Cisco 351-001 Online Practice Questions and Exam Preparation

Cisco 351-001 Online Questions & Answers

• Question 481:

  Which circumstance can cause packet loss due to a microburst?

  A. slow convergence
  B. a blocked spanning-tree port
  C. process switching
  D. insufficient buffers
  D. insufficient buffers

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  Micro-bursting is a phenomenon where rapid bursts of data packets are sent in quick succession, leading to periods of full line-rate transmission that can overflow packet buffers of the network stack, both in network endpoints and routers and switches inside the network. Symptoms of micro bursts will manifest in the form of ignores and/ or overruns (also shown as accumulated in "input error" counter within show interface output). This is indicative of receive ring and corresponding packet buffer being overwhelmed due to data bursts coming in over extremely short period of time (microseconds).

  Reference: http://ccieordie.com/?tag=micro-burst

• Question 482:

  You are performing a system diagnostics on a CSU in local loop mode and notice that the mineseen counter has failed to increment. Which type of problem does this behavior indicate?

  A. a cabling problem
  B. an encoding problem
  C. a framing problem
  D. a timing problem
  D. a timing problem

• Question 483:

  NO: 203

  Refer to the exhibit.

  

  Which option is the result of this configuration?

  A. Devices in OSPF area 15 can reach the summary route 192.168.0.0/16 and its more specific subnets.
  B. Devices in OSPF area 15 can reach only the more specific routes of 192.168.0.0/16.
  C. Devices in OSPF area 0 can reach the summary route 192.168.0.0/16 and its more specific subnets.
  D. Devices in OSPF area 0 can reach only the summary route of 192.168.0.0/16.
  A. Devices in OSPF area 15 can reach the summary route 192.168.0.0/16 and its more specific subnets.

  ---

  area range To consolidate and summarize routes at an area boundary, use the area range command in router configuration mode. To disable this function, use theno form of this command. Area area-id range ip-address mask [advertise | not-advertise] [cost cost] no area area-id range ip-address mask [advertise | not-advertise] [cost cost] Syntax Description area-id Identifier of the area about which routes are to be summarized. It can be specified as either a decimal value or as an IP address. ip-address IP address. mask IP address mask. advertise (Optional) Sets the address range status to advertise and generates a Type 3 summary link-state advertisement (LSA). not-advertise (Optional) Sets the address range status to DoNotAdvertise. The Type 3 summary LSA is suppressed, and the component networks remain hidden from other networks.

  Reference: http://www.cisco.com/c/en/us/td/docs/ios/12_2/iproute/command/reference/fiprrp_r/1rfospf. html

• Question 484:

  What is used to acknowledge the receipt of LSPs on a point-to-point network in IS-IS?

  A. hello
  B. CSNP
  C. PSNP
  D. IIH
  E. CSH
  C. PSNP

• Question 485:

  Which three statements are true about OSPFv3? (Choose three.)

  A. The only method to enable OSPFv3 on an interface is via the interface configuration mode.
  B. Multiple instances of OSPFv3 can be enabled on a single link.
  C. There are two methods to enable OSPFv3 on an interface, either via the interface configuration mode or via the router configuration mode.
  D. For OSPFv3 to function, IPv6 unicast routing must be enabled.
  E. For OSPFv3 to function, IPv6 must be enabled on the interface.
  F. Only one instance of OSPFv3 can be enabled on a single link.
  B. Multiple instances of OSPFv3 can be enabled on a single link.
  D. For OSPFv3 to function, IPv6 unicast routing must be enabled.
  E. For OSPFv3 to function, IPv6 must be enabled on the interface.

  ---

  Here is a list of the differences between OSPFv2 and OSPFv3: They use different address families (OSPFv2 is for IPv4-only, OSPFv3 can be used for IPv6-only or both protocols (more on this following)) OSPFv3 introduces new LSA types OSPFv3 has different packet format OSPFv3 uses different flooding scope bits (U/S2/S1) OSPFv3 adjacencies are formed over link-local IPv6 communications OSPFv3 runs per-link rather than per- subnet OSPFv3 supports multiple instances on a single link, Interfaces can have multiple IPv6 addresses OSPFv3 uses multicast addresses FF02::5 (all OSPF routers), FF02::6 (all OSPF DRs) OSPFv3 Neighbor Authentication done with IPsec (AH) OSPFv2 Router ID (RID) must be manually configured, still a 32-bit number

  Following is a simple example of OSPFv3 configuration on a Cisco IOS 12.4T router.

  ipv6 unicast-routing ipv6 cef ! interface GigabitEthernet 0/0 description Area 0.0.0.0 backbone interface ipv6 address 2001:DB8:100:1::1/64 ipv6 ospf network broadcast ipv6 ospf 100 area 0.0.0.0 Reference: http://www.networkworld.com/article/2225270/cisco-subnet/ospfv3-for-ipv4-and- ipv6.html

• Question 486:

  A configuration includes the line ip route 10.0.0.0 255.0.0.0 172.16.10.10 permanent.

  Which option is a benefit of configuring this static route as permanent?

  A. It allows the route to be redistributed into the network even if the outgoing interface is down.
  B. It allows the route to be saved in the running configuration of the device.
  C. It places a hidden tag on the route that can be matched on other devices.
  D. It allows the route to have a tracking status even if no tracking object is configured.
  A. It allows the route to be redistributed into the network even if the outgoing interface is down.

• Question 487:

  Refer to the exhibit.

  

  Which two statements about the VPN solution are true? (Choose two.)

  A. Customer A and customer B will exchange routes with each other.
  B. R3 will advertise routes received from R1 to R2.
  C. Customer C will communicate with customer A and B.
  D. Communication between sites in VPN1 and VPN2 will be blocked.
  E. R1 and R2 will receive VPN routes advertised by R3.
  C. Customer C will communicate with customer A and B.
  E. R1 and R2 will receive VPN routes advertised by R3.

  ---

  +

  VPN1 exports 10:1 while VPN3 imports 10:1 so VPN3 can learn routes of VPN1. + VNP1 imports 10:1 while VNP3 export 10:1 so VNP1 can learn routes of VPN3. -> Customer A can communicate with Customer C

  +

  VPN2 exports 20:1 while VPN3 imports 20:1 so VPN3 can learn routes of VPN2. + VPN2 imports 20:1 while VPN3 exports 20:1 so VPN2 can learn routes of VPN3.

  -> Customer B can communicate with Customer C

  Therefore answer C is correct.

  Also answer E is correct because R1 and R2 import R3 routes.

  Answer A is not correct because Customer A and Customer B do not import routes which are exported by other router. Customer A and B can only see Customer C.

  Answer B is not correct because a router never exports what it has learned through importation. It only exports its own routes.

  Answer D is correct because two VPN1 and VPN2 cannot see each other. Maybe in this question there are three correct answers.

• Question 488:

  Which statement is true regarding UDLD and STP timers?

  A. The UDLD message timer should be two times the STP forward delay to prevent loops.
  B. UDLD and STP are unrelated features, and there is no relation between the timers.
  C. The timers need to be synced by using the spanning-tree udld-sync command.
  D. The timers should be set in such a way that UDLD is detected before the STP forward delay expires.
  D. The timers should be set in such a way that UDLD is detected before the STP forward delay expires.

  ---

  UDLD is designed to be a helper for STP. Therefore, UDLD should be able to detect an unidirectional link before STP would unblock the port due to missed BPDUs. Thus, when you configure UDLD timers, make sure your values are set so that unidirectional link is detected before "STP MaxAge + 2xForwardDelay" expires.

  Reference: http://blog.ine.com/tag/stp/

• Question 489:

  Which two options are ways in which an OSPFv3 router handles hello packets with a clear address-family bit? (Choose two.)

  A. IPv4 unicast packets are discarded.
  B. IPv6 unicast packets are discarded.
  C. IPv4 unicast packets are forwarded.
  D. IPv6 unicast packets are forwarded.
  A. IPv4 unicast packets are discarded.
  D. IPv6 unicast packets are forwarded.

  ---

  A typical distance vector protocol saves the following information when computing the best path to a destination: the distance (total metric or distance, such as hop count) and the vector (the next hop). For instance, all the routers in the network in Figure 1 are running Routing Information Protocol (RIP). Router Two chooses the path to Network A by examining the hop count through each available path.

  

  Since the path through Router Three is three hops, and the path through Router One is two hops, Router Two chooses the path through One and discards the information it learned through Three. If the path between Router One and Network A goes down, Router Two loses all connectivity with this destination until it times out the route of its routing table (three update periods, or 90 seconds), and Router Three re-advertises the route (which occurs every 30 seconds in RIP). Not including any hold-down time, it will take between 90 and 120 seconds for Router Two to switch the path from Router One to Router Three. EIGRP, instead of counting on full periodic updates to re-converge, builds a topology table from each of its neighbor's advertisements (rather than discarding the data), and converges by either looking for a likely loop-free route in the topology table, or, if it knows of no other route, by querying its neighbors. Router Two saves the information it received from both Routers One and Three. It chooses the path through One as its best path (the successor) and the path through Three as a loop- free path (a feasible successor). When the path through Router One becomes unavailable, Router Two examines its topology table and, finding a feasible successor, begins using the path through Three immediately.

  Reference: http://www.cisco.com/c/en/us/support/docs/ip/enhanced-interior-gateway- routing-protocol-eigrp/16406-eigrp-toc.html

• Question 490:

  Which component of MPLS architecture uses protocols such as the label distribution protocol and tag distribution protocol to exchange labels?

  A. control plane
  B. data plane
  C. forwarding plane
  D. routing plane
  A. control plane