Voice over Internet Protocol (VoIP) is technology used to transmit voice over an IP network, which can be either a corporate network or the internet. Traditionally, time-sensitive non-bursty voice traffic was carried over connection-oriented, circuit-switched devices and networks (PBXs, PSTN, and ISDN). Once a circuit is set up, it is dedicated to a specific call until the call ends.

The voice is usually digitised ensuring excellent vocal quality. Data, however, being non-time sensitive traffic, has been carried in packets across connectionless devices and networks (Ethernet LANs, IP WANs). In this way, the communication channel is shared, thus reducing costs. Using voice-over-packet technologies, it’s possible to mix voice and data on a single network.

The benefits are:

• Optimised bandwidth
• Optimised network installation and management
• Easier converged application development

Why Drives Networking?

Almost 50% of mid-sized companies have a central location and one or more remote site(s). It typically consists of a headquarters, a production plant and warehousing facilities, and small branches or regional offices in national or international locations.

The decision to include remote sites in a single enterprise network is justified by:

Strategic reasons
System-wide networking allows previously remote business sites to become part of the overall business reducing the feeling of isolation while encouraging the development of a common work atmosphere. What had been disparate business entities are now part of a single networked enterprise.

Commercial reasons
Businesses are looking to provide their customers a uniform image when being greeted by the communications system, regardless of the location the customer is dealing with.

Economic reasons
In some cases operator billing represents 80% of the overall communication expenditure. By including remote site communication needs in a single enterprise network, communication costs are greatly reduced by cutting operator expenses. A layer of networking services can be provided over the legacy PSTN infrastructure. If the ISDN protocol is used, communication between business sites will be provided with the same level of service as communications that are external to the enterprise.

To improve networking services, businesses have expressed a need for new private communication services that fall into these five categories:

Optimising communication costs
Depending on the site’s geographical configuration, the inter-site traffic level, and the data communication bandwidth requirements, it’s financially beneficial to use alternative operator infrastructures such as a private switching network. When a business decides to use multiple infrastructures, there are a set of complementary services that can be used to further enhance cost optimisation. This can be achieved using voice compression techniques, overflow mechanisms between private and public networks in the case of peak traffic, communication “splitting” (public numbering plan routing to private networks), as well as local proximity “breakout” to the public network after being routed across the private network. All of these features contribute to the significant reduction in communication costs.

Improving services for users
Although the ISDN protocol provides a number of advanced services such as caller identification and min-messaging, certain enhanced corporate telephony services are not possible over a multi-site via the ISDN D channel protocol, such as: automatic call-back on busy, call transfers with attendant supervision, general availability of 2nd call, consultation calls, conference calls, call transfers, and automatic detection of mobile users (DECT/PWT) when they move to other locations.

Centralising communication resources
Offering services from a single communications server to all enterprise users equipped with a unique voice mail and directory, irrespective of their geographical location, can contribute greatly to the optimisation of communication costs and investments.

Centralising administration and management tools
Piloting central administration data (such as alarms, carrier and operator cost control) is an important factor for the measurement of efficiency and productivity by the network management team in charge of monitoring the network. However, in the case of a multi-location business, the option to maintain or de-centralise certain functions is frequently requested to allow local management of certain user parameters, or editing of local site metering, while still ensuring unified contact with the headquarters.

Improving Security
A primary business expectation is that network administrator access will have non-stop protection with secure data exchange between sites in the event of poor service or network transport infrastructure saturation.

Call handling can either be centralised or de-centralised. Ask your Evotec Account Manager about the organisational needs that are to be taken into consideration.

Quality of Service (QoS) in the LAN and WAN
When a VoIP communication is established, the voice packets travelling from the sender to the receiver may encounter three different problems: packet loss, delay and the variation in this delay, jitter. Obviously, this can have a negative impact on the quality of the conversation, as voice is so time-sensitive. To prevent such delays several solutions are available, e.g. by using an oversized bandwidth or by tagging and managing voice packets as priority packets over the data network.

How does it work?
Voice is a natural analogue signal. For VoIP, this signal must be digitalised on 64kb (using the G.711 algorithm), compressed if necessary (using G.723.1 or G.729A) and then packetised (encapsulated into IP packets). All IP phones equipped with a component, which digitises and packetises voice, the so-called DSP (digital signal processor).

The communication server (IP-PBX) manages the call setup between two phones using communication protocols and then offers the user a certain set of features to conduct her conversation of her work.

Evotec provides a range of options across multiple platforms; call your Evotec Account manager on 1300 133 996 today for more information.