Zte ZXR10 5900E Series User Manual page 65

Chapter 5 BGP Configuration
F 20 BGP SYNCHRONIZATION CONFIGURATION
IGURE
R2 learns the route 170.10.0.0 through the IBGP. The next-hop is
2.2.2.1. If R2 reaches the 170.10.0.0 then actual next-hop is R5.
R5 without the route 170.10.0.0 will throw off the packet. At the
moment R2 is also thrown off in R5 if R2 notifies R4 that it has the
route 170.10.0.0 itself.
It is necessary to make R5 have the route to the 170.10.0.0 if the
packet with the destination of 170.10.0.0 smoothly passes R5 and
reaches R3. Therefore route redistribution should be used to help
R5 learn the route through IGP. R2 must wait for R2 to learn route
by means of the IGP (through R5) before it advertises BGP route
to EBGP neighbor. This is called the route synchronization.
Synchronize both the BGP and the IGP with the synchronization
command.
ZXR10 5900E has booting as its synchronization function by de-
fault.
For the transitional AS, the route learned from other AS should be
advertised to the third party AS. If the non-BGP route exists inside
the AS, the route synchronization should be used. Here R2 adopts
route synchronization.
It is unnecessary to use route synchronization when not advertis-
ing the BGP route to the third party AS or when the routers inside
the As run the BGP.
The following configuration shows how to disable the R2 route syn-
chronization.
ZXR10_R2(config)#router bgp 100
ZXR10_R2(config-router)#network 150.10.0.0 255.255.255.0
ZXR10_R2(config-router)#neighbor 1.1.1.2 remote-as 400
ZXR10_R2(config-router)#neighbor 3.3.3.1 remote-as 100
ZXR10_R2(config-router)#no synchronization
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