Modeling Complexity of Enterprise Routing Design Xin Sun Sanjay G. Rao Geoffrey G. Xie School of Computing and School of Electrical and Department of Computer Information Sciences Computer Engineering Science Florida International University Purdue University Naval Postgraduate School xinsun@cs.fiu.edu
[email protected] [email protected] ABSTRACT to choose from [23]. Often, multiple designs exist to meet the same operational objectives, and some are significantly Enterprise networks often have complex routing designs given easier to implement and manage than others for a target net- the need to meet a wide set of resiliency, security and rout- work. For example in some cases, route redistribution may ing policies. In this paper, we take the position that minimiz- be a simpler alternative to BGP for connecting multiple rout- ing design complexity must be an explicit objective of rout- ing domains [16]. Lacking an analytical model to guide the ing design. We take a first step to this end by presenting a operators, the current routing design process is mostly ad systematic approach for modeling and reasoning about com- hoc, prone to creating designs more complex than necessary. plexity in enterprise routing design. We make three contri- butions. First, we present a framework for precisely defining In this paper, we seek to quantitatively model the com- objectives of routing design, and for reasoning about how a plexity associated with a routing design, with a view to de- combination of routing design primitives (e.g. routing in- veloping alternate routing designs that are less complex but stances, static routes, and route filters etc.) will meet the ob- meet the same set of operational objectives.