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27 Cards in this Set
- Front
- Back
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ACK
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acknowledge good transmission at the datalink layer
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NACK
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Report error in transmission at the datalink layer
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CSMA/CD
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(Carrier Sense Multiple Access/Collision Detection)- decentralized MAC scheme where multiple devices use the resource, they listen for activity, and pause if the media is in use
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ATM
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(Asynchronous Transfer Mode)- attempted to unify packet and circuit switching, voice and data, runs with cells of 53 bytes instead of up to 1500 bytes, allows for better real-time communication, but increases overhead to 10%
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RTP
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(Real Time Protocol)- adds headers that contain sequence numbers to ensure that the UDP datagrams are placed in proper sequence and that they contain time stamps so that jitter can be eliminated.
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FHSS
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(Frequency Hopping Spread Spectrum)- wireless technology, hop among allowable frequencies, efficient use of band, resistant to interference, difficult to eavesdrop
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DSSS
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(Direct Sequence Spread Spectrum)- multiple devices use the same frequencies, add a code to distinguish among transmissions, high throughput
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OFDM
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(Orthogonal Frequency Division Multiplexing) – like a virtual parallel cable, send multiple bits at the same time on multiple freq., choose freq. and timing to minimize interference, efficient use of the spectrum with a very high throughput
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CSMA/CA
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like CSMA/CD, but Collision Avoidance, asking permission to talk and establishing temporary circuits
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TDMA
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(Time Division Multiple Access) for cellular, each convo assigned a timeslot, 10 slots per frequency, sender and receiver must be synchronized, 3x capacity of AMPS, some guard intervals, good minimal processing, bad some wasted bandwidth
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CDMA
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(Code Division Multiple Access)- each convo assigned a code, 10x capacity of AMPS, uses multiple frequency, degrades with high use, but is very effiecient
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GSM
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(Global System for Mobile Communications)- similar to TDMA, easy interoperability, uses SIM cards, Subscriber Identity Module
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GPRS
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(General Packet Radio Service)- built on TDMA, near 56Kbps, allocates unused bandwidth from voice
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1xRTT
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(1 times Radio Transmission Technology)- Uses 1 1.25 MHz radio channel, built on CDMA, approx 100Kbps
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EDGE
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(Enhanced Data rates for GSM Evolution)- built on TDMA, similar to GPRS, better phase shifting, over 200Kbps
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EV-DO
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(Evolution-Data Optimized)- often referred to as D-O, built on CDMA, up to 3Mbps
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SONet
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(Synchronous Optical NETwork)- like T1 over fiber, categorized by Optical Carrier
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WDM
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(Wavelength Division Multiplexing)- treat different colors as different channels in SONET, also Dense WDM, DWDM used to describe more than 8 colors, theoretical max of 1000 Gbps
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CBR
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ATM bandwidth approach for (Constant Bit Rate), a virtual leased line
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VBR
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ATM bandwidth approach for (Variable Bit Rate), minimum rate and bursts
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ABR
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ATM bandwidth approach for (Available Bit Rate), anything left over
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MPLS
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(Multi Protocol Label Switching)- like ATM with simplified addressing and bigger cells, minimizing overhead
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IP
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(Internet Protocol)- providing global addresses and routing tools to route data to other networks than the LAN, IPv4 uses 32 bit addresses in 4 8 bit segments
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DHCP
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(Dynamic Host Configuration Protocol)- IP address assigned each time you connect to the network rather than kept
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NAT
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(Network Address Translation)- reuses IP addresses behind a router, Router has globally unique IP address and serves as proxy for all hosts it holds, Ex. 192.168.x.x, 10.x.x.x
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TCP
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(Transmission Control Protocol)- aka Transport CP, purpose of connections, error control, flow control, and protocol multiplexing
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UPD
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(User Datagram Protocol) - unreliable transport layer protocol in TCP/IP
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