Section 4: Understanding TCP/IP

Convert the binary number 01100100 to decimal.

100.

Convert the decimal number 167 to binary.

10100111

An IP address is a hierarchical address that consists of what two parts?

Network ID: Describes the network to which the IP address or device belongs Host ID: The ID that identifies a specific host

What are the five types of reserved IPv4 addresses?

Network address: The address of the network is an IP address that has binary 0s in all the host bit positions. Direct broadcast address: An address for each network that allows communication to all hosts on a network. The direct broadcast address has all 1s in the host bit positions. Local broadcast address: Used to allow hosts to communicate with all hosts on a local network. The address used is 255.255.255.255. Local loopback address: Used to let the system send a message to itself for testing. This address is 127.0.0.1. All zeros address: Used to indicate hosts in "this" network and used only as a source address.

What does RFC 1918 define?

RFC 1918 defines reserved (private) networks and addresses that are not routed on the Internet. These addresses are as follows: 10.0.0.0 to 10.255.255.255 172.16.0.0 to 172.31.255.255 192.168.0.0 to 192.168.255.255

What does route aggregation mean when referring to VLSM?

Route aggregation means combining routes to multiple networks into one larger IP network or aggregated IP subnets within the class rules.

In a default Class A network, how many octets are used for host addresses?

Three octets are used for host addresses. One octet consists of 8 bits; thus a default Class A network uses 24 bits for host addresses. The maximum number of hosts a Class A network can have is 16,777,214 (224 - 2).

What two common protocols function at the transport layer of the TCP/IP model?

Two protocols that function at the transport layer of the TCP/IP model are as follows: TCP (Transmission Control Protocol): A connection-oriented, reliable protocol UDP (User Datagram Protocol): A connectionless and unacknowledged protocol

What are the benefits of variable-length subnet masking (VLSM)?

VLSM gives a network administrator the option of including more than one subnet mask within a network and of subnetting an already subnetted network address. VLSM benefits include: More efficient use of IP addresses: Without VLSM, companies must implement a single subnet mask within an entire Class A, B, or C network number. Better-defined network hierarchical levels: VLSM allows more hierarchical levels within an addressing plan and allows aggregation of network addresses.

How many hosts are available for use in a default Class C network?

254 hosts are available.A default Class C network uses 8 bits for host addresses. Thus 28 - 2 = 254.

How many usable IP addresses are provided in a default Class C network address?

254 usable IP addresses are provided. The formula to calculate usable IP addresses is 2n-2, where n is the number of host bits.

What is an IP address used for?

An IP address uniquely identifies a device on an IP network.

What is the role of the subnet mask in an IP network?

The subnet mask identifies the network and host portion of an IP address. It is used by hosts to identify the destination IP address as either local or remote and is also used by routers to determine the path to route packets.

What functions does the transport layer perform?

The transport layer performs the following functions: Session multiplexing Identification of different applications Segmentation Flow control Connection-oriented Reliability

What is the Internet Protocol (IP)?

-IP is a connectionless protocol that provides best-effort delivery and routing of packets. -IP has the following characteristics: Operates at Layer 3 (network) of the Open Systems Interconnection (OSI) reference model and the Internet layer of the TCP/IP (Internet) model. -Is connectionless, providing best-effort delivery of packets. Uses hierarchical addressing. -Has no built-in data recovery. Each packet is treated independently; thus each packet can travel a different way to its destination. -Operates independently of the medium that is carrying the data.

Convert the binary number 0101011011000010 to hexadecimal.

0x56C2

What is special about IP address 127.0.0.1?

127.0.0.1 is the loopback address.The loopback address is used to test the proper installation of the IP stack.

How many hosts are available for use in a default Class B network?

65,534 addresses are available.A default Class B network uses 16 bits for host addresses; thus 216 - 2 = 65,534.

What are the different classes of IP addressing and the address ranges of each class?

Class A: 1.0.0.0 to 126.255.255.255 Class B: 128.0.0.0 to 191.255.255.255 Class C: 192.0.0.0 to 223.255.255.255 Class D: 224.0.0.0 to 239.255.255.255 (Multicasting) Class E: 240.0.0.0 to 255.255.255.254 (Reserved)

What is CIDR?

Classless interdomain routing (CIDR) is an addressing scheme for the Internet that allows more efficient use of IP addresses than the old Class A, B, and C scheme. It is more flexible and offers route aggregation (supernetting). A CIDR address is a network address that does not use original Class A, B, and C rules. For example, a CIDR address can look like this: 192.168.2.0/29.

How many bits are in an IPv4 address? In an IPv6 address?

IPv4: 32 bits IPv6: 128 bits

A host computer has been correctly configured with a static IP address, but the default gateway is incorrect. Which layer of the OSI model is first affected by this misconfiguration?

Layer 3 is affected first.The default gateway sends IP packets to a remote network and functions at Layer 3 of the OSI model.

What is the correct network address for host 192.168.10.72/26?

The correct network address is 192.168.10.64. A quick way to find the network of a given subnet mask is to subtract the last portion of the subnet mask from 256. In this case, 256 - 192 = 64

What is the purpose of the default gateway?

The default gateway allows hosts to communicate with hosts that are on a different network segment.All data that is not destined for the same network of the sending device is sent to the default gateway for delivery.

If an IP addressed device wants to communicate with all devices on the local network, what is the destination IP address of its broadcast?

The destination IP address is 255.255.255.255.This address is also called the local broadcast address.

What is the range of binary values for the first octet in Class B addresses?

The first octet for a Class B IP address is 128-191 in decimal, which is 10000000-10111111 in binary.If you see similar questions on the ICND 1 exam, remember the following: Class A addresses always have the high-order bit as 0. For example, 0xxxxxxx. Class B addresses always have the high-order bit as 1 and the second bit as 0. For example, 10xxxxxx. Class C addresses always have the high-order bit and second bit as 1. The third bit is 0. For example,110xxxxx.

As a network administrator, you have a Class B address. Assuming that the ip subnet zero command is enabled on the router, what subnet mask allows you to have 100 subnetworks with at least 500 usable hosts?

The subnet mask is 255.255.254.0. 255.255.254.0 in binary is as follows:11111111.11111111.11111110.00000000 All you care about are the last two octets. So you have 7 bits for the network and 9 bits for host addresses. Seven bits of subnetting provide 128 subnets, and 9 bits of host subnetting provide 510 hosts per subnet.

Your Internet provider has given you the IP network address of 172.16.0.0/16. You have 18 networks, each with 1200 hosts. You want to assign one IP range per subnet, leaving room for future growth. Assuming that the ip subnet zero command is enabled on all routers, what subnet mask would best achieve your goals?

The subnet mask of 255.255.248.0 would best achieve your goals. If you look at this subnet mask in binary, you can see that you have 5 subnet bits for the network address:11111111.11111111.11111000.00000000If you use the subnet equation 25 = 32, 32 available networks will be provided with the subnet mask, which fulfills the requirement for 18 networks and allows adequate growth. This leaves you with 11 bits to be assigned to hosts. This gives you 2046 (211 - 2) addresses, giving you more than enough IP addresses to be assigned to hosts. If you use a subnet mask of 255.255.240.0, you will meet the requirement of 1200 hosts (212 - 2 = 4094 available hosts) but not have enough networks (24 = 16 available networks).

How many usable subnets and usable hosts do you have if you subnet the network address 192.168.1.0 with the subnet mask 255.255.255.240?

You have 16 subnets with 14 hosts in each network. You can apply these bits to the following formula, where x is the amount of borrowed bits:Amount of subnets = 2xAmount of hosts = 2x - 2Therefore, 24 - 2 = 14 subnets.