網路管理軟體Network Management

Products Include: Nucleus SNMP, Nucleus RMON and Nucleus SPAN

Most embedded devices require management of some type. In the days before network connectivity of embedded devices was so common this was often done via a serial connection. There are numerous problems with this. First, the interface was generally a terminal application. This does not exactly provide for a rich, flexible user interface. It was often necessary to write custom software, not only for the embedded application, but also for the host machines used to manage the embedded device. Today there are much better options available, options that give you the best of all possible worlds. These solutions provide a richer interface, they are open, provide quicker time to market, and there are a wide variety of third party tools that exist.

Most embedded network devices will require management of some type. The de facto standard for the management of network devices is the Simple Network Management Protocol (SNMP). This site location is your guide to Nucleus SNMP and Accelerated Technology's other network management products.

Nucleus SNMP

Nucleus SNMP is an embedded implementation of the Simple Network Management Protocol (SNMP). SNMP defines a framework for the management of network-capable devices. Nucleus SNMP, an SNMPv1 agent, allows remote management of MIB's via an SNMP manager. A MIB, or Management Information Base, can be thought of as data structures that the agent, at the request of a SNMP manager, can act upon. So from a desktop SNMP manager a "get" request could be issued to examine the value of some field in a MIB. A "put" request allows for the value of a field to be changed. The agent is responsible for parsing requests from the server, extracting the information from the appropriate MIB, and sending the answer to the manager.

Nucleus SNMP includes support for MIB-II. MIB-II is a standard MIB that defines the objects of a TCP/IP protocol stack that can be managed. Nucleus SNMP also supports traps, which can be thought of as alarms. Finally, Nucleus SNMP provides a simple model for creating and supporting new MIB definitions, or enterprise specific MIB's. To help developers with their own MIB's, Nucleus SNMP comes with an example enterprise specific MIB.

Nucleus SNMP Features:

• SNMP embedded agent
• Support for all ten groups of MIB-II (RFC 1213) included
• Flexible enterprise MIB creation
• Small in size, approximately 30Kbytes (MIPS RISC)
• Optimized internal memory management
• Distributed architecture
• Support for multiple interfaces
• Seamless integration with Nucleus RMON

Nucleus RMON & Nucleus RMON-LITE

The Remote Monitoring (RMON) MIB provides a comprehensive network management framework to achieve network fault diagnosis, trend analysis, planning and performance tuning of network devices. RMON works at the hardware and data link layers of the OSI network model. RMON's is used primarily in network infrastructure devices. A couple of examples would be switches and routers. As you would expect with a MIB, an SNMP agent is required to manage RMON. Nucleus RMON is designed to plug seamlessly into Nucleus SNMP.

Nucleus RMON has been designed to work well in embedded environments where processor and memory limitations are too severe for other RMON offerings. Nucleus RMON has a distributed architecture, which permits the front-end parsing and background collection activities of RMON to run as separate tasks, if desired.

Nucleus RMON conforms to those devices that collect statistics in hardware, but does not require hardware support. Nucleus RMON provides support for multiple MAC interfaces and simultaneous RMON group support for each interface. Nucleus RMON may be configured through a serial, telnet or MIB interface.

Nucleus RMON provides a "Roving" RMON capability. Roving RMON simply means that for limited environments, where all groups cannot be supported on all interfaces simultaneously, you may choose which groups are activated based on certain automatic threshold criteria or by your selection.

Nucleus RMON supports all nine groups of the RMON MIB (RFC 1757). Nucleus RMON-Lite supports the four most commonly used groups. These groups are Etherstats, Alarm, Event, and History. An advantage of RMON-Lite is that this subset can be implemented to support multiple interfaces without prohibitive per-packet processing, as can be the case with full RMON support.

Nucleus RMON Features:

• Support for all nine groups of RMON MIB (RFC 1757)
• Small in size, approximately 40Kbytes (MIPS RISC)
• Optimized internal memory management
• Distributed architecture
• Support for multiple interfaces
• Support for roving RMON
• Simultaneous background collectors
• Standard BSD sockets interface
• Intelligent packet queuing interface

Nucleus SPAN

Often left out of commercial embedded protocols is Spanning Tree, which is specified in IEEE 802.1d. Whenever two or more LAN bridges or switches are attached to a local area network, the possibility exists that more than one bridge/switch could connect the same segments. This could result in endless loops of packet traffic on the network. The Spanning Tree Algorithm is a method used to sense the structure of the network and prevent multiple paths between network segments.

Nucleus SPAN is a portable implementation of the Spanning Tree specification:

ISO/IEC 10038 ANSI IEEE Std 802.1D, First Edition 1993-07-08.

It is compact and easy to port to your target.

A typical implementation of Nucleus SPAN on a CISC processor requires approximately 24k of code space, 1.5k of data and 1k of BSS. Exact size depends on the specific user environment and processor choice. Example port code is included with the source.

Nucleus SPAN Features:

• Prevents duplicate paths in your network
• Direct implementation of 802.1d from IEEE specification
• Very small (6Kbytes MIPS RISC)
• Requires minimal system resources