Data Centers and IP PBXs
LAN Structures
Private Clouds
IP PBX Architecture
IP PBX Hosting
Local Area Networks(LANs)
at Enterprises
• Characteristics
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Ownership
Limited geography
High speeds
Shared devices
• Ethernet & TCP/IP
Facts about LANs
• Local in nature
• LAN mostly covers a small area
• Router ensures you reach outside
network
• LAN interconnects computers
• LANs can be 100 MB or higher
• Economical way to share printers
• LANs can be wireless
• LAN uses file server for network
operating system
• LANs have switches to connect
devices together
• LANs segments can be connected
by fiber optic cabling
• Can access LANs with a password
• Wi-Fi routers support multiple
protocols
• LAN switches reduce cost of
cabling devices together
• If main file server gets corrupted
all LAN devices can be infected
• LANs enable students to share
applications
• LANs can connect to alarm
systems
• LANs use Ethernet protocols
• Wi-Fi eliminates cost of wiring to
devices
LAN architecture
Architecture: how devices fit
together in a network.
Data Centers
Purpose of a data center
Environmental considerations
Cooling
Heating
Flooding
Secure access
Space issues
Not too large – space costs $
Not too Small– need to grow
Private Clouds
• Created within organizations
• Emulate cloud providers’ data center
structures
– Centralized applications
– Standardized applications
– Self service
• Take steps to achieve greater efficiencies
• If at provider; dedicate server to single
customer; costly
Automatic Failover (backup) to a Remote Site Using Replication
Software in Virtualized servers
Headquarters site
Ethernet LAN
Remote, backup site
WAN**
Ethernet LAN
Physical host
server with
virtual machines
Servers at
headquarters with
replication software
and virtual machines
Physical host
servers
Switch
SAN*
Redundant Switches
SAN*
*Storage area network
**Wide Area Network
Virtual LANs
• virtual local area networks (VLANs)
– “Tagged” as a separate LAN in software
– Packets in VLANs prioritized for better voice
quality and multi-media services
– Only certain packets reach them
– Shielded from some viruses
VoIP Architecture
A VoIP Telephone System
Remote office
Internet
Headquarters
PSTN
Voice over IP
system in box
Router
Wide area
network
Router
Layer 2 switch
Gateway
Communications
Centralized voice mail/unified
server
communications server
PSTN: Public switched
Telephone network
What do you know about IP PBXs
• Changes can be made in software
much easier than traditional TDM
systems
• Phone calls transmitted over the
internal IP network
• Media gateway has digital signal
processor to compress voice
• Can connect to PSTN (traditional
networks) and Internet (IP)
networks
• Have built in applications like
voice mail
• Can transfer voice/video over
network
• Can contain unified
communications email box
w/voice mail messages; one
software application also video
• Can integrate w/some mobile
phones
• Can easily add more phones/auto
attendants/applications
• Because it’s digital/ can store
more data/ recorded calls
• Easier to manage
Steps in VoIP PBX Selection
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How do you determine the organizations’ needs?
– Size of org. in number of people
– Number of sites;
– Requirements for conference calls – may need more phone
lines
– Employee functions – does each staff need a phone?
– Look at employee usage – phone bill $s; # of calls
– Call center needs? – customer support
– Budget; security needs
– infrastructure
– Growth? Financial officer, CEO
What are the 5 most important criteria for system selection?
– Cost, User friendliness; reliability, security; size & energy
needs
What questions will you ask vendors in order to evaluate them?
– What is the difference with competitors; references; service;
do they offer more equipment; maintenance? Specifications
of what’s included in contract & maintenance contract;
what’s included; # of phones, capacity without a processor;
cost?; redundancy? Global reach?
The Rationale for IP PBXs
• VoIP advantages
– Open standards
• Applications for call centers, voice mail etc.
• Telephone compatibilities
– Voice and data on interoffice trunks
– Centralized Administration
– Centralized Unified Communications
Hosted IP Telephone Systems - Rationale
• Rationale
– Lack of in-house expertise
– Uncertain growth
– Dispersed sites
• Media server, gateway and software at provider
• Web interface for customer programming
Provider with VoIP
hardware & software
Private or Public
Internet
VoIP Links
Should our Organization Use a Hosted
IP PBX?
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Absolutely
We don’t want to do maintenance
Just one Ethernet network
We have a positive vision of
technology
Easier for vendor not us to update
Save $ on staff
Upgrades by host
More skills at host
For small companies, hosted IP has
more services
Save on energy
Not stuck with capital for expensive
equipment – more flexible
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Never!
Like current system,
More $ monthly
Others will look down on
company image poor
Security worries
Want to control system
Tech. too new
If telephone line is cut no service
Not supported in enough
countries
Our intellectual property not
secure over Internet
What happens if host goes out of
business?
Summary
• LAN architecture
– Backbone
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Private clouds
Structure of VoIP telephone systems
Hosted IP telephone systems
VLANs (virtual local area networks) & Storage
Area Networks