the destination
address or network is unreachable.
IS-IS can generate default routes using either of the following mode:
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Procedure
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Issue 02 (2014-09-30)
Command-triggered default route generation mode
You can run the default-route-advertise command on a device so that the device adds a
default route to the LSP before sending the LSP to a neighbor. Therefore, the neighbor can
learn this default route.
ATT bit 1-triggered default route generation mode
IS-IS defines that a Level-1-2 router sets the ATT bit to 1 in the LSP to be advertised to a
Level-1 area if the Level-1-2 router can reach more Level-1 areas through the Level-2 area
than through the Level-1 area. After a Level-1 router in the Level-1 area receives the LSP,
it generates a default route destined for the Level-1-2 router. Based on the network
requirements, you can configure whether the Level-1-2 router sets the ATT bit carried in
the LSP and whether a Level-1 router generates a default route after it receives the LSP
carrying ATT bit 1.
NOTE
This mode applies only to Level-1 routers.
Configure command-triggered default route generation mode.
1. Run:
system-view
The system view is displayed.
2. Run:
isis [ process-id ]
The IS-IS view is displayed.
3. Run:
default-route-advertise [ always | match default | route-policy route-
policy-name ] [ cost cost ] [ tag tag ] [ level-1 | level-1-2 | level-2 ]
[ avoid-learning ]
IS-IS is configured to generate default routes.
Configure ATT bit 1-triggered default route generation mode.
1. Run:
system-view
The system view is displayed.
2. Run:
isis [ process-id ]
The IS-IS view is displayed.
3. Run the following command as required:
– To set the ATT bit in the LSPs sent by the Level-1-2 router, run the attached-bit
advertise { always | never } command.
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