internet ixp

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The main building of the

LINX (London Internet

Exchange)

Internet exchange pointFrom Wikipedia, the free encyclopedia

An Internet exchange point (IX or IXP) is a physical infrastructure through whichInternet service providers (ISPs) exchange Internet traffic between their networks(autonomous systems).

IXPs reduce the portion of an ISP's traffic which must be delivered via their upstreamtransit providers, thereby reducing the average per-bit delivery cost of their service.Furthermore, the increased number of paths learned through the IXP improves routinefficiency and fault-tolerance.

Contents

1 Function2 Operation

3 Traffic exchange across an Internet exchange point4 See also5 References6 External links

Function

The primary purpose of an IXP is to allow networks tointerconnect directly, via the exchange, rather thanthrough one or more third-party networks. Theadvantages of the direct interconnection are numerous,but the primary reasons are cost, latency, and

bandwidth.[1]

Traffic passing through an exchange is typically notbilled by any party, whereas traffic to an ISP's upstreamprovider is. The direct interconnection, often located inthe same city as both networks, avoids the need for datato travel to other cities (potentially on other continents)

to get from one network to another, thus reducinglatency.[2]

The third advantage, speed, is most noticeable in areasthat have poorly developed long-distance connections.ISPs in these regions might have to pay between 10 or100 times more for data transport than ISPs in NorthAmerica, Europe or Japan. Therefore, these ISPs typicallyhave slower, more limited connections to the rest of theinternet. However, a connection to a local IXP may allow

Internet exchange point - Wikipedia, the free encyclopedia http://en.wikipedia.org/wiki/Internet_excha

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An optical fiber photonic

switch at the AMS-IX

(Amsterdam Internet

Exchange)

them to transfer data without limit, and without cost,vastly improving the bandwidth between customers of

the two adjacent ISPs.[3]

Operation

A typical IXP consists of one or more network switches, to which each of the

participating ISPs connect. Prior to the existence of switches, IXPs typically utilizedfiber-optic inter-repeater link (FOIRL) hubs or Fiber Distributed Data Interface (FDDI)rings, migrating to Ethernet and FDDI switches as those became available in 1993 and1994.

Asynchronous Transfer Mode (ATM) switches were briefly used at a few IXPs in the lat1990s, accounting for approximately 4% of the market at their peak, and there was anabortive attempt by the Stockholm IXP, NetNod, to use SRP/DPT, but Ethernet hasprevailed, accounting for more than 95% of all existing Internet exchange switchfabrics. All Ethernet port speeds are to be found at modern IXPs, ranging from 10 Mbiports in use in small developing-country IXes, to ganged 10 Gbit/s ports in major centelike Seoul, New York, London, Frankfurt, Amsterdam, and Palo Alto.

The technical and business logistics of traffic exchange between ISPs is governed bymutual peering agreements. Under such agreements traffic is often exchanged withoucompensation. When an IXP incurs operating costs, they are typically shared among aof its participants.

At the more expensive exchanges, participants pay a monthly or annual fee, usuallydetermined by the speed of the port or ports which they're using, or much lesscommonly by the volume of traffic which they're passing across the exchange. Feesbased on volume of traffic are unpopular because they provide a counterincentive togrowth of the exchange. Some exchanges charge a setup fee to offset the costs of theswitch port and any media adaptors (gigabit interface converters, small form-factorpluggable transceivers, XFP transceivers, XENPAKs, etc.) that the new participantrequires.

Traffic exchange across an Internet exchange point

Internet traffic exchange between two participants on an IXP is facilitated by BorderGateway Protocol (BGP) routing configurations between them. They choose to announroutes via the peering relationship - either routes to their own addresses, or routes toaddresses of other ISPs that they connect to, possibly via other mechanisms. The otheparty to the peering can then apply route filtering, where it chooses to accept thoseroutes, and route traffic accordingly, or to ignore those routes, and use other routes toreach those addresses.

In many cases, an ISP will have both a direct link to another ISP and accept a route(normally ignored) to the other ISP through the IXP; if the direct link fails, traffic willthen start flowing over the IXP. In this way, the IXP acts as a backup link.

When these conditions are met, and a contractual structure exists to create a market t


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purchase network services, the IXP is sometimes called a transit exchange. TheVancouver Transit Exchange, for example, is described as a "shopping mall" of serviceproviders at one central location, making it easy to switch providers - "as simple as

getting a VLAN to a new provider."[4]

The VTE is run by BCNET, a public entity.

Advocates of green broadband schemes and more competitive telecom services oftenadvocate aggressive expansion of transit exchanges into every municipal area network

so that competing service providers can place such equipment as video on demand hoand PSTN switches to serve existing phone equipment, without being answerable to anmonopoly incumbent.

Further information: Peering

See also

Colocation centerRoute server

List of Internet exchange pointsList of Internet exchange points by size

Historical:

Commercial Internet eXchange (CIX) (historical)Federal Internet Exchange (FIX) (historical)Network Access Point (NAP) (historical)

References


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^ "BGP: the Border Gateway Protocol Advanced Internet Routing Resources. (viewed Jul10, 2010)" (http://www.bgp4.as/internet-exchanges) . Bgp4.as. 2011-10-20.http://www.bgp4.as/internet-exchanges. Retrieved 2011-11-22.

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^ "BCNET's transit exchange helps Novus+Entertainment save on Internet costs andimprove performance" (https://wiki.bc.net/atl-conf/display/BCNETPUBLIC/2009/05/27/Transit+Exchange+helps+Novus+Entertainment+Save+on+Internet+Costs+and+Iprove+Performance) . Wiki.bc.net. 2009-05-27. https://wiki.bc.net/atl-conf/display/BCNETPUBLIC/2009/05/27/Transit+Exchange+helps+Novus+Entertainment+Save+on+Internet+Costs+and+Iprove+Performance. Retrieved 2011-11-22.

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External links

Packet Clearing House: Directory of Internet Exchange Points(http://www.pch.net/ixpdir)Internet Exchanges (http://www.dmoz.org/Computers/Internet/Routers_and_Routing/Internet_Exchanges//) at the Open Directory ProjectExchange point information (http://www.ep.net/)PeeringDB (http://www.peeringdb.com/)Internet exchange points (http://www.bgp4.as/internet-exchanges)European Internet Exchange Association (http://www.euro-ix.net)IXP's Internet Exchange Points (http://www.datacentermap.com/ixps.html)

Retrieved from "http://en.wikipedia.org/w/index.php?title=Internet_exchange_point&

oldid=469301947"Categories: Internet exchange points Routing Wide area networks

This page was last modified on 3 January 2012 at 11:35.Text is available under the Creative Commons Attribution-ShareAlike License;additional terms may apply. See Terms of use for details.Wikipedia is a registered trademark of the Wikimedia Foundation, Inc., anon-profit organization.


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