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London Internet Exchange

London Internet Exchange
Abbreviation LINX
Founded 1994
Location  United Kingdom, London
Members 639 as of September 2015
Ports 1,527 as of September 2015
Peak 3.043 Tbit/s as of September 2015
Daily (avg.) 2.122 Tbit/s as of September 2015
Telehouse Docklands, home of the London Internet Exchange since 1994.

The London Internet Exchange ("LINX") is a mutually governed Internet exchange point (IXP) that provides peering services and public policy representation to over 500 Internet Service Providers (ISPs) and other network operators. LINX operates IXPs in London, Manchester (IXManchester), Edinburgh (IXScotland), Cardiff, and North Virginia, USA (LINX NoVA).

LINX was founded in 1994 by a group of ISPs and educational networks and is a founder member of Euro-IX, a Europe-wide alliance of Internet Exchanges. It is currently one of the largest neutral IXPs in Europe in terms of average throughput.

LINX is a not-for-profit organisation (Company Limited by Guarantee). Internet service providers join LINX as members and sign a memorandum of understanding. Members collectively 'own' the company and all members have a single vote at AGMs and EGMs in matters relating to finances, constitution, and what activities LINX may carry out. Members also periodically elect the LINX non-executive board of directors. Members meet at regular LINX meetings to discuss technical, corporate governance, and regulatory matters. LINX has a mandate to not actively compete with its members.


  • History 1
    • Not for profit organisation 1.1
    • LINX in the twenty-first century 1.2
  • Technology 2
  • Public Affairs 3
  • Local Exchanges 4
    • IXManchester 4.1
    • IXScotland 4.2
    • IXCardiff 4.3
    • LINX NoVA 4.4
  • Other activities 5
  • See also 6
  • See also 7
  • References 8
  • External links 9


Back in November 1994, using a donated piece of equipment no bigger than a video recorder and without any legal contracts, five UK-based Internet service providers (ISPs) linked their networks in order to exchange data and avoid paying high transatlantic bandwidth costs.

LINX effectively began when two ISPs (PIPEX and UKnet) linked their networks via a 64-kilobit serial link to save the cost and time delay involved in routing data across the Atlantic to US Internet exchanges.

When Demon Internet, UKERNA - the UK academic network - and other ISPs showed interest in establishing similar serial links, Keith Mitchell, then chief technical officer of PIPEX, initiated a meeting with BT to discuss the creation of a London-based Internet exchange.

PIPEX provided the LINX founders with a Cisco Catalyst 1200 switch with eight 10-megabit ports. Rack space was leased at a then virtually empty data centre operated by Telehouse International Corporation of Europe Ltd at Coriander Avenue in London's Docklands.

Switching the first data through the Telehouse hub was a momentous event that was accomplished by primarily technical specialists who were unconcerned about the formalities of legal contracts. However, while PIPEX continued to provide administrative and technical oversight, the need for a formal constitution was eventually recognised.

The solution was to form a company limited by guarantee. Lawyers produced a draft memorandum and constitution which was extensively modified by members. The company was formed in 1995 and a board of five non-executive directors was elected, with Keith Mitchell as the initial chairman.

Not for profit organisation

From the beginning it was agreed that LINX would be a non-profit organisation run for the benefit of members and governed collectively through regular member meetings, a practice which continues to this day.

While PIPEX continued to provide administrative oversight - charged at cost to LINX - member meetings were held every two months (now every three months) to decide strategic direction. Eventually, it was accepted that the purely co-operative system of operation at LINX was becoming overly demanding and in late 1996 Keith Mitchell accepted the role of full-time chairman, working with a personal assistant from offices in Peterborough.

In the summer of 1996 LINX became the first Internet exchange in the world to deploy a 100-megabit switch - a Cisco Catalyst 5000. In January 1999 it pioneered the implementation of a Metropolitan Area Network (MAN) running over gigabit Ethernet connections.

As the Internet grew in popularity, legislators and law enforcement agencies inevitably decided it must be regulated. LINX increasingly found itself taking on non-core activities, such as providing expert advice on behalf of its members (and, therefore, the whole industry) to a wide range of official agencies.

In 1999 LINX appointed its first full-time regulation officer in Roland Perry to advise organisations such as the Home Office Internet Task Force, the National Hi-Tech Crime Unit, the Department of Trade and Industry and relevant departments of the EU Commission. In 2003 Roland was succeeded by Malcolm Hutty when Roland left to form his own advisory group.

LINX also actively and financially supports the Internet Watch Foundation which, since 1996, has worked to eradicate child abuse images from the UK Internet. Initial funding from LINX was instrumental in enabling the IWF to launch and the decision to create the IWF and define its charter was taken at a LINX member meeting in Heathrow.

LINX in the twenty-first century

2000 - a training manager was appointed to introduce an accredited training programme for Internet engineers and technicians.

2001 - LINX amended its corporate structure to make the post of chairman non-executive and appointed its first chief executive officer, John Souter, previously UK managing director of German-owned Varetis Communications.

2002 - LINX was the first exchange to introduce 10G Ethernet operation, using equipment from Foundry Networks - in fact the second of their world-wide customers to deploy their technology.

2003 - This year saw the launch of the 'LINX from Anywhere' service, a facility that permits smaller ISPs to piggyback on the networks of existing members to obtain a secure, virtual presence on the LINX exchange without incurring the manpower and rackspace costs of having their own installation in London.

2004 - LINX considerably expanded its footprint, with four new points of presence (PoPs) - all in the Docklands area of London.

2005 - LINX members vote to make Public Affairs one of the company's "core functions", placing it on an equal footing with peering and interconnection.

2006 - LINX membership reached 200.

2008 - LINX expanded again opening three new PoPs, this time adding considerably to the geographical diversity by doing so in the City of London, North Acton and Slough. It also heralded new relationships with data centre operators, with the addition of Interxion and Equinix (to the pre-existing ones of Telehouse and Telecity).

2011 - The LINX primary LAN was redesigned to a VPLS-based infrastructure with a new vendor, Juniper Networks.

2012 - The ConneXions reseller programme launched. Also this year LINX became the first Internet Exchange in the world to install a Juniper PTX5000 in a live network and the exchange opened its first site outside London in Manchester (IXManchester).

2013 - In the Autumn two further local exchanges were launched. IXScotland in Edinburgh and LINX NoVA in North Virginia, USA, the exchange's first sites outside England.

2014 - In the Autumn a local exchange was launched, IXCardiff in Wales.


In London LINX operates two physically separate networks or switching platforms on different architectures using equipment from different manufacturers (Extreme Networks and Juniper Networks). These networks are deployed over ten locations, each connected by multiple 100 Gigabit Ethernet or 10 Gigabit Ethernet connections over fibre networks.[1]

The ten London locations are:

Connecting is also possible from remote locations via the 'LINX from Anywhere' scheme [2] via a range of layer 2 service/MPLS carriers.

Redundancy of the network is managed using rapid-failover protection mechanisms such a VPLS service over an MPLS core (MPLS/VPLS) from Juniper and Extreme's Ethernet Automatic Protection System (EAPS). These restore connectivity within tenths of a second in the event of the loss of a network segment.

In addition to the main peering infrastructure, LINX provides managed private interconnections (via Single Mode Fibre) between LINX members, and works with a number of fibre carriers to provide rapid connection between LINX members for private circuits. These PI circuits may be used for any purpose but are mainly intended for Private Peering arrangements between members. Private Peering is sometimes more appropriate for managing large flows of traffic between ISPs and/or Content Providers.

Public Affairs

One of LINX's core functions is to represent its members in matters of public policy. LINX's Public Affairs department works to obtain advance warning of public policy developments that could affect LINX members, to inform members about important policy developments at a time when it is still possible to influence them, and to educate, inform and influence regulators and legislators.

At the UK level, LINX liaises directly with policy makers on matters such as content regulation, telecoms regulation, privacy and data protection, e-mail spam, online fraud/phishing, law enforcement, counter-terrorism, and any other topics that affect LINX members.

At the European level, LINX is an active member of EuroISPA, and works with EuroISPA's other national associations to influence European policy.

LINX also works actively with partner organisations such as the Internet Watch Foundation (IWF) and the Internet Society (ISOC). LINX was instrumental in the creation of the Internet Watch Foundation, the UK hotline for reporting and removing child sexual abuse material from the Internet, and continues to advise the IWF as a member of its Funding Council.

As a mutual, membership based organisation, all of LINX's Public Affairs activity is informed and guided by extensive and ongoing consultation with LINX members.

Local Exchanges


Launched in April 2012 IXManchester was initially a single-site platform based on a standalone Brocade BigIron RX-16 switch, repurposed from the Primary LAN in London. A new design extends the network to two new sites - M247's IceColo & Joule House and brings in completely new hardware from Extreme Networks.

The new network will be configured as an EAPS protected ring, topology currently used for the secondary LINX LAN in London. All sites will use a Summit X670v switch, capable of connecting 48x10Gb member ports. Telecity Williams will also have a smaller Summit X460 switch for terminating slower ports.

The links between sites will be provisioned on a dark fibre provided by NTL and lit by LINX with the use of SFP+ DWDM transceivers and passive DWDM MUX units. Initial ISL capacity will be configured at 20Gbit/s but easily upgradeable to 80Gbit/s if required.


Located in Pulsant’s South Gyle data centre in Edinburgh (formerly Scolocate), IXScotland was officially launched in November 2013. The site will use the latest hardware from Extreme Networks enabling all the advanced features expected from a modern exchange.


Located in BT’s Stadium House data centre in Cardiff. IXCardiff was officially launched on 15 October 2014 in an effort to decentralise UK internet traffic.


Following discussions with the US network community, and its own members, LINX decided to launch an open peering exchange in North America in late 2013. Formally to be known as LINX NoVA, the exchange will be closely aligned with, and endorsed by, the newly formed Open-IX, using systems and processes that have proved successful in Europe and the wider world for nearly 20 years.

Based in the North Virginia/Washington DC area LINX NoVA initially spanned three data centres - EvoSwitch in Manassas, DuPont Fabros in Ashburn and Coresite in Reston - and will be connected using dark fibre lit by LINX. An agreement for a fourth colo site, also in Ashburn, is expected shortly.

The LINX NoVA exchange will use cutting edge MX960 router equipment from Juniper Networks capable of delivering 100G member ports from launch with the three PoPs all connected by diverse dark fiber lit by LINX.

LINX NoVA will be developed in the same way as the LINX primary LAN in London (VPLS, separated core and edge, etc.) but as a stand-alone site not connected back to the LANs operated in the UK.

Other activities

LINX also carries on a number of non-core activities (NCAPs) from time to time, for example the LINX Accredited Internet Technician (LAIT) training programme.

Other services provided include a time service using atomic clocks, as well as hosting for other "Good of the Internet" services including various Internet statistics projects, numerous secondary name servers for various ccTLD domains, and instances of the F, K and I root nameservers.

See also

Some other Internet exchange points in London:

LINX hosts a number of meetings where network operators can exchange information: see List of Internet Network Operators' Groups for a list of other organizations holding similar meetings.

See also


  1. ^ "LINX Network Topology". London Internet Exchange. 
  2. ^ "LINX Anywhere". 

External links

  • Official Website
    • Looking glass
    • LINX Memorandum of Understanding
    • LINX Public Affairs
  • LINX overtakes US as biggest data hub
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