Parallel and pipelined architectures for high speed ip packet forwarding

---

Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Elektrik ve Elektronik Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2011

Öğrenci: OĞUZHAN ERDEM

Danışman: CÜNEYT FEHMİ BAZLAMAÇCI

Özet:

A substantial increase in the number of internet users and the traffic volume bring new challenges for network router design. The current routers need to support higher link data rates and large number of line cards to accommodate the growth of the internet traffic, which necessitate an increase in physical space, power and memory use. Packet forwarding, which is one of the major tasks of a router, has been a performance bottleneck in internet infrastructure. In general, most of the packet forwarding algorithms are implemented in software. However, hardware based solutions has also been popular in recent years because of their high throughput performance. Besides throughput, memory efficiency, incremental/dynamic updates and power consumption are the basic performance challenges for packet forwarding architectures. Hardware-based packet forwarding engines for network routers can be categorized into two groups that are ternary content addressable memory (TCAM) based and dynamic/static random access memory (DRAM/SRAM) based solutions. TCAM-based architectures are simple and hence popular solutions for today’s routers. However, they are expensive, power-hungry, and oer little adaptability to new addressing and routing protocols. On the other hand, SRAM has higher density, lower power consumption, and higher speed. The common data structure used in SRAM-based solutions for performing longest prefix matching (LPM) is some type of a tree. In these solutions, multiple memory accesses are required to find the longest matched prefix. Therefore, parallel and pipelining techniques are used to improve the throughput. This thesis studies TCAM and SRAM based parallel and pipelined architectures for high performance packet forwarding. We proposed to use a memory efficient disjoint prefix set algorithm on TCAM based parallel IP packet forwarding engine to improve its performance. As a fundamental contribution of this thesis, we designed an SRAM based parallel, intersecting and variable length multi-pipeline array structure (SAFIL) for trie-based internet protocol (IP) lookup. We also proposed a novel dual port SRAM based high throughput IP lookup engine (SAFILD) which is built upon SAFIL. As an alternative to traditional binary trie, we proposed a memory efficient data structure called compact clustered trie (CCT) for IP lookup. Furthermore, we developed a novel combined length-infix pipelined search (CLIPS) architecture for high performance IPv4/v6 lookup on FPGA. Finally, we designed a memory efficient clustered hierarchical search structure (CHSS) for packet classification. A linear pipelined SRAM-based architecture for CHSS which is implemented on FPGA is also proposed.