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Improving and Analyzing LC-Trie Performance for IP-Address Lookup
KTH, School of Electrical Engineering (EES), Communication Networks.
KTH, School of Computer Science and Communication (CSC).
KTH, School of Electrical Engineering (EES), Communication Networks.ORCID iD: 0000-0002-3704-1338
2007 (English)In: Journal of Networks, ISSN 1796-2056, Vol. 2, no 3, 18-27 p.Article in journal (Refereed) Published
Abstract [en]

IP-address lookup is a key processing function of Internet routers. The lookupis challenging because it needs to perform a longest prefix match. In this paper, wepresent our modifications to an efficient lookup algorithm, the LC-trie, based ona technique called prefix transformation. Thereafter, the LC-trie’s performance isanalyzed for both the original and our modified algorithm using real and syntheticallygenerated traces. The performance study includes trie search depth, prefixvector access behavior, cache behavior and packet lookup time. The study is basedboth on experiments and a model for packet lookup time. The results show thatthe modified algorithm requires only 30% of the lookup time of the original algorithm.In particular, the modified algorithm is capable of performing 60 millionpacket lookups per second on a Pentium 4, 2.8 GHz, computer for a real traffictrace. Further, the results show that the performance is about five times better onthe real trace compared to a synthetically generated network trace. This illustratesthat the choice of traces may have a large influence on the results when evaluatinglookup algorithms.

Place, publisher, year, edition, pages
2007. Vol. 2, no 3, 18-27 p.
Keyword [en]
IP-address lookup, trie, prefix transformation, performance evaluation
National Category
URN: urn:nbn:se:kth:diva-9411ScopusID: 2-s2.0-51049091794OAI: diva2:113876
QC 20100726Available from: 2008-10-30 Created: 2008-10-30 Last updated: 2013-09-09Bibliographically approved
In thesis
1. On the Design of Next-Generation Routers and IP Networks
Open this publication in new window or tab >>On the Design of Next-Generation Routers and IP Networks
2008 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

This thesis investigates distributed router architectures and IP networks with centralized control. While the current trend in IP-router architectures is towards decentralized design, there have also been research proposals for centralizing the control functions in IP networks. With continuous evolution of routers and IP networks, we believe that eventually IP networks in an autonomous system (AS) and a distributed router might converge into one network system. This system, which can be considered both as a distributed router and a centrally-controlled IP network, is divided into a control plane and a forwarding plane. The control plane is responsible for routing, management and signalling protocols, while the forwarding plane is responsible for forwarding packets.

The work in this thesis covers both the forwarding and control planes. In the forwarding plane, we study network processor systems that function as forwarding elements in a distributed router. We introduce a system model and a simulation tool based on the model. Using the simulation tool, we investigate network processor system design by studying throughput, utilization, queueing behavior and packet delays. In addition to network processor systems, we study IP-address lookup, which is one of the key packet processing functions in Internet routers. Our work in IP-address lookup contains an efficient lookup algorithm, a scheme to divide the lookup procedure into two-stages in a distributed router, and an approach to perform efficient lookup on a router supporting multiple virtual routers.

In the control plane, we study three emerging research issues with centralized control. We provide a thorough study of the routing convergence process in networks with centralized control, and compare it with decentralized link-state routing protocols. We propose an efficient approach to perform traffic engineering and routing in networks with centralized control, and compare it with an approach using optimized link weights. Finally, we present an approach to perform loop-free updates of forwarding tables when the forwarding paths change. This loop-free update approach is particularly useful in networks with centralized control.

The results presented in this thesis are useful for building next-generation routers and IP networks with centralized control that might eventually converge into one network system.

Place, publisher, year, edition, pages
Stockholm: KTH, 2008. vii, 34 p.
Trita-EE, ISSN 1653-5146 ; 2008:040
router architecture, IP-network architecture
National Category
urn:nbn:se:kth:diva-9381 (URN)
Public defence
2008-11-26, M1, KTH, Stockholm, 14:00 (English)
QC 20100726Available from: 2008-11-03 Created: 2008-10-28 Last updated: 2010-07-26Bibliographically approved

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