Hybrid SDN Evolution: A Comprehensive Survey of the State-of-the-Art

Software-Defined Networking (SDN) is an evolutionary networking paradigm which has been adopted by large network and cloud providers, among which are Tech Giants. However, embracing a new and futuristic paradigm as an alternative to well-established and mature legacy networking paradigm requires a lot of time along with considerable financial resources and technical expertise. Consequently, many enterprises can not afford it. A compromise solution then is a hybrid networking environment (a.k.a. Hybrid SDN (hSDN)) in which SDN functionalities are leveraged while existing traditional network infrastructures are acknowledged. Recently, hSDN has been seen as a viable networking solution for a diverse range of businesses and organizations. Accordingly, the body of literature on hSDN research has improved remarkably. On this account, we present this paper as a comprehensive state-of-the-art survey which expands upon hSDN from many different perspectives

Developing the Fringe Routing Protocol

An ISP style network often has a particular traffic pattern not typically seen in other networks and which is a direct result of the ISP’s purpose, to connect internal clients with a high speed external link. Such a network is likely to consist of a backbone with the clients on one ‘side’ and one or more external links on the other. Most traffic on the network moves between an internal client and the external world via the backbone. But what about traffic between two clients of the ISP? Typical routing protocols will find the ‘best’ path between the two gateway routers at the edge of the client stub networks. As these routers connect the stubs to the ISP core, this route should be entirely within the ISP network. Ideally, from the ISP point of view, this traffic will go up to the backbone and down again but it is possible that it may find another route along a redundant backup path. Don Stokes of Knossos Networks has developed a protocol to sit on the client fringes of this ISP style of network. It is based on the distance vector algorithm and is intended to be subordinate to the existing interior gateway protocol running on the ISPs backbone. It manipulates the route cost calculation so that paths towards the backbone become very cheap and paths away from the backbone become expensive. This forces traffic in the preferred direction unless the backup path ‘shortcut’ is very attractive or the backbone link has disappeared. It is the analysis and development of the fringe routing protocol that forms the content of this ME thesis