Juniper Exam JN0-480 Topic 5 Question 40 Discussion

The leaf device in AS 65000 will receive three routes for the 10.100.0.0/16 prefix, one from each spine device in AS 65001, AS 65002, and AS 65003. Since ECMP load balancing is enabled, the leaf device will install all three routes in its routing table and distribute the traffic among them. The other options are incorrect because:

B) 1 is wrong because the leaf device will not receive only one route for the prefix. It will receive multiple routes from different spine devices and use ECMP to load balance among them.

C) 2 is wrong because the leaf device will not receive only two routes for the prefix. It will receive three routes from three spine devices, as explained above.

D) 4 is wrong because the leaf device will not receive four routes for the prefix. It will receive three routes from three spine devices, as explained above. The fourth spine device in AS 65004 is not directly connected to the leaf device and will not advertise the prefix to it.Reference:

IP Fabric Underlay Network Design and Implementation

BGP Multipath load sharing iBGP and eBGP

ECMP Load Balancing