Not only voice communication can be done via voice network. Data network can now be utilized for voice communications. Although the data communications network, the resulting sound quality proved to remain optimal. That is a manifestation of a technology called Internet Protocol Telephony (IP Telephony). Internet Protocol itself, before, is the standard used for data transmission between computers only. However, the existence of IP Telephony, existing infrastructure can be used not only for data communication, but also sound.

Utilization of data networks for voice, of course, will be more cost-saving communications. It has been proven by various companies, mostly operating in the field of information technology (IT), especially for banking has changed telephone communication with IP PBX telephony.

Apparently, it does improve efficiency. Because the network data infrastructure can be used both for voice networks, in this case for the development of a network only once to fulfill both functions.

Effectiveness that can be obtained with IP Telephony, among others, more cost effective. With a clear network will facilitate the handling, it also saves administrative costs. That is, for small office may only need a single administrator to handle all computer and telephone networks as well, since both are integrated in this IP-based network.

Another convenience that can be drawn from the existence of IP Telephony Unified Messaging. Development possibilities for merging voice and data revenues in a single mail-box is easier. For example, today, to hear messages left by callers can be directly accessed via computer by opening an e-mail mailbox.

IP Telephony functions almost the same as all the standard functions of the PBX, such as redial, call forwarding, transfer, hold and conference. In addition, IP Telephony, also has additional features, such as miss call, receive calls and address book where we can find someone by name extensions directly from the handset. With redundancy in IP telephony systems, can eliminate the single point of failure, which is generally common in PBX systems.

Handsets used in IP telephony has the integrated functions, such as the extension list each employee and a list of calls from customers or business partners. Another function that can be used in IP Telephony is a function where users can enter an announcement and other information directly to the handset.

On the other hand, employees can also directly read the announcement through the handset. They also can check for messages left by callers directly on the computer, and helps employees focus more on his mailbox for all types of correspondence. With these functions, clearly will increase the effectiveness of employees.

In addition to improving employee effectiveness, IP Telephony is also more cost effective than the PBX operation. If the count is calculated, with IP telephony infrastructure maintenance costs minimized. Savings can be done because the number of cables that exist in each user can be reduced by approximately 33% to 50% per user.

Not only that, the connection between the equipment also becomes a little more. If earlier to be able to combine voice mail server and e-mail system required channel specific channel, then with the IP Network, a unified messaging solution has been integrated in a single server. Upgrade costs PBX / ACD is often done, given the age and nature of the proprietary use, no need to spend a higher cost.

More low cost of network administration maintenance voice / data encourage increased productivity of employees who perform maintenance of the network with network management system more integrated. With more effective staff performance in terms of maintenance of the network, it automatically costs incurred for the number of staff can also be suppressed. If computed globally, then the savings that can be done about 22% comes from the communication channel, 34% of the cost of equipment maintenance and communication channels, and 44% of the cost of network administration.

The use of IP telephony is no different from traditional telephone systems, especially in basic functions, making it easier for employees to use the system. Viewed from the menu, the IP Telephony system is very user-friendly and not complicate the employees in its use.

To enrich the functions of IP Telephony, also developed what is called the Architecture for Voice, Video and Integrated Data (AVVID). The design of CISCO was developed to help provide answers to many challenges that exist in the business environment, particularly the development of solutions based on Internet technology.

Moreover, with AVVID infrastructure development can be viewed as a means to support the development of better business. For example, the development of applications for customer care, supply change management that require network services that are end-to-end, high availability, security, scalability, quality and performance. AVVID is a bigger part of IP Telephony as well as a framework in which various Cisco solutions can be integrated with each other for business purposes.

In business AVVID effective enough to use. In the financial industry, for example, with AVVID IP Contact Center Solution approach proved capable of improving customer service.

In addition, the financial industry is also very careful with the security of its data network, requiring security AVVID solution, which can effectively provide voice and data protection.

Security Aspects in The Development of Hosted IP PBX.
Abstract: We have a growing concern is how many companies can make cost reductions, improving productivity and delaying or avoiding investment. On the other hand that can not be avoided is the need for data communication (email, file transfer, etc.) are increasing rapidly and more mobile workers that require access to data services wherever located. Hosted IP PBX becomes an alternative solution matters described above, but in the development of IP

A. General
IP Services PBX (IP-based PBX) is one of many communication services that will be used in the future along with the increasing needs of users will be converged communications services and the increasing breadth of available IP network.

Hosted IP PBX connects the Intranet / LAN (Local Area Network), a company with branches or with PSTN (LAN interconnection) with a centralized IP PBX system. Users who already have a LAN as a communication network can be connected with an IP PBX services that can form a network of private voice network with a cheaper rental.

The benefits and advantages of this model of IP PBX services, among others:

• Provide a private telephone network service with a more economical cost (cost efficiency) because it can enjoy the communication cost is cheaper than conventional telephone.
• Wide area coverage and customers can build a personal network (close user group) for the area to spread.
• Costs are much cheaper because communication only occurs in a Close User Group.
• Hosted IP PBX also offers cost savings because the entire system is managed by the operator Hosted IP PBX.

In addition to ease of access to IP PBX also offers features more advanced than analog PBX. Some advanced features such as IP PBX:

• Find Me / Follow Me is a feature that is able to raise the call when the call occurred and where the telephone number being called is not active, the system will forward calls to another number which is set earlier in the IP PBX system.
• Web customization is the ability of end users to make calls according to their needs customization.

B. Potential Risk of development of the IP PBX.

1. Network security level of the weak data.The weak level of network security data is due to a weak level Firewall Security. IP Telephony In many protocols and ports that can not be separated by an IP Telephony service. H.323 uses several protocols for signaling and using real-time transport protocol (RTP) as the media, as well as SIP using RTP as media. As a result H.323 uses ports 7 to 11 numbers and only two static port number. IP telephony also uses TCP and UDP can be initiated from the intranet and internet networks. To stream data is usually in the firewall ports that have the potential to be used must be opened and this means the opportunities for crime.
2. The increased operational cost due to reduced performance Firewall. To keep the network in order to have a good level of security, one of which is done using private IP addresses. As a consequence the firewall should implement network address translation (NAT), which would convert the private IP addresses into public IP Address. As a consequence it will increase the processing load on the firewall and will reduce the throughput.
3. Loss of revenue due to loss of communication.As distributed systems, IP PBX has many individual components that must be protected. The attack on one point will be able to influence the system and allow other users can not use the facilities needed.

Endpoints and servers (including the voice gateway, IP phone, and call control server) will be the target of attacks through the IP Network. Endpoint and the server is likely infected with a virus and can cause corruption of data. The attack may also change the routing and other configuration information.

Two main principles in the design and security framework is a simple configuration and access restrictions as necessary. Commonly used strategy is to divide in several domains and access restrictions for each domain in accordance with its function. This will make it easier to identify potential sources of risk of crime.

Domain End User Devices such as IP Phone and PC Client is more focused to consider the potential of a virus attack. Media Domain which is connected to the server, such as Gateway, message servers, conferencing servers should consider these data can be accessed anywhere and which are not accessible, the data can not be accessed can be fatal in the system as a whole. Domain Call Control includes call control servers, routing servers and user databases must be placed on a level that has most of the validation and capability. This domain contains the critical services and sensitive data. Operational and Maintenance Domain Access should only be accessed with the ability to control a reliable authentication. This will be able to avoid the chances of a crime.

D. Specifications Tool in Supporting Security System
End User Device (IP Phone): As an end user device IP Phone provides voice and call signaling connection setup, and other features such as web browsing and wireless connectivity. To support the overall security system IP Phone must have the ability to:

Firewall: To support a firewall security system must:

1.  Monitoring of call setup signaling and voice traffic is just passing the already authorized.
2.  Opening ports in a dynamic that has been allocated only on those calls that have been authorized.
3.  Close ports when the call disconnected.
4.  Support to call the audit log.
5.  Ensure that traffic is passed only traffic with a source address and a clear purpose.

• Operating System that is used should always been updated with the latest patching and only used for call control. Service-service while unused better off.
• Using a proven operating system like Linux or Unix and estimated the years ahead operating system is still considered the best from the security side.
• Able to perform authentication and authorization to access all devices and users.
• Support strong authentication for various configurations and software.
• Support signaling hop by hop authentication with per-packet basis.
• Support call setup encryption.

Hosted IP PBX is an alternative to reduce operational costs and increase productivity with features supported service that is very adequate. However, implementation considerations and the need for careful planning, especially in terms of security. There are four segments (the end user, a media that is connected to the server, call control and Operations &  Maintenance Access), each of which need proper handling and requirements for IP PBX services are running well.