Configuring The Is-Is Protocol; Figure 4-8 Route-Leaking - Zte ZXR10 5900E Series Configuration Manual

Chapter 4 IS-IS Configuration
Route-leaking
Attatch bit: The RFC1195 defines that if an L1/L2 router in an area is connected with a
router in another area, the L1/L2 router sets the ATT bit in its L1 LSP to inform the L1
router in this area that there is an egress. the L1 router in this area selects the nearest L2
on which the ATT bit is set as the egress of the area, and then a default route is generated.
The L1 router selects the nearest L1/L2 router as the egress of this area, but the nearest
route is not necessarily the optimum route, the second optimum route may be used.
Therefore, the RFC2966 defined the route-leaking. To avoid the use of second optimum
route, the routing information in the backbone area is leaked to the Level–1 area. Using
this method, the common areas also have the routing information of the entire IS-IS route
domain.
For the route-leaking operation, see Figure 4-8.

Figure 4-8 Route-leaking

4.2 Configuring the IS-IS Protocol

The IS-IS configuration described in this section is based on IP routing. If no instance or
interface is specified in the following configurations, the process ID is assumed to be 0 and
VLAN100 is used as the interface.
Enabling the IS-IS Protocol
To enable the IS-IS protocol on the ZXR10 5900E, perform the following steps:
4-11
SJ-20150114102049-003|2015-01-15 (R1.0) ZTE Proprietary and Confidential