Motorola PowerQUICC II MPC8280 Series Reference Manual page 956

Channel-Specific Parameters
Table 29-9. CHAMR Field Descriptions—CES Mode (continued)
Bits Name
13 CESM Circuit emulation service mode.
0 Normal mode
1 CES mode
14 UDC User-defined cell support.
0 User-defined ATM cells are not supported.
1 User-defined ATM cells are supported.
15 UTM Underrun template mode.
0 Retransmit the last buffer.
1 Send the user-defined template.
29.3.4 Channel-Specific SS7 Parameters
Based on the HDLC protocol, the signalling system #7 (SS7) protocol is used to manage
public service networks. The SS7 protocol operates on signal units (SU), which are
analogous to HDLC frames. The physical, data link, and network layer functions of the SS7
protocol are called the message transfer part (MTP). Implementing the MTP layer 2 (data
link) functions in host software is difficult with multiple performance issues. The
MPC8280 SS7 microcode enables applications requiring multi-channel SS7 processing.
The SS7 controller is implemented using the MCC hardware with microcode running on
the CPM. Each MCC implements the following layer 2 portions of the MTP:
• Signal unit (SU) retransmission
• Automatic fill-in signal unit (FISU) transmission
• Short SU filtering
• Duplicate fill-in and link-status signal unit (FISU/LSSU) filtering
• Octet counting
• Signal unit error rate monitoring
• Good frame counter and bad frame counting
• Initial alignment (supports alignment error rate monitoring)
Host software, however, is needed to handle the following higher-level functions of the
MTP layer 2 not supported by the SS7 controller:
• Link state control
• Flow control
SS7 features are as follows:
• Up to 128 independent communication channels (64 channels per MCC)
• Independent mapping for receive and transmit
29-18
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MPC8280 PowerQUICC II Family Reference Manual
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