Self-Test Vol. 1 Unit 5 Flashcards
What is the internet?
A network of networks; a series of private computer networks connected to each other.
What is the name for networks that use the same software and protocols as the public internet, but exist as a portion of an entity’s private network?
Intranet
What term describes a group of computers and devices that share a common communication line and resources in a small geographical area?
LAN
What type of network interconnects several local area networks by bridging them with backbone lines?
MAN
What is the name for a network connected between two cities?
WAN
Primary addressing in WLANs is achieved by using what type of address?
MAC
List the advantages to using WLAN?
Mobility, ease of installation, and lower costs
List each of the IEEE wireless standards.
802.11 a/b/g/n
The 802.11n standard operates at what frequency?
2.4GHz and 5 GHz
What network provides a private tunnel through the Internet?
VPN
What type of configuration does the Air Force use for most VPN traffic?
Gateway-to-gateway
What is a physical topology?
A map or description of the layout of the network media that interconnects the device on a network.
What is a logical topology?
The way in which devices communicate and transmit data throughout the network.
What is the rule of thumb to distinguish physical from logical topologies?
If you can see if and touch it, it’s physical.
If you cannot see it or touch it, it’s logical.
Because a topology affects the network’s capabilites, what is the impact of choosing one topology over another?
Type of equipment the network needs, capabilities of the equipment, growth of the network, and the way the network is managed.
What are the advantages of a bus topology?
Inexpensive to install, easy to add more workstations, requires less cable, works well for small networks.
What are the disadvantage of a bus topology?
No longer recommended; if backbone breaks, only limited number of devices, difficult to isolate problems, slower access time.
What are the advantages of a star topology?
Easy to add more devices, broken cable doesn’t affect entire network, easy to find device, upgradable, most common topology.
What are the disadvantages of a star topology?
Requires more media, failure of central hub can bring down network, higher costs.
What are the advantages of a ring topology?
Greater speed, no collision, easier to locate problems, no terminators needed.
What are the disadvantages of a ring topology?
Requires more cable, break in cable brings network down, adding devices suspends networks, not commonly used.
What are the two most common hybrid topologies?
Star-wired ring and star-wired bus
What data transport method grew out of the need for a worldwide standard to allow interoperability of information, regardless of the information type or “end-system”?
ATM
How many bytes make up the ATM cell, header, and payload?
53 bytes
ISDN channels are separated into two sub-channels, list and describe the sub-channels.
Sub-channel B 56 Kbps or 64 Kbps and are used for both voice and data. Each B channel can carry a separate telephone call. The D-channel is a 16 Kbps use to carry call control (or supervisory) information. Ther information on the “D” channel tells the network switches what to do with the traffic on the “B” channels.
What the full bandwidth of a T1 line is not needed it can be divided in 64 Kbps increments known as what?
Fractional T-1
What Ethernet standard has supplanted Fast Ethernet in wired networks?
GbE (Gigabit Ethernet)
Define modems.
A device that modulates signals to encode digital info and demodulates signals to decode the transmitted info.
What are the two types of modems used?
Dial-up and dedicated.
What is one of the principal functions of a CSU?
To provide a barrier for electrical interference from either side of the unit.
What is the main function of a DSU?
To adapt the digital data stream produced by the customer’s equipment to the signaling standards of the telephone carrier equipment.
What is the primary use for a bridge?
To decrease network congestion and propagates a signal like a repeater.
What do LAN switches provide between network devices?
Collision-free, high-speed communication
Can a switch connect LANs of different bandwidths? If so, give example.
Yes, through buffering.
What type of switching is required when a moving frame from a low-speed LAN to a high-speed LAN?
Store-and-forward switching.
What is the fundamental difference between Layer 2 and Layer 3 switching?
The layer at which each forwarding decision is made.
Routers operate at which layer of the OSI model?
Layer 3
What does a typical router contain?
An internal processor, an OS, memory, I/O jacks for different types of network connectors, and a management console interface.
Routers compare metrics to determine optimal routes; these methods differ depending on what?
Depending on the routing algorithm used.
What are routing protocols that manage traffic within an autonomous system called?
IGP
Name two methods for directing data on the network.
Static and dynamic routing
What is static routing?
A technique in which a network admin programs a router to use specific paths between nodes.
What is dynamic routing?
Routing that automatically calculates the best path between the two nodes and compiles this info into a routing table.
What are the two methods that encryption can be applied?
Link-by-link or an end-to-end basis.
What is the most common telephone device used for voice encryption?
STE
What are the most common types of all metallic cable used in networks?
Twisted-pair and coaxial
Which cable type is associated with the original designs of the Ethernet standard?
Coaxial
List and describe the four most common coax cable types.
RG-6, RG-58, RG-8, RG-11
What medium is primary carrier for voice telecommunications?
Twisted-pair cable
List and describe the categories of twisted pair cable.
CAT 1, CAT 3, CAT 5, CAT 5e, CAT 6, and CAT 6a
What three things do an optical communications system require to transport communications?
A light source, a transmitter, and a receiver
List the advantages of fiber optic systems over conventional cable systems.
Larger bandwidth, freedom from interference, low cost, and lightweight.
Is fiber optic cable immune to EMI?
Yes
What is the most common wireless networking standard?
IEEE 802.11
