By Topic

Fast firewall implementations for software and hardware-based routers

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

3 Author(s)

Routers must perform packet classification at high speeds to efficiently implement functions such as firewalls and diffserv. Classification can be based on an arbitrary number of fields in the packet header. Performing classification quickly on an arbitrary number of fields is known to be difficult, and has poor worst-case complexity. In this paper, we re-examine two basic mechanisms that have been dismissed in the literature as being too inefficient: backtracking search and set pruning tries. We find using real databases that the time for backtracking search is much better than the worst-case bound; instead of Ω((logN)k-1), the search time is only roughly twice the optimal search time. Similarly, we find that set pruning tries (using a DAG optimization) have much better storage costs than the worst-case bound. We also propose several new techniques to further improve the two basic mechanisms. Our major ideas are: (i) backtracking search on a small memory budget, (ii) a novel compression algorithm, (iii) pipelining the search, (iv) the ability to trade-off smoothly between backtracking and set pruning. We quantify the performance gain of each technique using real databases. We show that on real firewall databases our schemes, with the accompanying optimizations, are close to optimal in time and storage.

Published in:

Network Protocols, 2001. Ninth International Conference on

Date of Conference:

11-14 Nov. 2001