R8A20110BG Datasheet, PDF (3/9 Pages) Renesas Technology Corp – Network Signature Matching Co-Processor (1 M-bit Full Ternary CAM)

R8A20110BG (MARIE)
Functional Description
1. Denser and Low power CAM
MARIE is a new Network Signature Matching Co-Processor ideal for IDS applications. The specially designed
custom SRAM cell takes advantage of space and power increasing MARIE’s overall performance.
2. Half Sized Global Mask Search Register
In a conventional TCAM the Global Mask Search Register consists of the same number of register bits as number of
CAM bits. During a search command the Global Mask Search Register controls the bits that participate in the
search. In MARIE’s TCAM the Global Mask Search Register controls two CAM bits at the same time, making
MARIE’s GMSR one half the size of a conventional CAM. As a result range mask can be achieved, but bit mask is
not supported. GMSR is only used during search.
Search Comparand Key
DQ
Global Mask Search
0
1
1
X
1
1
X
0
Full Ternary CAM Array
The number of GMSR is same as that of CAM array.
GMSR bit count corresponds to TCAM bit count.
Figure 1 Global Mask Search (conventional)
Search Comparand Key
DQ
Global Mask Search
0
1
X
X
1
1
X
0
Full Ternary CAM Array
The number of GMSR is half size of that of CAM array.
A GMSR bit affects to two-TCAM bits at the same time.
Figure 2 Global Mask Search (MARIE)
Rev.1.00 Feb 21, 2005 page 3 of 8