Term
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Definition
| the electrical transmission of data among systems, whether through analog, digital, or wireless transmission types. |
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Term
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Definition
| a standard set of rules that determines how systems will communicate across networks |
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Term
| open network architecture |
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Definition
| one that no vendor owns, that is not proprietary, and that can easily integrate various technologies and vendor implementations of those technologies. |
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Term
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Definition
| message is constructed within a program on one computer and is then passed down through the network protocol’s stack. A protocol at each layer adds its own information to the message; thus, the message grows in size as it goes down the protocol stack. The message is then sent to the destination computer, and the encapsulation is reversed by taking the packet apart through the same steps used by the source computer that encapsulated it. |
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Term
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Definition
| are capable of communicating with other open systems because they implement international standard protocols and interfaces. |
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Term
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Definition
layer 7 - works closest to the user and provides file transmissions, message exchanges, terminal sessions, and much more.
This layer does not include the actual applications, but rather the protocols that support the applications.
When an application needs to send data over the network, it passes instructions and the data to the protocols that support it at the application layer. This layer processes and properly formats the data and passes the same down to the next layer within the OSI
model.
Some examples of the protocols working at this layer are the Simple Mail Transfer Protocol (SMTP), Hypertext Transfer Protocol (HTTP), Line Printer Daemon (LPD), File Transfer Protocol (FTP), Telnet, and Trivial File Transfer Protocol (TFTP). |
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Term
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Definition
| layer 6 - receives information from the application layer protocol and puts it in a format all computers following the OSI model can understand. For example: the sender could create a Word file in Word 2010, while the receiver uses Open Office. The receiver can open this file because the presentation layer on the sender’s system converted the file to American Standard Code for Information Interchange(ASCII), and the receiver’s computer knows it opens these types of files with its word processor, Open Office. This layer also handles data compression and encryption issues. There are no protocols that work at the presentation layer. |
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Term
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Definition
layer 5, is responsible for establishing a connection between the two applications, maintaining it during the transfer of data, and controlling the release of this connection
works in three phases: connection establishment, data transfer, and connection release.
Session layer protocols control application-to-application communication
Some protocols that work at this layer are Structured
Query Language (SQL), NetBIOS, and remote procedure call (RPC). |
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Term
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Definition
| When the conversation is over, this path is broken down and all parameters are set back to their original settings |
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Term
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Definition
provides end-to-end data transport services and establishes the logical connection between two communicating computers.
they will first agree on how much information each computer will send at a time, how to verify the integrity of the data once received, and how to determine whether a packet was lost along the way.
The main protocols that work at this layer are TCP, UDP, Secure Sockets Layer (SSL), and Sequenced Packet Exchange (SPX)
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Term
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Definition
layer 3 - The main responsibilities of the network layer are to insert information into the packet’s header so it can be properly addressed and routed, and then to actually route the packets to their proper destination
The protocols at the network layer must determine the best path for the packet to take.
IP is a common protocol working at the network layer.
Other routing protocols are the Internet Control Message Protocol (ICMP), Routing Information Protocol (RIP), Open Shortest Path First (OSPF), Border Gateway Protocol (BGP), and Internet Group Management Protocol (IGMP). |
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Term
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Definition
The outer format of the data packet changes slightly at each layer, and it comes to a point where it needs to be translated into the LAN or wide area network (WAN) technology binary format for proper line transmission
LAN and WAN technologies can use different protocols, network interface cards (NICs), cables, and transmission methods. Each of these components has a different header data format structure, and they interpret electricity voltages in different ways. The data link layer is where the network stack knows what format the data frame must be in to transmit properly over Token Ring, Ethernet, ATM, or Fiber Distributed Data Interface (FDDI) networks.
divided into two functional sublayers: the Logical Link Control (LLC) and the Media Access Control (MAC).
protocols that work at the data link layer are the Point-to Point Protocol (PPP), ATM, Layer 2 Tunneling Protocol (L2TP), FDDI, Ethernet, and Token Ring. |
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Term
| Logical Link Control (LLC) |
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Definition
| The LLC, defined in the IEEE 802.2 specification, communicates with the protocol immediately above it, the network layer. |
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Term
| Media Access Control (MAC) |
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Definition
| The MAC will have the appropriately loaded protocols to interface with the protocol requirements of the physical layer. |
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Term
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Definition
layer 1 - converts bits into voltage for transmission
This layer controls synchronization, data rates, line noise, and transmission techniques. |
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Term
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Definition
| Transmission Control Protocol/Internet Protocol - is a suite of protocols that governs the way data travel from one device to another. |
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Term
| connection-oriented protocol |
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Definition
| which means it ensures packets are delivered to the destination computer. |
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Term
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Definition
| It has neither packet sequencing nor flow and congestion control, and the destination does not acknowledge every packet it receives |
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Term
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Definition
| connectionless protocol that provides the addressing and routing capabilities for each package of data. |
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Term
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Definition
| Port numbers up to 1023 (0 to 1023) |
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Term
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Definition
| UDP and TCP use ports to communicate with upper OSI layers and to keep track of various conversations that take place simultaneously. The ports are also the mechanism used to identify how other computers access services. |
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Term
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Definition
| When a TCP or UDP message is formed, source and destination ports are contained within the header information along with the source and destination IP addresses |
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Term
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Definition
| Ports 1024 to 49151 can be registered with the Internet Corporation for Assigned Names and Numbers (ICANN) for a particular use. Vendors register specific ports to map to their proprietary software |
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Term
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Definition
| Ports 49152 to 65535 and are available to be used by any application on an “as needed” basis. |
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Term
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Definition
| which means transmission in both directions is possible using the same transmission line. |
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Term
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Definition
| If an attacker can correctly predict the TCP sequence numbers that two systems will use, then she can create packets containing those numbers and fool the receiving system into thinking that the packets are coming from the authorized sending system. She can then take over the TCP connection between the two systems. |
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Term
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Definition
| A subnet is created from the host portion of an IP address to designate a “sub” network. This allows us to further break the host portion of the address into two or more logical groupings |
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Term
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Definition
| allows large IP ranges to be divided into smaller, logical, and more tangible network segments. |
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Term
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Definition
| classless interdomain routing (CIDR) was created because a Class B address range is usually too large for most companies, and a Class C address range is too small, so CIDR provides the flexibility to increase or decrease the class sizes as necessary. CIDR is the method to specify more flexible IP address classes. |
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Term
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Definition
| IP provides a Time to Live (TTL) value that is decremented every time the packet passes through a router. |
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Term
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Definition
| IP can also provide a Type of Service (ToS) capability, which means it can prioritize different packets for time-sensitive functions. |
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Term
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Definition
| larger packets provided by IPv6 |
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Term
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Definition
| a technique where the routing infrastructure automatically determines the tunnel endpoints so that protocol tunneling can take place without preconfiguration. |
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Term
| Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) |
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Definition
| Treats the IPv4 network as a virtual IPv6 local link, with mappings from each IPv4 address to a link-local IPv6 address. |
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Term
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Definition
| 802.1AE is the IEEE MAC Security standard (MACSec), which defines a security infrastructure to provide data confidentiality, data integrity, and data origin authentication. Where a Virtual Private Network (VPN) connection provides protection at the higher networking layers, MACSec provides hop-by-hop protection at layer 2 |
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Term
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Definition
| defines a globally unique per-device secure identifier cryptographically bound to the device through the use of public cryptography and digital certificates. |
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Term
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Definition
| User Datagram Protocol (UDP) Connectionless, unreliable transport layer protocol, which is considered a “best effort” protocol. |
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Term
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Definition
| DoS attack where an attacker sends a succession of SYN packets with the goal of overwhelming the victim system so that it is unresponsive to legitimate traffic. |
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Term
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Definition
| Transition mechanism for migrating from IPv4 to IPv6. It allows systems to use IPv6 to communicate if their traffic has to transverse an IPv4 network. |
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Term
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Definition
| Transition mechanism for migrating from IPv4 to IPv6. It allows systems to use IPv6 to communicate if their traffic has to transverse an IPv4 network, but also performs its function behind NAT devices. |
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Term
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Definition
| refers to the number of electrical pulses that can be transmitted over a link within a second |
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Term
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Definition
| is the actual amount of data that can be carried over a connection. |
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Term
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Definition
| Binary digits are represented and transmitted as discrete electrical pulses. Signaling allows for higher data transfer rates and high data integrity compared to analog signaling. |
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Term
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Definition
| Continuously varying electromagnetic wave that represents and transmits data. Carrier signals vary by amplification and frequency. |
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Term
| Asynchronous communication |
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Definition
| Transmission sequencing technology that uses start and stop bits or similar encoding mechanism. Used in environments that transmit a variable amount of data in a periodic fashion. |
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Term
| Synchronous communication |
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Definition
| Transmission sequencing technology that uses a clocking pulse or timing scheme for data transfer synchronization. |
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Term
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Definition
| Uses the full bandwidth for only one communication channel and has a low data transfer rate compared to broadband. |
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Term
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Definition
| Divides the bandwidth of a communication channel into many channels, enabling different types of data to be transmitted at one time. |
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Term
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Definition
| Cabling in which copper wires are twisted together for the purposes of canceling out EMI from external sources. UTP cables are found in many Ethernet networks and telephone systems. |
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Term
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Definition
| Twisted-pair cables are often shielded in an attempt to prevent RFI and EMI. This shielding can be applied to individual pairs or to the collection of pairs. |
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Term
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Definition
| Gradual loss in intensity of any kind of flux through a medium. As an electrical signal travels down a cable, the signal can degrade and distort or corrupt the data it is carrying. |
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Term
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Definition
| A signal on one channel of a transmission creates an undesired effect in another channel by interacting with it. The signal from one cable “spills over” into another cable. |
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Term
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Definition
| Cable is jacketed with a fire-retardant plastic cover that does not release toxic chemicals when burned. |
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Term
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Definition
| Each system connects to two other systems, forming a single, unidirectional network pathway for signals, thus forming a ring. |
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Term
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Definition
| Systems are connected to a single transmission channel (i.e., network cable), forming a linear construct. |
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Term
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Definition
| Network consists of one central device, which acts as a conduit to transmit messages. The central device, to which all other nodes are connected, provides a common connection point for all nodes. |
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Term
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Definition
| Network where each system must not only capture and disseminate its own data, but also serve as a relay for other systems; that is, it must collaborate to propagate the data in the network. |
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Term
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Definition
| Common LAN media access technology standardized by IEEE 802.3. Uses 48-bit MAC addressing, works in contention-based networks, and has extended outside of just LAN environments. |
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Term
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Definition
| LAN medium access technology that controls network communication traffic through the use of token frames. This technology has been mostly replaced by Ethernet. |
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Term
| Fiber Distributed Data Interface |
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Definition
| Ring-based token network protocol that was derived from the IEEE 802.4 token bus timed token protocol. It can work in LAN or MAN environments and provides fault tolerance through dual-ring architecture. |
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Term
| Carrier sense multiple access with collision detection |
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Definition
| A media access control method that uses a carrier sensing scheme. When a transmitting system detects another signal while transmitting a frame, it stops transmitting that frame, transmits a jam signal, and then waits for a random time interval before trying to resend the frame. This reduces collisions on a network. |
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Term
| Carrier sense multiple access with collision avoidance |
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Definition
| A media access control method that uses a carrier sensing scheme. A system wishing to transmit data has to first listen to the channel for a predetermined amount of time to determine whether or not another system is transmitting on the channel. If the channel is sensed as “idle,” then the system is permitted to begin the transmission process. If the channel is sensed as “busy,” the system defers its transmission for a random period of time. |
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Term
| Internet Group Management Protocol (IGMP) |
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Definition
| Used by systems and adjacent routers on IP networks to establish and maintain multicast group memberships. |
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Term
| Media access control (MAC) |
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Definition
| Data communication protocol sublayer of the data link layer specified in the OSI model. It provides hardware addressing and channel access control mechanisms that make it possible for several nodes to communicate within a multiple-access network that incorporates a shared medium. |
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Term
| Address Resolution Protocol (ARP) |
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Definition
| translates the IP address into a MAC address |
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Term
| Dynamic Host Configuration Protocol (DHCP) |
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Definition
| A network configuration service for hosts on IP networks. It assigns IP addresses, DNS server, subnet mask, and other important network configuration data to each host through automation. |
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Term
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Definition
| A series of techniques applied to ensure the security of an existing DHCP infrastructure through tracking physical locations, ensuring only authorized DHCP servers are accessible, and hosts use only addresses assigned to them. |
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Term
| Reverse Address Resolution Protocol (RARP) and Bootstrap Protocol (BootP) |
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Definition
| Networking protocols used by host computers to request the IP address from an administrative configuration server. |
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Term
| Internet Control Message Protocol (ICMP) |
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Definition
| A core protocol of the IP suite used to send status and error messages. |
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Term
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Definition
| A DoS attack type on a computer that involves sending malformed or oversized ICMP packets to a target. |
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Term
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Definition
| A DDoS attack type on a computer that floods the target system with spoofed broadcast ICMP packets. |
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Term
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Definition
| A DDoS attack type on a computer that floods the target system with a large amount of UDP echo traffic to IP broadcast addresses. |
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Term
| Simple Network Management Protocol (SNMP) |
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Definition
| A protocol within the IP suite that is used for network device management activities through the use of a structure that uses managers, agents, and Management Information Bases. |
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Term
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Definition
| resolves hostnames into IP addresses and has distributed databases all over the Internet to provide name resolution. |
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Term
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Definition
| The process of replicating the databases containing the DNS data across a set of DNS servers. |
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Term
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Definition
| A set of extensions to DNS that provide to DNS clients (resolvers) origin authentication of DNS data to reduce the threat of DNS poisoning, spoofing, and similar attack types. |
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Term
| Simple Mail Transfer Protocol (SMTP) |
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Definition
| An Internet standard protocol for electronic mail (e-mail) transmission across IP-based networks. |
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Term
| Post Office Protocol (POP) |
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Definition
| An Internet standard protocol used by e-mail clients to retrieve e-mail from a remote server and supports simple download-and-delete requirements for access to remote mailboxes. |
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Term
| Internet Message Access Protocol (IMAP) |
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Definition
| An Internet standard protocol used by e-mail clients to retrieve e-mail from a remote server. E-mail clients using IMAP generally leave messages on the server until the user explicitly deletes them. |
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Term
| Simple Authentication and Security Layer (SASL) |
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Definition
| A framework for authentication and data security in Internet protocols. It decouples authentication mechanisms from application protocols and allows any authentication mechanism supported by SASL to be used in any application protocol that uses SASL. |
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Term
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Definition
| Open mail relay An SMTP server configured in such a way that it allows anyone on the Internet to send e-mail through it, not just mail destined to or originating from known users. |
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Term
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Definition
| Activity in which the sender address and other parts of the e-mail header are altered to appear as though the e-mail originated from a different source. Since SMTP does not provide any authentication, it is easy to impersonate and forge e-mails. |
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Term
| Sender Policy Framework (SPF) |
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Definition
| An e-mail validation system designed to prevent e-mail spam by detecting e-mail spoofing, a common vulnerability, by verifying sender IP addresses. |
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Term
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Definition
| A way of attempting to obtain data such as usernames, passwords, credit card information, and other sensitive data by masquerading as an authenticated entity in an electronic communication. Spear phishing targets individuals, and whaling targets people with high authorization (CEO, COO, CIO). |
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Term
| Network address translation (NAT) |
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Definition
| The process of modifying IP address information in packet headers while in transit across a traffic routing device, with the goal of reducing the demand for public IP addresses. |
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Term
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Definition
| A collection of connected IP routing prefixes under the control of one or more network operators that presents a common, clearly defined routing policy to the Internet. They are uniquely identified as individual networks on the Internet. |
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Term
| Distance-vector routing protocol |
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Definition
| A routing protocol that calculates paths based on the distance (or number of hops) and a vector (a direction). |
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Term
| Link-state routing protocol |
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Definition
| A routing protocol used in packetswitching networks where each router constructs a map of the connectivity within the network and calculates the best logical paths, which form its routing table. |
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Term
| Border Gateway Protocol (BGP) |
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Definition
| The protocol that carries out core routing decisions on the Internet. It maintains a table of IP networks, or “prefixes,” which designate network reachability among autonomous systems (ASs). |
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Term
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Definition
| This takes place when an attacker captures packets at one location in the network and tunnels them to another location in the network for a second attacker to use against a target system. |
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Term
| Spanning Tree Protocol (STP) |
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Definition
| A network protocol that ensures a loop-free topology for any bridged Ethernet LAN and allows redundant links to be available in case connection links go down. |
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Term
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Definition
| Allows a sender of a packet to specify the route the packet takes through the network versus routers determining the path. |
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Term
| Multiprotocol Label Switching (MPLS) |
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Definition
| A networking technology that directs data from one network node to the next based on short path labels rather than long network addresses, avoiding complex lookups in a routing table. |
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Term
| Virtual local area network (VLAN) |
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Definition
| A group of hosts that communicate as if they were attached to the same broadcast domain, regardless of their physical location. VLAN membership can be configured through software instead of physically relocating devices or connections, which allows for easier centralized management. |
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Term
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Definition
| An exploit that allows an attacker on a VLAN to gain access to traffic on other VLANs that would normally not be accessible. |
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Term
| Private Branch Exchange (PBX) |
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Definition
| A telephone exchange that serves a particular business, makes connections among the internal telephones, and connects them to the public-switched telephone network (PSTN) via trunk lines. |
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Term
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Definition
| A highly exposed device that will most likely be targeted for attacks, and thus should be properly locked down. |
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Term
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Definition
| This device has two interfaces and sits between an untrusted network and trusted network to provide secure access. A multihomed device just means it has multiple interfaces. Firewalls that have multiple interfaces allow for networks to be segmented based upon security zone, with unique security configurations. |
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Term
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Definition
| A firewall that communicates directly with a perimeter router and the internal network. The router carries out filtering activities on the traffic before it reaches the firewall. |
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Term
| Screened subnet architecture |
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Definition
| When two filtering devices are used to create a DMZ. The external device screens the traffic entering the DMZ network, and the internal filtering device screens the traffic before it enters the internal network. |
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Term
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Definition
| A firewall that runs within a virtualized environment and monitors and controls traffic as it passes through virtual machines. The firewall can be a traditional firewall running within a guest virtual machine or a component of a hypervisor. |
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Term
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Definition
| A system that acts as an intermediary for requests from clients seeking resources from other sources. A client connects to the proxy server, requesting some service, and the proxy server evaluates the request according to its filtering rules and makes the connection on behalf of the client. Proxies can be open or carry out forwarding or reverse forwarding capabilities. |
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Term
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Definition
| Systems that entice with the goal of protecting critical production systems. If two or more honeypots are used together, this is considered a honeynet. |
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Term
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Definition
| The combining of server, storage, and network capabilities into a single framework, which decreases the costs and complexity of data centers. Converged infrastructures provide the ability to pool resources, automate resource provisioning, and increase and decrease processing capacity quickly to meet the needs of dynamic computing workloads. |
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Term
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Definition
| The delivery of computer processing capabilities as a service rather than as a product, whereby shared resources, software, and information are provided to end users as a utility. Offerings are usually bundled as an infrastructure, platform, or software. |
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Term
| Electronic data interchange (EDI) |
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Definition
| The structured transmission of data between organizations. It is considered to describe the rigorously standardized format of electronic documents and commonly used in supply chains between customers, vendors, and suppliers. |
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Term
| Value-added network (VAN) |
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Definition
| A hosted EDI service offering that acts as an intermediary between business partners sharing standards-based or proprietary data via shared business processes. |
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Term
| Metropolitan area network (MAN) |
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Definition
| A network that usually spans a city or a large campus, interconnects a number of LANs using a highcapacity backbone technology, and provides up-link services to WANs or the Internet. |
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Term
| Synchronous Optical Networking (SONET) and Synchronous Digital Hierarchy (SDH) |
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Definition
| Standardized multiplexing protocols that transfer multiple digital bit streams over optical fiber and allow for simultaneous transportation of many different circuits of differing origin within a single framing protocol. |
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Term
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Definition
| A data link technology that is used as a metropolitan area network to connect customer networks to larger service networks or the Internet. Businesses can also use Metro Ethernet to connect distributed locations to their intranet. |
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Term
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Definition
| A telecommunication network that covers a broad area and allows a business to effectively carry out its daily function, regardless of location. |
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Term
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Definition
| A method of combining multiple channels of data over a single transmission line. |
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Term
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Definition
| Dedicated lines that can carry voice and data information over trunk lines. It is a general term for any of several digitally multiplexed telecommunications carrier systems. |
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Term
| Time-division multiplexing (TDM) |
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Definition
| A type of multiplexing in which two or more bit streams or signals are transferred apparently simultaneously as subchannels in one communication channel, but are physically taking turns on the single channel. |
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Term
| Wave-division multiplexing (WDM) |
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Definition
| Multiplying the available capacity of optical fibers through use of parallel channels, with each channel on a dedicated wavelength of light. The bandwidth of an optical fiber can be divided into as many as 160 channels. |
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Term
| Frequency-division multiplexing (FDM) |
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Definition
| Dividing available bandwidth into a series of nonoverlapping frequency sub-bands that are then assigned to each communicating source and user pair. FDM is inherently an analog technology. |
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Term
| Statistical time-division multiplexing (STDM) |
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Definition
| Transmitting several types of data simultaneously across a single transmission line. STDM technologies analyze statistics related to the typical workload of each input device and make real-time decisions on how much time each device should be allocated for data transmission. |
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Term
| Channel Service Unit (CSU) |
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Definition
| A line bridging device for use with T-carriers, and that is required by PSTN providers at digital interfaces that terminate in a Data Service Unit (DSU) on the customer side. The DSU is a piece of telecommunications circuit terminating equipment that transforms digital data between telephone company lines and local equipment. |
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Term
| Public-switched telephone network (PSTN) |
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Definition
| The public circuit switched telephone network, which is made up of telephone lines, fiber-optic cables, cellular networks, communications satellites, and undersea telephone cables and allows all phone-to-phone communication. It was a fixed-line analog telephone system, but is now almost entirely digital and includes mobile as well as fixed telephones. |
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Term
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Definition
| The set of protocols, technologies, methodologies, and transmission techniques involved in the delivery of voice data and multimedia sessions over IP-based networks. |
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Term
| Session Initiation Protocol (SIP) |
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Definition
| The signaling protocol widely used for controlling communication, as in voice and video calls over IPbased networks. |
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Term
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Definition
| (voice and phishing) Social engineering activity over the telephone system, most often using features facilitated by VoIP, to gain unauthorized access to sensitive data. |
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Term
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Definition
| A standard that addresses call signaling and control, multimedia transport and control, and bandwidth control for point-to-point and multipoint conferences. |
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Term
| Real-time Transport Protocol (RTP) |
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Definition
| Used to transmit audio and video over IP-based networks. It is used in conjunction with the RTCP. RTP transmits the media data, and RTCP is used to monitor transmission statistics and QoS, and aids synchronization of multiple data streams. |
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Term
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Definition
| When a specialized program is used to automatically scan a list of telephone numbers to search for computers for the purposes of exploitation and hacking. |
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Term
| Integrated Services Digital Network (ISDN) |
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Definition
| A circuit-switched telephone network system technology designed to allow digital transmission of voice and data over ordinary telephone copper wires. |
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Term
| Digital Subscriber Line (DSL) |
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Definition
| A set of technologies that provide Internet access by transmitting digital data over the wires of a local telephone network. DSL is used to digitize the “last mile” and provide fast Internet connectivity. |
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Term
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Definition
| A device that provides bidirectional data communication via radio frequency channels on cable TV infrastructures. Cable modems are primarily used to deliver broadband Internet access to homes. |
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