CISCO CCNA Exam – Q258

Which protocol is an open standard protocol framework that is commonly used in VPNs, to provide secure end-to-end communications?

A. RSA
B. L2TP
C. IPsec
D. PPTP

Correct Answer: C

Explanation:
IPSec is a framework of open standards that provides data confidentiality, data integrity, and data authentication between participating peers at the IP layer. IPSec can be used to protect one or more data flows between IPSec peers.

CISCO CCNA Exam – Q257

At which layer of the OSI model does PPP perform?

A. Layer 2
B. Layer 3
C. Layer 4
D. Layer 5

Correct Answer: A

Explanation:
The Point-to-Point Protocol (PPP) provides a standard method for transporting multi-protocol datagrams over point-to-point links. PPP was originally emerged as an encapsulation protocol for transporting IP traffic between two peers. It is a data link layer protocol (layer 2 in the OSI model)

CISCO CCNA Exam – Q256

The command frame-relay map ip 10.121.16.8 102 broadcast was entered on the router. Which of the following statements is true concerning this command?

A. This command should be executed from the global configuration mode.
B. The IP address 10.121.16.8 is the local router port used to forward data.
C. 102 is the remote DLCI that will receive the information.
D. This command is required for all Frame Relay configurations.
E. The broadcast option allows packets, such as RIP updates, to be forwarded across the PVC.

Correct Answer: E

Explanation:
Broadcast is added to the configurations of the frame relay, so the PVC supports broadcast, allowing the routing protocol updates that use the broadcast update mechanism to be forwarded across itself.

CISCO CCNA Exam – Q255

Which two options are valid WAN connectivity methods? (Choose two.)

A. PPP
B. WAP
C. DSL
D. L2TPv3
E. Ethernet

Correct Answers: A, C

Explanation:
The Point-to-Point Protocol (PPP) provides a standard method for transporting multi-protocol datagrams over point-to-point links. PPP was originally emerged as an encapsulation protocol for transporting IP traffic between two peers. It is a data link layer protocol used for WAN connections.
DSL is also considered a WAN connection, as it can be used to connect networks, typically when used with VPN technology.

CISCO CCNA Exam – Q254

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

Correct Answer: B

Explanation:
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, including IP. PPP also has built-in security mechanisms, such as Password Authentication Protocol (PAP) and Challenge Handshake Authentication Protocol (CHAP).

CISCO CCNA Exam – Q253

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

Correct 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. Below is the output of this command (notice Cisco is the default encapsulation so it is not listed here, just press Enter to use it).
CISCO CCNA Exam – Q253

HDLC is a WAN protocol same as Frame-Relay and PPP so it is not a Frame Relay encapsulation type.

CISCO CCNA Exam – Q252

RouterA is unable to reach RouterB. Both routers are running IOS version 12.0.
CISCO CCNA Exam – Q252

After reviewing the command output and graphic, what is the most likely cause of the problem?

A. incorrect bandwidth configuration
B. incorrect LMI configuration
C. incorrect map statement
D. incorrect IP address

Correct Answer: C

Explanation:
First we have to say this is an unclear question and it is wrong. The “frame-relay map ip” statement is correct thus none of the four answers above is correct. But we guess there is a typo in the output. Maybe the “ip address 172.16.100.2 255.255.0.0″ command should be “ip address 172.16.100.1 255.255.0.0″. That makes answer C correct.

CISCO CCNA Exam – Q251

Refer to the exhibit.
CISCO CCNA Exam – Q251

What is the meaning of the term dynamic as displayed in the output of the show frame-relay map command shown?

A. The Serial0/0 interface is passing traffic.
B. The DLCI 100 was dynamically allocated by the router.
C. The Serial0/0 interface acquired the IP address of 172.16.3.1 from a DHCP server.
D. The DLCI 100 will be dynamically changed as required to adapt to changes in the Frame Relay cloud.
E. The mapping between DLCI 100 and the end station IP address 172.16.3.1 was learned through Inverse ARP.

Correct Answer: E

Explanation:
Inverse Address Resolution Protocol (Inverse ARP) was developed to provide a mechanism for dynamic DLCI to Layer 3 address maps. Inverse ARP works much the same way Address Resolution Protocol (ARP) works on a LAN. However, with ARP, the device knows the Layer 3 IP address and needs to know the remote data link MAC address. With Inverse ARP, the router knows the Layer 2 address which is the DLCI, but needs to know the remote Layer 3 IP address.

When using dynamic address mapping, Inverse ARP requests a next-hop protocol address for each active PVC. Once the requesting router receives an Inverse ARP response, it updates its DLCI-to-Layer 3 address mapping table. Dynamic address mapping is enabled by default for all protocols enabled on a physical interface. If the Frame Relay environment supports LMI autosensing and Inverse ARP, dynamic address mapping takes place automatically. Therefore, no static address mapping is required.

CISCO CCNA Exam – Q250

Which statement describes the process ID that is used to run OSPF on a router?

A. It is globally significant and is used to represent the AS number.
B. It is locally significant and is used to identify an instance of the OSPF database.
C. It is globally significant and is used to identify OSPF stub areas.
D. It is locally significant and must be the same throughout an area.

Correct Answer: B

Explanation:
The Process ID for OSPF on a router is only locally significant and you can use the same number on each router, or each router can have a different number-it just doesn’t matter. The numbers you can use are from 1 to 65,535. Don’t get this confused with area numbers, which can be from 0 to 4.2 billion.

CISCO CCNA Exam – Q249

Which statement is correct regarding the operation of DHCP?

A. A DHCP client uses a ping to detect address conflicts.
B. A DHCP server uses a gratuitous ARP to detect DHCP clients.
C. A DHCP client uses a gratuitous ARP to detect a DHCP server.
D. If an address conflict is detected, the address is removed from the pool and an administrator must resolve the conflict.
E. If an address conflict is detected, the address is removed from the pool for an amount of time configurable by the administrator.
F. If an address conflict is detected, the address is removed from the pool and will not be reused until the server is rebooted.

Correct Answer: D

Explanation:
An address conflict occurs when two hosts use the same IP address. During address assignment, DHCP checks for conflicts using ping and gratuitous ARP. If a conflict is detected, the address is removed from the pool. The address will not be assigned until the administrator resolves the conflict.