Intel IXP400 manual Scheduled Transmission, Buffer Transmission for a Scheduled Port

Intel® IXP400 Software

Access-Layer Components: ATM Driver Access (IxAtmdAcc) API

—if the overall user application involves a port configured with a VC supporting a very different traffic rate. This tuning is at the client’s discretion and, therefore, is beyond the scope of this document.

In the case of OAM, a PDU containing OAM cells for any port, VPI, or VCI must be submitted for transmission on the dedicated OAM-VC for that port. This is true regardless of whether an AAL-5/ AAL-0-48/AAL-0-52 transmit service connection exists for the given VPI or VCI. The dedicated OAM-VC will be scheduled just like any other VC.

4.5.1Scheduled Transmission

The scheduling entity controls the VC from which cells are transmitted and when they are transmitted. Buffers on each VC are always sent in the sequence they are submitted to IxAtmdAcc. However, cells from different VCs can be interleaved.

Figure 14 shows VC connection and buffer transmission for a scheduled port.

Figure 14. Buffer Transmission for a Scheduled Port

Data Client	Tx Ctrl
	Client
	(Scheduling
	Component)

2: ixAtmdAccTxConnect(port,vpi,vci, connParams)

5: connId

6: ixAtmdAccTxPduSubmit(connId, mbuf*, numCells))

1: ixAtmdAccScheduledModeEnable(port, schedulerCallbacks)

4: VcId

8: ixAtmdAccTxProcess(port, scheduleTable)

AtmdAcc

	3: IxAtmdAccTxSchVcIdGetCB(port,vpi,vci,connId)
9: hwSend(mbuf, numCells)*	7: IxAtmdAccTxVcDemandUpdateCB(vcId,numCells)

B2284-01

1.A control client wants to use an ATM traffic shaping entity that will control the transmission of cells on a particular port, ensuring VCs on that port conform to their traffic descriptor values. The client, therefore, calls ixAtmdAccScheduledModeEnable() — passing the port and some callback functions as parameters.

IxAtmdAcc has no client connections active for that port and accepts the scheduler registration.

2.Later, a data client wants to use the IxAtmdAcc AAL-5/AAL-0-48/AAL-0-52/OAM transmit service for a VC on the same port, and therefore calls ixAtmdAccTxVcConnect().

In the case of the OAM transmit service, the connection will be on the dedicated OAM-VC for that port.

3.IxAtmdAcc calls the IxAtmdAccTxSchVcIdGetCallback () callback registered for the port. By making this call, IxAtmdAcc is asking the traffic shaping entity if it is OK to allow traffic on

April 2005	IXP400 Software Version 2.0	Programmer’s Guide
58	Document Number: 252539, Revision: 007