An Overlay Internetworking Architecture for Ambient Networks

Several different internetworking architectures are being discussed within the Ambient Networks (AN) project. This paper describes the Overlay architecture. Its name is derived from the use of an overlay control plane that allows for internetworking between different network technologies, as well as for control of functionality that is today found in different and sometimes proprietary middleboxes such as NATs, firewalls, mobility agents, and media routers. Routing of control plane signalling messages is based on globally unique, hierarchical, and topologically significant locators. These global locators are mapped one-to-one to local and network technology specific locators such as public and private IPv4 addresses, or IPv6 addresses. Cryptographic host identifiers are used for host identification in line with the Host Identity Protocol framework being developed in the IETF. To reduce the address administration, the routing of signalling messages in access networks can optionally be based on the cryptographic host identifiers. In the user plane, legacy transport protocols such as TCP, UDP, and RTP are used end-to-end. Gateways relay the transport protocol frames between different network technologies, and perform the middlebox functions. The architecture supports backwards compatibility with the legacy IPv4 socket API. Also, migration scenarios where Ambient Networks are interconnected by a legacy IPv4 backbone network are supported.