ICT169 - mid sem - final

Which two options are improvements provided by IPv6 as compared to IPv4? (Choose two.)

• Standardizes the use of NAT

• Uses a simpler header to provide improved packet handling

• Header supports additional fields for complex packets

• Increased IP address space

Answer explanation

B. Uses a simpler header to provide improved packet handling:

IPv6 simplifies the header structure compared to IPv4. Headers have a fixed size, making them more predictable and efficient. Eliminates some of the complexity and variable header lengths found in IPv4 headers. This

simplification improves packet handling efficiency and routing performance.

C. Header supports additional fields for complex packets:

While IPv6 simplifies the core header, it also introduces a mechanism for adding optional extension headers. Extension headers allow IPv6 to support additional functionality when needed, such as fragmentation, security, or routing. This flexibility enables IPv6 to handle complex packet processing scenarios while maintaining a streamlined core header.

Which devices will not forward an IPv4 broadcast packet by default?

• Router

• Ethernet switch

• Windows PC

• All devices forward IPv4 packets by default

Answer explanation

Routers are network devices responsible for forwarding packets between different network segments. By default, routers do not forward IPv4 broadcast packets from one subnet to another. They limit broadcast traffic to the local subnet.

Which subnet mask would be used if exactly 4 host bits are available?

• 255.255.255.248

• 255.255.255.126

• 255.255.255.240

• 255.255.255.224

Answer explanation

A subnet mask with 4 host bits would be represented as "/28" in CIDR notation. Here's what the subnet mask would look like in binary:

11111111.11111111.11111111.11110000

In this subnet mask, the first 28 bits are set to 1 (representing the network portion), and the last 4 bits are set to 0 (representing the host portion).

How many host bits are available for the address: 255.255.255.224

• 5

• 3

• 27

• 32

Answer explanation

The subnet mask 255.255.255.224 can be represented in binary as follows:

11111111.11111111.11111111.11100000

In this subnet mask, the first 27 bits are set to 1 (representing the network portion), and the remaining 5 bits are set to 0 (representing the host portion).

What does the IP address 172.17.4.250/24 represent?

(HINT: how many hosts are in the /24 range?)

• Network address

• Broadcast address

• Host address

• Multicast address

Answer explanation

In binary, the subnet mask "/24" would look like this: 11111111.11111111.11111111.00000000

Calculate the network address and broadcast address as follows:

• Network Address: 172.17.4.0 (The lowest address in the subnet, where all host bits are set to 0).

• Broadcast Address: 172.17.4.255 (The highest address in the subnet, where all host bits are set to 1).

So, the IP address "172.17.4.250/24" is part of a network with a range of addresses from 172.17.4.1 to 172.17.4.254 and it represents a specific host within that network.

What is an advantage of using DHCP to dynamically assign IP addresses to hosts on large networks?

• Changes to the addressing scheme require only the DHCP subnet range to be reconfigured.

• Having leased IP addresses means that there are always more addresses available than there are devices.

• Hosts can be assigned addresses from different subnets as the type network traffic changes.

• Servers are assigned an IP address only when a client requests a service.

Answer explanation

DHCP ensures that when the addressing scheme changes, only the DHCP subnet range or configuration settings on the DHCP server need to be updated.

DHCP assigns IP addresses dynamically to devices (hosts) on a network. When a device connects to the network or needs to renew its IP address lease, it can request an IP address from a DHCP server.

Along with IP addresses, DHCP provides subnet masks to devices. The subnet mask determines the network portion of the IP address and the host portion, helping devices correctly identify their local network

DHCP simplifies network administration by automating the IP address assignment process, reducing configuration errors, and providing a flexible and scalable solution for managing IP address assignments in both small and large networks.

How many broadcast domains are shown in the topology?

• Five

• Two
• Three
• Six

Answer explanation

There are three broadcast domains, one on each side of the router.

Routers, unlike switches, do not forward broadcast traffic. When H2 sends that broadcast frame, it will be forwarded by SW2 to R1 but that’s it.

Is there any option to create multiple broadcast domains on a switch?

There sure is, it can be done with VLANs (Virtual LAN).

What identifier is used at the data link layer to uniquely identify an Ethernet device?

• MAC address

• TCP port number

• IP address

• sequence number

Answer explanation

At the data link layer, an Ethernet device is uniquely identified by its MAC (Media Access Control) address.

The MAC address, often referred to as the hardware address or Ethernet address, is a globally unique identifier assigned to every Ethernet network interface card (NIC) or network adapter.

It is a 48-bit (6-byte) address typically represented as a sequence of hexadecimal digits, separated by colons or hyphens, such as "00:1A:2B:3C:4D:5E."

What is one function of the ARP protocol?

• resolving an IPv4 address to a MAC address

• maintaining a table of domain names with their resolved IP addresses

• mapping a domain name to its IP address

• obtaining an IPv4 address automatically

Answer explanation

If your network is using the IPv4 communications protocol, the Address Resolution Protocol, or ARP, is what you need to map IPv4 addresses to MAC addresses.

Every IP device on an Ethernet network has a unique Ethernet MAC address. When a device sends an Ethernet Layer 2 frame, it contains these two addresses, Destination MAC address & Source MAC address.

One function of the ARP (Address Resolution Protocol) protocol is to map an IP address to its corresponding MAC (Media Access Control) address within a local network or subnet. ARP is used to discover and associate the hardware (MAC) address of a device with its IP address on the same local network segment.

What statement describes a characteristic of MAC addresses?

• They must be globally unique

• They are added as part of a Layer 3 PDU

• They have a 32-bit binary value

• They are only routable within a private network

Answer explanation

"MAC addresses are globally unique identifiers assigned to network interface cards (NICs) by their manufacturers."

This statement highlights a key characteristic of MAC addresses. Each MAC address is assigned by the manufacturer of the network adapter, and it should be globally unique, ensuring that no two devices on the planet should have the same MAC address. This uniqueness is essential for proper Ethernet-based communication to avoid address conflicts within a network.