15
3980-A2-GZ40-20
November 1996
Table 5
SDC Negotiation Configuration Scenarios
Originating Modem
Answering Modem
Negotiation Results
SDC enabled with LAPM_Buffer
negotiation.
SDC enabled.
SDC connection.
SDC enabled with LAPM_Discon
negotiation.
SDC enabled.
SDC connection.
SDC enabled with LAPM_Buffer
negotiation.
SDC disabled.
Buffer mode connection.
*
SDC enabled with LAPM_Discon
negotiation.
SDC disabled.
Disconnect.
**
SDC disabled.
SDC enabled with LAPM_Buffer negotiation.
Buffer mode connection.
*
SDC disabled.
SDC enabled with LAPM_Discon negotiation.
Disconnect.
***
*
If during the negotiation phase, the modem with SDC enabled receives data from the remote modem indicating that it
has SDC disabled, the link will not be established between the two modems. For example, the link will not be
established if the remote modem is configured for Async mode with an EC mode of V42/MNPorBfr, V42/MNPorDsc,
LAPM_Buffer, or LAPM_Discon.
**
On a leased line, the originating modem sends an endless EC negotiation sequence with the SDC request parameter.
Data cannot be successfully transmitted.
***
On a leased line, the answering modem waits indefinitely for an EC negotiation sequence with an SDC request
parameter. Data cannot be successfully transmitted.
Monitoring SDC Performance
If SDC is enabled, six performance measurements related to SDC can be displayed on the DCP. These
measurements are available in the SDC submenu of the Status branch and are divided into two groups: TX
(transmit) measurements and RX (receive) measurements.
Status
VF
Identity
DTE
Test
Configure
Control
Remote
“Status”
496-14951
Call_Setup
Security
Options
Record
SDC
TX
RX
