Data Centers and IP PBXs

LAN StructuresPrivate Clouds

IP PBX ArchitectureIP PBX Hosting

Local Area Networks(LANs) at

Enterprises• Characteristics

– 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 centerEnvironmental considerations

Cooling HeatingFloodingSecure access

Space issuesNot 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

Physical host servers

Ethernet LAN

*Storage area network

Ethernet LAN

Redundant Switches

Servers at headquarters with replication software and virtual machines

Headquarters site Remote, backup site

Physical host server withvirtual machines

SAN*

SAN*

**Wide Area Network

Switch

WAN**

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

Wide area network

Centralized voice mail/unified communications server

Voice over IP system in box

Layer 2 switchCommunications server

Headquarters

Remote office

Gateway

Router

Router

PSTN: Public switchedTelephone network

A VoIP Telephone System VoIP Architecture

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• 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 PublicInternet

VoIP Links

Should our Organization Use a Hosted IP PBX?

• 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

• 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

• Private clouds• Structure of VoIP telephone systems• Hosted IP telephone systems• VLANs (virtual local area networks) & Storage

Area Networks