Zte ZXR10 GER - Figure 101 Bgp Synchoronization

ZXR10 GER (V2.6.03) General Excellent Router User Manual Volume-I
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FIGURE 101 BGP SYNCHORONIZATION
AS100
AS300
AS400
2.2.2.1/30
150.10.0.0/24
2.2.2.2/30
R3 R4
3.3.3.1/30
R1 R2
R5
170.10.0.0/24
170.10.0.0/24 170.10.0.0/24
1.1.1.2/30
1.1.1.1/30
R2 learns routes to destination 170.10.0.0 by means of
IBGP, and the next hop is 2.2.2.1. It can be seen from the
above figure that, for R2 to reach 170.10.0.0, the actual next
hop is R5. However, R5 does not have a route to 170.10.0.0,
so it will drop the packet. In this case, if R2 notifies R4 of its
route to 170.10.0.0, the route will also be dropped in R5.
For packets to destination 170.10.0.0 to arrive at R3 through R5
smoothly, R5 should have a route to 170.10.0.0. Therefore,
route redistribution should be used to make R5 learn the route
by means of IGP. Before R2 advertises a BGP route to EBGP
neighbors, it should wait for R2 to learn the route by means of
IGP (via R5). This process is called route synchronization.
By default, the synchronization function of ZXR10 GER is in
enabled status.
A transitional AS should advertise routes learned from other ASs
to a third AS. If a non-BGP route exists inside the AS, route
synchronization is needed. Here, R2 uses route synchronization.
If it is not necessary to advertise a BGP route to a third AS or all
the routers in an AS run the BGP, route synchronization is not
needed.
The following configuration disables route synchronization on R2.
Configuration of R2:
ZXR10_R2(config)#router bgp 100
ZXR10_R2(config-router)#network 150.10.0.0
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
Route
Redistribution
Transitional AS