Alcatel Carrier Internetworking Solutions Omni Switch/Router User Manual

Page 844

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The WAN Port Software Menu

Page 28-18

Split Clocking

Split clocking, which is also known as “loop timing,” uses an additional control signal
(

TXCE

) to keep the

submodule

and external DTE clocking synchronized. In split clocking,

the external DTE takes the incoming transmit clock from the submodule and loops it back
to TXCE. The submodule then uses this signal to clock in data from the external DTE
device. Split clocking should only be used if the

submodule

is a physical

DCE

device and

you are using a non-

RS-232

cable, such as

V.35

.

Important Note

Split clocking is required if the access rate of the

submodule

port is greater than 256 kbps and it is acting

as a DCE device. If split clocking is not used at these
data rates, data out-of-phase errors, aborts, or CRC
errors may occur.

Split clocking is the default when the

submodule

port is a physical

DCE

device and a non-

RS-232

DCE

cable is connected to the port.

Protocol Type

The protocol type can be set to either Frame Relay or Point to Point Protocol (PPP). The
default setting is Frame Relay.

Important Note

A port must be set to either Frame Relay or PPP before
any other protocol-related parameters can be set.

Receive Clock

Often, due to delays added to timestamps in when running through switch hardware, the
receive clock time is significantly different than expected from the transmitting data source.
To correct the problem, it is possible to set the receive clock to invert the delay information.
The following options are available:

Normal

The port uses the internal clock time as the timestamp for receive data (timestamp infor-
mation is not modified).

Inverted

The port uses an inverted timestamp for receive data.

TOS for Voice Data

Set the priority for voice data streams. The value must be entered in hexadecimal format
translated from binary, and can use either IP Precedence or Differentiated Services Code Point
(DSCP). Enter

0

to disable this feature. See Type of Service (ToS) on page 28-2 above for a

more detailed explanation of ToS.

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