IP Phone Design for IT Departments

In her third post of the week on IP phone design SNOM Technology AG Marketing Manager Lesley Hansen explores the issues that have to be taken into consideration to keep the CIO happy – IP phone design for IT departments.

The average Information Technology (IT) Department is a busy places, especially since IT and Telecoms have now come together in one area of responsibility within most organisations. The challenges posed by telephony have increased since hot desking and mobile working have become an intrinsic part of business life.

The scale may change but the same challenges apply whether you are an individual running IT for a small business or a team running IT for a large company. In addition to maintaining existing systems and handling moves, adds and changes most IT departments are actively working to introduce new systems and applications and they often also provide a helpdesk function for assistance to all staff with use systems and application software.

So when we introduce the IT department to a new IP handset it is important to have recognised the demands and pressures they are under and so we need to have made sure we have incorporated their requirements while designing the product. Critical considerations for IT are those characteristics that facilitates the easy and cost effective operation of their department. In practical terms this means we need to consider issues of support, adds, moves and changes, return on investment, configuration, maintenance and use of the handset in multiple scenarios and situations.

Supporting Moves, Adds and Changes

Moves, adds and changes (MAC) is the general term for the routine work performed on computer and telephony equipment in a business and includes installations, relocations and upgrades. The professional handset must be easy to set up and administer ongoing and must not break the IT budget and MACs can be one of the most costly aspects of supporting a telephone system.

Adding additional IP handsets involves the configuration and installation of the new handsets and it’s synchronisation with the PBX or Telephony server. With professional IP handsets today this can be done remotely by the network manager or by the Value Added Reseller using predefined user characteristics and then the preconfigure handset can be despatched directly to site to be plugged in by the user. The saves the IT specialists from travelling to site and allows them to have a central controlled view of the installations.

Change is inevitable in business as organizations grow, expand, and adapt to new market demands. Whether the changes involves moving staff or equipment in the present location or moving to an entirely new location there is a potential cost involved to the IT Team as they deploy new IP handsets or allocate users to new handsets. One of the advantages that can be designed in to an IP handset it that it can be relocated by plugging into a new Ethernet port and will automatically re synchronise with the PBX or Telephony Server.

Security Considerations

Security is a big issue today – so it is important to design IP handsets to support encryption and Snom handsets are all designed in accordance with the EU privacy recommendations. A risk of MACs is that it introduces an opportunity to security attacks. Remote Provisioning delivers substantial benefits for ITSPs & End Users, but Provisioning Servers must be secured. As a vendor we are aware that Provisioning Servers are a prime target for attack to steal SIP credentials which can then be used to make fraudulent calls.

Key protection considerations according to the Internet Telephony Services Providers’ Association (ITSPA) recommendations for provisioning are authentication of provisioning requests which should ideally be using HTTPS client certificates, ensuring that SIP passwords are deleted from SIP servers as soon as provisioned and avoiding the use of TFTP for remote provisioning. All of these considerations are important to the IT department when selecting an IP handset and Snom’s provisioning application is fully compliant with the ITSPA Recommendations for Provisioning Security, released in July 2014.

Securing VoIP communication minimizes threats to the network and the risk of theft of private information by a hackers. Security issues with a VoIP implementation often have little to do with the telephony system. If an existing network has security vulnerabilities, these can be exploited once VoIP is implemented. Your choice of handset can play a vital part in addressing security concerns. For example the Snom 710 comes with a preinstalled security certificate for quick and secure provisioning without manual interaction. It also supports the latest VoIP security protocols to ensure secure desktop communications.

Support and Cost of Downtime

Another concern for the IT specialist is downtime, a report from a major telephone supplier last year indicated that one in five companies fire an employee when a network outage occurs. The sectors where IT staff were most at risk of losing their jobs due to core network errors were the natural resources, utilities and telecoms sectors, where one in three companies fired employees. This is because network downtime is costly to the business. Gartner analyst Andrew Lerner in mid-2014 cited a figure of  $5,600 p/minute, which extrapolates to well over $300K p/hour. Even if these figures seem excessively high for your business it makes the point that the reliability, resilience and durability for all components of the network are key to the business and if neglected risk business profitability, and so the IT specialist is looking for an IP Handset that is reliable and easy to support.

Snom handsets are designed to have an have exceptionally low RMA’s – we ensure this is the case to reduce the cost to the business both in downtime and in support costs.

Costs of Ownership (COO) and Return on Investment (ROI)

A solution that will be cost effective and easy to roll out means considering not only the cost of acquisition, but the cost of ownership and life of the product but also the durability of the handset and it’s connecting network, as they effect the cost of operation and their IT budgets.

Interoperability is also key as it effects not only the cost of the solution today but also the cost to the business if changes are needed in the future. Only when all these aspects are taken into account will the IP Handset be considered to deliver value for money to the IT department. Ensure the handsets you are considering are compatible with a large number of SIP components and VoIP systems of other manufacturers. Standard based handsets reduce operational cost and complexity and so have the ability to reduce the cost of building and supporting a telephony infrastructure. Interoperability enables “best-of-breed” deployments, this best-of-breed environment meets the requirements for rapidly deploying IP Telephony solutions. Interoperability also empowers you to leverage existing investments effectively extending the life of existing components and protecting the investments you’re your business has made.

IP Handset durability is also important in this area because if reduced this increases the exchanges required due to faulty handsets, with knock on costs for repair or replacement. To keep the cost of ownership down a vendor need to ensures that the product life is sufficiently long to provide the project with a return on investment.

Further posts in this week’s guides to how to design an IP phone can be found below:

How to design an ip phone

How to design an ip phone for voice quality

Designing IP Phones for Voice Quality

In the second of this week’s posts on designing IP phones SNOMTechnology AG UK Marketing Manager Lesley Hansen explores the subject of designing IP phones for Voice Quality.

Voice quality is not a single thing, and it can be highly subjective. Although you can measure the voice quality of a codec used in the IP Phone each vendor’s implementation of these codecs may be different, resulting in higher or lower voice quality. But voice quality is one of the primary requirement in IP Phone design for a professional and enterprise handset and skimping on voice quality testing is one of the easiest ways for a vendor to avoid development costs and produce a sub quality handset.

What is Toll Quality?

Toll Quality is the panacea. The aim of every VoIP Vendor, and the claim of many vendors is to provide Toll Quality Voice. That is voice quality equal to that of the analogue long-distance public switched network. But it is not measurable. A common benchmark telephony vendors and carriers use and the ITU has adopted to determine the quality of is the mean opinion score (MOS). MOS is a test that has been used for decades in telephony networks to obtain the human user’s view of the quality of the network. A MOS score of 4 is perceptible but not annoying and 5 is rated as excellent. But MOS provides a subjective measurement based on a single set of circumstances. For instance the MOS score given in a quite office and that given in an office with extensive background noise would be different.

Measuring Voice over IP (VoIP) is more objective, and uses a calculation based on performance of the IP network over which it is carried. The calculation is defined in the ITU-T PESQ P.862 standard. Like most standards, the implementation is somewhat open to interpretation by the manufacturers. Even more significant, depending on the implementation by the IP Phone manufacturers, a calculated MOS of 3.9 in a VoIP network may actually sound better than the formerly subjective score of > 4.0 that was considered to be the equivalent to Toll Quality.

Building the Handset

The design of the handset will also affect audio quality, this includes aspects such as the thickness of the plastic selected and the shape of the phone. For best quality IP Phone design an audio engineer is involved with the industrial designer from the first stage of each new phone design. The audio engineer can explain the audio rules to the designer.

For instance every speaker needs a chamber to create depth of voice, the curves on the phones will affect how audio signal is reflect, and the thickness of the plastic used is critical to the final audio quality achieved.

Handset design is a trade-off between the rules of audio and the aesthetic vision of the designer. It is this seeking for high quality audio combined with pleasing aesthetic design that forces IP Phone developers to improve and come up with new solutions that take them beyond today’s knowledge on achieving high quality audio.

Selecting the CODECs

The word codec is a shortening of ‘compressor-decompressor’ or, more commonly, ‘coder-decoder’. A codec encodes a data stream or signal for transmission, storage or encryption, or decodes it for playback or editing. As with conventional telephony, with VoIP the speech is initially captured in analogue form with a microphone. This analogue information is then transferred into a digital format by a converter and changed through codecs into corresponding audio-binary formats.

In order for the data to be converted correctly back into speech after being transported, the receiver must use the same codec as the sender. Depending on the codec used, the data can be compressed to differing extents in this process. Most codecs use a procedure through which information not important for the human ear is omitted. This reduces the amount of data and thus reduces the bandwidth required for transfer. However, if too much information is omitted, the speech quality will suffer.

Different codec procedures handle the audio compression with different levels of efficiency. Some are specifically designed to achieve a low bandwidth at any cost. Depending on the codec, therefore, the bandwidth needed and the speech quality will vary. The design skills of the IP Phone manufacturer in the management of codecs creates a clear differentiation between vendors.

Refining Voice Quality

Methods such as jitter buffers, echo suppression, echo cancellation and packet loss concealment can be used in IP handset design to improve voice quality.

Echo suppressors work by detecting a voice signal going in one direction on a circuit, and then inserting loss in the other direction. This added loss prevents the speaker from hearing his own voice. Echo cancellation is based on recognizing the originally transmitted signal that re-appears, with some delay, in the transmitted or received signal. Once the echo is recognized, it can be removed by subtracting it from the transmitted or received signal.

When silence suppression is on, comfort noise needs to be generated locally by the IP Handset at the other end of the call so that the other party will not mistakenly believe that the call has been terminated. By preventing echo from being created or removing echo if it is already present voice quality is improved, at Snom we call this Automatic Noise Reduction.

IP Phones echo controls are implemented digitally using a digital signal processor (DSP) or software and at Snom we implement to the ITU requirements. Digital signal processing is the mathematical manipulation of the information signal to modify or improve it. DSP is not one size fits all. Different DSP coefficient pre-sets are needed for different room types. Refining the voice using these techniques will improve the subjective quality, as an additional benefit the process also increases the effective use of bandwidth as silence suppression prevents echo from traveling across the voice network.

Transmitting high quality voice over IP is made more difficult due to packet loss and jitter. A technique used to reduce jitter involves buffering audio packets at the receiving handset, so that slower packets arrive in time to be played out in the correct sequence at the appropriate times. The objective of jitter buffering is to keep the packet loss rate low and so improve the voice quality. A fixed method, which uses a fixed buffer size, is easier to implement than an adaptive method, but will result in less satisfactory audio quality because there is no optimal delay when network conditions vary with time.

Snom handsets support adaptive jitter buffers which although more complex and expensive to implement perform continuous estimation of the network delays and dynamically adjust the playout delay at the beginning of each transmission so ensuring a high quality of voice.

Packet loss concealment (PLC) is a technique to mask the effects of packet loss in VoIP communications. Because the voice signal is sent as packets on a VoIP network, they may travel different routes to get to destination. At the receiver a packet might arrive very late, corrupted or simply might not arrive. This could happen where a packet is rejected by a server which has a full buffer and cannot accept any more data. In a VoIP connection, the receiver should be able to cope with packet loss.

All these voice techniques enhance and improve voice quality, and are quantifiable and measurable components of high quality IP Phone design and should be viewed as absolute requirements in professional and enterprise handsets.

Testing the Voice Quality

Testing voice quality on a new product should begin as soon as a first injection of plastic is produced and continue throughout the life cycle of the product.  In Snom we believe in the value of doing our testing house and have made a considerable investment in German engineered state of the art Audio equipment that will simulate not only the voice from the phone handset and speaker phone and in relationship to the human head, but also test for voice quality under different conditions such as with background noise from a busy office or factory and in a variety of network conditions. Ongoing testing ensure the quality of voice provided by VoIP phones and VoIP accessories and end points including wired and wireless headsets, speakerphones and conference audio-devices.

Accurate and effective audio measurements require time, preparation and patience. Snom’s testing in done in our Head office in Berlin using our state-of-the-art audio quality measurement equipment and anechoic chamber facility. Leading measurement technology combined with the know-how and experience of the Snom audio quality team enables comprehensive subjective and objective testing to determine audio quality parameters to maximize VoIP device potential. The measurement system uses the IP phone specifications .published in the latest ETSI and TIA releases.

Check out a past article on SNOM audio quality testing here. Also the first post in this series of designing IP phones can be found here.

What is involved in designing an IP Phone?

Lesley Hansen is UK Marketing Manager of German SIP handset vendor SNOM Technology AG and is this week guest editor of trefor.net. This role of guest editor is one that I have introduced to bring a focus on specific themes and is an enhancement of the “themed weeks” that have become so successful on this blog.

Lesley is a time served veteran of the telecoms industry and SNOM are one of the oldest players in the SIP game. SNOM were there right at the beginning of the SIP industry before commercial services were available. When SNOM introduced their first handset the only other vendors around were Siemens and Pingtel (long since deceased). SNOM and Lesley are uniquely positioned to talk about their subject.

This week Lesley  has at my invitation put together  a series of posts outlining the issues and challenges involved in the design and manufacture of IP Telephony handsets. SNOM are obviously going to get a lot of mentions in this series but the intent is not to be a sales pitch for the company. It is natural for Lesley to refer to her own company’s experience in writing the pieces. In this first post Lesley outlines the areas that she is going to cover this week.  She refers to articles that are coming during the week and to which I will link as they go live. I leave the rest to her…

This is the introduction to a multi-part series of articles looking at the issues involved in designing an IP phone. Founded in 1996, Snom Technology AG manufactured the world’s first SIP Handset and continues today to provide a market leading brand of professional and enterprise IP Handsets. As such we are exceptionally well qualified to discuss the concerns and challenges of designing IP Phones.

What is an IP Handset?

A VoIP or IP phone is simply a handset that uses Voice over IP (VoIP) technology to allow calls to be made and received over an IP network (like the Internet) instead of using the traditional Public Switched Telephone Network (PSTN). The audio signals from the voice calls are digitized into IP data packets, the handset is connected to an IP network and these IP packets are routed through a private IP network or over the public Internet creating a connected voice call.

IP Phones look very much like traditional office handsets but they are based on a different underlying technology. The use of IP Technology raised potential issues of call quality due to the breaking of the voice into small data packets and these have to be managed in the handset design, and since IP Phones interface with VoIP system telephony software, they have to be able to support features and capabilities that were not provided by traditional office phones. This additional functionality makes the user interface more critical to ensure an easy to use and reliable handset. A good quality of design in an IP Phone can make the IP Handset a valuable resource for many years. A poor design can deliver poor quality voice and become an expensive resource to support and a source of much frustration from business users.

Designing to meet user expectations

Users have clear demands. They want their IP Phones to work and they want them to look good. The problems in designing an IP Phone arise when we try to quantify what working and looking good really means. Elegance and simplicity are very important in phone design but must be balanced with practicality and ease of use this is one of the challenges of IP Phone design. (Further Information: Article on Designing for Beauty)

People are very finicky about voice quality in VoIP because they were used for years to the impeccable quality of landline phones.  The standard for voice quality on a telephone handset has therefore been set by the PSTN and this is what we refer to as toll quality voice.

Voice quality was one of the darkest spots on VoIP’s reputation the early years after its introduction. Now there has been much improvement. For toll quality voice to be achieved on an IP Phone the issues created by using a packet based network where there are no inherent controls on the order or speed of delivery of the packets have to be considered in the phone design. Echo, choppy voice, broken voice, buzzing and delayed speech are common descriptions of problems experienced with the early VoIP connections.  Although some of these factors are the result of a variety of factors not all related to the handset itself, the handset design must minimise the effect of each of these. The one of these most attributed to the IP Handset is echo and designing for echo cancellation and control is key. (Further Information:  article on Voice Quality)

Designing for the demands of IT

One of the challenges with an IP Phone is that the handset has to be configured before the phone can talk to the IP Telephony PBX or IP Server, so before the phone can be used. Provisioning is critical, at its core, the provisioning process monitors access rights and privileges to ensure the security of an enterprise’s resources and user privacy. As a secondary responsibility, it ensures compliance and minimizes the vulnerability of systems to penetration and abuse. In a good quality phone design it is possible to configure phones centralised, which saves a lot of time and money in sending personnel to site.

But the demand is not only these during setup, the design should also ensure updating phones or setting special configurations is easy. This is possible because of this centralisation. Auto-provisioning or auto-configuration is the name we give to this easy and time-saving way to configure IP-phones for IP-PBXs. With auto-provisioning, all user information is entered at the central web interface of the PBX or form the IP Phone management software.  Required data includes the MAC address of the IP-phone, the desired extension and the caller ID which is displayed on the called party phone display. The IP-phone receives the configuration over the local IP network. (Further Information:  Article on Designing for the IT Department)

Ensuring IP Telephony is not compromising the Business

The growing reliance on VoIP has reduced business telephony costs, but it also increases their complexity and this needs to be kept in mind in the IP Handset design. Security has become one of the hottest issues in telecom management. IP telephony not only increases the complexity of data networks, particularly in hybrid telephony environments built with equipment from multiple vendors but it increases security risks. For IP telephony management to be effective it cannot focus solely on reporting on network usage, ensuring dial tone availability and managing call quality, it must place an emphasis on security and protecting the enterprise from telephony-borne attacks.

Today telecom managers face pressure to protect the organization from telephony-related threats, and to do it all while cutting costs and improving ROI. Security measures such as encrypting voice services, placing VoIP equipment behind firewalls, and defending against Denial of Service (DoS) attacks are just some of the steps you can take when introducing VoIP into your organization’s network infrastructure.  Other measures include guarding against toll fraud, securing phone records, and protecting the phones. While there is no such thing as a bulletproof VoIP implementation, you can protect your business by selecting IP Handsets designed to provide high quality security to the business. (Further Information:  article on Designing for Security)

No man is an island – and neither is an IP Phone!

Many solutions using IP Phones are hybrids. A hybrid telephony solution could be mixing either IP or PSTN, it could involve a mix of hosted and on premise telephony services and to get the fully set of functionality needed by the business it is likely to include hardware from multiple vendors. Even if an IP Telephony solution is deployed as single vendor, single deployment single technology it is highly likely that over time elements of third party products or new technologies will be introduced.

It is therefore very important when designing an IP Handset that standard are complied with consistently to ensure the IP Phone is able to operate in a mixture of existing and potential environments. Snom’s operates an interoperability program that gives customers the opportunity to find out which components work with each other. To assure the interoperability between the IP Phones and other elements of the IP Telephony solution, all Snom handsets undergo a range of interoperability tests in our labs. Advanced features such as transfer and Music on Hold are required to work. For our partners gaining the Snom Advanced level of interoperability means that the customer can be assured that the tested functionality works smoothly. (Further Information:  article on Designing for Interoperability)

And the final design criteria – cost

The best quality and most elegantly designed IP Phone in the world will not be widely accepted unless it meets the business expectations regarding cost. Cost in its broadest sense will include cost of acquisition, cost of deployment, cost of ownership and return on investment. Any IP Phone design must consider each and every one of these aspects. (Further Information:  article on Designing for the Financial Director)

Snom’s investment in Handset design is significant and over 45% of our workforce is focused on Handset design, testing and development. This approach has made Snom a leader in the market and unique software and hardware developments on the Snom handsets are emulated by many other IP Telephony and Handset manufacturers.

Lots and lots of VoIP posts on trefor.net – check em out here