Alcatel Carrier Internetworking Solutions Omni Switch/Router User Manual

Page 998

Configuring an E1 Port

Page 33-10

6) Transmit Clock Source

The source of the transmit clock. Loop timing means the receive clock (recovered from
receive data) is used as the transmit clock. Local timing indicates the local clock source
(generated from

PLL

s) is used as the transmit clock.

The transmit clock source is related to the clocking mode used in circuit emulation services.
In synchronous clock mode, both sides of the

connection will use a local clock source.

However, in SRTS and adaptive clocking, the

port receives the clock on one end (loop

timing) and regenerates the clock locally (local timing) on the other end. In such a case, the

port receiving the clock from the network should be configured to

loop timing

and the

other end of the link should be configured to

local timing

7) Loopback Mode

The loopback configuration for this port. Loopback configurations describe the relation
between the device attached to an

port and the framing functionality within the

port.

Framing functionality assembles

frames into multiframes, depending on how the port is

configured. Possible values are as follows:

none

The port is not in a loopback state. This is the typical live network state for an
E1 port.

payload

The received signal at this E1 port is looped out of the port after passing
through the port’s framing functionality. This state should only be used for
debugging purposes.

line

The received signal at this E1 port does not go through the port’s framing
functionality, and is looped straight back out the port. This state should only
be used for debugging purposes.

inward

The transmitted signal from the

inwawrd

side of this port is looped back inter-

nally. The signal passes through the E1 framing functionality before looping
back. This state should only be used for debugging purposes.

8) Signalling

The type of signaling used on this port. Only the

none

and

CAS

(Channel Associated Signal-

ling) options are applicable to a circuit emulation service port. The

CCS

(Common Signal

Channeling) option is used with external

ISDN

ports. If you select the

CAS

option, then you

are enabling Channel Associated Signalling, which is used with

multiframes. In Channel

Associated Signaling, timeslot 16 in frame 0 of the multiframe is used for multiframe synchro-
nization and control. Timeslot 16 of frames 1 through 15 are used to carry A, B, C, and D
signaling bits.

9) Trap Generation

Enables all of the

SNMP

-based traps related to circuit emulation service ports.