JN0-351 Exam Dumps : Enterprise Routing and Switching Specialist (JNCIS-ENT)

• A is correct because IBGP updates the next-hop attribute to ensure reachability within an AS. This is because the next-hop attribute is the IP address of the router that advertises the route to a BGP peer. If the next-hop attribute is not changed by IBGP, it would be the IP address of an external router, which may not be reachable by all routers within the AS. Therefore, IBGP updates the next-hop attribute to the IP address of the router that received the route from an EBGP peer1.
• B is correct because IBGP peers advertise routes received from EBGP peers to other IBGP peers. This is because BGP follows the rule of advertising only the best route to a destination, and EBGP routes have a higher preference than IBGP routes. Therefore, IBGP peers advertise routes learned from an EBGP peer to all BGP peers, including both EBGP and IBGP peers1.

In this scenario, you should create an aggregate route1. Aggregate routes are used for advertising summarized network prefixes1. They help minimize the number of routing tables in an IP network by consolidating selected multiple routes into a single route advertisement1. This approach is in contrast to non-aggregation routing, in which every routing table contains a unique entry for each route1.

Therefore, option A is correct. Options B, C, and D are not correct because:

• Static route using the resolve feature: This type of route uses the resolve feature to install a static route in the routing table only if a specific condition is met1. However, it does not provide the capability to summarize multiple routes into a single prefix.
• Generate route: This type of route generates a route that is always present in the routing table and can be used to summarize routes. However, it does not have the capability to only advertise the route when specific BGP routes are being received from a neighbor1.
• Static route using qualified next hops: This type of route allows for the specification of multiple next-hop addresses for a static route1. However, it does not provide the capability to summarize multiple routes into a single prefix.

• C is correct because Layer 2 control traffic is permitted on the secondary link of a redundant trunk group (RTG) on EX Series switches. Layer 2 control traffic includes protocols such as LLDP, LACP, and STP, which are used to exchange information and coordinate actions between switches1. According to the Juniper Networks documentation2, Layer 2 control traffic is allowed to pass through both the active and the secondary links of an RTG, but data traffic is only forwarded through the active link. This allows the switches to maintain their Layer 2 adjacencies and monitor the link status on both links.
• D is correct because if the active link fails, then the secondary link automatically takes over in an RTG on EX Series switches. An RTG consists of two trunk links: an active or primary link, and a secondary or backup link2. The active link is used to forward data traffic, while the secondary link is in standby mode. If the active link fails or becomes unavailable, the secondary link immediately transitions to a forwarding state and takes over the data traffic without waiting for normal STP convergence2. This provides fast recovery and redundancy for the network.