Freescale Semiconductor MPC8260 - Manual (Page 947)

ATM Controller and AAL0, AAL1, and AAL5
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
Freescale Semiconductor 30-27
30.5.3 ABR Flow Control Setup
Follow these steps to setup ABR flow control:
1. Initialize the ABR data structure: RCT, TCT, RCT-ABR protocol-specific, TCTE-ABR
protocol-specific.
2. Initialize ABR global parameters in the parameter RAM. See Section 30.10.1, “Parameter RAM.”
3. Program the AAL-type in the RCT and TCT to AAL5 and set TCT[ABRF].
NOTE
ABR flow control is available only with AAL5.
4. The time stamp timer generates the RM cell’s time stamp, which the ABR flow control monitors
to maintain source behavior in steps #3 and #7 of Section 30.5.1.1, “ABR Flow Control Source
End-System Behavior.” Enable the time stamp timer by writing to the RTSCR; see Section 14.3.8,
“RISC Time-Stamp Control Register (RTSCR).”
5. Initialize the ABR parameters (CPS_ABR and LINE_RATE_ABR) in the APCT; see
Section 30.10.4.1, “APC Parameter Tables.” Note that when using ABR, the CPS (cells per slot)
parameter in the APCPT should be a power of two.
6. Finally, send the ATM TRANSMIT command to restart channel transmission.
30.6 OAM Support
This section describes the PowerQUICC II’s support for ATM-layer (F4 out-of-band, and F5 in-band)
operations and maintenance (OAM) of connections. Alarm surveillance, continuity checking, remote
defect indication, and loopback cells are supported using OAM receive and transmit AAL0 cell queues.
Using dedicated support, performance management block tests can be performed on up to 64 connections
simultaneously. The CP automatically inserts forward monitoring cells (FMC) and generates
backward-reporting cells (BRC) as recommended by ITU I.610.
30.6.1 ATM-Layer OAM Definitions
Table 30-8 lists pre-assigned header values at the user-network interface (UNI).
Table 30-9 lists pre-assigned header values at the network-node interface (NNI).
Table 30-8. Pre-Assigned Header Values at the UNI
Use GFC VPI VCI PTI CLP
Segment OAM F4 flow cell xxxx aaaa_aaaa 0000_0000_0000_0011 0a0 a
End-to-end OAM F4 flow cell xxxx aaaa_aaaa 0000_0000_0000_0100 0a0 a
Segment OAM F5 flow cell xxxx aaaa_aaaa aaaa_aaaa_aaaa_aaaa 100 a
End-to-end OAM F5 flow cell xxxx aaaa_aaaa aaaa_aaaa_aaaa_aaaa 101 a
a = available for use by the appropriate ATM layer function