Hello, Everyone! The sharing time is coming, the next 10 questions and answers:)
QUESTION 31
At which layer of the OSI model does PPP perform?
A.
Layer 2
B.
Layer 3
C.
Layer 4
D.
Layer 5
Answer: A
Explanation:
Point-to-Point Protocol (PPP) is a data link protocol commonly used in establishing a direct connection between two networking nodes. It can provide connection authentication, transmission encryption (using ECP, RFC 1968), and compression.
QUESTION 32
The command show frame-relay map gives the following output:
Serial 0 (up): ip 192.168.151.4 dlci 122, dynamic, broadcast, status defined, active
Which statements represent what is shown?(Choose three.)
A.
192.168.151.4 represents the IP address of the remote router
B.
192.168.151.4 represents the IP address of the local serial interface
C.
DLCI 122 represents the interface of the remote serial interface
D.
DLCI 122 represents the local number used to connect to the remote address
E.
broadcast indicates that a dynamic routing protocol such as RIP v1 can send packets across this PVC
F.
active indicates that the ARP process is working
Answer: ADE
Explanation:
http://www.cisco.com/en/US/docs/ios/12_2/wan/command/reference/wrffr4.html#wp1029343
QUESTION 33
What can be done to Frame Relay to resolve split-horizon issues?(Choose two.)
A.
Disable Inverse ARP.
B.
Create a full-mesh topology.
C.
Develop multipoint subinterfaces.
D.
Configure point-to-point subinterfaces.
E.
Remove the broadcast keyword from the frame-relay map command.
Answer: BD
Explanation:
IP split horizon checking is disabled by default for Frame Relay encapsulation to allow routing updates to go in and out of the same interface. An exception is the Enhanced Interior Gateway Routing Protocol (EIGRP) for which split horizon must be explicitly disabled. Certain protocols such as AppleTalk, transparent bridging, and Internetwork Packet Exchange (IPX) cannot be supported on partially meshed networks because they require split horizon to be enabled (a packet received on an interface cannot be transmitted over the same interface, even if the packet is received and transmitted on different virtual circuits). Configuring Frame Relay subinterfaces ensures that a single physical interface is treated as multiple virtual interfaces. This capability allows you to overcome split horizon rules so packets received on one virtual interface can be forwarded to another virtual interface, even if they are configured on the same physical interface.
QUESTION 34
What are three reasons that an organization with multiple branch offices and roaming users might implement a Cisco VPN solution instead of point-to-point WAN links? (Choose three.)
A.
reduced cost
B.
better throughput
C.
broadband incompatibility
D.
increased security
E.
scalability
F.
reduced latency
Answer: ADE
Explanation:
http://www.cisco.com/en/US/products/ps5743/Products_Sub_Category_Home.html#~Benefits
QUESTION 35
Which command is used to enable CHAP authentication, with PAP as the fallback method, on a serial interface?
A.
Router(config-if)# ppp authentication chap fallback ppp
B.
Router(config-if)# ppp authentication chap pap
C.
Router(config-if)# authentication ppp chap fallback ppp
D.
Router(config-if)# authentication ppp chap pap
Answer: B
Explanation:
http://www.cisco.com/en/US/docs/ios/12_2/security/configuration/guide/scfathen.html
QUESTION 36
What is the result of issuing the frame-relay map ip 192.168.1.2 202 broadcast command?
A.
defines the destination IP address that is used in all broadcast packets on DCLI 202
B.
defines the source IP address that is used in all broadcast packets on DCLI 202
C.
defines the DLCI on which packets from the 192.168.1.2 IP address are received
D.
defines the DLCI that is used for all packets that are sent to the 192.168.1.2 IP address
Answer: D
Explanation:
frame-relay map ip 192.168.1.2 202 command statically defines a mapping between a network layer address and a DLCI. The broadcast option allows multicast and broadcast packets to flow across the link.
The command frame-relay map ip 192.168.1.2 202 broadcast means to mapping the distal IP 192.168.1.2 202 to the local DLCI . When the "broadcast" keyword is included, it turns Frame Relay network as a broadcast network, which can forward broadcasts. http://www.cisco.com/en/US/docs/ios/wan/command/reference/wan_f2.html#wp1012264
QUESTION 37
Which Layer 2 protocol encapsulation type supports synchronous and asynchronous circuits and has built-in security mechanisms?
A.
HDLC
B.
PPP
C.
X.25
D.
Frame Relay
Answer: B
Explanation:
High-Level Data Link Control (HDLC) - HDLC is the default encapsulation type on point-to-point, dedicated links, and circuit-switched connections. It is used typically when communicating between two Cisco devices. It is a bit-oriented synchronous data link layer protocol.
Point-to-Point Protocol (PPP) - Provides router-to-router and host-to network connections over synchronous and asynchronous circuits. PPP was designed to work with several network layer protocols, such as IP, and IPX. PPP also has built in security mechanisms such as PAP and CHAP X.25/Link Access Procedure, Balanced (LAPB) - ITU-T standard that defines how connections between DTE and DCE are maintained for remote terminal access and computer communications in public data networks. X.25 specifies LAPB, a data line layer protocol. X.25 is a predecessor to Frame Relay.
Frame Relay - Industry standard, switched data link layer protocol that handles multiple virtual circuits. It is a next-generation to X.25 that is streamlined to eliminate some of the time-consuming processes (such as error correction and flow control) that were employed in X.25.
QUESTION 38
Which encapsulation type is a Frame Relay encapsulation type that is supported by Cisco routers?
A.
IETF
B.
ANSI Annex D
C.
Q9333-A Annex A
D.
HDLC
Answer: A
Explanation:
Cisco supports two Frame Relay encapsulation types: the Cisco encapsulation and the IETF Frame Relay encapsulation, which is in conformance with RFC 1490 and RFC 2427. The former is often used to connect two Cisco routers while the latter is used to connect a Cisco router to a non-Cisco router. You can test with your Cisco router when typing the command
Router(config-if)#encapsulation frame-relay ? on a WAN link.
Note: Three LMI options are supported by Cisco routers are ansi, Cisco, and Q933a. They represent the ANSI Annex D, Cisco, and ITU Q933-A (Annex A) LMI types, respectively.
HDLC is a WAN protocol same as Frame-Relay and PPP so it is not a Frame Relay encapsulation type.
QUESTION 39
The internetwork infrastructure of company XYZ consists of a single OSPF area as shown in the graphic. There is concern that a lack of router resources is impeding internetwork performance. As part of examining the router resources, the OSPF DRs need to be known. All the router OSPF priorities are at the default and the router IDs are shown with each router. Which routers are likely to have been elected as DR? (Choose two.)
A.
Corp-1
B.
Corp-2
C.
Corp-3
D.
Corp-4
E.
Branch-1
F.
Branch-2
Answer: DF
Explanation:
There are 2 segments on the topology above which are separated by Corp-3 router.
Each segment will have a DR so we have 2 DRs.
To select which router will become DR they will compare their router-IDs. The router with highest (best) router-ID will become DR. The router-ID is chosen in the order below:
The highest IP address assigned to a loopback (logical) interface. If a loopback interface is not defined, the highest IP address of all active router's physical interfaces will be chosen.
In this question, the IP addresses of loopback interfaces are not mentioned so we will consider IP addresses of all active router's physical interfaces. Router Corp-4 (10.1.40.40) & Branch-2 (10.2.20.20) have highest "active" IP addresses so they will become DRs.
QUESTION 40
A network administrator needs to configure a serial link between the main office and a remote location. The router at the remote office is a non-Cisco router. How should the network administrator configure the serial interface of the main office router to make the connection?
A.
Main(config)# interface serial 0/0
Main(config-if)# ip address 172.16.1.1 255.255.255.252
Main(config-if)# no shut
B.
Main(config)# interface serial 0/0
Main(config-if)# ip address 172.16.1.1 255.255.255.252
Main(config-if)# encapsulation ppp
Main(config-if)# no shut
C.
Main(config)# interface serial 0/0
Main(config-if)# ip address 172.16.1.1 255.255.255.252
Main(config-if)# encapsulation frame-relay
Main(config-if)# authentication chap
Main(config-if)# no shut
D.
Main(config)# interface serial 0/0
Main(config-if)#ip address 172.16.1.1 255.255.255.252
Main(config-if)#encapsulation ietf
Main(config-if)# no shut
Answer: B
Explanation:
Cisco High-Level Data Link Controller (HDLC) is the Cisco proprietary protocol for sending data over synchronous serial links using HDLC. So HDLC runs only in Cisco router. PPP is not proprietary protocol it's a open source every cisco router and non-cisco router understand the PPP protocol.So we need to configure the PPP protocol if connection is between cisco and non-cisco router.
