© All information contained in this article is the exclusive intellectual property of KRUGEL EXIM. The article may not be copied in whole or in part, without the prior permission of KRUGEL EXIM.
ISO/IEC 11801 is the most important international standard for structured cabling systems. It sets the basic requirements for the transmission parameters of structured cabling systems, their components and for the topology of the network's physical layer. Compliance with this standard is the requirement and at the same time the guarantee of functionality of all standartized transmission protocols designated for information technologies.
Formal changes and the new standard structure
The new standard ISO/IEC 11801:2017 devided into series of 6 sections (standards):
- ISO/IEC 11801-1:2017 Information technology – Generic cabling for customer premises, Part 1: General requirements
- ISO/IEC 11801-2:2017 Information technology - Generic cabling for customer premises, Part 2: Office premises
- ISO/IEC 11801-3:2017 Information technology - Generic cabling for customer premises, Part 3: Industrial premises
- ISO/IEC 11801-4:2017 Information technology - Generic cabling for customer premises, Part 4: Single-tenant homes
- ISO/IEC 11801-5:2017 Information technology - Generic cabling for customer premises, Part 5: Data Centres
- ISO/IEC 11801-6:2017 Information technology - Generic cabling for customer premises, Part 6: Distributed building services (see the description below)
The content of the original ISO/IEC 11801 Ed.: 2.2: 2011 standard can be found in the first two parts within this new edition. Basic requirements for the transmission channel, permanent link and individual components of the structured cabling systems are the subjects of Part 1. Performance categories of the cabling and network topology in office premises are defined in Part 2.
As a completely new standard, Part 6 defines requirements for structured cabling systems in a new perspective area of distributed services:
- telecommunications, e.g. wireless access points, distributed antenna systems;
- energy management, e.g. lighting, power distribution, incoming utility metering;
- environmental control, e.g. temperature, humidity;
- personnel management, e.g. access control, cameras, passive infra-red (PIR) detectors, time and attendance monitoring, electronic signage, audio-visual projectors;
- personal information and alarms, e.g. paging, patient monitoring, nurse call, infant security;
- intelligent building systems;
- communications between devices (i.e. “internet of things”).
Performance categories and transmission protocols changes
Table 1 provides an overview of standardised performance categories of copper cabling, supported transmission protocols and their dedicated environments. Category 3 is not included in the table, as it is exclusively utilized for connecting voice services to rack cabinets and is not a part of general purpose structured cabling systems.
1. New performance categories Category 8.1 and Category 8.2
A major change in the field of copper cabling networks is the establishment of two new performance categories: Category 8.1 and Category 8.2. In both cases 2 GHz bandwith is required and both categories support the Ethernet 25GBASE-T and Ethernet 40GBASE-T transmission protocols.
The criteria for transmission parameters, electromagnetic interference immunity (EMI) and Alien Crosstalk resistance for the performance Category 8.2 are more strict than for Category 8.1.
A detailed analysis of the specification shows that the Category 8.1 is based on improved Category 6A modules and connectors with the RJ45 interface and technologically refined Cat.6A cables. This fact is confirmed by the standard guarantee of backward compatibility of the Category 8.1 with the performance category Category 6A.
Category 8.2 enables a usage of two different interfaces. The first is the interface module/connector typical for components known under commercial brands "GG45" or "ARJ45". The second accepted interface relates to the components with commercial name TERA connector. Neither of these are compatible with the RJ45 interface. Performance Category 8.2 is backward compatible with Category 7A, which indicates that the performance Category 8.2 is technical and technological upgrade of the components and cables of the Category 7A.
The functionality of Ethernet 25GBASE-T and Ethernet 40GBASE-T protocols for performance categories Category 8.1 and Category 8.2 are guaranteed only up to a distance of 30m (26m permanent link and two 2-meter long patch cords). Because of this limitation performance categories Category 8.1 and Category 8.2 are explicitely specified only for data centres by the new standard (see the yellow marked columns in the table).
2. New performance categories OM5 and OS1a
In the field of single mode fibre optical cabling networks the OS1a performance category has been introduced. Compared to the category OS1, OS1a enables usage of wavelengths in the area of waterpeak 1383nm. However all manufactures currently offer products in category OS2 with even better transmission characteristics. For this reason we will not engage ourselves deeper into the subject of the category OS1a.
OM5 is a new category based on the improved multimode optical fibres which enable wavelength multiplexing. It will be sufficient to use 2 fibres to reach transmission speeds of 40 Gbit/s and 100 Gbit/s in the future. In the event that the category OM5 is used for the transmission of known standardized protocols, the characteristics and conditions of the category OM5 implementation are identical to the category OM4.
3. Transmission protocols Ethernet 2,5GBASE-T and Ethernet 5GBASE-T
Transmission protocols Ethernet 2,5GBASE-T and Ethernet 5GBASE-T, standardized since September 2016, have originally been developed with the aim of increasing transmission speeds on existing Category 5 and Category 6 cabling networks to 2,5 Gbit/s or 5 Gbit/s. Respectively Table 1 demonstrates (please note the blue marked lines) that both of these transmission protocols within the new ISO/IEC 11801:2017 are supported only by performance categories Cat.6A and higher. The functionality of these protocols cannot be guaranteed for categories Cat.5 and Cat.6 for the of frequent problems with Alien Crosstalk in actual installations.
4. Transmission protocols ATM, Token Ring and FDDI
Legacy and long dormant transmission protocols ATM, Token Ring and FDDI have been removed from the new ISO/IEC 11801:2017 publication. These are no longer internationally supported applications for information technologies.
Performance categories vs. premises and distributed services
1. Performance categories in the office environment
To meet the requirements of the new standard for cabling networks installed in office premises, must be utilized Category 6 at a minimum. To reach transmission speeds above 1Gbit/s, components of at minimum of Category 6A (please note the columns marked in pink in the Table 1).
2. Performance categories for distributed services
Thanks to the growing number of devices and components with their own IP address and to the pursuit of standardization of the communication protocols in distributed services of buildings (see the description in the part "Formal changes and the new structure of the standard"), the structured cabling system becomes a necessary part of these systems. The structured cabling systems implemented in distributed services, the components and cables of at least Category 6A must to be installed (please note the columns in the Tabel 1 marked green).
Components vs. premises and distributed services
The changes to the standard regarding the types of permissible connectors for different premises are highlighted below:
a) within office premises only LC connectors are to be used for all new installations
(SC connectors are allowed to be used for extension of existing networks)
b) within industrial and residential premises exclusively LC connectors are allowed to be used
c) in data centres LC, SC and MPO connectors are allowed to be used
The new ISO/IEC 11801:2017 standard features 394 pages of technical text and diagrams, which represents an angmentation of nearby 60% in comparison with the previous edition ISO/IEC 11801 Ed.: 2.2: 2011. This article highlights only the most important information from the new standard and the most significant changes necessary for planning and building of structured cabling networks in conformity with the international standards. We will revisit this topic in subsequent articles and provide our own commentary and more focused and detailed explanations of the implications of the new standard and more focused and detailed explanations of the effects of the new standard in real life situations.
Author: team of the R&D employees of KRUGEL EXIM company