Ethernet ALA September 2007 Seminar: The five key characteristics

Report on Ofcom’s September 2007 seminar

Executive Summary

The deployment of fibre technologies of varying architectures increasingly deep into the access network poses particular challenges for the mandating of access to physical infrastructure in support of competition. Whilst Ofcom remains firmly committed to passive line access remedies such as SLU, it also makes sense to consider, at the same time, how best to maximise innovation and competition at the active level (i.e. in OSI terms, layer 2 and above), an approach we now refer to as Active Line Access ('ALA') ^(-1-). The telecommunication’s industry has converged on Ethernet as the technology of choice for the transport of IP-based services in Next Generation Networks, and our assumption is therefore that ALA will be based on Ethernet standards.

As part of the Carrier Ethernet World Congress, Ofcom chaired a seminar to stimulate a debate on the standardisation of an ALA product which would maximise the scope for competitive innovation, making it, if possible, comparable with that achieved by access to the physical infrastructure through passive line access. To kick off the debate we suggested some essential characteristics of Carrier grade Ethernet Access:

1. Multicast
2. Quality of Service
3. Security
4. Flexible range of aggregation points
5. Flexible range of Customer Premises Equipment (CPE)

The seminar was chaired by Peter Ingram, Ofcom CTO, with speakers and panellists from BT, C&W, QSC, Alcatel Lucent, Huawei, Cisco and the MEF. Attendees included regulators, operators, vendors, consultants and property developers. Overall the major conclusions were the following:

• The five characteristics proposed by Ofcom were agreed in principle, although there were differing views on the level of functionality and features that should be made available and implemented in an Ethernet ALA. Some argued for a minimal ALA product which would move the ability and responsibility for developing functionality from the infrastructure owner to the CPs. Others preferred an Ethernet ALA that could be flexibly customized based on required functionality;
• It was agreed that the ALA product should be independent of the underlying NGA infrastructure offering a consistent interface across GPON, VDSL, PtP etc. Equally, it should use systems and processes as far as possible consistent with existing interfaces, for example those defined by the DSL Forum;
• There was limited discussion of quality of service, aggregation and security as it was apparent there was general consensus on the technical policy aims ie to transparently support appropriate classes of services; aggregation at exchange, metro and core; and basic transport security. It was agreed that, as a shared infrastructure, security in GPON is necessarily limited at the infrastructure level and it would be up to CPs to implement better security measures higher up, eg in applications. There was much more debate on CPE and Multicast where the policy objectives are not yet as clear (see below)
• Multi-cast remains the subject of greatest debate. Some CPs asserted that multicast support is essential and that without it viable competition with incumbent triple play offerings would not be possible. It was BT’s view that a basic ALA product should be as simple as possible and therefore multicast should be implemented by CPs rather than the ALA provider.
• Competition could and should allow for many different IP devices and service providers in the home, however having multiple CPE may cause equipment and environmental challenges (eg power consumption). The development of horizontal retail markets might help overcome this but this would require a ‘wires only’ CPE interface similar to those which exist for the supply of DSL equipment.
• There was general consensus that ALA should be specified by CPs and incumbents together and standardised as quickly as possible. In the UK , Openreach will discuss options for the specification of its ALA offering (GEA) and take on board CP input.
• The extent of industry engagement and the slow rate of standardisation are barriers to the delivery of ALA. An industry wide forum of some kind is required. Speakers undertook to do all they could to promote industry engagement to resolve outstanding issues. Ofcom previewed its plans for further seminars and engagement including a UK seminar and conference follow ups.

The rest of this report gives more detail on the seminar presentations, background and agenda. Pdfs of the presentations can be found at http://www.ofcom.org.uk/telecoms/discussnga/eala/ethernetala/. Please go to http://www.ofcom.org.uk/telecoms/discussnga/eala/ethernetala/ for details of the follow up technical workshop in London on 26th November 2007.

Chinyelu Onwurah
Head of Telecoms Technology
+44 (0)20 7981 3802
chinyelu.onwurah@ofcom.org.uk

Chris Mulley
Technology Analyst
+44 (0)20 7981 3932
chris.mulley@ofcom.org.uk

Footnotes:

1.- See Ofcom consultation on Future Broadband, http://www.ofcom.org.uk/consult/condocs/nga/