Juniper JN0-351 Practice Test - Questions Answers, Page 5

An ISO NET address is a type of network address used by the IS-IS routing protocol.It identifies a point of connection to the network, such as a router interface, and is also called a Network Service Access Point (NSAP)1.

An ISO NET address consists of three parts: an area ID, a system ID, and a selector2. The area ID identifies the IS-IS area to which the device belongs. The system ID uniquely identifies the device within the area.The selector identifies a specific service or function on the device, such as routing or management2.

An ISO NET address must be unique for each device in the network, because it is used by IS-IS to establish adjacencies, exchange routing information, and compute shortest paths2. If two devices have the same ISO NET address, they will not be able to communicate with each other or with other devices in the network. Therefore, it is important to assign different ISO NET addresses to each device in the network.

The default MAC age-out timer on an EX Series switch is300 seconds12.The MAC age-out timer is the maximum time that an entry can remain in the MAC table before it ''ages out,'' or is removed31.This configuration can influence efficiency of network resource use by affecting the amount of traffic that is flooded to all interfaces1.When traffic is received for MAC addresses no longer in the Ethernet routing table, the router floods the traffic to all interfaces1.

Ais correct because generated routes require a contributing route.A contributing route is a route that matches the destination prefix of the generated route and has a valid next hop1.A generated route is only installed in the routing table if there is at least one contributing route available2. This ensures that the generated route is reachable and useful.If there is no contributing route, the generated route is not added to the routing table2.

Bis correct because generated routes show a next hop in the routing table.A generated route inherits the next hop of its primary contributing route, which is the most preferred route among all the contributing routes2.The next hop of the generated route can be either an IP address or an interface name, depending on the type of the contributing route2.The next hop of the generated route can also be modified by a routing policy3.

A broadcast storm is a network condition where a large number of broadcast packets are sent and received by multiple devices, causing congestion and performance degradation1.A broadcast storm can occur when there are loops in the network topology, meaning that there are multiple paths between two devices2.

A spanning tree protocol is a network protocol that prevents loops from being formed when switches or bridges are interconnected via multiple paths.It does this by creating a logical tree structure that spans all the devices in the network, and disabling or blocking the links that are not part of the tree, leaving a single active path between any two devices3.

By eliminating loops, a spanning tree protocol also eliminates broadcast storms, as broadcast packets will not be forwarded endlessly along the looped paths.Instead, broadcast packets will be sent only along the tree structure, reaching each device once and avoiding congestion3.

Junos devices support various types of tunnels for different purposes12.

Option B is correct.Generic Routing Encapsulation (GRE) is a tunneling protocol that can encapsulate a wide variety of network layer protocols inside virtual point-to-point links over an Internet Protocol network1.Junos devices support GRE tunnels1.

Option D is correct.IPsec (Internet Protocol Security) is a protocol suite for securing Internet Protocol (IP) communications by authenticating and encrypting each IP packet of a communication session1.Junos devices support IPsec tunnels1.

Option A is incorrect. Spanning Tree Protocol (STP) is not a type of tunnel.It's a network protocol designed to prevent loops in a bridged Ethernet local area network2.

Option C is incorrect.While Junos devices do support IP-IP (also known as IP tunneling), it's not supported on all Junos devices1.

Ais correct because you need to configure BGP multihop to enable redundancy for the EBGP peering between the two routers.BGP multihop is a feature that allows BGP peers to establish a session over multiple hops, instead of requiring them to be directly connected1.By default, EBGP peers use a time-to-live (TTL) value of 1 for their packets, which means that they can only reach adjacent neighbors1.However, if you configure BGP multihop with a higher TTL value, you can allow EBGP peers to communicate over multiple routers in between1. This can provide redundancy in case of a link failure or a router failure between the EBGP peers.

Bis correct because you need to configure loopback interface peering to enable redundancy for the EBGP peering between the two routers.Loopback interface peering is a technique that uses loopback interfaces as the source and destination addresses for BGP sessions, instead of physical interfaces2.Loopback interfaces are virtual interfaces that are always up and reachable as long as the router is operational2.By using loopback interface peering, you can avoid the dependency on a single physical interface or link for the BGP session, and use multiple paths to reach the loopback address of the peer2. This can provide redundancy and load balancing for the EBGP peering.

Cis correct because you need to configure routes for the peer loopback interface IP addresses to enable redundancy for the EBGP peering between the two routers.Routes for the peer loopback interface IP addresses are necessary to ensure that the routers can reach each other's loopback addresses over multiple hops2.You can use static routes or dynamic routing protocols to advertise and learn the routes for the peer loopback interface IP addresses2. Without these routes, the routers will not be able to establish or maintain the BGP session using their loopback interfaces.

Cis 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.

Dis 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.

Option B is correct.Flooding is a mechanism used in Layer 2 bridging where the switch sends incoming packets to all its ports except for the port where the packet originated1.This is done when the switch doesn't know the destination MAC address or when the packet is a broadcast or multicast1.

Option C is correct.Learning is another mechanism used in Layer 2 bridging where the switch learns the source MAC addresses of incoming packets and associates them with the port on which they were received23.This information is stored in a MAC address table, also known as a bridge table23.

Option A is incorrect.Blocking is a state in Spanning Tree Protocol (STP) used to prevent loops in a network2.It's not a mechanism used in building and maintaining a Layer 2 bridge table2.

Option D is incorrect.Listening is also a state in Spanning Tree Protocol (STP) where the switch listens for BPDUs to make sure no loops occur in the network before transitioning to the learning state2.It's not a mechanism used in building and maintaining a Layer 2 bridge table2.

Ais correct because you can deploy only stateless firewall filters on an EX Series switch.A stateless firewall filter is a filter that evaluates each packet individually based on the header information, such as source and destination addresses, protocol, and port numbers1.A stateless firewall filter does not keep track of the state or context of a packet flow, such as the sequence number, flags, or session information1.EX Series switches support only stateless firewall filters, which are also called access control lists (ACLs) or packet filters2.

Cis correct because you can apply firewall filters to both Layer 2 and Layer 3 traffic on an EX Series switch.Layer 2 traffic is traffic that is switched within a VLAN or a bridge domain, while Layer 3 traffic is traffic that is routed between VLANs or networks3.EX Series switches support three types of firewall filters: port (Layer 2) firewall filters, VLAN firewall filters, and router (Layer 3) firewall filters4. You can apply these filters to different interfaces and directions to control the traffic entering or exiting the switch.