Cisco 351-001 Online Practice Questions and Exam Preparation

Cisco 351-001 Online Questions & Answers

• Question 971:

  Which TCP mechanism prevents the sender from sending data too quickly for the receiver to process?

  A. Congestion control
  B. Error detection
  C. Selective acknowledgement
  D. Flow control
  D. Flow control

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  In data communications, flow control is the process of managing the rate of data transmission between two nodes to prevent a fast sender from overwhelming a slow receiver. It provides a mechanism for the receiver to control the transmission speed, so that the receiving node is not overwhelmed with data from transmitting node.

  Reference: http://en.wikipedia.org/wiki/Flow_control_(data)

• Question 972:

  Which two protocols are used to establish IPv6 connectivity over an MPLS network? (Choose two.)

  A. 6PE
  B. 6VPE
  C. RSVP
  D. ISATAP
  E. LDP
  F. IPv6IP
  A. 6PE
  B. 6VPE

• Question 973:

  Which standard feature can be exploited by an attacker to perform network reconnaissance?

  A. IP-directed broadcast
  B. maintenance operations protocol
  C. ICMP redirects
  D. source quench
  C. ICMP redirects

• Question 974:

  Which technology can MSDP SA filters use to filter traffic?

  A. route maps
  B. community lists
  C. prefix lists
  D. class maps
  A. route maps

• Question 975:

  Which two types of traffic are blocked when the storm control threshold for multicast traffic is reached on a port? (Choose two.)

  A. BPDU
  B. OSPF
  C. CDP
  D. IS-IS
  E. LLDP
  B. OSPF
  D. IS-IS

• Question 976:

  Which option describes what the default RT filter indicates when you implement the BGP RT constrained route distribution feature?

  A. A peer receives only a default route for each VRF.
  B. A peer receives all routes, regardless of the RT value.
  C. A peer receives routes only for RTs that are used on that router.
  D. A peer receives no routes, regardless of the RT value.
  B. A peer receives all routes, regardless of the RT value.

• Question 977:

  You are implementing new addressing with EIGRP routing and must use secondary addresses, which are missing from the routing table. Which action is the most efficient solution to the problem?

  A. Disable split-horizon on the interfaces with secondary addresses.
  B. Disable split-horizon inside the EIGRP process on the router with the secondary interface addresses.
  C. Add additional router interfaces and move the secondary addresses to the new interfaces.
  D. Use a different routing protocol and redistribute the routes between EIGRP and the new protocol.
  A. Disable split-horizon on the interfaces with secondary addresses.

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  Normally, routers that are connected to broadcast-type IP networks and that use distance- vector routing protocols employ the split horizon mechanism to reduce the possibility of routing loops. Split horizon blocks information about routes from being advertised by a router out of any interface from which that information originated. This behavior usually optimizes communications among multiple routers, particularly when links are broken. However, with nonbroadcast networks, situations can arise for which this behavior is less than ideal. For these situations, you might want to disable split horizon with EIGRP and RIP. If an interface is configured with secondary IP addresses and split horizon is enabled, updates might not be sourced by every secondary address. One routing update is sourced per network number unless split horizon is disabled.

  Reference: http://www.cisco.com/c/en/us/td/docs/ios/12_2/ip/configuration/guide/fipr_c/1cfrip.html

• Question 978:

  Refer to the exhibit.

  

  Why is the prefix 1.1.1.1/32 not present in the routing table of R1?

  A. There is a duplicate router ID.
  B. There is a subnet mask mismatch on Ethernet0/0.
  C. The router LSA has an invalid checksum.
  D. There is an OSPF network type mismatch that causes the advertising router to be unreachable.
  D. There is an OSPF network type mismatch that causes the advertising router to be unreachable.

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  A common problem when using Open Shortest Path First (OSPF) is routes in the database don't appear in the routing table. In most cases OSPF finds a discrepancy in the database so it doesn't install the route in the routing table. Often, you can see the Adv Router is not- reachable message (which means that the router advertising the LSA is not reachable through OSPF) on top of the link-state advertisement (LSA) in the database when this problem occurs. Here is an example: Adv Router is not-reachable LS agE. 418 Options: (No TOS-capability, DC) LS TypE. Router Links Link State ID. 172.16.32.2 Advertising Router: 172.16.32.2 LS Seq Number: 80000002 Checksum: 0xFA63 Length: 60 Number of Links: 3 There are several reasons for this problem, most of which deal with mis-configuration or a broken topology. When the configuration is corrected the OSPF database discrepancy goes away and the routes appear in the routing table. Reason 1: Network Type Mismatch Let's use the following network diagram as an example:

  

  R4-4K R1-7010 interface Loopback0 ip address 172.16.33.1 255.255.255.255

  interface Serial2 ip address 172.16.32.1 255.255.255.0 ip ospf network broadcast

  router ospf 20 network 172.16.0.0 0.0.255.255 area 0 interface Loopback0 ip address 172.16.30.1 255.255.255.255 ! interface Serial1/0 ip address 172.16.32.2 255.255.255.0 clockrate 64000

  router ospf 20 network 172.16.0.0 0.0.255.255 area 0 R4-4K(4)# show ip ospf interface serial 2 Serial2 is up, line protocol is up Internet Address 172.16.32.1/24, Area 0 Process ID 20, Router ID 172.16.33.1, Network Type BROADCAST, Cost: 64 Transmit Delay is 1 sec, State DR, Priority 1 Designated Router (ID) 172.16.33.1, Interface address 172.16.32.1 Backup Designated router (ID) 172.16.32.2, Interface address 172.16.32.2 Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:08 Neighbor Count is 1, Adjacent neighbor count is 1 Adjacent with neighbor 172.16.32.2 (Backup Designated Router) Suppress hello for 0 neighbor(s)

  R1-7010(5)# show ip ospf interface serial 1/0 Serial1/0 is up, line protocol is up Internet Address 172.16.32.2/24, Area 0 Process ID 20, Router ID 172.16.32.2, Network Type POINT_TO_POINT, Cost: 64 Transmit Delay is 1 sec, State POINT_TO_POINT, Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:02 Neighbor Count is 1, Adjacent neighbor count is 1 Adjacent with neighbor 172.16.33.1 Suppress hello for 0 neighbor(s)

  As you can see above, Router R4-4K is configured for broadcast, and Router R1-7010 is configured for point-to-point. This kind of network type mismatch makes the advertising router unreachable.

  R4-4K(4)# show ip ospf database router 172.16.32.2

  Adv Router is not-reachable LS agE. 418 Options: (No TOS-capability, DC) LS TypE. Router Links Link State ID. 172.16.32.2 Advertising Router: 172.16.32.2 LS Seq Number: 80000002 Checksum: 0xFA63 Length: 60 Number of Links: 3 Link connected to: another Router (point-to-point) (Link ID) Neighboring Router ID. 172.16.33.1 (Link Data) Router Interface address: 172.16.32.2 Number of TOS metrics: 0 TOS 0 Metrics: 64

  Link connected to: a Stub Network (Link ID) Network/subnet number: 172.16.32.0 (Link Data) Network Mask: 255.255.255.0 Number of TOS metrics: 0 TOS 0 Metrics: 64 R1-7010(5)# show ip ospf database router 172.16.33.1 Adv Router is not-reachable LS agE. 357 Options: (No TOS-capability, DC) LS TypE. Router Links Link State ID. 172.16.33.1 Advertising Router: 172.16.33.1 LS Seq Number: 8000000A Checksum: 0xD4AA Length: 48 Number of Links: 2

  Link connected to: a Transit Network (Link ID) Designated Router address: 172.16.32.1 (Link Data) Router Interface address: 172.16.32.1 Number of TOS metrics: 0 TOS 0 Metrics: 64

  You can see that for subnet 172.16.32.0/24, Router R1-7010 is generating a point-to-point link and Router R4-4K is generating a transit link. This creates a discrepancy in the link- state database, which means no routes are installed in the routing table.

  R1-7010(5)# show ip route 172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks C 172.16.32.0/24 is directly connected, Serial1/0 C 172.16.30.1/32 is directly connected, Loopback0 Solution To solve this problem, configure both routers for the same network type. You can either change the network type of Router R1-7010 to broadcast, or change Router R4-4K's serial interface to point-to-point.

  Reference: http://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first- ospf/7112-26.html

• Question 979:

  Refer to the exhibit.

  

  Notice that debug ip bgp updates have been enabled. What can you conclude from the debug output?

  A. This is the result of the clear ip bgp 10.1.3.4 in command.
  B. This is the result of the clear ip bgp 10.1.3.4 out command.
  C. BGP neighbor 10.1.3.4 performed a graceful restart.
  D. BGP neighbor 10.1.3.4 established a new BGP session.
  A. This is the result of the clear ip bgp 10.1.3.4 in command.

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  If you enter the clear ip bgp out command for a BGP peer, that router resends its BGP prefixes to that peer. This does not cause a change in the best path on the receiving BGP peer. Hence, there is no change in the Table Version on that

  peer. When you run the debug ip bgp updates on the receiving router, you see:

  BGP(0): 10.1.3.4 rcvd UPDATE w/ attr: nexthop 10.1.3.4, origin i, metric 0, merged path 4, AS_PATH BGP(0): 10.1.3.4 rcvd 10.100.1.1/32...duplicate ignored The received update is recognized as a duplicate, so it is ignored and no best path

  change occurs.

  Reference: http://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol- bgp/116511-technote-tableversion-00.html

• Question 980:

  Which two options are advantages of NetFlow version 9 over NetFlow version 5? (Choose two.)

  A. NetFlow version 9 adds support for IPv6 headers.
  B. NetFlow version 9 adds support for MPLS labels.
  C. NetFlow version 9 adds support for the Type of Service field.
  D. NetFlow version 9 adds support for ICMP types and codes.
  A. NetFlow version 9 adds support for IPv6 headers.
  B. NetFlow version 9 adds support for MPLS labels.

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  NetFlow version 9 includes support for all of these fields that version 5 supports and can optionally include additional information such as Multiprotocol Label Switching (MPLS) labels and IPv6 addresses and ports.