Chapter 3 Exam Essentials Flashcards
Differentiate between the DoD and the OSI network models.
The DoD model is a condensed version of the OSI model, composed of four layers instead of seven, but is nonetheless like the OSI model in that it can be used to describe packet creation and devices and protocols can be mapped to its layers.
Identify Process/Application layer protocols
Telnet is a terminal emulation program that allows you to log into a remote host and run programs. File Transfer Protocol (FTP) is a connection-oriented service that allows you to transfer files. Trivial FTP (TFTP) is a connectionless file transfer program. Simple Mail Transfer Protocol (SMTP) is a sendmail program.
Identify Host-to-Host layer protocols
Transmission Control Protocol (TCP) is a connection-oriented protocol that provides reliable network service by using acknowledgments and flow control. User Datagram Protocol (UDP) is a connectionless protocol that provides low overhead and is considered unreliable.
Identify Internet layer protocols.
Internet Protocol (IP) is a connectionless protocol that provides network address and routing through an internetwork. Address Resolution Protocol (ARP) finds a hardware address from a known IP address. Reverse ARP (RARP) finds an IP address from a known hardware address. Internet Control Message Protocol (ICMP) provides diagnostics and destination unreachable messages.
Describe the functions of DNS and DHCP in the network
Dynamic Host Configuration Protocol (DHCP) provides network configuration information (including IP addresses) to hosts, eliminating the need to perform the configurations manually. Domain Name Service (DNS) resolves hostnames—both Internet names such as www.lammle.com and device names such as Workstation 2—to IP addresses, eliminating the need to know the IP address of a device for connection purposes.
Identify what is contained in the TCP header of a connection-oriented transmission.
The fields in the TCP header include the source port, destination port, sequence number, acknowledgment number, header length, a field reserved for future use, code bits, window size, checksum, urgent pointer, options field, and finally, the data field.
Identify what is contained in the UDP header of a connectionless transmission
The fields in the UDP header include only the source port, destination port, length, checksum, and data. The smaller number of fields as compared to the TCP header comes at the expense of providing none of the more advanced functions of the TCP frame
Identify what is contained in the IP header.
The fields of an IP header include version, header length, priority or type of service, total length, identification, flags, fragment offset, time to live, protocol, header checksum, source IP address, destination IP address, options, and finally, data.
Compare and contrast UDP and TCP characteristics and features.
TCP is connection-oriented, acknowledged, and sequenced and has flow and error control, while UDP is connectionless, unacknowledged, and not sequenced and provides no error or flow control
Understand the role of port numbers
Port numbers are used to identify the protocol or service that is to be used in the transmission.
Identify the role of ICMP
Internet Control Message Protocol (ICMP) works at the Network layer and is used by IP for many different services.
It is used by network devices, including routers, to send error messages and operational information indicating, for example, that a requested service is not available or that a host or router could not be reached.
Define the Class A IP address range
The IP range for a Class A network is 1–126. This provides 8 bits of network addressing and 24 bits of host addressing by default.
Define the Class B IP address range
The IP range for a Class B network is 128–191. Class B addressing provides 16 bits of network addressing and 16 bits of host addressing by default.
Define the Class C IP address range.
The IP range for a Class C network is 192 through 223. Class C addressing provides 24 bits of network addressing and 8 bits of host addressing by default.
Identify the private IP ranges. What are private IP addresses?
The Class A private address range is 10.0.0.0 through 10.255.255.255. The Class B private address range is 172.16.0.0 through 172.31.255.255. The Class C private address range is 192.168.0.0 through 192.168.255.255.
Instead of having devices inside a home or business network each use a public IP address, of which there’s a limited supply, private IP addresses provide an entirely separate set of addresses that still allow access on a network but without taking up a public IP address space.
