Traditional switches work on 2-nd or I 3-eat a level of model OSI, switching blocks of data under the address information located in heading block. Thus switches have no representation about type and character of the transferred information. In process of the Internet development arises necessity of operative and qualitative access to the applied information containing on the Internet. In fact content is the goods, delivered to the user. Therefore it is much more important to provide not switching of data blocks, and switching of the information, as do switches of 7-th level.

Level 7 switches work on 4 - 7 levels of model OSI, processing such information protocols and applications, as HTTP, FTP, Telnet. Today for all the problem of the jams arising on the Internet because of which the user should expect long occurrence of a page on the screen of the computer is known. One of the reasons of jams - insufficient productivity of servers on the basis of which information services (sites WWW) will be organized. A traditional way of servers connection to the Internet following: the server is connected to a firewall, the firepwall is connected to a router, the router is connected to the Internet. In most cases such configuration satisfies both clients, and owners of information system, however when there is a necessity of mass service, it is necessary to increase productivity of the specified hardware.

The statistics shows, that doubling of servers productivity occurs each 18 months, and growth of loadings on them is doubled each 3 months. During any moment escalating of productivity becomes impossible, and so-called "mirrors" - as a matter of fact, copies of the basic server on other servers are created. Access to mirrors is possible to the alternative address. The user should carry out a choice of the necessary server, but features of the man's psychology do not do "mirror" by effective enough means of web-system realization.

Effective variant of the problem decision is a cluster creation. In cluster physical a server are united through the computer network by switches of 3-rd level. Unique lack of cluster consists that distribution of information resources is possible, but not applications of users inquiries processing (Apache, IIS). As a result the leading server directly connected to the Internet, continues to remain a bottleneck.

All these problems have easy decision at use level 7 switches. The similar class of the equipment today is issued by many leading telecommunication companies (Cisco, Nortel, Foundry Networks, Extreme Networks, Intel).

Switches of the information provide performance of following basic functions:

• Creation of virtual servers as sets of physical servers under one IP address;
• Increase of servers reliability due to reservation;
• Creation geographically distributed web-systems;
• Uniform distribution of the traffic between firewalls;
• Optimization of hardware resources;
• Management of the communication line passband;
• Formation of an information stream in view of a various kind of information priority;
• cashing information;
• Acceleration of operations on transfer crypto traffic with use of technology SSL.

Cluster contains leading server on which processing of the user inquiries is carried out, and subordinates on whom the information is located. The leading server is compelled to provide processing of users inquiries independently. The virtual server is a group of the same physical servers which are connected to various ports level 7 switch and which level 7 switch are represented by means as the uniform server addressed by IP one address. Such approach allows to operate a virtual server far off, with application of standard means Telnet and FTP.

To provide uniform distribution of loading, level 7 switch periodically sends on each physical server special inquiry in the form of package TCP or in format HTTP, remembers time of the answer and directs the acted user inquiries about that server, which time of the answer minimally.

Terrorist attacks can lead to that servers of the big number of mass-media and any other companies will appear are inaccessible because of their overload, and also because of an overload of the international and long-distance communication lines. For example, as it has occured on September, 11th.

For prevention of such threat it is possible to create the distributed information system of high reliability. In such system all physical servers of the client are united under one name URL. For such association it is used level 7 switch.

When the user enters URL, the browser sends inquiry about definition of corresponding IP address. In the standard way, with use of DNS, this inquiry reaches level 7 switch which chooses the least loaded and most relatives territorially to the client server. After that level 7 switch transfers its address back to the user. Further the browser of the user forms inquiry with use of this address. For a choice of the least loaded server special protocol DSSP (Distributed Site State Protocol) is used. By means of this protocol all level 7 switch, a part of geographically distributed virtual server, define factor of loading each other.

To each region the international organization IANA on-line allocates a range of IP. Level 7 switch analyzes the address of the user, defines region to which it concerns, and transfers the user the address of the least loaded and most a server close to them.

Having created a high-efficiency virtual server, its owner will face a problem of insufficient throughput of firewalls. To distribute loading between them in the ways described above, it is impossible, as firewalls work with a continuous information stream, instead of with sessions TCP or HTTP.

For uniform distribution of the traffic between firewalls means of administration managerial control it is created a little subnets IP, each of which is served by the fireproof wall. Acting in level 7 switch the traffic in regular intervals shares on some parts and is transferred in a corresponding firewall. After processing the traffic the subsequent level 7 switch collects all in a uniform information stream and transfers it in a virtual server. Division of the entering traffic into parts is carried out so that all entering packages IP with the identical address acted in one subnet.

The information containing on the Internet, it is possible to divide into two types: static and dynamic. For storage and processings of the information of these two types are required physical servers to which various demands are made. The high-efficiency server which should accept tens thousand times a second inquiries of the user is necessary for the dynamic information, do sample of a database, form it for display to the screen and transfer the user.

For the static information the server of average productivity, but with the greater size of disk space is required. For sharing to a server with the static information separate IP address is appropriated, and the server with the dynamic information provides sample of the necessary data to this address. Such model demands labour-consuming manual work on formation of hypertext references to static resources and complicates translation web-system into other address or other name URL.

Level 7 switch allows to simplify and accelerate service such system. For this purpose level 7 switch analyzes name URL, trying to discover in it the name of a directory or a name of a file on the pattern set by the manager. After that there is an automatic substitution of the real information from other server. At change of IP address or name URL the manager only will change IP address or name URL in the table of substitutions, and level 7 switch will start to substitute new values automatically.

Many owners commercial web systems wish to provide the differentiated approach to various categories of users, for example, to provide better access to paid resources. It allows to generate flexible tariffs, to involve new users and to get that competitive advantage.

For today there are no network means of the such approach organization for a site from a server up to a transport network. Probably to organize the differentiated quality service, analyzing IP address of the user. However on the Internet that can use various terminals or dynamic IP. Level 7 switches addresses allow to define such user or the analysis of files cookies, or analyzing name URL of a paid resource typed by it.