CISCO CCNA 200-301 Q150

Which of the following are classless routing protocols? (Choose four.)

A. Open Shortest Path First (OSPF)
B. Enhanced Interior Gateway Routing Protocol (EIGRP)
C. Interior Gateway Routing Protocol (IGRP)
D. Routing Information Protocol version 1 (RIPv1)
E. Border Gateway Protocol (BGP)
F. Routing Information Protocol version 2 (RIPv2)

Correct Answer: A, B, E, F

Explanation:
Open Shortest Path First (OSPF), Enhanced Interior Gateway Routing Protocol (EIGRP), Border Gateway Protocol (BGP), and Routing Information Protocol version 2 (RIPv2) are classless routing protocols.
Intermediate-System-to-Intermediate System (IS-IS) is also a classless routing protocol. The options IGRP and RIPv1 are incorrect because these are classful routing protocols.

The following are characteristics of classless routing protocols:
– The subnet mask is advertised with each route by using classless routing protocols.
– Flexible route summarization and supernetting (CIDR) are allowed in classless routing protocols.
– Classless routing protocols support variable length subnet masks (VLSM), which allow different subnets of a given IP network to be configured with different subnet masks.

One of the main advantages of using a classless routing protocol is its ability to minimize the effects of discontiguous networks. When subnets of the same classful network are separated by another classful network, the networks are called discontiguous.

Examine the diagram below:


The LAN networks extending from Router A and Router B are derived from the same Class C network, 192.168.1.0/24. A classful routing protocol such as RIP v1 would not be able to determine the direction to send the packets, but since classless protocols include the subnet mask in advertisements, they would not suffer the same problem. Whenever networks with non-default subnet masks are used, a classless routing protocol will be required.
Below are some examples of networks that do not have default masks. You can recognize them by the fact that they are not /8, /16, or /24. 192.168.10.0/27
10.5.6.0/22
172.68.0.0/18

All of the classless protocols discussed here are interior routing protocols with the exception of Border Gateway Protocol (BGP), which is an external routing protocol used to connect different autonomous systems. For example, BGP would be used to connect two OSPF autonomous systems (AS).

CISCO CCNA 200-301 Q149

You are configuring a serial link between a Cisco router and a router produced by another vendor. What would be the advantages of using Point to Point Protocol (PPP) over High Level Data Link Control (HDLC) in this scenario?

A. HDLC has a proprietary “type” field that may be incompatible with equipment from other vendors.
B. HDLC is not available on non-Cisco routers.
C. PPP is faster.
D. PPP performs error checking.

Correct Answer: A

Explanation:
High Level Data Link Control (HDLC) has a proprietary “type” field that may be incompatible with equipment from other vendors. It is recommended that PPP always be used when combining equipment from multiple vendors because this Data Link layer WAN protocol is an industry standard. PPP is implemented in the same manner on all PPP-capable equipment.

HDLC is available on non-Cisco routers. However, the Cisco implementation has a “type” field that may prevent the connection from working. PPP is not faster than HDLC.

PPP performs error checking, but so does HDLC.

CISCO CCNA 200-301 Q148

Which of the following are NOT valid IPv6 addresses? (Choose all that apply.)

A. 225.1.4.2
B. ::FFFF:10.2.4.1
C. ::
D. 2001:0:42:3:ff::1
E. fe80:2030:31:24
F. 2001:42:4:0:0:1:34:0
G. 2003:dead:beef:4dad:ab33:46:abab:62

Correct Answer: A, E

Explanation:
The addresses 255.1.4.2 and fe80:2030:31:24 are not valid IPv6 addresses.

225.1.4.2 is incorrect because it is an IPv4 multicast address. The address fe80:2030:31:24 is incorrect because it does not represent a 16-byte IPv6 address, with colons separating each 2-byte segment.

IPv6 addresses are 16 bytes, or 128 bits in length. The following are valid IPv6 addresses.

::FFFF:10.2.4.1 is an example of an IPv4-compatible IPv6 address, where the first 10 bytes (80 bits) of the address are set to 0 the next 2 bytes (16 bits) are set to FFFF and the last 32 bits are the IPv4 address

:: is the IPv6 “unspecified address.” It is a unicast address not assigned to any interface, and is used by a DHCP-dependent host prior to allocating a real IPv6 address.

2001:0:42:3:ff::1 is a valid IP address, with the :: representing two segments (4 bytes) of compressed zeros.

2001:42:4:0:0:1:34:0 is a valid IP address, with only the leading zeros of each segment truncated.

2003:dead:beef:4dad:ab33:46:abab:62 has 16 bytes, is divided correctly by colons into eight sections, utilizes the dropping of leading zeros in each section correctly, and uses the letters a-f in the three section that spell out dead beef 4 dad.

CISCO CCNA 200-301 Q147

Given the following output, which statements can be determined to be true? (Choose three.)

RouterA2# show ip ospf neighbor

Neighbor ID Pri State Dead Time Address Interface 192.168.23.2 1 FULL/BDR 00:00:29 10.24.4.2 FastEthernet1/0
192.168.45.2 2 FULL/BDR 00:00:24 10.1.0.5 FastEthernet0/0
192.168.85.1 1 FULL/- 00:00:33 10.6.4.10 Serial0/1
192.168.90.3 1 FULL/DR 00:00:32 10.5.5.2 FastEthernet0/1
192.168.67.3 1 FULL/DR 00:00:20 10.4.9.20 FastEthernet0/2
192.168.90.1 1 FULL/BDR 00:00:23 10.5.5.4 FastEthernet0/1
<<output omitted> >

A. This router is the DR for subnet 10.1.0.0.
B. The DR for the network connected to Fa0/0 has an interface priority greater than 2.
C. The DR for the network connected to Fa0/1 has a router ID of 10.5.5.2.
D. The DR for the serial subnet is 192.168.85.1.
E. This router is neither the DR nor the BDR for the Fa0/1 subnet.
F. RouterA2 is connected to more than one multi-access network.

Correct Answer: B, E, F

Explanation:
The show ip ospf neighbor command displays a list of all OSPF routers with which you have established a neighbor relationship. The following describes the command output:

– Neighbor ID: the Router ID (RID) of the neighboring router
– Pri: the interface priority of the neighboring router, which is used to determine which router should serve the function of a Designated Router (DR)
– State: the functional state of the neighboring router
– Dead Time: the period that the router will wait to hear a Hello packet from this neighbor before declaring the neighbor down
– Address: the IP address of the neighboring router on this subnet
– Interface: the local interface over which the neighbor relationship (adjacency) was formed

The output for neighbor 192.168.45.2 is as follows:

192.168.45.2 2 FULL/BDR 00:00:24 10.1.0.5 FastEthernet0/0

This indicates that the interface priority of neighbor 192.168.45.2 is 2. The default OSPF interface priority is 1, and the highest interface priority determines the designated router (DR) for a subnet. This same line reveals that this neighbor is currently the backup designated router (BDR) for this segment, which indicates that another router became the DR. It can be then be assumed that the DR router has an interface priority higher than 2. (The router serving the DR function is not present in the truncated sample output.)

The output for the two neighbors discovered on F0/1 is as follows:

192.168.90.3 1 FULL/DR 00:00:32 10.5.5.2 FastEthernet0/1
192.168.90.1 1 FULL/BDR 00:00:23 10.5.5.4 FastEthernet0/1

This output indicates that router 192.168.90.3 is the DR, and router 192.168.90.1 is the BDR for this network. Since there can only be one DR and BDR per segment, this indicates that the local router is neither the DR nor the BDR. (OSPF considers these DROther routers.)

The fact that multiple DRs are listed in this output indicates that RouterA2 is connected to more than one multi-access segment, since each segment will elect a DR.

It cannot be determined if this router is the DR for subnet 10.1.0.0. The output indicates that router 192.168.45.2 is the BDR for this network, but with the truncated output, it cannot be determined if this router is the DR.

The DR for the network connected to Fa0/1 does not have a router ID of 10.5.5.2. The Address field of the show ip ospf neighbor command indicates the IP address of the neighbor’s interface, not the router ID of the neighbor.

The DR for the serial subnet is not 192.168.85.1, since point-to-point serial interfaces do not elect DRs and BDRs. This is indicated by the output below:

192.168.85.1 1 FULL/- 00:00:33 10.6.4.10 Serial0/1

CISCO CCNA 200-301 Q146

Which of the following are Wide Area Network (WAN) protocols? (Choose three.)

A. PPP
B. AAA
C. WEP
D. STP
E. HDLC
F. Frame Relay

Correct Answer: A, E, F

Explanation:
Point-to-Point Protocol (PPP), High-Level Data Link Control (HDLC), and Frame Relay are WAN protocols.

PPP is a WAN protocol is defined in Request for Comments (RFCs) 1332, 1661, and 2153. PPP works with asynchronous and synchronous serial interfaces as well as High-Speed Serial Interfaces (HSSI) and Integrated Services Digital Network (ISDN) interfaces (BRI and PRI).

Some of the characteristics of PPP are:
– Can be used over analog circuits
– Can encapsulate several routed protocols, such as TCP/IP Provides error correction
– Should be used rather than HDLC when non-Cisco routers are involved, as it is implemented consistently among vendors PPP authentication can be used between the routers to prevent unauthorized callers from establishing an ISDN circuit

To change the encapsulation from the default of HDLC to PPP when connecting to a non-Cisco router, such as a Juniper, you would use the following command:

router(config)#interface serial S0 router(config-if)#encapsulation ppp

HDLC is a WAN protocol used with synchronous and asynchronous connections. It defines the frame type and interaction between two devices at the Data Link layer.

Frame Relay is a group of WAN protocols, including those from International Telecommunication Union (ITU-T) and American National Standards Institute (ANSI). Frame Relay defines interaction between the Frame Relay customer premises equipment (CPE) and the Frame Relay carrier switch. The connection across the carrier’s network is not defined by the Frame Relay standards. Most carriers, however, use Asynchronous Transfer Mode (ATM) as a transport to move Frame Relay frames between different sites.

Authentication, Authorization, and Accounting (AAA) is incorrect because this is a scheme to monitor access control and activities on networked devices. Wired Equivalent Privacy (WEP) is a security scheme for wireless networks and therefore it is incorrect.

Spanning Tree Protocol (STP) is for loop avoidance in redundant topologies. This option is incorrect because this protocol is used on Local Area Network (LAN).

CISCO CCNA 200-301 Q145

Which statement is supported by the following output?

router# show ip protocols Routing Protocol is “eigrp 3”
Sending updates every 90 seconds, next due in 24 seconds
<<some output omitted> >
EIGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0
EIGRP maximum hopcount 100 EIGRP maximum metric variance 1 Redistributing: eigrp 3
Automatic network summarization is not in effect Maximum path: 4
Routing for Networks:
172.160.72.0
192.168.14.0
<<some output omitted> >

A. EIGRP supports load-balancing over three equal-cost paths
B. EIGRP supports load-balancing over three unequal-cost paths
C. EIGRP supports load-balancing over four equal-cost paths
D. EIGRP supports load-balancing over four unequal-cost paths

Correct Answer: C

Explanation:
The Maximum path: 4 output indicates that Enhanced Interior Gateway Routing Protocol (EIGRP) will support round-robin load-balancing over four equal-cost paths. This is a default setting, and is a true statement for most routing protocols (including RIP, OSPF and IS-IS). Equal-cost paths are different routes to the same destination network with identical metrics, as determined by the routing protocol. Most routing protocols allow this maximum to be raised up to 16 with the maximum-paths command.

EIGRP has the additional benefit of allowing unequal cost load-balancing. With unequal cost load-balancing, the router can be configured to include less desirable (higher-metric) paths in the routing table. The router will then send a balanced percentage of traffic over both the best route and the less desirable paths, such as sending two packets over the best path plus one over a less desirable path. EIGRP will never perform unequal-cost load-balancing by default; it must be configured with a variance command. Therefore, you cannot state that EIGRP supports load-balancing over unequal-cost paths in this example.

You cannot state that EIGRP will support load-balancing over three paths because the output displays the Maximum path: 4 value.

CISCO CCNA 200-301 Q144

Which type of switching process requires a switch to wait for the entire frame to be received before forwarding it to a destination port?

A. store and forward
B. cut-through
C. fragment free
D. frame-forward

Correct Answer:

Explanation:
The store and forward switching process requires a switch to wait until the entire frame is received before forwarding it to a destination port. The store and forward method increases latency as it buffers the entire frame and runs a Frame Check Sequence (FCS) before forwarding it to destination port. However, it ensures error- free frame forwarding because its filters all frame errors.

The cut-through switching process does NOT require a switch to verify the FCS in a frame before forwarding it to the destination port. This type of internal switching method is faster than the store and forward process, but may forward error frames.

The fragment-free switching process only waits to receive the first 64 bytes of the frame before forwarding it the destination port. Fragment-free internal switching assumes that if there is no error in the first 64 bytes of the data, the frame is error free. The assumption is based on the fact that if a frame suffers a collision, it occurs within the first 64 bytes of data. Fragment-free forwarding speed lies between that of store and forward and cut-through.

The term frame-forward is not a valid internal switching process for Cisco

CISCO CCNA 200-301 Q143

Which type of Dynamic Host Configuration Protocol (DHCP) transmission is used by a host to forward a DHCPDISCOVER packet to locate a DHCP server on the network?

A. unicast
B. broadcast
C. multicast
D. anycast

Correct Answer: B

Explanation:
Hosts broadcast DHCPDISCOVER messages to locate a DHCP server. The following steps are followed during the allocation of the IP address dynamically using a DHCP server:

– The client device broadcasts a DHCPDISCOVER message to locate a DHCP server.
– The DHCP server replies with a DHCPOFFER unicast message with configuration parameters, such as an IP address, a MAC address, a domain name, and a lease for the IP address for the client device.
– The client returns a DHCPREQUEST broadcast, which is a formal request for the offered IP address to the DHCP server.
– The DHCP server replies to client device with DHCPACK unicast message, acknowledging the allocation of the IP address to this client device.

Dynamic Host Configuration Protocol (DHCP) is an enhancement over Bootstrap Protocol (BOOTP) and is used to automate the distribution of IP address to clients from a central server. BOOTP protocol was also used to distribute IP addresses, but was inflexible to changes in the network.

DHCP offers the following three advantages that also addressed the inflexibility of the BOOTP protocol:
– Automatic allocation of permanent IP addresses
– Automatic allocation of time bound (leased) IP addresses
– Provision of assigning static IP address or defining a pool of reserved IP address DHCP does not use multicast messages.

Anycast is a concept of IPv6 protocol and is not valid type used by DHCP.

CISCO CCNA 200-301 Q142

Which Cisco command will display the version and configuration data for Secure Shell (SSH)?

A. show ssh
B. show ip ssh
C. debug ssh
D. debug ip ssh

Correct Answer: B

Explanation:
The show ip ssh command is used to display the version and configuration data for SSH on a Cisco router. The following is sample output of the show ip ssh command:

router#show ip ssh
SSH Enabled – version 1.5
Authentication timeout: 120 secs; Authentication retries: 2

This show ip ssh command output displays the enabled status of the SSH protocol, the retries parameter (configured at two attempts), and the timeout of 120 seconds.

The following message will appear when the show ip ssh command is issued and SSH has been disabled:

router# show ip ssh
%SSH has not been enabled

To enable SSH include the transport input SSH command when configuring authentication on a line. For example, the configuration of a Cisco network device to use SSH on incoming communications via the virtual terminal ports, with a specified password as shown from the partial output of the show run command is shown below:

line vty 0 4
password 7 030752180500 login
transport input ssh

It is important to note the login command on the third line of the above ouput is critical for security. This command instructs the device to prompt for a username and password using SSH. If this line reads no login, SSH might be otherwise be correctly configured, but the device will never prompt for the username and password.

The debug ip ssh command is used to display debug messages for SSH.

The debug ssh command is not a valid Cisco command.

CISCO CCNA 200-301 Q141

You are the network administrator for your company. You want to use both IPv6 and IPv4 applications in the network. You also want to ensure that routers can route both IPv6 and IPv4 packets.

Which deployment model should be implemented to accomplish the task?

A. IPv6 over IPv4 tunnels
B. IPv6 over dedicated Wide Area Network (WAN) links
C. Dual-Stack Backbones
D. Protocol translation

Correct Answer: C

Explanation:
A dual-stack backbone deployment model should be used to accomplish the task in this scenario. When routers route both IPv6 and IPv4 packets, it is called dual stack routing or a dual-stack backbone.

The following deployment models are available for IPv4 to IPv6 migration:

– IPv6 over IPv4 tunnels: IPv6 traffic is encapsulated into IPv4 packets. Then these packets are transferred over an IPv4 WAN. This model eliminates the need to create separate circuits to connect to the IPv6 networks. This model increases protocol overhead because of the IPv6 headers and requires one end to be capable of both protocols

– Protocol translation: A translation method of allowing an IPv6 host to communicate with an IPv4 host. This is accomplished with the help of Network Address Translation – Protocol Translation (NAT-PT) used to configure translation between IPv6 and IPv4 hosts. NAT-PT allows communication between IPv6 hosts and applications, and native IPv4 hosts and applications.

– IPv6 over dedicated WAN links: A new deployment of IPv6 is created. In this model, IPv6 hierarchy, addressing, and protocols are used by all nodes. However, this model involves cost for creating IPv6 WAN circuits. This solution is not designed for LAN translation but rather translation over WAN links.

– Dual-Stack Backbones: A hybrid model in which backbone routers have dual-stack functionality, which enables them to route both IPv4 and IPv6 packets. It is suitable for an enterprise that uses both IPv4 and IPv6 applications. Running IPv6 and IPv4 together in a network is known as dual-stack routing.