ITU-T SG 5 Technical Session on "New Infrastructure Elements in the Access Network"
Beijing, China, 16 May 2007
At the invitation of the SG 5 Chairman, Mr Jan Erreygers, Tyco Electronics, made a presentation on New Infrastructure
Elements in the Access Network in the ITU-T SG 5 session on Wednesday 16 May 2007.
Summary of the Technical Session
The Technical Session started with an introduction of the reasons why a significant number of new types of equipment have
appeared in the access network. The mains reasons are the widespread deployment of ADSL and VDSL broadband access, unbundling
of the access network, increasing broadband bandwidth, IPTV services and the evolution towards an NGN network.
Then a description of the new infrastructure elements was presented with special attention to topics of the Study Group 5
work program that may have to be studied or reviewed in order to take the new types of equipment into account:
- xDSL splitters are being installed in the Main Distribution Frame. The main driver for this type of equipment is
the need for space saving and reduction of cabling in the central office.
- A need has grown for metallic access to cable pairs for broadband testing. This has led to the introduction of a
variety of systems for test access. An overview of the different types of metallic tests was presented: DSLAM integrated
test access (ITAM), external rack based test access (ETAM), main distribution frame (MDF) installed test access (pluggable
FTAM & integrated FTAM) and combined splitter & test access infrastructure installed in the MDF.
- The demand for higher broadband bandwidth has resulted in the need to install DSLAMs closer to the customer because
there is a trade-off between bandwidth and loop length. This has created the need for outside plant cabinets that are suitable
for the installation of active electronic equipment. The main technical requirements for active electronics cabinets were presented:
temperature range, degree of protection against moisture and water, thermal management, protection against vandalism, internal
sensors and local or remote powering.
- The installation of cabinets for active electronic equipment may not always be possible due to lack of space, risk of
damage by traffic, vandalism or local regulations. This has led to the introduction of underground enclosures for active electronic
equipment. The requirements for this type of infrastructure are generally the same as for above ground cabinets. Heat management
and sealing against moisture ingress are however more challenging.
- Automated Main Distribution Frame/Crossconnect (AMDF) equipment is being introduced in the telecom world. The objective is
to eliminate the manual process of installing jumpers between the equipment side and line side of the MDF or crossconnect. Different
aspects of the business case for the introduction of AMDFs in the central office and in cabinets for active equipment were discussed.
An overview of the different technologies (relays, electromechanical switching and MEMS) and there relative merits were presented.
- Recently there is a trend to install VDSL DSLAMs very close to the customers, e.g. in the basement of appartment buildings.
Full line provisioning is generally anticipated. This type of installation does not require an AMDF but still requires a possibility
to switch to the VDSL splitter or to bypass the VDSL. The functionality of such splitter bypass device has been described.
In the conclusion it has been pointed out once more that these new infrastructure elements are all directly connected to the copper network.
Therefore they are directly exposed to overvoltages and overcurrents and it has to be made sure that they adequately withstand the
electromagnetic environment in the access network.
Presentation
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