Routing at Large Scale: Advances and Challenges for Complex Networks
A wide range of social, technological and communication systems can be described as complex networks. Scale-free networks are one of the well known classes of complex networks in which nodes' degrees follow a power-law distribution. The design of scalable, adaptive and resilient routing schemes in such networks is very challenging. In this article we present an overview of required routing functionality, categorize the potential design dimensions of routing protocols among existing routing
... es, and analyze experimental results and analytical studies performed so far to identify the main trends/trade-offs and draw main conclusions. Besides traditional schemes such as hierarchical/shortest-path path-vector routing, the article pays attention to advances in compact routing and geometric routing since they are known to significantly improve scalability in terms of memory space. The identified trade-offs and the outcomes of this overview enable more careful conclusions regarding the (un-)suitability of different routing schemes to large-scale complex networks and provide a guideline for future routing research. 1 The probability that a node selected uniformly at random has a certain number of links. 2 In the Internet, an autonomous system is a single network or a group of networks that is managed and supervised by a single administrative entity or organization. 3 The power-law component of the Internet seems to be decreasing while the assortativity (likelihood of nodes with the same degree being connected) is increasing. 4 The process of finding/selecting paths between given nodes of a communication network. 5 Schemes that maintain the path information to reach a destination. 6 A routing paradigm that derives paths based on locators. Particularly it enables routing the packets based on addresses that are specific to the network location instead of relying on any arbitrary flat address space. 7 The distance between two nodes is the number of edges in the shortest path between the nodes.