Presenter : Shi-qu Yu Date : 2011/08/31

Outline POLP[2] and BPFL algorithm BPFL Search Engine POLP Search Engine Performance

POLP algorithm POLP:Parallel optimized linear pipeline algorithm Main idea : Split the original binary tree into non-overlapping subtrees that are distributed across P pipelines. Chose Pipeline :Base on the first I bits of the IP address.

PFL Algorithm

BPFL Algorithm An extension of the PFL algorithm Advantage of BPFL: Frugally uses the memory resources so the large lookup tables can fit the on-chip memory. Next-hop information->External memory Lookup table->On-chip memory The subtree prefixes are stored in the corresponding balanced trees(PFL:register)

BPFL Algorithm(cont.) External memory is accessed only once at the end of the lookup when the next-hop information is retrieved. The on-chip lookup table is organized as a binary tree divided into levels that are searched in parallel. If the substree is sparsly->Only indices of existing nodes are kept.

BPFL Search Engine BPFL search engine top-level

BPFL Search Engine (cont.) Find the subtree at this level.Process prefix search.

BPFL Search Engine (cont.) Subtree search engine at level i.

BPFL Search Engine (cont.) Subtree search engine at level i.

BPFL Search Engine (cont.) Prefix search engine at level i.

BPFL Search Engine (cont.)

POLP Search Engine

POLP Search Engine(cont.) Pipeline structure.

POLP Search Engine(cont.) Stage i structure.

Performance Altera’s Stratix II EP2S180F1020C5 chip [10]. The SRAM memory is used as the external memory.

Performance(cont.) BPFL(DS=8)

Performance(cont.) POLP(I=16)

Performance(cont.) BPFL(DS=8)

Performance(cont.) POLP(I=16)