Tag: Cisco Certified Network Associate (200-301 CCNA)

Cisco Certified Network Associate (200-301 CCNA) – Question531

Which two actions are performed by the Weighted Random Early Detection mechanism? (Choose two.)

A. It supports protocol discovery.
B. It guarantees the delivery of high-priority packets.
C. It can identify different flows with a high level of granularity.
D. It can mitigate congestion by preventing the queue from filling up.
E. It drops lower-priority packets before it drops higher-priority packets.

Correct Answer: DE

Explanation:

Explanation:
Weighted Random Early Detection (WRED) is just a congestion avoidance mechanism. WRED drops packets selectively based on IP precedence. Edge routers assign IP precedences to packets as they enter the network.
When a packet arrives, the following events occur:
1. The average queue size is calculated.
2. If the average is less than the minimum queue threshold, the arriving packet is queued.
3. If the average is between the minimum queue threshold for that type of traffic and the maximum threshold for the interface, the packet is either dropped or queued, depending on the packet drop probability for that type of traffic.
4. If the average queue size is greater than the maximum threshold, the packet is dropped.
WRED reduces the chances of tail drop (when the queue is full, the packet is dropped) by selectively dropping packets when the output interface begins to show signs of congestion (thus it can mitigate congestion by preventing the queue from filling up). By dropping some packets early rather than waiting until the queue is full, WRED avoids dropping large numbers of packets at once and minimizes the chances of global synchronization. Thus, WRED allows the transmission line to be used fully at all times.
WRED generally drops packets selectively based on IP precedence. Packets with a higher IP precedence are less likely to be dropped than packets with a lower precedence. Thus, the higher the priority of a packet, the higher the probability that the packet will be delivered.
Reference:
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/qos_conavd/config…

Cisco Certified Network Associate (200-301 CCNA) – Question530


Refer to the exhibit. An engineer deploys a topology in which R1 obtains its IP configuration from DHCP. If the switch and DHCP server configurations are complete and correct, which two sets of commands must be configured on R1 and R2 to complete the task? (Choose two.)

A. R1(config)# interface fa0/0
R1(config-if)# ip helper-address 198.51.100.100
B. R2(config)# interface gi0/0
R2(config-if)# ip helper-address 198.51.100.100
C. R1(config)# interface fa0/0
R1(config-if)# ip address dhcp
R1(config-if)# no shutdown
D. R2(config)# interface gi0/0
R2(config-if)# ip address dhcp
E. R1(config)# interface fa0/0
R1(config-if)# ip helper-address 192.0.2.2

Correct Answer: BC

Cisco Certified Network Associate (200-301 CCNA) – Question527

What are two roles of the Dynamic Host Configuration Protocol (DHCP)? (Choose two.)

A. The DHCP server assigns IP addresses without requiring the client to renew them.
B. The DHCP server leases client IP addresses dynamically.
C. The DHCP client is able to request up to four DNS server addresses.
D. The DHCP server offers the ability to exclude specific IP addresses from a pool of IP addresses.
E. The DHCP client maintains a pool of IP addresses it is able to assign.

Correct Answer: BD

Cisco Certified Network Associate (200-301 CCNA) – Question526

Which function does an SNMP agent perform?

A. It sends information about MIB variables in response to requests from the NMS
B. It manages routing between Layer 3 devices in a network
C. It coordinates user authentication between a network device and a TACACS+ or RADIUS server
D. It requests information from remote network nodes about catastrophic system events

Correct Answer: A

Cisco Certified Network Associate (200-301 CCNA) – Question525

Which command enables a router to become a DHCP client?

A. ip address dhcp
B. ip dhcp client
C. ip helper-address
D. ip dhcp pool

Correct Answer: A

Explanation:

Explanation:
If we want to get an IP address from the DHCP server on a Cisco device, we can use the command “ip address dhcp”.
Note: The command “ip helper-address” enables a router to become a DHCP Relay Agent.

Cisco Certified Network Associate (200-301 CCNA) – Question524

A network engineer must back up 20 network router configurations globally within a customer environment.
Which protocol allows the engineer to perform this function using the Cisco IOS MIB?

A. ARP
B. SNMP
C. SMTP
D. CDP

Correct Answer: B

Explanation:

Explanation:
SNMP is an application-layer protocol that provides a message format for communication between SNMP managers and agents. SNMP provides a standardized framework and a common language used for the monitoring and management of devices in a network.
The SNMP framework has three parts:
An SNMP manager
An SNMP agent
A Management Information Base (MIB)
The Management Information Base (MIB) is a virtual information storage area for network management information, which consists of collections of managed objects.
With SNMP, the network administrator can send commands to multiple routers to do the backup.