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Unformatted text preview: Theory and New Primitives for Safely Connecting Routing Protocol Instances Franck Le Carnegie Mellon University [email protected] Geoffrey G. Xie Naval Postgraduate School [email protected] Hui Zhang Carnegie Mellon University [email protected] ABSTRACT Recent studies have shown that the current primitives for connect- ing multiple routing protocol instances (OSPF 1, OSPF 2, EIGRP 10, etc.) are pervasively deployed in enterprise networks and the Internet. Furthermore, these primitives are extremely vulnerable to routing anomalies (route oscillations, forwarding loops, etc.) and at the same time too rigid to support some of today’s operational objectives. In this paper, we propose a new theory to reason about routing properties across multiple routing instances. The theory di- rectly applies to both link-state and vector routing protocols. Each routing protocol still makes independent routing decisions and may consider a combination of routing metrics, including bandwidth, delay, cost, and reliability. While the theory permits a range of so- lutions, we focus on a design that requires no changes to existing routing protocols. Guided by the theory, we derive a new set of connecting primitives, which are not only provably safe but also more expressive than the current version. We have implemented and validated the new primitives using XORP. The results confirm that our design can support a large range of desirable operational goals, including those not achievable today, safely and with little manual configuration. Categories and Subject Descriptors: C.2.6 [Computer-Communication Networks]: Internetworking General Terms: Design, Theory Keywords: Connecting primitives, route redistribution, route se- lection 1. INTRODUCTION Recent empirical studies [24, 21, 5] challenge the traditional, simple “BGP over your favorite IGP” view of the Internet routing architecture. As illustrated in Figure 1, they reveal that the Inter- net routing landscape is in reality much more complex. ISPs and enterprise networks deploy tens to hundreds of routing protocol in- stances simultaneously [21, 5], and those routing instances are of- tentimes interconnected in diverse ways . In a recent study , the authors found that 57% of the analyzed networks have more than three routing instances, which is greater than a single IGP and Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee....
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This note was uploaded on 02/23/2012 for the course CS 591 taught by Professor Dongyanxu during the Fall '10 term at Purdue.
- Fall '10