The UK has increased the spread of neutral exchange points in the country with the two IXPs in London now being joined by ones located in Manchester, Leeds and Edinburgh. In the 2000s, there were at least 4 well-known IXPs in London along with several smaller ones. However, it appears that the city cannot sustain so many neutral IXPs as LINX and LONAP are the only two that remain. There are a number of commercial interconnection services available in London and other major centres from network providers such as Edge-IX.
The London Internet Exchange (LINX)
LINX is one of the world’s largest and longest-established Internet exchanges. LINX currently has about 400 members in over 50 countries. While most of the members are from Europe, many are based outside this region, particularly from North America but also from Africa, the Middle East, Asia and Oceania. LINX facilities have over 890 connected member ports with about 450 member-facing 10GigE ports and over 1.2Tb/sec of peak traffic.
LINX is a mutually owned membership association for Internet operators that also represents the interests of its members on related public policy matters. Initially, LINX membership was restricted to operators of Internet access networks (traditional ISPs). In 2000, this restriction was relaxed and now a wide variety of networks peer at LINX exchanges, including large content providers such as the Google, Yahoo and the BBC. The diversity of service providers peering at LINX is increasing and includes gaming and gambling specialists, media streaming providers, DDoS mitigation specialists, software-as-a-service providers, and advertising networks.
LINX operates a number of separate switching infrastructures, including two in London and one in Manchester, and provides technical support for one in Scotland. The LINX London network consists of two separate high-performance Ethernet switching platforms installed across ten locations:
- Telehouse North
- Telehouse East
- Telehouse West
- TelecityGroup, 6&7 Harbour Exchange Square
- TelecityGroup, 8&9 Harbour Exchange Square
- TelecityGroup, Bonnington House, Millharbour
- TelecityGroup, Sovereign House, Marsh Wall
- TelecityGroup, Powergate
- Equinix, London-4
- Interxion, London City.
LINX does not own any of these sites but is a tenant in an existing co-location facility or carrier hotel. At least two switches (one from each vendor) are installed in each LINX London location. The locations are interconnected by multiple 10-gigabit Ethernet circuits (across dark fibre) to form two physically separate backbone rings (one with Juniper equipment, the other with Extreme).
Most LINX members connect to both switching platforms that reduce the impact of any downtime on a single network element. For extra redundancy, some members choose to connect at multiple locations. LINX also provides a 'Linx from Anywhere' remote peering service that is provided by layer 2 carriers to enable peering at LINX from around the globe. About 50 LINX members currently use this method to connect, hosting no equipment in London but taking an Ethernet port from one of its partners instead. Normally, the member pays the carrier for the transport service and LINX for its standard fees although some carriers may bundle LINX fees as well. This is part of LINX's ConneXions service that allows third parties to resell LINX 10GE or 100GE ports.
Physical protection of the dark fibre network is achieved by using diverse paths where available. Management of the redundancy of the network uses rapid-failover protection mechanisms (EAPS or MRP) so that in the event of a network interruption, the redundant links are activated within tenths of a second.
The Manchester site, known as IXManchester, is run on Brocade switches located in Telecity Williams House. Members can also connect to IX Manchester from Telecity Kilburn. Members of IX Manchester are full members of LINX, paying the same membership fee and having the same voting rights. The LAN in Manchester is completely separate to the two London LANs and is open to all LINX members. This location was the first in an on-going regional peering programme that includes plans for other major UK locations.
The most recent of these is IX Scotland, hosted at the Pulsant SouthGyle data centre in Edinburgh that was launched in October 2013. There have been at least two efforts to set up an IXP in Edinburgh in the past 15 years, both of which ultimately failed. In 2004, LINX supported one of these - UIXP - with a loan of hardware and general assistance, but unfortunately, UIXP was unable to continue operations because the data centre hosting the IXP, Scolocate, withdrew support. IX Scotland has a steering group that is responsible for managing the community while LINX provides the technical support. To access IX Scotland, it is necessary to be a LINX Member.
To address the scarcity of public peering options in the US as compared to Europe, LINX has also been involved in setting up European-style non-profit interconnection facilities in the US known as Open IX. Traditionally, private peering has been the dominant model in North America, but there is a demand from network operators for mutually-owned public peering in the United States. The biggest IXPs in the world are all based in Europe with only one North American exchange being in the world's top 10 (Terremark's NAP of the Americas located in Miami), a situation that contrasts with the fact that there is more traffic in the US than anywhere else. The aim of the Open IX project is to work with major data centres to allow third-party interconnect platforms in their premises.
The first Open-IX exchange was launched in October 2013 in the Northern Virginia area with a choice of three different physical data centre locations. Called LINX NoVA, the exchange is built with Juniper MX series routers and is will be available in Ashburn, Reston and Manassas. The sites will be connected by diverse dark fibre lit by LINX.
The Open-IX proposal states that in order to participate, each data centre needs to agree to open up their Meet-Me-Rooms (MMR) to the operator of the interconnect service and agree to an initial term of five years. Services will include the provision of a public Internet exchange, private VLAN and private wavelengths plus point-to-point dark fibre.
LINX also has a twinning programme to support IXPs in emerging markets and has twinned with the Zambian exchange, ZIXP.
LONAP is a neutral, not-for-profit IXP that has been based in London since 1997. LONAP currently has 134 members, making it the 2nd largest IXP with traffic currently peaking at about 44Gbps. LONAP membership is usually the first step in peering for smaller ISP’s and hosting companies prior to joining LINX.
As a membership organisation, the exchange is owned by the networks that participate in it. As a condition of membership, the rules of the exchange require a member to connect and peer at the exchange, but membership is open to any organisation worldwide that wishes to peer. Membership of the organisation is UK GBP2,000 per year; this fee provides for two 1 Gbit/s connections to the exchange at no further charge. 10 Gbit/s Ethernet ports are charged at UK GBP2,500 per year.
LONAP uses a network of interconnected Extreme X series switches linked to each other through diverse 10 Gbps fibre rings that connect five sites in the London Docklands and City areas; Telehouse Docklands North & East, Telecity Sovereign House, Telecity Harbour Exchange and InterXion London City.
In addition to these sites, remote peering is possible via LONAP, using a third-party layer 2 network, with dark fibre or wavelengths. Members based in multiple points of presence (PoPs) can connect to LONAP in more than one location in order to increase their service resiliency. Members are permitted to pass traffic between their own ports and can request private VLANs between their own ports or to other members, for purposes such as for DSL aggregation. LONAP has on-site spares of the critical equipment that powers the network; these spares assist in responding quickly to any problems that may arise. An off-network, 'out-of-band' connection is present at LONAP sites so that problems can be addressed remotely without waiting for staff to be on site.
After two years of preparatory work to establish an exchange in the Yorkshire area, IXLeeds was set up in 2010. It is an independent not-for-profit IXP based in Leeds with 18 members and about 2Gbps of peak traffic.