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and Electronics Engineers (IEEE). One of its functions is to develop networking standards in the IEEE 802.3 series. These standards define signalling, processes and protocols for transmitting data using Ethernet technology over copper and fibre optic cables. The IEEE also lays down the
minimum cable performance required to meet specific network standards. However, it does not develop cabling standards, and refers instead to the standards developed by the TIA and ISO.
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Currently the IEEE is focused on 40G and 100G Ethernet networks, but what are they? In fact, 40G and 100G are references to the IEEE802.3ba standard that lays down requirements for networks capable of transmitting data at rates of 40 gigabytes and 100 gigabytes per second respectively. The IEEE802.3ba standard
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defining 40G and 100G networks only recognises optical fibre and twin-axial copper cable media. It does not recognise twisted pair copper cable. Additionally, twin-axial copper cables are only recognised up to a link length of 10m, as with copper links longer than 10m, these high-speed network protocols are not expected to be capable of offering reliable performance. Unfortunately, there is talk
about development of a new standard supporting 40G and 100G transmission on twisted copper cable and the need to future proof against this new standard. To say that there is a new standard in development or even under consideration for 40G and 100G transmission on twisted copper cable is misleading and spreads misinformation.
The twist
As of August 2011, there is absolutely no activity in the IEEE 802.3 group aimed at investigating the use of twisted pair copper cabling as a medium for 40G and
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100G networks. In addition, the TIA and ISO have not recognised any proposals to study twisted pair copper cabling as a medium for 40G and 100G networks, which would be the precursor to proposing the development of a standard. The IEEE has no plans to
study the use of copper twisted pair cabling for 40G and 100G transmission. This means that the IEEE cannot pass to the TIA and ISO the basic transmission requirements for a twisted pair copper solution supporting 40 and 100G, such as carrier frequency and transmission characteristics (IL, RL, NEXT, ACRF, PS ANEXT, PS AACRF, etc). Therefore, given the significant
problems that would be involved in developing a copper horizontal link capable of supporting 40G or 100G, it is not known if a copper twisted pair solution is even possible. Neither is it known whether, in the future, the IEEE, TIA and ISO will choose to study 40G or 100G over copper twisted pair and whether such studies would lead to the development of a standard. We do know however that a standard will take years to develop – if it ever happens.
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In view of what has been discussed so far, it is clear that when specifying test equipment for data networks, it is important to know both what is currently possible and what is currently planned. This will ensure that the right choices are made and money is well spent. Focusing on what is not possible and is not even planned guarantees that poor choices will be made and money wasted chasing functionality that purports to support non-existent future standards. Some companies market network
certification testers with high prices that are ‘justified’ by claims of being able to test far into the future. This is nonsense, because as we have seen, the future is yet to be defined.
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