LPM-CAM: Longest-prefix match based on CAM
GENERAL DESCRIPTION
LancsNet LPM-CAM performs the Longest Match Routing algorithm used by IP routers to select an entry from a routing table. The router uses the longest (prefix) match to determine the egress (outbound) interface and the address of the next device to which to send a packet. Our specialized LPM-CAM IP is cascaded by multiple CAM memory in parallel that allows storing and loop-up simultaneously many IP prefixes with decent bandwidth and minimum latency. The provided RTL core can be easily customized and optimized for the need of specific IP ranges and prefixed.
KEY FEATURES
Features
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- Support all prefix length (/0 to /32)
- Fully pipelined design for lookup operation every clock cycle
- Fixed 5-cycle latency for lookup operation (15-20ns) when internal memory is used
- Maximum >300M lookup/s **
- Optionally utilizing external memory for large entries (lower latency)
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**20K/28K entries, 4-sub CAMs on Xilinx Kintex7 and Virtex 7
Configurability
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- Memory-mapped AXI4-lite
- Total entries
- Hash functions
- Number of prefix tables for parallel lookup
- (optional) switchable between internal and external memory.
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Technology Agnostic
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- VHDL source code available, designed and tested for FPGA* and ASIC
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* In production with customers
Example Implementation – LancsNet LPM-CAM (area-optimized version)
| Family | Part |
Fmax (MHz) |
LUT | LUTRAM | FF | BRAM | DSP | IP Config |
| Artix7 | XC7A200T | 244.6 | 564 | 0 | 483 | 29 | 0 | 20K entries |
| Kintex7 | XC7K325T | 317.6 | 564 | 0 | 483 | 29 | 0 | 20K entries |
| Virtex7 | XC7VX550T | 323.6 | 564 | 0 | 483 | 29 | 0 | 20K entries |
| Artix7 | XC7A200T | 244.6 | 684 | 0 | 565 | 40 | 0 | 28K entries |
| Kintex7 | XC7K325T | 317.6 | 684 | 0 | 565 | 40 | 0 | 28K entries |
| Virtex7 | XC7VX550T | 323.6 | 684 | 0 | 565 | 40 | 0 | 28K entries |
APPLICATIONS
L3 Switch and Router, NG Firewall, Network aggregator, network accelerators
An example application of the LPM-CAM in Router FIB lookup, L3 switch core
DELIVERABLES
The IP core and the simulation testbench are provided with extensive documentation and technical support from our technical teams. By default, the encrypted format IP core is provided, full source code is available for interested partners/developers under a specific agreement
FOR DEMO ON HARDWARE AND SIMULATION
Contact us sales@lancsnet.com
PRICING AND FURTHER INFORMATION
Request for quote & datasheet at sales@lancsnet.com
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