Cabletron Systems 1800 - Manual (Page 85)

FRM Conf iguring Frame Relay 7-17
Rcv Clock (TT) from DTE
allows the clock to be looped back from the DTE using the TT (Terminal Timing)
signal, which can be helpful on high-speed lines. Generally, if the local interface is
physical DCE and the line speed is above 256 Kbps, this parameter should be set to
Y .
(Make sure the remote DTE is configured to provide the terminal timing.)
CSU/DSU Operating Mode
determines whether the attached modem connection can be normal or limited distance
(LDM), where the distance depends on the wire gauge, number of splice points, and
line speed. For example, 26-gauge wire and a line speed of 64K bps allows a distance
of 15000 feet. Lowering the speed to 56K increases the allowable distance to 18400
feet. If 19-gauge wire is used, the distances can be multiplied by three.
RTS Control
if configured as Constant means that RTS (Request to Send) will always be asserted;
if configured as External, the CSU/DSU will control RTS.
Link Layer Management
determines whether, and what type of, configurable network management (e.g., status
enquiries to the port) will be used: none, LMI (Local Management Interface), or ANSI
T1.617 Annex D (an ANSI-standard LMI).
N1 Polling Count
specifies the number of polling cycles between requests for Full Status reports, which
include status of all PVCs on the physical link. Every "
T1 " seconds (see " T1 Link
Integrity Timer " on page 7-17), the logical DTE will send a Status Enquiry to the
network, requesting status of the network link. Each exchange of one enquiry and one
message (response) is a polling cycle. After every "
N1 " cycles, an enquiry for a Full
Status report will be sent.
If this port is configured as logical DCE, status enquiries will be initiated at the DTE,
and the local node will respond with status messages.
N2 Error Threshold
is the number of link reliability and/or protocol errors that can occur during the period
defined by
N3 Monitored Events Count before the logical DCE will be declared
inactive.
N3 Monitored Events Count
is the number of error-free polling cycles after which the DCE will be declared active
if the first poll resulted in an error. If the first poll was error free, the DCE will be
declared active after that poll. (If the
N2 Error Threshold is exceeded during the N3
count, the DCE will be declared inactive, and the N3 count will be restarted.)
T1 Link Integrity Timer
determines how often the logical DTE will initiate a Status Enquiry message to the
DCE.
T2 Polling Verification Timer
indicates how long the logical DCE will wait between Status Enquiry messages from
the DTE before recording an error.