LAN for IP video surveillance

Video surveillance systems based on IP CCTV devices need adequate IP networks for transmitting video data and providing communication among the devices and computers or transcoders.

IP CCTV devices send video or video and audio in the form of data stream, usually compressed in MPEG-4 (SP, ASP, AVC/H.264) or MJPEG format. Compression limits the required band. However, the quality of video and audio strongly decreases with higher compression ratios. Some applications may require full resolution (e.g. megapixel cameras) or maximum frame rate - in such cases the required bandwidth can be very wide.

In the case of multiple devices the data streams add and may reach the maximum capacity of the network.

If the network is not properly designed, installed, or operated, it will cause problems in using the whole IP CCTV system or its fragments.

Typical results of inadequate LAN wiring and capacity:

• low frame rates, lower than that set in cameras (too little network capacity)
• improper decoding of images on computer or transcoder (interrupted data stream)
• loss of connection

High quality and efficient LAN network requires methodical approach on every stage of its building, based on adequate technical standards.

In this article there are considered only local networks for IP video surveillance, based on copper cables and cooperating devices.

The building process (of IP network) can be divided into the following stages or phases:

Every stage has to comply with adequate standards/codes.

New building that is to be monitored using IP CCTV technology requires design of power network (AC and DC) for IP devices and computers, grounding/earthing system (including common bonding network and bonding of the protective conductor), means of EMC (electromagnetic performance).

The power networks have to comply with all national standards/codes and ensure protection against electric shock. It is very important to equalize potentials. Where a neutral conductor is used also to connect equipment enclosures, care must be taken that the neutral conductor never rises to a high voltage with respect to local ground.
In the case of older buildings, the wire system has to be checked and adapted to the current regulations.

The next stage is designing of structural cabling system. There should be considered use of shielded and unshielded cables. Depending on transmission parameters and kind of the building, there should be designed risers, horizontal raceways, inter-building cabling.

A good design is the basis for proper implementation - installation planning and installation work. For this stage there are also adequate national standards/codes that have to be obeyed. They standardize quality requirements (including testing methods) and help to provide exhaustive documentation needed for maintaining the cabling system in the future.

The target phase is a regular operation of the cabling, also including maintaining and servicing the wiring system. It is very important to perform regular inspections that will allow to avoid unexpected failures of the network, which could jeopardize reliability of CCTV system.

EN 50173-1:2007
Information technology -- Generic cabling systems --
Part 1: General requirements

This standard provides users with an application independent generic cabling system and an open market for cabling components, a flexible cabling scheme such that modifications are both easy and economical.
It also provides guidance for building professionals (e.g. architects) how to accommodate the cabling before specific requirements are known; i.e., in the initial planning either for construction or refurbishment.
The industry and standardization bodies get cabling system applications that support current products and provide a basis for future product development.

EN 50173-2:2007
Information technology -- Generic cabling systems --
Part 2: Office premises

Generic cabling systems for use in office premises (both isolated buildings and campuses). Balanced copper cabling and cabling with optical fiber links. Additional requirements for the cabling in office premises, with links up to 2000m.

EN 50173-3:2007
Information technology -- Generic cabling systems --
Part 3: Industrial premises

Rules of implementation generic cabling for a wide range of communications purposes connected with automation, control and monitoring of industrial premises (balanced copper cabling and cabling with optical fiber links). It is a development of the requirements contained in EN 50173-1. Additional requirements specific for the cabling in industrial premises, with links up to 10,000m. The additional requirements include: a) the structure of generic cabling suitable for use in industrial premises; b) completion study; c) additional demands due to industrial environment.

EN 50173-4:2007
Information technology -- Generic cabling systems --
Part 4: Homes

Generic cabling systems for use in homes for a number of purposes, employing balanced and coaxial cables. They may be installed in a part of a building (encompassing more than one apartment), in an isolated building or in a group of buildings. Additional requirements specific for the cabling in residential buildings.

EN 50173-5:2007
Information technology -- Generic cabling systems --
Part 5: Data centers

Generic cabling systems for a wide range of communications purposes in data centers (balanced copper cabling and cabling with optical fiber links). Additional requirements for the cabling in data centers, with links up to 2000m.

EN 50174-1:2002
Information technology -- Cabling installation -- Part 1: Specification and quality assurance

Detailed requirements and instructions for specification and quality assurance of information technology cabling. Vocabulary/definitions for: - cabling specification, - documentation of quality assurance procedures, - documentation of the cabling and its administration, - instructions on servicing and maintenance. There are 43 definitions.

EN 50174-2:2002
Information technology -- Cabling installation -- Part 2:
Installation planning and practices inside buildings

Detailed requirements for installation planning, designing, implementation, and maintenance of the cabling inside buildings (balanced copper cabling and cabling with optical fiber links). Information technology cabling used in analog and digital telecommunications systems. Designing strategy (routing), the principles of designing and implementing balanced copper and optical fiber cabling and cabling, depending on the application, electromagnetic environment, building infrastructure, equipment used. There are 18 definitions.

EN 50174-3:2005
Information technology -- Cabling installation -- Part 3:
Installation planning and practices outside buildings

Detailed requirements for installation planning, designing, implementation, and maintenance of the cabling outside buildings (balanced copper cabling and cabling with optical fiber links). Information technology cabling used in analog and digital telecommunications systems. Designing strategy (routing), the principles of designing and implementing balanced copper and optical fiber cabling and cabling, depending on the application, and physical environment (climatic, mechanical, and electromagnetic influence). Procedures for conformity assessment.

EN 50346:2002 and A.1:2007
Information technology -- Testing of installed cabling --
Testing of installed cabling

Specification of requirements for testing installed balanced copper cabling and cabling with optical fiber links. Reliable and reproducible procedures of testing transmission capability of structural cabling systems. Every procedure provides: tested parameter, measurement method, arrangement, cable interface, measuring procedure, calibration system, interpretation and documentation of measurements. The limits of the tested parameters are in adequate standards and specifications.

ISO/IEC 2382-25:1996
Information technology -- Vocabulary --
Part 25: Local area networks

There have been defined 75 terms concerning local area networks, network devices, transmission protocols etc.