VSC7440 datasheet(261/444 Pages) MICROSEMI

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Functional Descriptions

VMDS-10492 VSC7440 Datasheet Revision 4.2

244

}

// port_num

if (csr.cmd_port_num_ena) {

tti_tbl_entry.port_num = csr.cmd_port_num_val;

}

// qu_num

if (csr.cmd_qu_num_ena) {

tti_tbl_entry.qu_num = csr.cmd_qu_num_val;

}

// Write back to TTI table

tti_tbl[addr] = tti_tbl_entry;

}

3.25.5

Injection Queues

DTI and TTI may inject into any egress queue in the queue system. In injection context, the queues can

be divided into the following categories:

•

Normal queues. These queues are processed by each level of SEs in HSCH. Frames injected into

such queues are thus subject to the M-DWRR and shaping algorithms of the SEs. Frames are

injected into the tail of the selected queue.

•

Port injection queue without shaping. These queues, one for each port, inject frames on the port with

higher priority than normal queues. The state of the DLB shaper is disregarded and is not updated

with the size of the transmitted frame.

Injected frames are injected into the tail of the queue, but due to the high priority, the queue will

normally be (almost) empty.

•

Port injection queue with shaping. These queues, one for each port, inject frames on the port with

higher priority than normal queues. The state of the port shaper is respected and is updated with the

size of the transmitted frame.

Injected frames are injected into the tail of the queue, but due to the high priority, the queue will

normally be (almost) empty.

The queue into which a TTI or DTI injects frames is controlled by the QU_NUM parameter. The actual

value to be used for these parameters depend on the HSCH configuration. For more information, see

Queue Mapping, page 219.

For injections into the ingress data path, frames must be looped through VD1 and QU_NUM must be

configured to select a VD1 queue.

3.25.6

Adding Injection Frame

To add a frame for injection by AFI, the CPU must follow this procedure:

Set AFI::MISC_CTRL.AFI_ENA to 1 before any use of AFI.

Send the frame to AFI. AFI_INJ must be set in the IFH. For more information, see Frame Headers,

page 13.

Poll AFI::NEW_FRM_CTRL.VLD to await the frame being received by AFI.

When the frame has been received by AFI, then copy frame information from AFI::NEW_FRM_INFO

to an unused entry in the Frame table.

Clear AFI::NEW_FRM_CTRL.VLD.

TTI: Set up the TTI table to have the frame injected with the desired interval and to the desired

queue and port. For more information, see Timer Triggered Injection, page 238.

DTI: For injection of a sequence of frames, repeat steps 1 through 4.

Set up the DTI Table to inject the frames. For more information, see Table 162, page 234.

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