Cisco 100-490 Practice Test - Questions Answers, Page 3

The correct IPv6 address notation follows the format of eight groups of four hexadecimal digits, separated by colons. The address must have exactly eight groups unless it uses the double colon (::) to represent consecutive groups of zero value. The double colon can only appear once in an address to avoid ambiguity.

Option A is incorrect because it includes a subnet mask (/128) which is not part of the actual address notation. Option B is incomplete as it does not contain enough groups and ends with a single colon. Option C has too many groups (nine instead of eight) and is therefore not a valid IPv6 address. Option D is the correct notation with eight groups of four hexadecimal digits, where necessary leading zeros are included.

IPv6 Address Types, Notation, and Structure Explained1.

IPv6 address formats - IBM2. =========================

The Cisco Nexus 3432D-S and Cisco Nexus 3408-S are part of the Cisco Nexus 3400 Series switches that support 400-Gbps Ethernet ports. The Cisco Nexus 3432D-S is designed with 32 ports of 400G, providing high-density and high-throughput capabilities1. The Cisco Nexus 3408-S offers flexibility with 100G or 400G Line-Card Expansion Modules (LEMs), allowing for configurations with 32 ports of 400G2. These switches are engineered for data centers requiring high performance, low latency, and power efficiency, with the Cisco Nexus 3432D-S offering industry-leading performance-per-watt power efficiency at low latency1.

NVRAM (Non-Volatile Random Access Memory) is the default storage location for the startup configuration file of a Cisco router or switch.expand_more Here's why:

Non-Volatility: NVRAM retains its contents even when the device loses power.expand_more This is essential for storing the startup configuration, which contains critical settings like interface configurations, routing protocols, and passwords.

Read/Write Capability: Unlike ROM, NVRAM allows you to both read and write data. This makes it possible to modify the configuration and save the changes into NVRAM as the startup configuration.

Other Memory Types and Their Functions:

RAM (Random Access Memory): RAM is volatile memory, meaning it loses its contents when the device is powered off.expand_more It's used to store the running configuration (currently active configuration), routing tables, and other temporary data required for the device's operation.

ROM (Read-Only Memory): ROM is non-volatile and stores the bootstrap program used to initiate the boot process of the device.expand_more It's not modifiable by the user.expand_more

Flash: Flash memory is also non-volatile.expand_more It's primarily used to store the Cisco IOS image (operating system) and can also store backup configuration files and other data.

The commands that can be used to identify the serial number of a Cisco router are show inventory and show version. The show inventory command provides detailed information about the hardware inventory, including the serial numbers of the device and its components1. The show version command displays the router's configuration, including the version of the operating system, the last reboot reason, and the hardware serial number, which is listed as the ''Processor board ID'' in the command output2. These commands are essential for network administrators to document and manage network equipment.

Topic 3, Cisco IOS Software Operation

The configuration register on Cisco routers and switches controls specific bootup behaviors. Here's how to modify it:

1. In ROMmon Mode:

rommon>confreg 0x2102 : This command is used when the device is in ROMmon mode (a basic operating system loaded when the full Cisco IOS cannot be found). ROMmon offers limited functionality and is often used for troubleshooting or password recovery.

2. In Global Configuration Mode:

router(config)#config-register 0x2102 : This command is used from within the Cisco IOS itself when you have normal access to the router. You would enter privileged EXEC mode and then global configuration mode to use it.

Importance of Configuration Register Settings:

The most common reasons to modify the configuration register are:

Password Recovery: Setting the configuration register to 0x2142 tells the router to ignore the startup configuration (stored in NVRAM), allowing you to bypass password protection.

Changing Boot Behavior: Settings can control the boot sequence, such as specifying where the Cisco IOS image should be loaded from.

Cisco Configuration Register: https://www.cisco.com/c/en/us/support/docs/routers/10000-series-routers/50421-config-register-use.html

Understanding the Configuration Register (Cisco): https://networklessons.com/cisco/ccna-routing-switching-icnd1-100-105/configuration-register-cisco-ios

A . Correct. SSH, or Secure Shell, is indeed a protocol that provides a secure remote access connection to network devices. It encrypts the data to ensure secure transmission over insecure networks like the internet1.

C . Correct. Telnet connections are not secure and are terminated when a router reboots. This is because Telnet does not have any mechanism to maintain the connection in case of network interruptions or device reboots1.

B, D, and E are incorrect because: B. SSH uses TCP port 22 by default, not port 23, which is used by Telnet1. D . Telnet does not provide a secure connection; it transmits data in plain text, which can be intercepted easily1. E. SSH is preferred over Telnet for security reasons because it provides encrypted connections and authentication mechanisms, which Telnet does not1.

Reference := 1: GeeksforGeeks - Difference between SSH and Telnet 2: phoenixNAP - Telnet vs. SSH: How Is SSH Different From Telnet? 3: Guru99 - Telnet vs SSH -- Difference Between Them 4: Difference Between - Difference Between Telnet and SSH

The address that facilitates the routing of packets over an IP network is the network address. In the context of IP networking, this refers to the IP address, which is used to identify each host on a network and to determine the best path for data packets to travel from their source to their destination. Routers use IP addresses to make decisions about where to forward packets so that they reach the correct destination. The network layer of the OSI model, where IP operates, is responsible for this routing process123.

The other options listed do not facilitate routing in the same way:

Physical (A) and MAC (D) addresses are used at the data link layer to deliver packets on the same local network.

Transport (B) refers to the transport layer, which is responsible for end-to-end communication and data flow control but does not route packets over an IP network.

IPv4 addresses consist of four octets, each ranging from 0 to 255. The addresses are used to uniquely identify devices on a network.

A . 255.255.255.255 is reserved for broadcast messages to all hosts on the local network, so it cannot be assigned to a single host.

B . 10.1.1.20 falls within the range of private IP addresses (10.0.0.0 to 10.255.255.255) and can be assigned to a host within a private network.

C . 0.0.0.0 is used to denote an unknown or non-applicable target address, often used as a default route, and cannot be assigned to a host.

D . 192.168.10.15 is also within the range of private IP addresses (192.168.0.0 to 192.168.255.255) and can be assigned to a host within a private network.

E . 292.10.3.4 is not a valid IPv4 address because the first octet exceeds the maximum value of 255.

IPv4 Addressing

Valid IP Address

IP Address Validation

A Wide Area Network (WAN) connection typically involves several components that work together to enable data communication over large distances. Two key components of a WAN connection are:

CSU/DSU (Channel Service Unit/Data Service Unit): This device acts as a gateway between the local area network (LAN) and the WAN.It converts the digital signals used in the LAN to the signals used in the WAN, which are often analog12.

Router: A router is used to connect multiple networks together and direct data traffic.In the context of a WAN, routers are responsible for determining the best path for data to travel across the network12.