3D152 Volume 2 UREs

"One bit can indicate only two possible messages. When a second bit is added, the number of possible messages increases to four (22). A further increase to 3 bits increases the possibilities to eight different choices (23). The number of bits (called X) available can have 2 to X possible combinations to represent
information. For example, a code with 8 bits (28) can represent 256 possible messages or symbols. Generally 8 bits of data refers to a unit of data transmission known as a “byte.”" Page 1-2

"Dynamic host configuration protocol (DHCP) is an automated means of assigning a unique IP address to every device on a network." Page 2-8

"The Ping utility is used to determine if a network node is connected or responding. It sends a series of Internet Control Message Protocol (ICMP) echo request messages to the target node. The results, an ICMP echo reply, identify the target node’s response and the time (delay in milliseconds) it took for the target to receive the request and respond." Page 3-17

"UDP is a connectionless transport service. In other words, UDP offers no assurance that packets will be received in the correct sequence. In fact, this protocol does not guarantee that the packets will be received at all." Page 2-6

"Media Access Control (MAC) address. This is the physical address of any device—such as the NIC in a computer—on the network. The MAC address, which is made up of two equal parts, is 6 bytes long." Page 2-11

"Establishes and maintains character synchronization prior to the message block and during transmission. Also used as time fill in the absence of control characters and data." Table on Page 1-21

"Access lists on routers are essential to performing basic protection mechanisms and defining traffic flows." Page 5-3

"A major contribution of the IEEE in the field of computer networking is Project 802; a collection of standards for local area network (LAN) architectures, protocols, and technologies. The 802 specifications define the operation of the physical network components—cabling, network adapters, and connectivity devices such as routers and switches." Page 1-5

"The trace route test is used to see the path that packets are traveling and the time (delay in milliseconds) it takes the packets to complete the trip. Each node that processes the packet responds with the IP address of its ingress (inward) network interface. The results list the IP address of the network interface of each node the packet is routed through until the packet reaches the target node. The response time (delay in milliseconds) it took for each node to respond is also displayed." Page 3-17

"a transceiver is a combination transmitter/receiver in a single package." Page 3-1

"A MAN is a network that interconnects users with computer resources in a geographic area or region larger than that covered by even a large LAN but smaller than the area covered by a WAN. The term is applied to the interconnection of networks in a city into a single larger network." Page 1-29

"The network interface card (NIC), as its name suggests, is an expansion card you install in your computer to connect, or interface, your computer to the network. The NICs can be viewed as the actual interface between workstations, servers, clients, and the shared media of the network. These devices provide the physical, electrical, and electronic connections to the network media." Page 3-1 through 3-2

"EIA/TIA 568A& B: Commercial Building Telecommunications Cabling Standard." Page 1-4

"The TDR detects impedance changes along a cable. The operation of the TDR is similar to radar. Pulses of energy are transmitted down the cable." Page 3-11

"Virtual private networks (VPN) allow the AF to extend network resources across a public shared infrastructure employing the same management policies applied to a protected network." Page 3-8

"Whereas COPs are based on characters, bit-oriented protocols (BOP) are based on bits and the position of the bits." Page 1-24

"A switch is a device that subdivides a network into smaller logical pieces, or segments." Page 3-3

"With the exception of the layers on each end, any layer in the OSI model communicates with three other OSI layers: the layer directly above it, the layer directly below it, and its peer layer in other networked devices." Page 1-16

"A WAN is a network that links LANs and MANs by using long-distance communication links that are leased or purchased from a telecommunications company. Long-distance communication links can be described as telephone lines, microwave, or satellite communications. A WAN connects networks that are typically separated by geographical distances. These distances are between two cities within a state, between two states, across a country, or around the world." Page 1-29

"A LAN is a group of computers and associated devices that share a common communications line and typically share the resources of a single processor or server within a small geographic area (for example, within an office building)." Page 1-29

"A router’s strength lies in its intelligence. Not only can routers keep track of the locations of certain nodes on the network, as switches can, but they can also determine the shortest, fastest path between two nodes." Page 3-5

"The application layer is the OSI layer closest to the end user, which means that both the OSI application layer and the user interact directly with the software application." Page 1-15

"The BGP is the routing protocol of internet backbones and is not used to route between nodes on an autonomous LAN—that is, it is used on border and exterior routers." Page 3-7

"The wire-map test configuration uses the injector for complete mapping of wiring at both ends of the cable. With the scanner and the injector connected at opposite ends of a link or cable, the correct wire map reading can be determined. The display shows the manner in which each wire is mated to the connectors at both ends of the cable. This feature helps to identify crossover and straight-through cables." Page 3-13

"A protocol analyzer provides a capability for digital network diagnostics and for developing communications software." Page 3-13

"Vulnerability scanners perform rigorous examinations of systems to identify weaknesses that might allow security violations. These products use two techniques for performing these examinations. First, passive, host-based mechanisms inspect system configuration files for unwise settings, system password files for weak passwords, and other system objects for security policy violations. These checks are followed, in most cases, by the second technique, active. In active examination, a networkbased assessment that reenacts common intrusion detection scripts and records system responses to the scripts." Page 5-14

"On the other hand, the more subtle and complex rules that an IDS uses to analyze system activity allow it to detect vulnerabilities and intrusions that a firewall may miss, including attacks that bypass the firewall. Examples are tunneling and application-based attacks." Page 5-12 Question was written incorrectly in book possibly?

"Trivial file transfer protocol (TFTP) is a protocol that enables file transfers between computers, but it is simpler (or more trivial) than FTP. A significant difference between FTP and TFTP is that TFTP relies on UDP at the Transport layer." Page 2-7

"Control utility programs that provide unrestricted access to sensitive data. Some utility programs provide unrestricted access to system commands and data to “superusers” (e.g., system administrators)." Page 5-9

"A number of points are worth emphasizing in relation to VLSM:
 Start with the shortest mask. Plan the subnets that support the most hosts. This is typically the mask used on most or all of the LAN segments.
 Choose one or more available subnets and subnet further. This is sometimes called “subnetting the subnets.” It is important to remember that this can be done only with one or more subnets that have not already been used up.
 Aim to use contiguous subnets where possible. Although it is not essential, it certainly makes very good sense to choose a continuous range of addresses and apply a particular mask to them. The advantage of this type of consistency is that it can be determined from the third octet address that this is a LAN segment and also that the mask is 24-bit." Page 2-17

"The oldest routing protocol, RIP, which is still widely used, factors in only the number of hops between nodes when determining a path from one point to another." Page 3-6

"The first line of defense is to require a logon ID and password combination to gain access to the PC's operating system." Page 5-9

"A “default deny” posture to deny everything that is not specifically authorized." Page 5-8

"File transfer protocol (FTP) is used to send and receive files by way of TCP/IP. In FTP exchanges, a host running the FTP server portion accepts commands from another host running the FTP client portion." Page 2-6

"The IEEE has subdivided the data link layer into two sublayers: LLC and media access control (MAC)." Page 1-14

"The time a switch takes to figure out where to forward a data unit is called its latency." Page 3-4

"The octets are split into two sections: Net and Host. The Net section always contains the first octet. It is used to identify the network that a computer belongs to. Host (sometimes referred to as Node) identifies the actual computer on the network. The Host section always contains the last octet." Page 2-11

"A computer on a TCP/IP network uses a subnet mask to determine what network it is on and whether a computer that it needs to send data to is located on a local network or on a remote network." Page 2-12

"The RS–530 is also based on a 25-pin connection (fig. 1–2). It works in either balanced or unbalanced electrical circuits." Page 1-11

"The term datagram usually refers to an information unit whose source and destination are network layer entities that use connectionless network service." Page 1-18

"Teredo attempts to solve the lack of functionality issue 6to4 has with Network Address Translation (NAT). Tunneling from the hosts presents an issue for NAT: IPv6 packets that are
encapsulated within IPv4 have the Protocol field in the IPv4 header set to 41." Page 2-21

"IEEE is a worldwide nonprofit association of technical professionals that promotes the development of standards and acts as a catalyst for new technology in all aspects of the engineering industry, including computer networking, telecommunications, electric power, aerospace, and consumer electronics." Page 1-5

"Ping is a utility that can verify that TCP/IP is installed, bound to the network interface card (NIC), configured correctly, and communicating with the network. It is often employed simply to determine whether a host is responding (or “up”). Ping uses ICMP services to send echo request and echo reply messages that determine the validity of an IP address." Page 2-9

"Peer-to-peer networking enables users to share resources, files, and printers in a decentralized way." Page 1-30

"Node discovery automatically runs in the background when the protocol analyzer application is activated." Page 3-17

"Managed devices are controlled and monitored using four basic SNMP commands: read, write, trap, and traversal operations." Page 4-2

"Configuration management provides the capability to initialize, reconfigure, operate, and shut down managed devices." Page 4-4

"Standardized transmission check sums must be employed throughout the network to be sure of data integrity. In case of an incident or catastrophic failure, routine data backup is used to help make sure of data integrity." Page 5-10

"At its most primitive, a hub is a repeater with more than one output port. A hub typically contains multiple data ports into which the patch cables for network nodes are connected." Page 3-2

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