EMS Networking

6.1.4.1 EMS Data Channels

To ensure that the EMS can stably manage the equipment in it, reliable EMS channels must be provided for the EMS. The EMS channels generally fall into two kinds: Inband EMS channels and outband EMS channels.

Since the TCP/IP is adopted as the transmission EMS protocol between the EMS and the managed equipment, the only standard for judging the effectiveness of the EMS channels is to check if TCP/IP links are established between the EMS (the EMS server) and the managed equipment, whether the inband or outband channels. A simple method is to use the ICMP Ping tool to judge so.

• In-band EMS

The NetNumen N31 manages data products, these products themselves can provide inband data channels for EMS information, therefore, the SNMP-based management information does not need the establishment of a DCN network, and instead, EMS data are transmitted together with service data in the same data network.

Since there is no need to establish a special DNC network for the EMS, the inband EMS brings low cost and is easy to construct, but its stability varies with the reliability of the equipment itself because it uses the channels provided by the equipment. In addition, if the network structure is complex with too many layers in the case of inband EMS, many

70 © 2009 ZTE Corporation. All rights reserved. ZTE Confidential Proprietary factors will affect the transmission of EMS information and may cause the instability of the EMS channels.

Because the EMS adopts the centralized management mode, the EMS data of all the managed equipment are converged at the EMS, where the data volume is tremendous.

Therefore, we can consider configuring a standalone router in the EMS center to transmit all the EMS data and avoid affecting the backbone equipment.

• Outband EMS

In many application cases, standalone data channels (outband) are needed for the equipment configurations to ensure the reliability of the equipment configurations.

The outband management mode improves the reliability of the EMS. Because the EMS data are transmitted through the data network established by the managed equipment in the case of using the inband channels, the fault information will not be able to be reported timely and the EMS thus cannot timely monitor the network and send personnel to repair the faults when faults occur to some node equipment to cause the link break of the data channels. In contrast, in the outband management mode, users can log in to each node to observe the running status of the node equipment and configure it to shoot the troubles once the network performance is found abnormal. Since the outband channels are separated from the data network, the inband management channels are mutually complementary to the outband management channels to ensure the reliability of the EMS.

The outband channels are generally implemented via the existing data network, for example, the DCN network in the 97 Project. Or the EMS can also connect the serial port of the managed NE via MODEM through the dialup network to implement remote configuration based on man-machine commands.

6.1.4.2 Centralized Management

The NetNumen N31 is an EMS constructed over the data communication network. It can maintain and manage all kinds of network equipment in a centralized manner in a broad area and complex application environment. The centralized management mode is generally used for the networking, that is, the EMS manages plenty of equipment distributed in the managed network in a centralized manner.

In the centralized management mode, the EMS is composed of the client and the server and the whole managed network has only one server that exchanges management information with all the managed equipment. In contrast, there may be multiple clients and they connect with the server to implement man-machine interactions with users but cannot directly connect the equipment. The client configurations may take the following two modes: Local client and remote client.

• Local client: Both the client and the server are located in the same LAN and they implement the centralized management of the entire network together.

• Remote client: The client is connected with the server via the WAN and can be located in the remote equipment room to manage the local equipment by dividing management domains. Also, the remote client does not directly connect the managed equipment.

The remote client networking can implement hierarchical management in the centralized management mode, as shown in Figure 16. When the system manages a network across multiple domains, the network is split into several subnets (generally these subnets are divided according to the areas or the equipment type) and all the equipment in the network are connected to the upper-level EMS to exchange management information with the EMS. In the upper-level EMS center, administrators can monitor the running status of the entire network (including several subnets) through the local terminals.

The lower-level EMS center for managing the subnets is extended from the remote client in the upper-level EMS center to the local client to monitor the local subnet. In the lower-level EMS center, no EMS server is configured but there are only management terminals to exchange management information with all the equipment in the local subnet via the EMS sever in the upper-level EMS center. In the EMS server, management rights can be set according to the management area and content, so that the management terminals in the lower-level EMS can only access the subnets within its management right scope after login to the EMS server. The lower-level EMS client can both monitor the network through graphical interactions and output a variety of reports, so this is equivalent to the Manager-Agent mode in terms of management content.

When the remote client mode is used to implement hierarchical management, the management rights of different subnets are assigned by the upper-level EMS and the data are uniformly maintained by the level EMS, thus ensuring that the upper-level EMS can monitor the entire network and correct & reliable data are obtained.

Figure 16 Centralized Management Mode

Two issues exist when the remote client mode is used to implement hierarchical management:

• The server needs higher performance. Since there is only one EMS server in the entire network to exchange information with all equipment in the network, it has

72 © 2009 ZTE Corporation. All rights reserved. ZTE Confidential Proprietary heavy processing load and so its configurations must be quite high. When the server is faulty, the management of the entire network will be affected.

• It is necessary to provide data transmission channels for the remote clients with high bandwidth requirement (at least 2M).