A Practical Guide To The World
Of LAN Telephony
Charles Rutledge
VP Marketing
Quintum Technologies, Inc.
Introduction To The World Of LAN Telephony

Goal – Provide A Practical Perspective To The
Deployment Of IP Telephony Systems
 Why IP Telephony?
 IP Telephony Issues
 IP Telephony Case Studies
 Conclusions
IP Telephony Can Provide Significant
Savings

Attractive ROI on LD calling
 Domestic calling can payback in less than a year
 International calling can payback in WEEKS!!

Less Investment Than Traditional PBXs
 Up to 40% less expensive than traditional PBX solutions
 Single cable drop to the desktop

One system to support multiple sites
 Centralized voice mail
 Consolidate toll and inbound 800 calling

Administrative costs can be lowered
 A single voice and data network (Administration – Training)
 Centralized administration for multiple sites
 Lower costs for (MACs) Moves, Adds, and Changes
LAN Telephony Also Support Valuable
Convergence Applications!

Open Architecture
 Ability to utilize different vendors to
support specific businesses needs
 No vendor lock in!

Valuable and Innovative Applications
 Support for branch offices/remote workers
 Unified Messaging
• 20 to 40 min saved per day!
 Wireless (802.11)
 PDA Phone
 Web application integration
• IP Contact Centers – collaboration –
• Instant Messaging - Video
There Are Issues That Face VoIP
Implementation

Quality of Service
 Voice Quality
 IP Network

Standards
 Interoperability
 H.323 - SIP



Security
Existing Infrastructure
Cost/Budget
IT Managers Are Faced With Balancing
The Risks With The Rewards!!
Manage The IP Telephony Risk
- Deployment Strategy Radical Revolution Or Easy Evolution

Either may be right – or something in between
IP PBX
IP Voice
Server
Converged PBX
PBX
WAN VoIP
PBX
VoIP Gateway
VoIP
Gateway
PSTN
IP NETWORK
PSTN
IP NETWORK
IP NETWORK
PSTN
Remote Office
Gateway
Remote Office
Gateway
VoIP Gateway
PBX
LAN Telephony Systems Can Be Integrated
With Existing PBX To Evolve The Network

Add an IP Voice Server or IP enable the existing PBX.
PBX
IP Voice
Server
Home Office
Branch Office
IP NETWORK
Remote Office
Gateway
VoIP
Gateway
PSTN
Existing Network
There Are A Variety of Deployment Issues!
Protocol - Standards
Voice Quality
H.323 vs. SIP
QoS
Bandwidth Requirements
Legacy Infrastructure
Network Integration
Security
NAT/Firewall - VPN
Availability/Survivability
Review Existing Infrastructure – Plan The Network
H.323 Or SIP – Which To Use?

Today it is an H.323 world
 Established protocol – lots of it out there
 Lots of vendors equipment interoperate
 Telephony like signaling – complex

SIP offers promise for the next generation
 Newer standard – Internet based
 Simpler – Create “sessions”
• Like HTTP – Wealth of available development resources
• Integration with web based applications
• Access via any SIP enabled technology – phone, video, IM


Both will likely survive and interoperate
Open Standards – Take advantage of it!
 Protect the future of your investment
Resources:
www.sipcenter.com
www.protocols.com
Good Network Characteristics Are Required
To Support High Quality Voice

Business LANs today provide good network
characteristics – Better voice than the PSTN
 Switched Ethernet to the desktop – lots of bandwidth
 Estimate bandwidth requirements
Resources:
• LAN –G711 with 20 ms packetization
• Assume worst case busy hour - 1 of 4 phones

www.erlang.com
WAN characteristics are more challenging




Latency: Typical <100 ms
Maximum < 200ms
Jitter: Typical < one sample
Maximum < 40ms
Packet Loss: Typical – < 1%
Maximum <5%
85% maximum utilization at peak traffic
Compression Can Minimize Bandwidth
Requirements On The WAN


VoIP on the WAN can provide “PSTN Quality” voice!
Understand and minimize bandwidth requirements
 G.729/G.723
 Silence suppression
• 35% savings
 Header compression
• 50% savings
 RTP multiplexing
• 50% savings
QoS Can Help Support Good Voice Quality

Support of VLAN and QoS capabilities
 IP Phones support of VLAN tagging
• Keep all the voice traffic on a layer 2 VLAN dedicated to
voice and signaling traffic – 802.1q
• Prioritization – 802.1p
 VoIP devices support of TOS or Diff-Serv
• Prioritize voice traffic through the routers and switches
 Required at every point in the network
Resources: http://compnetworking.about.com/cs/virtuallans/
Supporting QoS Can Create Challenges

QoS becomes more challenging the larger the network
 Multiple methods of differentiating service classes
• Requires compliance to the rules of the administrative domain
• QoS must understand all methods of differentiation
 QoS must be supported at every hop (internal & external) Or NO QoS
• Any hop where QoS is not supported becomes a potential congestion point
• QoS characteristics can be lost between domains

QoS is most needed where it is hard to support
 Worldwide networks have the greatest latency.
 Many remote sites use the internet

Utilize the PSTN for real time back up when the IP network
does not support the desired QoS!!
Security At The Edge – Getting Around NAT

Tale of two data paths – signaling and voice
 Call signaling provide the information to establish the call
and is translated by the NAT
 The signaling embeds the source and destination IP
addressing for the media – unknown to the NAT

Various solutions
 VoIP aware firewall – upgrades to existing some firewalls
 VoIP to VoIP gateway – VoIP Call Relay
 Site to Site VPNs
• Adds bandwidth and latency due to the encryption
Security For The Media – Who Could Be
Listening In?

There are a steps that can improve the security of the
media stream.
 Protection behind the firewall
• Support with some VoIP NAT capability
 Put VoIP equipment on virtual LANs and enable the
security features on the switches.
 VPN routes between sites to support VoIP
• Latency? QoS?
 RTP encryption where possible
Working With The Existing Infrastructure

Do I need to throw away my PBX?
 Many systems can be “IP-Enabled” allowing IP
phones to be added and PBX extension to branch
offices.

Some IP-PBXs are easily integrated in with the
existing PBX
 Put the IP-PBX on the same dial plan – add a group
at a time.
 Support remote offices over IP
Survivability Is Critical – You Never Want To
Lose The Phones


Deploy Redundant Voice servers
Deliver power to the phones over the Ethernet
 Ethernet switches that deliver the power on back-up power
supplies

Remote office gateway need to be able to support
calls when the connection to the server is lost
 Back-up call management – support IP calling to other
locations

Real-time PSTN back-up for off net calling
Agriculture Bank Of China Is Connecting
100s Of Branch Offices
A800
Phone
Banking
Tenor GateKeeper
D3000
CENTREX
Server
Other regional
and local
branches
Financial
Network
PSTN
A400
PBX
Regional Branch
Switch
Switch
PSTN
Local Branch
Agriculture Bank Of China Is Connecting
100s Of Branch Offices

Deployment of 100 offices was completed in 30 days.
 LD calls are sent over the VoIP network to local branches for
“Hop Off” on to the PSTN.
 Phone Banking calls “Hop On” to the VoIP network.
 Less than 5% of calls fall back to the
PSTN with no changes to the IP network.
 $50,000/month savings
without Phone Banking.

Now 500 sites!
Getronics Government Solutions Is Migrating
Their Voice Network To IP Telephony
Nortel PBX
Tenor VoIP Gateway
Tenor VoIP Gateway
Nortel PBX
PSTN
bConvergent
OpenVoice
Server
IP NETWORK
Virginia
Maryland
Colorado
Colorado
Alabama
Illinois
Hawaii
Getronics Wanted To Integrate IP Telephony
Into Its Existing Infrastructure

Advanced features to Executive Account Managers
 Find Me/Follow Me
 Voice Mail/e-mail integration with the existing exchange
server
 Web based profiles



Seamless operation between IP phones and PBX
Reduce toll charges between sites
Move other employees over in phases
Panacea Pharmaceuticals Converged Infrastructure
Saves On Partner Communication
bConvergent
OpenVoice
Server
Tenor D2400 T1
Gateway
PSTN
IP NETWORK
10/100 Switch
Boston
Tenor A800 Analog
Gateways
IP Conference
Phone
Chicago
IP to the Desktop
Low Cost Analog Phones for the LAN
Tokyo
IP Conference
Phone
IP Conference
Phone
Panacea Pharmaceuticals Wanted An Efficient
Voice System

Improved efficiency
 Web based e-mail and voice mail

Lower cost infrastructure – New facility
 Single drop (IP) at each desktop – Saved $100/drop
 Reduced network administration

Network cost savings
 Regular conference calls with research partners over IP

Cost effective solution with full PBX features
 OpenVoice server, 4 Quintum VoIP gateways (3 8 port analog – 1 T1)
 10 Polycom IP phones – 24 analog phones
 $400 per station vs. $750 to $1000 for a traditional PBX
Key Steps To Follow When Deploying IP
Telephony

Planning and evaluating for VoIP deployment
 Assessment of the existing infrastructure
 Evaluation of VoIP requirements
Upgrading the IP as required
 Lay out the network
 Run a pilot – Identify any issues
 Full implementation

What Is The Right Way To Deploy IP
Telephony

Objectives
 Cost Savings
 Efficient Operation
 Applications


Existing Network
Infrastructure
Cost of
Implementation
It Depends!!!!!!!
IP Telephony Implementation Strategies
Uncertain
Maximize
Existing
Equipment
17%
Mixed
Approach
42%
23%
18%
Deploy in New and
Replacement Scenarios
Source: Phillips Group InfoTech
Conclusion



IP Telephony can successfully be deployed with voice
quality at least as good at the PSTN
IP telephony offers both cost and application benefits
There are issues that need to be understood!
 Solutions are available based on the needs of your network!

There are a variety approaches that allow you to begin
small and grow your IP telephony network
Thank You!