JN0-351 Exam Dumps - Juniper JNCIS-ENT Questions and Answers

B  is correct because duplex and speed settings are required to match on both participating devices.  According to the Juniper Networks documentation 1 , all the interfaces in a LAG must have the same speed and be in full-duplex mode. This ensures that the LAG can operate as a single logical link without any performance or compatibility issues.

C  is correct because member links are not required to be contiguous ports.  According to the Juniper Networks documentation 2 , you can group any Ethernet interfaces on a switch into a LAG, regardless of their physical location or slot number. This provides flexibility and scalability for configuring LAGs on switches.

The BGP attribute that you would use to forward all Internet traffic through the R1 device is the  local preference 1 .

The local preference is an attribute that is used within an autonomous system (AS) and exchanged between iBGP routers 1 .  It is used to select an exit point from the AS 1 .  The path with the highest local preference is preferred 1 .  By setting a higher local preference for the routes received from R1, you can make R1 the preferred exit point for all Internet traffic 1 .

According to the OSPF protocol, the designated router (DR) is the router that acts as the focal point for exchanging routing information on a multi-access network segment, such as a LAN 1 .  The DR election process is based on the following criteria, in order of precedence 1 :

The router with the highest OSPF priority becomes the DR. The default priority is 1, and a priority of 0 means the router will not participate in the election.

If there is a tie in priority, the router with the highest router ID becomes the DR. The router ID is a 32-bit number that uniquely identifies a router in an OSPF domain. It can be manually configured or automatically derived from the highest IP address of a loopback interface or a physical interface.

If there is a tie in router ID, the router that was first to become an OSPF neighbor becomes the DR.

In your scenario, two routers share the same highest priority and start time. This means that they have equal chances of becoming the DR based on the first and third criteria. Therefore, the second criterion will be used to break the tie, which is the router ID.  The router with the highest router ID will become the DR, and the other router will become the backup designated router (BDR), which is ready to take over the role of DR if it fails 1 .

According to the Juniper documentation 1 , the source and destination addresses of a GRE tunnel interface must be in different subnets. If they are in the same subnet, the router will not be able to route the GRE packets correctly. In the exhibit, the source and destination addresses are both in the 192.168.197.0/24 subnet, which is invalid for GRE tunneling. Therefore, the correct answer is D. References:  Configuring GRE Tunnel Interfaces | Junos OS

The routers that are directly connected to the Dallas and Denver subnets are not advertising the connected subnets.  This can be resolved by redistributing the connected subnets into OSPF 1 .

Option C suggests to configure and apply a routing policy that redistributes the connected Dallas and Denver subnets.  This is correct because redistribution allows routes from one routing protocol to be communicated to another, and in this case, it allows the connected subnets to be advertised through OSPF 1 .

Option D suggests enabling the passive option on the OSPF interfaces that are connected to the Dallas and Denver subnets.  This is also correct because in OSPF, a passive interface is an interface that belongs to the OSPF router, but does not send OSPF Hello packets 1 .  It’s typically used on an interface that you don’t want to use for OSPF adjacencies, but you still want to advertise its IP address 1 . Therefore, enabling passive interface can help in advertising the Dallas and Denver subnets.

A. The routes displayed have traversed one or more autonomous systems. True. The AS path attribute shows AS numbers (e.g., 65401 65520.), indicating the route ' s traversal through various autonomous systems. D. The routes displayed are being learned from an IBGP peer. True. The absence of the ' * > i ' marker before the prefixes indicates they are being learned from an IBGP peer. Therefore, the correct statements are A. The routes displayed have traversed one or more autonomous systems. and D. The routes displayed are being learned from an IBGP peer.

Default BGP keepalive timer in Junos is 30 seconds

The default keepalive time for BGP is 30 seconds, which means that BGP peers send keepalive messages to each other every 30 seconds to verify the liveness of the BGP session. If no keepalive message is received from a peer within the hold time, which is 90 seconds by default, the peer is considered to be unavailable and the BGP session is closed. The keepalive time and the hold time can be configured manually for each BGP peer or peer group, but they must match on both ends of the BGP session. The keepalive time should be one third of the hold time for optimal performance. Therefore, option C is correct and the other options are incorrect. References:  BGP keepalive messages and hold time - Juniper Networks

 In a Rapid Spanning Tree Protocol (RSTP) topology, the root bridge is determined by the switch with the lowest bridge priority value 1 2 .  If all switches have the same priority, then the root bridge is assigned to the switch whose MAC address’s hex value is the lowest 2 .  The default bridge priority value is 32768 3 2 . However, without the actual exhibit, it’s difficult to definitively determine which device is the root bridge.  But based on the options provided, if we assume that the local device has a lower bridge priority or a lower MAC address than other devices in the network, then it could be considered as the root bridge for this RSTP topology 4 5 .