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Computer Communiation Exam1 Cheat Sheet (DRAFT) by

This is a draft cheat sheet. It is a work in progress and is not finished yet.


define format, order of messages sent and received among network entities, and actions taken on message transm­ission, receipt

network structure

access networks, physical media:­wired, wireless commun­ication links
TDM = time division multip­lexing time divided into frames fixed duration fixed number time slots
network core: •inter­con­nected router­s•n­etwork of networks
FDM = frequency division multip­lexing: diff CHs transm­itted in diff frequency bands


4 Sources of packet delays
dnodal = dproc + dqueue + dtrans +dprop
dproc : nodal proces­sing, check bit errors, determine output link
dqueue: queueing delay, time waiting at output link for transm­ission, depends on congestion of router
dtrans: how long it takes to get on link
L (bits)­/R(bps)
dprop: propag­ation delay
d (m)/s


applic­ati­on(­http), transp­ort­(TCP), networ­k(IP), link(W­iFi), physic­al(­bits)
app, sessio­n(c­hec­kpo­int­ing), transport, network, link, physical


transm­ission control protocol
user datagram protocol
reliable transport, flow control, congestion control, DNP( timing, minimum throughput guarantee, security), connec­tio­n-o­riented
unreliable data transfer, DNP
1 IP & 1 port
streaming, DNS (domain name system)