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 |  |
 |
 | NOTE: This protocol is not available on the ACC 4-port
E1/T1 cards. |
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 |  |
 |
The HDLC-NRM (SDLC) protocols are polled
protocols, supporting both a primary and secondary station. Multiple
stations may be defined on a line. However, stations on a line must
be either all primary or all secondary.
The HDLC protocols are fully defined in three standards documents published
by the International Standards Organization (ISO). These standards
are ISO 3309, 7809 and 4335, full references to which are given
at the end of this chapter.
The HDLC Normal Response Mode protocols product implements
both the primary and secondary station procedures for the Unbalanced
operation Normal response mode class, as defined in ISO 7809.
The frame types supported are those for the basic repertoire,
as defined in ISO 7809 clause 3.2.2.1. These frames are as follows:
Commands | Responses |
|---|
I | I |
RR | RR |
RNR | RNR |
SNRM | UA |
DISC | DM |
| FRMR |
Three optional extended features are provided in addition
to the defined standard features. These features are:
The first two features are more fully described in Chapter 4 “Protocol Specific Configuration” while the third feature is covered in Appendix B “SDLC Loop Mode Option”.