System Functions. Structure of Functional Units. Functional Units. Synchronous Timing Unit and Clock Interface Unit, страница 2

n  Supports virtual concatenation and cross-connect at VC-4 level.

n  Maps/demaps the SDH signal.

n  IEEE802.1p/IEEE802.q-supporting port feature.

n  Supports the IEEE802.3X protocol, with adjustable transmission distance supported by the flow control performance. At present, the optical module employed has a transmission distance of 550 m or 10 km.

3.2.3  Cross-Connect Unit

The OptiX OSN 9500 provides higher order and lower order cross-connect boards. GXCH and EXCH, as the optional higher order cross-connect boards, provide non-blocking cross-connection at VC-4 level. GXCL, as the lower order cross-connect board, provides 20 G cross-connection at VC-12 level.

Table 3-2 Comparison among GXCH, EXCH and GXCL

Types	Cross-connection level	Cross-connect capacity of a single subrack
GXCH	VC-4	2560 x 2560 VC-4s (400 G)
EXCH	VC-4	4608 x 4608 VC-4s (720 G)
GXCL	VC-12 or VC-3	8064 x 8064 VC-12 (20 G)

n  A single GXCH board supports a cross-connect capacity of 200 G, and a single subrack, 400 G.

n  A single EXCH board supports a cross-connect capacity of 360 G, and a single subrack, 720 G.

n  GXCL board supports lower order cross-connection with maximum capacity of 20 G.

n  It implements flexible service grooming at granularity of VC-4, VC-3, VC-12 level, including loopback, cross-connect, multicast and broadcast.

n  It supports the 1+1 protection at board level, with the active and standby boards for mutual backups. In the event that the active board goes faulty, the service can be reliably switched over to the standby board automatically.

3.2.4  Synchronous Timing Unit and Clock Interface Unit

The JSTG board provides system clock for the whole system. When the system works in tracing mode, one of the line and external timing sources can be selected as the timing reference. Selecting timing sources from various priorities and using the S1 byte ensure the reliable operation of the network timing system. The system can also work in holdover mode or free-run mode. The JSTG board provides external synchronization clock output.

The OptiX OSN 9500 has two 2 MHz or two 2 Mbit/s G.703 standard input interfaces by JSTI board, two 2 MHz or two 2 Mbit/s G.703 output interfaces. All the interfaces provide 75 W direct connection, and 120 W connection through cables with impedance conversion function.

3.2.5  System Control and Communication Unit

The JSCC board is the system control and communication board. It is responsible for management and communication of the synchronous equipment, and provides interface for connection with the NM. Additionally, it processes the intelligent protocol and signaling. The intelligent protocol and signaling refer to the routing protocol and the connection-oriented GMPLS signaling that realize the intelligent service grooming.

System control function refers to the synchronous equipment management function (SEMF), which is responsible for collecting the alarms and performance events of other boards in the system and performing corresponding management operations.

The communication function refers to the MCF which enables the communication between the JSCC board and other boards and NM terminal. It also exchanges OAM information with other NEs through the DCC, thus facilitating a unified management of the NM over this NE equipment and other NEs networkwide.

3.2.6  Control and Communication Unit

This unit controls information and facilitates communication between various boards in the subrack through the JCOM board.

3.2.7  Orderwire Processing Unit

The orderwire function of the OptiX OSN 9500 is implemented by the JEOW board. It provides the maintenance interfaces, for example, RS-232 interface and orderwire phone interface, for the system to process the call orderwire and serial port orderwire.

3.2.8  BA/PA Unit

The BA unit can be configured with JBA2 board for 2-channel booster amplification, and the PA unit can be configured with JBPA board for 2-channel pre-amplification.

3.2.9  Dispersion Compensation Unit