Transcript Document

Voice over IP (VoIP)
NCAB Presentation
Jeff Custard
VoIP—What is it?
Voice packets transported using IP
 Traditional networking infrastructure
carries voice traffic
 Standards based (e.g., H.323, G.711,
G.729, RTP, UDP, IP, RSVP)
“Acronym Soup”
DYA-Define Your Acronyms!
– [see NETS “Projects page” info and
articles or my “network acronym
decoder” page at
Buzz words
“Multiservice networking” and
– Data, voice, and video on one
– The driving benefit (among the many
touted) is reduced costs
IP Telephony benefits:
Single wiring closet
 Choice of phone power
 Flexible IP address assignment
 Easy adds, moves, and changes
 Voice quality guarantees
 Redundancy
Quality of Service (QoS) issues
Have to deal with packet loss, jitter,
and delay
QoS issues, continued
At the edge of the network:
Additional bandwidth
Queuing (WFQ, CQ, PQ, CB-WFQ)
Packet classification (IP Precendence, policy
routing, RSVP, IP RTP Reservce, IP RTP
– Shaping traffic flows and policing (GTS, FRTS,
– Fragmentation (MCML PPP, FRF.12, MTU, IP
– Jitter control on end routers
QoS issues, continued
At the network backbone:
– Packet over SONET
– IP and ATM inter-working
Powering the phones
3 ways to deliver 48V to the phone:
– “Inline power” (over the same cable
used for Ethernet connection)
– Powered patch panel inserted between
existing switch and end devices
– AC power adapter to wall socket
“Phone discovery” feature
NETS VoIP Team & Resources
People: Scot Colburn, Jeff Custard,
Teresa Shibao, Jim VanDyke
 Equipment: IP Telephones, Cisco
CallManager, Cisco 3640 routers
(plus various voice-related
interfaces), switches delivering inline
power, and existing data outlets
“The sandbox”
Initial testbed already deployed—
we’ve gone through basic setup and
component interaction
 Full “test deployment” – within the
next month (25 IP Phones; variety of
system and user configurations)
Project Goals
Learn about and test current VoIP
 Determine viability of VoIP solutions
for UCAR
 Test interaction with current PBX and
other “unified messaging” solutions
Related Documents
Lots of information and additional
links at: