Glossary S

S1 byte

In an SDH network, each network element traces step by step to the same clock reference source through a specific clock synchronization path, thus realizing the synchronization of the whole network. If a clock reference source traced by the NE is lost, the clock of this NE will trace another clock reference source of lower level. To implement protection switching of clocks in the whole network, the NE must learn about the clock quality information of the clock reference source it traces. Therefore, ITU-T defines S1 byte to transmit the network synchronization status information. It uses the lower four bits of the multiplex section overhead S1 byte to indicate 16 types of synchronization quality grades. The specific coding information is shown in the following table. Auto protection switching of clocks in the synchronous network can be implemented by using S1 byte and following the certain switching protocol.

Safe control switch

The APR safe switch is set in consideration of the long-span networking requirement, which cannot allow too low output optical power. If the safe control switch is turned off, APR restarting optical power is the specified output power of the OAU. Otherwise, the APR restarting optical power is restricted to less than 10dBm.

Script file

It is the text file describing the physical information and configuration information of the entire network, including the NE configuration file, port naming file, end-to-end configuration file, NE physical view script file, NMS information file and service implementation data script file.

SD trigger condition

SD refers to signal degradation. The multiplex section protocol defaults to start switching in case of signal loss. In practice, signal degradation severely affects some services, so protection switching is needed. Or, you can turn off this trigger condition through the switch to avoid MS switching when the signal degrades.

SDH NNI

SDH Network Node Interface. It is applied to build communications connection with the equipment beyond the U2000 Web LCT management area. Usually, the NMS creates a protection sub-network by creating a logical system on the port of an idle line board, and the NE must be a TM without protection and fiber connection. Though both the SDH NNI and the isolated node are implemented via the logical system, the isolated node is a logical system not belonging to any protection sub-network or SDH NNI. An isolated node satisfying specified conditions can be used to create an SDH NNI, and a node is independent when the SDH NNI is deleted from the network layer. SDH NNI is widely used in the 10GV2, because no tributary board is available. An SDH NNI should usually be created to support the E4 service. As no logical system is available in the 10GV2, the SDH NNI is fulfilled only on the NMS side, without providing the searching function.

Search domain

Search field refers to the range of IP addresses being searched. In the TCP/IP, the IP addresses include:

Category A address (1.0.0.0---126.255.255.255). For example, 10.*.*.*, whose search field is 10.255.255.255, all 10.*.*.* to be searched.

Category B address (128.0.0.0---191. 255. 255. 255). For example, 129.9.*.*, whose search field is 129.9.255.255, all 129.9.*.* to be searched.

Category C address (192.0.0.0---223. 255. 255. 255). For example, 192.224.9.*, whose search field is 192.224.9.255, all 192.224.9.* to be searched.

Category D address (224.0.0.0---230.255.255.255), which is reserved.

Category E address (240.0.0.0---247.255.255.255), which is reserved.

Net-id 127.*.*.*, in which .*.*.* can be any number. This net-ID is a local address.

Secondary filter trail

In this search mode, the NMS re-searches the trail data displayed by the current client according to the given search conditions, helping the customer find the trail data which interests him the most.

Serial port extended ECC

The ECC channel realized by means of serial port.

Server layer trail and client layer trail

There is an inclusion relation between the trails of different levels, e. g. a trail of a certain level contains multiple trails of lower levels. In such a structure, the upper level trail bearing another trail of lower level is called the server layer trail, while the lower level trail is called the client trail.

Service clock working route

In the 1600G system, it is the route of a service clock from the source to the sink. The working route can be in the form of point-to-point or broadcast (That is, an input clock source corresponds to multiple output clock sources).

Service configuration strategy

When pass-through services are configured on the newly added nodes, the mode of high-order or low-order to pass through can be selected. When the VC12 service over a VC4 exceeds a preset threshold, higher order cross-connect is selected, otherwise lower order cross-connect is selected. When the services are not VC12 ones, they shall be converted into VC12 equivalents. For example: if there are 2 VC3 and 4 VC12 services on a VC4, there should be 21x2+4 = 46 VC12 services. If the threshold value is 42, pass-through of this VC4 shall be made through higher order cross-connect.

Service loading indication

The payload loading indication is used to set the path of the tributary board. Usually it is used for path alarm suppression. When the tributary payload loading indication of this path is set as "Unloaded", alarms of this path related to the service can be suppressed.

SLIP

SLIP, the abbreviation for Serial Line Interface Protocol, defines the framing mode over the serial line to implement transmission of messages over the serial line and provide the remote host interconnection function with a known IP address.

SNCP node

Set the SNC node on the protection sub-network to support sub-network connection protection that spans protection sub-networks. The SNCP node of the ring sub-network can support electric circuit dually feed and selectively receive a timeslot out of the ring, thus implementing sub-network connection protection. The SNCP node is generally set on the node on the line board with the path protection type of the dual fed and selectively received.

Spread type

The spread type of ATM service includes point-to-point (p2p) and point-to-multipoint (including p2mpRoot and p2mpLeaf). The p2p spread type supports real-time bi-directional communication service. The two communication parties are in the same status and participate the session actively. p2mpRoot and p2mpLeaf belong to the point-to-multipoint spread type. It supports point-to-multipoint multicast service. During the creation of a point-to-multipoint (multicast) connection, a connection to identify this group of connections is necessary. This connection is a p2mpRoot connection, while other connections are p2mpLeaf connections. If there is a p2mpLeaf connection in a group of connections, the p2mpRoot cannot be deleted. To create a multicast connection, the p2mpRoot connection must be created before the creation of p2mpLeaf connection.

Sub-network

Sub-network is the logical entity in the transmission network and comprises a group of network management objects. A sub-network can contain NEs and other sub-networks. Generally, a sub-network is used to contain the equipment which are located in adjacent regions and closely related with one another, and it is indicated with a sub-network icon on a topological view. The U2000 Web LCT supports multilevels of sub-networks. A sub-network planning can better the organization of a network view. On the one hand, the view space can be saved, on the other hand, it helps the network management personnel focus on the equipment under their management.

Sub-network connection protection

Sub-network connection protection uses the 1+1 mode. SNCP is of 1+1 protection mode. Payloads are transmitted simultaneously on both the working and the protection sub-network connections. When the working sub-network connection fails, or when its performance deteriorates to a certain level, at the receiving end of the sub-network connection, the signal from the protection sub-network connection is selected according to the preference rule. Switching usually takes the single-end switching mode, thus no protocol is needed

Sub-network mask

Also referred to as the network mask off code, it is used to define network segments, so that only the computers in the same network segment can communicate with one another, thus suppressing broadcast storm between different network segments. Based on the sub-network mask, IP addresses can be divided into three types. Type A: With the sub-network mask of 255. 0. 0. 0, one address of this type has 256*256*256 IP address resources; Type B: With the sub-network mask of 255. 255. 0. 0, one address of this type has 256*256 IP address resources; Type C: With the sub-network mask of 255. 255. 255. 0, one address of this type has 256 IP address resources

Sub-network number

It is used to differentiate the different network sections in the sub-network conference. Actually it is the first several digits (one or two) of the user phone number. An orderwire phone number is composed of the sub-network number and the user number.

Switching priority

There may be the case that several protected boards need to be switched; thus the tributary board switching priority should be set. If the switching priority of each board is set the same, the tributary board that fails later cannot be switched. The board with higher priority can preempt the switching of that with lower priority. For the OptiX 155/622 and the OptiX 2500 equipment, there are three switching priorities: "Priority 1", "Priority 2", and "Priority 3". For the OptiX 2500+ equipment, the switching priority is classified into priorities 1 - 8, where priority 1 is the highest one, and priority 8 is the lowest one. For the OptiX 10G(Metro 5000), the highest switching priority is priority 1 and the lowest one is priority 5.

Switching restoration time

It refers to the period of time between the start of detecting and the moment when the line is switched back to the original status after protection switching occurs in the MSP sub-network.

Synchronize NE time

Send the system time of the U2000 Web LCT server to NEs so as to synchronize all NEs with the server.