Summary of IP Phone and IP router technology application experience

There are still many things worth learning about the IP router technology. Here we will mainly introduce the experience of IP phones and IP router technology. There are still many problems to solve when the IP Phone is transferred to the local device. There will be many policy issues to solve, such as operating licenses. There are also problems that need to be solved in different technical and policy fields such as number resources and interconnection between networks. Apart from these problems, there are still many technical breakthroughs.

In fact, these technical problems do not only exist in the future IP address market. Currently, long-distance VoIP networks of domestic carriers are mostly built on dedicated communication networks. The IP address and security issues are not prominent. However, the private network is only a transitional method. From the perspective of triple play, IP phones must be integrated into public IP networks. To achieve this goal, both the long-distance network and the long-distance network must solve these problems.

1. Network Address

For such a large-scale IP router technology, the lack of IP Address resources is the first problem to be solved. In fact, this is also a problem that troubles China's broadband access development, but it will become more obvious in terms of IP phone communication. The adoption of private addresses is very undesirable for carriers. It is impossible for carriers to use private addresses everywhere, which makes it inconvenient to build a nationwide network. Private addresses are used for the entire large network, and it is difficult to avoid problems in the interconnection between networks. NAT is required when private addresses are used. NAT devices generally support Web browsing and sending and receiving emails. However, many NAT devices cannot support two-way IP phone communication. The same problem also exists in IP telephone services in the form of PCtoPC and PCtoPhone. For example, if you use the dial-up Internet access method provided by your ISP, a PC can only obtain one dynamically allocated IP address, and the user can only dial out. The other party cannot know the location of the caller exactly, the result is that the incoming call fails.

IPv6 is naturally the best result, but it cannot be very accurate to know when IPv6 will be used globally. Even if it starts to be promoted, it will take some time. Some people think that at this stage we should work harder on NAT, such as supporting more applications, such as IP telephone communication.

2. Security Issues

The security of IP phones is also an urgent problem. Security issues are divided into two aspects: first, the IPIP router technology and the Ethernet carrying it have inherent defects in information security, as a communication service, the user's personal privacy and business security must be guaranteed. On the other hand, it is for the operator, how to ensure the security of their own business, not fraud. If there is no security guarantee, if someone connects the IP address Telephone Gateway to a carrier's network, the IP address of the carrier's gateway is obtained through the operator's network guard, it is not a shocking story to realize the "Implementation" of IP phones without knowing it.

H.235 is a security solution that people talk about a lot about. Whether or not H.235 can be used can ensure security, and the corresponding cost and control problems need to be carefully considered. In addition, for IP Phone devices that adopt confidentiality measures, different vendors may need a coordinated process in terms of interoperability.

3. Service Quality

In addition to address and security, another important issue is service quality. The current IP network has inherent defects in service quality support for real-time services. To solve the service quality of IP phones, we must solve the quality problems of the IP network. People pin their hopes on IPDiffServe, MPLS, and other technologies. The IP telephone VPN solution for independent resources is also considered a good solution. Optical Communication, especially the DWDM technology, makes the Bandwidth growth rate of the communication network far exceed Moore's Law. Some people think that using unlimited bandwidth can solve the service quality of the IP network. However, traffic engineering can only improve service quality and cannot completely solve the problem of service quality. Classified services are the direction. IP address telephone networks at the telecom level should introduce new ideas and new concepts. To solve the service quality of IP phones, we should not rely solely on the improvement of the IP network, but also find a solution on the IP phone itself.

4. Power Supply Problems

Traditional telephones have been very mature over the past century in terms of power supply. In the case of mains power outages, telephone lines can still ensure communication with the outside world. As a basic telecommunications service in most countries, voice communication plays a lifeline to a large extent. In the enterprise's IPPBX, Cisco, Avaya, and other companies can add power supply modules on Ethernet switches to solve the feed problem through five lines, cisco, like the first vswitch that can be fed to the ipvst6500 series, has multiple redundant power supplies to ensure uninterrupted power supply. However, similar solutions can meet the requirements of the future IP address market, and the ethernet cable standards for power supply to phones and gateways have not yet come out. In addition to a few manufacturers, terminals that we can see in many ways cannot do this. We need to add power supplies. In addition, power consumption issues for these terminal devices also need to be solved.

It should be said that the power supply problem is unavoidable in the Ethernet Access Field. Many switches placed in the head of the building are directly supplied through the mains supply. Due to cost considerations, many switches do not have redundant power supplies, even if the mains supply is disconnected, all communications will end. From the perspective of communication, we can achieve triple play. From the perspective of power supply, some people think that we still cannot integrate the twisted pair wires.

In fact, it is not just a problem of power supply. For the new IP phone technology, the reliability and stability of devices are also the focus of attention. Some vendors make efforts in network guard and SoftSwitch devices. The Network guard and softswitch call servers are all based on general computer platforms. Telecom-grade products generally use very stable computing platforms like Unix. multiple servers are hot backups of each other. Some vendors also integrate Cluster, load balancing and other technologies in their Softswitch solutions, various technologies are used to avoid the impact of spof on communication. In the eyes of the computer industry, the measures taken are remarkable. However, it seems hard for some people in the traditional telecom field to be convincing enough. If this problem is extended, the stability and reliability of network devices on the entire IP network cannot satisfy people, at least with suspicion. Manageability and maintainability are also issues that need to be solved by the IP network.

5. network convergence

How to communicate with existing PSTN networks, interworking with intelligent networks, and the development of IP telephone Intelligent Network Services is a problem that needs to be solved in both long distance and domestic networks. There are still many problems that need to be solved in the interconnection between IP and fixed telephone networks. For example, IPIP router technology problems. If the IP phone gets the resources of the phone number, can the two networks make a call? It is understood that the domestic industry is stepping up research and developing relevant standards to solve such problems.

6. Softswitch

In the traditional circuit switching telephone network, all services provided to users are directly related to switches, and services and control are completed by switches. The functions required by the vswitch and the new services provided by the vswitch must be completed at each switching node. To add new businesses, You need to revise the standards and then transform the vswitch. Each provision of a new business takes a long period of time.

The network in the new era will be an open and hierarchical structure. This network topology can use packet-based bearer transmission. It is an open endpoint topology that can deliver voice and data services as well. The bearer part of the network is separated from the control part, allowing them to evolve separately, effectively breaking the structure of a single integrated switch, and using open interfaces between units. This approach ensures that users can purchase their desired devices at every level without too many restrictions. Likewise, layer-based Softswitch technology enables communication between terminals based on different bearer networks, such as Cable, DSL, and Ethernet.

However, if the new generation of network cannot replace the original circuit switching in an instant, the original telephone network will be there for a long time. At this time, a technology is required to build a new group network, and to achieve the convergence of traditional telephone networks and new networks. Softswitch is a solution based on the sub-networking technology. It can solve this problem well.

The functions implemented by Softswitch are not just long-distance IP phones. As data services are growing, traditional voice switches cannot undertake a large number of long-time data call services, such as dial-up Internet access ). The Softswitch technology can be used to unmount Internet services. The dial-up service is directly transferred to the ISP network before it enters five types of switches. Softswitch can replace four types of exchange switches. Softswitch can also replace five types of switches. The price of five types of switches is often a major obstacle for emerging operators and service providers to enter the market. The price of Softswitch is low, and it can provide richer services.

Softswitch devices require various media gateways and signaling gateways to be supported in the lower layer. Softswitch or call server) is responsible for Basic Call Control. Through the open interfaces provided by Softswitch, telecom operators are very convenient in adding new services, and can use the power of third-party software developers to continuously add new services to the network. Some vendors in the field of softswitch said that adopting this technology will exponentially shorten the launch time of new businesses. The implementation speed and service richness of IP Phones should far exceed that of traditional telephone networks. From the current situation, there are two ways to implement value-added services of IP phones or smart network services. One is to use protocols such as PINT in accordance with the architecture of the intelligent network to Achieve Smart service intercommunication between the PSTN network and the IP router technology. Like today's Internet, new application servers are constantly added through open interfaces to add applications. Of course, we have to do a lot of work in terms of standardization. In China, we have already begun to develop standards for IP Phone Service supplementation. IP phones are welcomed and rapidly developed with their low long-distance telephone fees. We have reason to believe that IP phones are a choice for users, both abroad and in China, the IP phone service is bound to develop rapidly.