Configuring The Sim Local Management Interface - 3Com SuperStack II PathBuilder S330 Reference Manual

Configuring the SIM
Local Management
Interface
Terminal Timing Source — This parameter applies only when the attached cable
is DCE type cable. The setting for the Terminal Timing depends on the nature and
speed of the device application, but the typical configuration is Internal—the
PathBuilder S330/S310 switch provides the clock for the device application. In any
case, the Terminal Timing Source setting for the PathBuilder S330/S310 serial port
must be the opposite of that for the device. For example, if the Terminal Timing
Source for the router is set to Internal, then you must set the Terminal Timing
Source for the serial port to External.
Internal — Configures the port to use the internal clock as the terminal timing
source. The PathBuilder S330/S310 switch provides the clock to clock in the
data traffic from a router or other data device.
External — Configures the port to use an external device as the terminal
timing source. The PathBuilder S330/S310 switch accepts the clock for data
from the router or other data device.
Receive Timing Phase — Receive timing phase control. This parameter applies
only when the attached cable is DCE type cable. Depending on the speed of the
device application and the clock phases, particularly those of the return clock, you
may have to set Receive Timing Phase to Inverted (invert the clock) to ensure
correct clock and data phase. This option is used most often to correct for cable
length delays when Terminal Timing is set to Internal.
Normal — The receive timing from the remote endpoint (node) is normal
clocking.
Inverted — The receive timing from the remote endpoint (node) is inverted
clocking.
Data Rate — The data rate supported by the port: 48K, 97K, 195K, 390K, 781K,
1.5M, 3.1M, or 6.2M. This parameter applies only when the attached cable is DCE
type cable. It is a very important parameter, as it allows you to direct the SIM to
shape particular data applications so as not to exceed the guaranteed bandwidth
established by your service provider in your service contract. The Data Rate setting
also allows you to optimize the entire WAN ATM application by traffic engineering
your ATM access applications so as to maintain traffic flow across the network.
Min. Flag Bytes — The minimum number of flag bytes required to distinguish a
frame: 1, 2, 4, 6, 8, 10, 12, or 14.
FCS Size — The number of bytes to use for FCS (Frame Check Sequence)
calculation for each frame. FCS is the CRC remainder sent at the end of a frame.
This parameter is valid only for HDLC/SDLC data.
Admin. Status — Administrative status: Out of Service or In Service.
Local Management Interface (LMI) configuration relates to the periodic polling
that is performed between pairs of Frame Relay devices to determine the status of
PVC connections and to verify the link integrity. This polling is done through a
procedure known as Status Enquiry. Two types are polling are performed: full
status (FS) and link integrity verification (LIV). Full status polling also includes link
integrity verification.
You can set the LMI protocol only if the Link Type is set to Frame Relay on the SIM
Port Configuration menu. If the Link Type is set to DXI or SDLC, the LMI
Configuration option does not appear on the SIM Port Configuration Port/LMI
selection menu, shown earlier in Figure 86.
Configuring the Serial Interface 97