Overlay network

An overlay network is a computer network that is based on an existing network ( underlay called ). Main features of an overlay network are:

  • (logical ) network above existing infrastructure
  • Often its own address space with its own address (regardless of the underlay )
  • Possibly using its own path selection method

The overlay network is therefore to build up additional topology (physical, logical, structural, ... ) are used. With the newly created structure can be, for example, current technologies such as IPv6 test or create alternative routes for the data. Peer-to -peer networks, such as Gnutella and are also constructed in a Chord overlay network structure via which, for example, a certain power and efficient searching coordination are possible. Also on these overlays can set up, for example, for monitoring the P2P overlay SkyEye is used, which introduces its own address space and bring their own protocols that require the functionality of the P2P overlays more overlays.

The Internet was in its infancy an overlay network over the existing telephone network. In part, this is so even today, because there are still users who connect via modem to the Internet. Meanwhile, the telephone network is VoIP but increasingly to an overlay network based on the Internet.

Some examples of overlay networks are:

  • Content Addressable Network ( CAN)
  • Chord
  • DiffServ ( separated by physical network into multiple logical classification of network resources into different classes of service )
  • Freenet
  • Gnutella, Gnutella2
  • I2P
  • Kademlia
  • Retroshare
  • MBone, 6bone, abone
  • P -Grid
  • Pastry / Tapestry
  • PNRP
  • RON
  • XBone
  • SkyEye
  • Network Type
Chord (peer-to-peer) Peer Name Resolution Protocol
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