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January 18, 2011

CPS-10Q

CPS-10Q Datasheet

2010 Integrated Device Technology, Inc. All rights reserved.

11.4 Data Packet Latency in “Cut-Through” Mode (Typical)

Note:

1. Values shown in Table 7 are typical for single input port to single output port with matching input and output port rates in “Cut-Through” mode, no other switch

loading. For specific values under other specific application usage scenarios and traffic conditions, please contact IDT technical support.

In “Store-and-Forward” mode and “Cut-Through” mode when trace and filter are enabled at the same time, only the latency for packets sending to the

trace port will increase by the time taken to send 20 bytes into the port (20bytes * 1/[port_speed * 0.8]) The latency for other traffic flow will be unaf-

fected.

11.5 Maintenance Packet Latency (Typical)

Note:

1. Values are guaranteed by characterization, but are not production tested.

11.6 Doorbell packet latency (Typical)

Note:

1. Values are guaranteed by characterization, but are not production tested.

Pay Load Size

1.25GHz

2.5GHz

3.125GHz

1X

4X

1X

4X

1X

4X

8 Byte

369 ns

322 ns

233 ns

217 ns

205 ns

195 ns

16 Byte

366 ns

320 ns

225 ns

217 ns

204 ns

197 ns

32 Byte

354 ns

320 ns

224 ns

218 ns

204 ns

195 ns

64 Byte

351 ns

322 ns

223 ns

220 ns

203 ns

196 ns

128 Byte

351 ns

318 ns

224 ns

218 ns

203 ns

196 ns

256 Byte

351 ns

317 ns

222 ns

216 ns

205 ns

195 ns

Table 7 Switch Latency Table (Cut-Through Mode)

1.25GHz

1.25GHz

2.5GHz

2.5GHz

3.125GHz

3.125GHz

Mode

1X

4X

1X

4X

1X

4X

Store-and-forward

571 ns

460 ns

395 ns

344 ns

352 ns

315 ns

Cut-Through

566 ns

449 ns

386 ns

334 ns

344 ns

315 ns

Table 8 Maintenance Packet (20 words) Latency

1.25GHz

1.25GHz

2.5GHz

2.5GHz

3.125GHz

3.125GHz

Mode

1X

4X

1X

4X

1X

4X

Store-and-forward

395 ns

323 ns

246 ns

225 ns

219 ns

208 ns

Cut-Through

378 ns

317 ns

230 ns

221 ns

209 ns

208 ns

Table 9 Doorbell Packet Latency