Packet Reordering in Network Processors

Govind, S and Govindarajan, R and Kuri, Joy (2007) Packet Reordering in Network Processors. In: IEEE International Parallel and Distributed Processing Symposium, 2007. IPDPS 2007., 26-30 March 2007 , Long Beach, CA.

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Abstract

Network processors today consist of multiple parallel processors (micro engines) with support for multiple threads to exploit packet level parallelism inherent in network workloads. With such concurrency, packet ordering at the output of the network processor cannot be guaranteed. This paper studies the effect of concurrency in network processors on packet ordering. We use a validated Petri net model of a commercial network processor, Intel IXP 2400, to determine the extent of packet reordering for IPv4 forwarding application. Our study indicates that in addition to the parallel processing in the network processor, the allocation scheme for the transmit buffer also adversely impacts packet ordering. In particular, our results reveal that these packet reordering results in a packet retransmission rate of up to 61%. We explore different transmit buffer allocation schemes namely, contiguous, strided, local, and global which reduces the packet retransmission to 24%. We propose an alternative scheme, packet sort, which guarantees complete packet ordering while achieving a throughput of 2.5 Gbps. Further, packet sort outperforms the in-built packet ordering schemes in the IXP processor by up to 35%.

Item Type:	Conference Paper
Publisher:	IEEE
Additional Information:	Copyright 2007 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
Department/Centre:	Division of Electrical Sciences > Electronic Systems Engineering (Formerly Centre for Electronic Design & Technology) Division of Electrical Sciences > Computer Science & Automation Division of Interdisciplinary Sciences > Supercomputer Education & Research Centre
Date Deposited:	13 Oct 2011 09:45
Last Modified:	13 Oct 2011 09:45
URI:	http://eprints.iisc.ac.in/id/eprint/41367

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