Juniper Juniper Certifications JN0-361 Questions & Answers

• Question 91:

  What are two benefits of using MVRP? (Choose two.)

  A. It reduces network administration and overhead

  B. It dynamically creates and prunes VLANs

  C. It provides redundancy for Layer 2 interfaces

  D. It dynamically translates Layer 2 addresses to Layer 3 addresses

  Correct Answer: AB

  The Multiple VLAN Registration Protocol (MVRP) simplifies VLAN management by dynamically managing VLAN registration in a LAN. MVRP helps reduce administration and network overhead by dynamically pruning VLAN information when a switch no longer has active access ports, and by dynamically creating newly configured VLANs.

• Question 92:

  By default, which two tasks does an Ethernet bridge perform in response to receiving a multicast frame? (Choose two.)

  A. It learns the MAC address of any responding nodes and updates its bridge table with the source MAC address and ingress port

  B. It drops the frame

  C. It floods the frame out of all interfaces except the one on which it was received

  D. It floods the frame out of particular interfaces based on its multicast MAC table.

  Correct Answer: AC

  Multicast packets are flooded out all ports except for the port on which it was received. When an unknown destination responds to traffic that has been flooded through a switch, the switch learns the MAC address fo that node and updates its bridge table with the source MAC address and ingress port.

• Question 93:

  On an MX Series device, which parameter is used to configure the timeout interval fo entries in the MAC table?

  A. global-mac-table-aging-time

  B. global-mac-limit

  C. switch-mac-table-aging-time

  D. switch-mac-limit

  Correct Answer: A

  Switches have an efficient method of managing stale MAC addresses, which is an aging timer. For MX Series devices, the aging timer defaults to a value of 300 seconds. This value can be changed using the global-mac-table-aging-time parameter under the [edit protocols l2-learning] hierarchy.

• Question 94:

  Which bridging mechanism is used to ensure that only active entries are in the bridge table?

  A. learning

  B. forwarding

  C. flooding

  D. filtering

  E. aging

  Correct Answer: E

  Aging is used to ensure that the bridge table remains current by removing the stale entries.

• Question 95:

  An Ethernet bridge is configured such that all interfaces are in a single broadcast domain. Which two tasks does an Ethernet bridge perform in response to receiving a frame with an unknown unicast destination MAC address? (Choose two.)

  A. It drops the frame.

  B. It floods the frame out of all interfaces except the one on which is was received.

  C. It learns the destination MAC address when it sees return traffic from the device.

  D. It learns the source MAC address when it sees return traffic from that device.

  Correct Answer: BC

  When a bridge receives a data frame with an unknown destination MAC address, the frame is flooded out all other ports in the same broadcast domain. Once the bridge sees return traffic from this MAC address, it adds the address to the bridge table.

• Question 96:

  Which two problems occur when increasing numbers of users are added to traditional hub-based Ethernet LAN? (Choose two.)

  A. There is a greater chance for collisions to occur

  B. The MAC table sizes increase

  C. Some devices will not see certain traffic

  D. There is unnecessary consumption of network bandwidth

  Correct Answer: AD

  As nodes are added to a shared Ethernet LAN, the likelihood of collisions increases, which in turn consumes more network bandwidth, adversely effecting performance.

• Question 97:

  -- Exhibit -

  [edit]

  user@Router-X# show policy-options

  policy-statement nhs

  term 1 {

  from {

  protocol bgp;

  neighbor 10.0.21.2;

  }

  then next-hop self;

  }

  }

  A Junos device has an external peering session to 10.0.21.2 and several internal peers.

  How can the policy reference in the exhibit be used to ensure routes are usable?

  A. Apply it as an import policy to internal BGP peers

  B. Apply it as an export policy to internal BGP peers

  C. Apply it as an import policy to external BGP peers

  D. Apply it as an export policy to external BGP peers

  Correct Answer: B

  As a best practice, always apply a next-hop self policy as an export policy to internal peers or to the BGP group to wich those peers belong. Improper application of a next-hop-self policy can cause suboptimal routing or result in hidden routes.

• Question 98:

  What are two valid actions that can be applied to a frame by a Layer 2 firewall filter? (Choose two)

  A. Log

  B. loss-priority

  C. sample

  D. count

  Correct Answer: BD

  You can specify the following filter actions (Note that log and sample are only available for layer 3 packets not layer 2 frames):

  *

  accept

  *

  count counter-name

  *

  discard

  *

  dscp code-point (family inet only)

  *

  forwarding-class class-name

  *

  ipsec-sa ipsec-sa (family inet only)

  *

  load-balance group-name (family inet only)

  *

  log (family inet and inet6 only)

  *

  logical-system logical-system-name (family inet and inet6 only)

  *

  loss-priority (high | medium-high | medium-low | low)

  *

  next term

  *

  next-hop-group group-name (family inet only)

  *

  policer policer-name

  *

  port-mirror (family bridge, ccc, inet, inet6, and vpls only)

  *

  prefix-action action-name (family inet only)

  *

  reject (family inet and inet6 only)

  *

  routing-instance routing-instance-name (family inet and inet6 only)

  *

  sample (family inet, inet6, and mpls only)

  *

  service-accounting (service filters and family inet or inet6 only)

  *

  service-filter-hit (service filters and family inet or inet6 only)

  *

  syslog (family inet and inet6 only)

  *

  three-color-policer policer-name

  *

  topology topology-name (family inet and inet6 only)

  *

  traffic-class code-point (family inet6) only

• Question 99:

  

  In the exhibit, all devices are sending routes to Router B.

  Which routes will be advertised from Router B to Router A?

  A. BGP routes learned from Router C only

  B. BGP routes leaned from Router E only

  C. BGP routes learned from Routers D and E only

  D. BGP routes learned from Routers C, D, and E

  Correct Answer: C

  IBGP learned routes will only be advertised to EGP peers.

• Question 100:

  Which type of BGP message is used to perform a soft clearing of a BGP session?

  A. refresh

  B. update

  C. notification

  D. open

  Correct Answer: A

  A refresh message is used to perform a soft clearing of a BGP session. Normally a BGP speaker cannot be made to readvertise routes that have already been sent and acknowledged. The route refresh message supports soft clearing of BGP sessions by allowing a peer to readvertise routes that have already been sent.