Transcript CS335 Networking & Network Administration

CS335
Networking &
Network Administration
Tuesday, June 1, 2010
IP telephony



Equipment is less costly than telephone
switches
Backward compatible with PSTN (public
switched telephone network)
Be able to work with calls that originate with
PSTN and terminate with IP telephone and
vice versa
Encoding



Audio is encoded using Pulse Code
Modulation (PCM)
The digitized audio is transferred using RealTime Transport Protocol (RTP) – RTP solves
some of the problems of duplication, jitter,
and out of order delivery
Each RTP message is encapsulated in UDP
datagram, which is further encapsulated in IP
datagram
Basic IP telephone system


IP telephone
Media Gateway Controller
Interoperation


Media Gateway
Signaling gateway
SIP – Session Initiation
Protocol





Operates at application layer
Encompasses all aspects of signaling, including
location of a called party, notification and setup
(ringing a phone), determination of availability, and
termination
Provides services such as call forwarding
Relies on multicast for conference calls
Allows the two sides to negotiate capabilities and
choose the media and parameters to be used
Example SIP session
IP telephones and electrical
power



Analog phones don’t need power
IP telephones need power also
Power over ethernet
FTP

BSD UNIX
FTP





Establish connection
Authorize
Put or Get files
List files
cd, cdup, ls
File types



Binary
Text
Verbose and quiet mode
TFTP



Trivial file transfer protocol
Uses udp
Devices use this to update software to
devices like switches, routers, etc.
NSF - Network File System





Accommodates applications that only need to
read or write a part of a file
Integrated into a computer’s file system
http://www.uwsg.iu.edu/usail/network/nfs/over
view.html
http://www.faqs.org/rfcs/rfc1094.html
http://www.tldp.org/LDP/nag/node140.html
WWW






Browsing
http
https
Html
Xml
Web caching
Dynamic Web








CGI
ASP
JSP
PHP
Lasso
Cold Fusion
Java
Javascript
RPC


Remote Procedure Call
Places procedures on more than one
machine
RPC

Remote
RPC

Communication stubs – software to
implement the RPC
Middleware









ONC RPC
CDE/RPC
MSRPC
CORBA
MSRPC2
COM/DCOM
JINI
SOAP
XML
RPC



http://www.microsoft.com/technet/security/bull
etin/MS04-012.mspx
http://www.cs.cf.ac.uk/Dave/C/node33.html
http://searchwebservices.techtarget.com/sDef
inition/0,,sid26_gci214272,00.html