Term
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Definition
• Dedicated, leased line that connects two locations
• Expensive compared to other WAN options
• Secure because only two locations are using the same media |
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Term
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Definition
• High-performance WAN protocol that uses packet-switching technology, which works over public networks
• Shared media among companies
• Uses SVCs and PVCs
• Fee based on bandwidth used |
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Term
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Definition
• First packet-switching technology developed to work over public networks
• Shared media among companies
• Lower speed than frame relay because of its extra overhead
• International standard and used more in countries other than the U.S.
• Uses SVCs and PVCs |
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Term
| Switched Multimegabit Data Service (SMDS) |
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Definition
| High-speed switching technology used over public network |
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Term
| Asynchronous Transfer Mode (ATM) |
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Definition
• High-bandwidth switching and multiplexing technology that has a low delay
• Uses 53-byte fixed-size cells
• Very fast because of the low overhead |
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Term
| Synchronous Data Link Control (SDLC) |
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Definition
• Enables mainframes to communicate with remote offices
• Provides polling mechanism to allow primary and secondary stations to communicate |
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Term
| High-level Data Link Control (HDLC) |
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Definition
• New and improved SDLC protocol
• A data encapsulation method for synchronous serial links
• Point-to-point and multipoint communication |
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Term
| High-Speed Serial Interface (HSSI) |
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Definition
| • DTE/DCE interface to enable high-speed communication over WAN links |
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Term
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Definition
• Combines voice and data over the same IP network media and protocol
• Reduces costs of implementing and maintaining two different networks |
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Term
| Packet filtering Firewall |
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Definition
| Network layer - Looks at destination and source addresses, ports, and services requested. Routers using ACLs dictate acceptable access to a network. |
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Term
| Application level proxy firewall |
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Definition
| Application layer - Looks deep into packets and makes granular access control decisions. It requires one proxy per service. |
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Term
| Circuit-level proxy firewall |
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Definition
| Network layer - Looks only at the header packet information. It protects a wider range of protocols and services than does an Application-level proxy, but does not provide the detailed level of control available to an application-level proxy. |
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Term
| Stateful Inspection Firewall |
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Definition
| Network layer - Looks at the state and context of packets. Keeps track of each conversation using a state table. |
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Term
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Definition
| Application layer - Faster because processing is done in the kernel. One network stack is created for each packet. |
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Term
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Definition
Physical Layer
Amplifies signal and extends networks |
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Term
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Definition
| Data Linker Layer - Forwards packets and filters based on MAC addresses; forwards broadcast traffic, but not collision traffic. |
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Term
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Definition
| Network Layer - Separates and connects LANs creating internetworks; routers filter based on IP addresses |
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Term
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Definition
| Data link Layer - Provides a private virtual link between communicating devices; allows for VLANs; reduces collisions; impedes network sniffing. |
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Term
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Definition
| Application Layer - Connects different types of networks; performs protocol and format translations |
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Term
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Definition
802.3
• Shared media—all devices must take turns using the same media and detect collisions
• Uses broadcast and collision domains
• Uses CSMA/CD access method
• Can use coaxial or twisted-pair media
• Transmission speeds of 10 Mbps–1 Gbps |
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Term
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Definition
802.5
• All devices connect to a central MAU
• Token-passing media access method
• Transmission speeds of 4–16 Mbps
• Uses an active monitor and beaconing |
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Term
| Fiber Distributed Data Interface (FDDI) Topology |
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Definition
802.8
• Token-passing media access method
• Dual counter-rotating rings for fault tolerance
• Transmission speeds of 100 Mbps
• Operates over long distances at high speeds and is therefore used as a backbone
• CDDI works over UTP |
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Term
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Definition
Uses a linear, single cable for all computers attached. All traffic travels the full cable and can be viewed by all
other computers. If one station experiences a problem, it can negatively affect surrounding computers on the same cable. Ethernet |
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Term
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Definition
| All computers are connected by a unidirectional transmission link, and the cable is in a closed loop. If one station experiences a problem, it can negatively affect surrounding computers on the same ring. FDDI |
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Term
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Definition
All computers are connected to a central device, which provides more resilience for the network. The central device is a single point of failure.
Logical bus (Ethernet) and ring topologies (Token Ring) |
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Term
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Definition
| A bus topology that does not have one linear cable, but instead uses branches of cables. Ethernet |
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Term
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Definition
Computers are connected to each other, which provides redundancy. Requires more expense in cabling and extra effort to track down cable faults.
Internet |
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Term
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Definition
| Method of resolving hostnames to IP addresses so that names can be used instead of IP addresses when referencing unique hosts on the Internet. |
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Term
| Network operating system (NOS) |
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Definition
| Special software designed to control network resource access and provide the necessary services to enable a computer to interact with the surrounding network. |
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Term
| Network Information System (NIS) |
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Definition
| Enables users and applications to locate and access files and programs anywhere on the network through a central NIS server. |
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Term
| Lightweight Directory Access Protocol (LDAP) |
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Definition
| Client/server protocol used to access network directories such as Microsoft Active Directory or NDS. |
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Term
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Definition
|
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Term
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Definition
| 172.16.0.0–172.31.255.255 16 contiguous |
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Term
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Definition
| 192.168.0.0–192.168.255.255 256 contiguous |
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Term
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Definition
| A secure, private connection through a public network or an otherwise unsecure environment. |
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Term
Carrier sense multiple access with
collision detection (CSMA/CD) |
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Definition
| Protocol used to monitor the transmission activity, or carrier activity, on the wire so that a device can determine when would be the best time to transmit data. |
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Term
| Carrier sense multiple access with collision avoidance (CSMA/CA) |
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Definition
| Access method in which each computer signals its intent to transmit data before it actually does so. |
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Term
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Definition
| Group of computers that are contending, or competing, for the same shared communication medium. |
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Term
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Definition
| Method of monitoring multiple devices and controlling network access transmission. |
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Term
| Routing Information Protocol (RIP) |
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Definition
| A standard that outlines how routers exchange routing table data and is considered a distance-vector protocol, which means that it calculates the shortest distance between the source and destination. |
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Term
| Open Shortest Path First (OSPF) |
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Definition
| Allows for a hierarchical routing network that has a backbone link connecting all subnets together. |
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Term
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Definition
| A firewall that communicates directly with a perimeter router and the internal network. |
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Term
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Definition
| External router filters (screens traffic before it enters the subnet. Traffic headed toward the internal network then goes through the firewall and possibly another router. |
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Term
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Definition
Single computer with separate NICs connected to each network
• Used to divide an internal trusted network from an external untrusted network
• Must disable computer’s forwarding and routing functionality so the two networks are truly segregated |
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Term
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Definition
| Connection-oriented channel that provides a consistent data throughput for time-sensitive applications, such as voice and video applications. Customers specify the necessary bandwidth requirement at connection setup. |
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Term
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Definition
| Connection-oriented channel that is best used for delay-insensitive applications because the data throughput flow is uneven. Customers specify their required peak and sustained rate of data throughput. |
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Term
| Unspecified Bit Rate (UBR) |
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Definition
| Connectionless channel that does not promise a specific data throughput rate. Customers cannot and do not need to control their traffic rate. |
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Term
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Definition
| Connection-oriented channel that allows for the bit rate to be adjusted. Customers are given the bandwidth that remains after a guaranteed service rate has been met. |
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Term
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Definition
| A standard that deals with video, real-time audio, and data packet–based transmissions where multiple users can be involved with the data exchange. |
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Term
| Data Terminal Equipment (DTE) |
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Definition
| A customer-owned device, such as a router or switch, that provides connectivity between the company’s own network and the frame relay network. |
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Term
| Data Circuit-Terminating Equipment (DCE) |
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Definition
| Service provider’s, or telecommunications company’s, device that does the actual data transmission and switching in the frame relay cloud. |
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Term
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Definition
| Capability that allows a protocol to distinguish between different classes of messages and assign priority levels. |
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Term
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Definition
| Proxy-based firewall solution. It is a circuit-based proxy firewall and does not use application-based proxies. |
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Term
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Definition
| Lies between the perimeter router and the LAN. |
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Term
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Definition
| A DMZ created by two physical firewalls. |
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