Voice over IP (VoIP) Service

 VoIP Basics

 Voice Over IP (Internet Protocol) is the technology of transporting voice communications over IP networks.

The current UH Manoa telephone system relies on physical wires that directly connect your handset to a port on the UH Manoa telephone switch at Bilger Addition. A separate data network connects the computer to switches and routers in the building basement, which is then connected to the UHNet via fiber cabling. This separation of voice and data networks will change with the implementation of VoIP.

With VoIP, voice communications run as IP Packets within the data network.  A separate voice network is no longer needed.

The handset acts as a normal telephone handset - the only apparent difference is that it connects to the data side of the datajack via standard Ethernet cabling and has an IP address. Existing phone numbers, five-digit dialing and multiple line appearances will be kept with no changes.

ITS managed Power over Ethernet (PoE) switches in the building wiring closets will provide power to the IP Phones through the Ethernet cable and will continue to power the phones for at least 15-20 minutes during a power outage.


 VoIP Handsets behave identically to the currently installed handsets. One change would be that basic analog handsets will be upgraded to single line digital display VoIP handsets.  For more information about the phone sets and user guides, go to  www.hawaii.edu/askus/1405 

The handsets are powered via Ethernet, commonly referred to as Power over Ethernet, or PoE (802.3af). The Ethernet switches in the wiring closets will sense if a device is capable of utilizing PoE and only after it determines that it is, will power be sent. This delay and check protects equipment that is not PoE aware.  Accidentally connecting a computer or other non PoE device directly to the datajack will not cause any damage.

As much as possible, ITS will disconnect the Ethernet cable from the computer in the office, connect it to the IP Phone and then run a cable from the IP Phone’s PC port to the computer.

Analog Lines

Current analog handsets will be replaced with a single line IP Phone. Analog lines for faxes, modems, conference phones, etc. will be provided over the IP network through analog gateways located in the main telecom closet in each building - thus no changes will be necessary for these devices.  Short downtimes will be required as jumpers are moved to the new equipment.
Avaya Voice Mail 

The new Avaya voicemail system provides the following key features:

  • Unified messaging - Voice messages can be forwarded to your email mailbox
  • Reach me - Incoming calls can be forwarded up to three numbers when there is no answer to the phone *
  • Notify me - Text message, phone call,  and/or email notification can be configured when a new voice mail message is received *

* Contact ITS at 956-6033 if you are interested in using these options.  For more information, see the FAQ at www.hawaii.edu/askus/1358

Quick Reference Guide:   Avaya Aura Messaging (voice mail) quick guide for Manoa  or  support.avaya.com/Libraries/Msg/60/user/en-US/QRG/

Avaya Aura Messaing Web Interface User Guide :  Avaya Aura User Guide

Network Design

The VoIP network, while running on the same physical network equipment as the existing data network, is completely separate and isolated.

All IP Phones across campus will be on the VoIP network which utilizes private RFC1918 addresses. At no time is the VoIP network interconnected with the UHNet and thus the IP Phones cannot be reached via the Internet. No IP address changes will be required for computers, nor will any additional IP addresses from departmental allocations be used.

The Ethernet switch port that the IP Phone connects to also provides access to the existing data network. The existing data network will be set “untagged” while the VoIP network will be “tagged”. Tagging refers to applying an 802.1Q or VLAN identifier to the Ethernet frame. The IP Phone will look at the “tagged” frame for voice communications and pass the “untagged” frame out its PC Port and onto the computer. As the data network is “untagged”, plugging a computer directly into the jack will continue to function as it does now.

VoIP bandwidth for a typical phone call averages about 16 kilobits per second in both directions.  Quality of Service (QoS) settings on all of the ITS switches from the building to the UHNet core will ensure that voice traffic is prioritized over any other traffic - thus even if an Ethernet port is fully utilized, the phone will ring and will be able to place a call with no effect to the sound quality.

As the IP Phones are powered by PoE Ethernet switches from a central location (wiring closets per floor), ITS will be able to provide at minimum a 15-20 minute runtime for the IP Phones in the event of a power outage. Certain locations may have longer run times due to the smaller number of switches and phones. Once UPS power is exhausted at any point throughout the network, IP Phones will not function.

Typical Network Diagram



Why are we switching to IP Phones?

Moving the phones towards a network based system opens up new services to our users and provides cost savings for the University.  

Will there be any phone outages?

For IP Phone handsets there will be no outages for the users. Until the old handset is removed, it will continue to function.

Analog lines to faxes and conference phones will incur an outage of approximately 30 minutes as jumpers are moved at the building and at Bilger Addition.

If they wish, users may use the ethernet port on their IP phone to connect their computer and free up the ethernet port on the Telecom outlet for other devices.

Will our network have to change?

No. Addition of the IP Phone will be transparent to your network. The existing data network that is currently coming out of the datajack will now show up on the PC Port of the IP Phone. No readdressing of any computers is necessary.

Will ITS use up my IP address allocation?

No. The IP Phones uses RFC1918 private address space that is completely independent of your allocation. You will not see the IP phones on your network.

Will the Phones work in a power outage?

Yes - ITS will power the phones from the wiring closets with Power over Ethernet switches that are UPS protected. ITS estimates that a typical runtime for the UPS will be at least 15-20 minutes. Some locations may run for a longer period of time.

Will my fax machines and conference phones work?

Yes. These extensions and jack numbers will be identified and analog service will be provided.  These devices will incur an outage of approximately 30 minutes as jumpers are moved to the new cabling.


Please rate the quality of this answer: Poor Fair Okay Good Excellent
Not the answer you were looking for? Try different keyword combinations and if you still can’t find your answer, please contact us.
Article ID: 1340
Created: Wed, 07 Dec 2011 5:14pm
Modified: Thu, 23 Jun 2016 8:39am