With the rapid development of TCP/IP networks, management is also needed to manage the network.
The Internet Architecture Board (IAB) recommends RFC 1052 which contains:
- Simple Network Management Protocol (SNMP)
- ISO Common Management Information Service / Common Management Information Protocol (CMIS / CMIP)
Meanwhile, the IAB recommends using SNMP.
Network Management
Substance:
- Simple Network Management Protocol (SNMP)
- Management Information Bases (MIBs)
- SNMP Architecture
- SNMP Protocol
- Development and use
- Implementing SNMP
- Multi Router Traffic Grapher
1. Simple Network Management Protocol (SNMP)
SNMP is one of the official protocols of the Internet Protocol suite created by the Internet Engineering Task Force (IETF). SNMP is an example of a layer 7 application used by a network management system to monitor network devices so that they can provide the information needed by their managers.
2. Management Information Bases (MIBs)
MIB is a database used for device management on a network. The database contains entity objects from network devices (such as routers or switches). Objects in MIB are defined using Abstract Syntax Notation One (ASN 1), and are named "Structure of Management Information Version 2 (SMIv2). The software used for parsing is called a MIB compiler.
RFCs that discuss include RFC1155 -- Structure and identification of Management Information for TCP/IP-based internets, RFC1213 -- Management Information Base for Network Management of TCP/IP-based internets, and RFC 1157 -- A Simple Network Management Protocol.
SNMP, communication that occurs between management station (example: console) with management object (such as router, gateway and switch), using MIB. Component that works to retrieve data is called SNMP agent, is software that can communicate with SNMP Manager.
3. SNMP Architecture
The SNMP framework consists of:
a. Master Agent
Master agent is software that runs on devices that support SNMP, which aims to respond to requests from SNMP from the management station. The master agent then forwards to the subagent to provide information about management with certain functions.
b. Subagent
Subagent is software that runs on devices that support SNMP and implements MIB. Subagent has the following capabilities:
- Collecting information from managed objects
- Configuring information of managed objects
- Responding to manager requests
- Raise an alarm or trap
c. Management Station
The management station is a client and makes requests and receives traps from the SNMP server.
4. SNMP Protocol
- PDUs from SNMP (version 1) include:
- GET REQUEST -- used to get management information
- GETNEXT REQUEST -- used iteratively to obtain sequences of management information.
- GET RESPONSE
- SET -- used to make changes to subsystems
- TRAP -- used to report on management subsystems
For the next version added PDU:
- GETBULK REQUEST -- faster iteration to get information
- INFORM -- acknowledge TRAP
SNMP uses UDP on port 161 for agents and 162 for managers. Managers send requests to agents on port 161 and are received by managers on port 162.
5. Development and use
Version 1
The RFC for SNMP, known as Simple Network Management Protocol version 1, in 1988:
- RFC 1065 -- Structure and identification of management information for TCP/IP-based internets
- RFC 1066 -- Management information base for network management of TCP/IP-based internets
- RFC 1067 -- A Simple Network Management Protocol
Then it became obsolete and was replaced with:
- RFC 1155 -- Structure and identification of management information for TCP/IP-based internets
- RFC 1156 -- Management information base for network management of TCP/IP-based internets
- RFC 1167 -- A Simple Network Management Protocol
Version 1 had a weakness in the authentication system because it sent passwords in plain text.
Version 2
Many people do not use version 2 due to framework incompatibility.
Simple Network Management Protocol version 2 (RFC 1441 -- RFC 1452) and also known as SNMP v2. GETBULK was introduced as an alternative to GETNEXT. Also introduced was Community-Based Simple Network Management Protocol version 2 or called SNMP v2c as a replacement for the User-Based Simple Network Management Protocol version 2 authentication system, or SNMP v2u which is used to improve the security of SNMP v1.
Version 3
This version is defined in RFC 3411 -- RFC 3418, namely Simple Network Management Protocol version 3, released in 2004.
In practice, SNMP can use SNMPv1, SNMPv2c, or SNMPv3 versions. Described in RFC 3584 -- Coexistence between Version 1, Version 2, and Version 3 of the Internet-Standard Network Management Framework.
Usage Examples
- Monitoring the usage time of a device (sysUpTimeInstance)
- Inventory of operating system versions (sysDescr)
- Collects information about an interface (ifName, ifDescr, ifSpeed, ifType, ifPhysAddr)
- Measures the interface throughput of the network (ifInOctets, ifOutOctets)
- Retrieving cache information from ARP (ipNetToMedia)
6. Implementing SNMP
snmpwalk
snmpwalk output
Router Graphing Software
There is a lot of information that can be displayed, such as performance, load and error rate of a network such as a router or switch. Then with a special function, the information obtained is processed into a graph. Examples of Multi Router Traffic Grapher and Cacti applications.
7. Multi Router Traffic Grapher
Multi Router Traffic Grapher or abbreviated MRTG is a free software used to monitor traffic load on network links. Where users can see reports in graphical form.
MRTG is written in perl and runs on UNIX/Linux and also on Windows and Netware operating systems. MRTG uses the Gnu GPL license.
MRTG Logo
First developed by Tobias Oetiker and Dave Rand, it was first used for router monitoring. Now it has been developed to be a report of various kinds. Complete information can be seen at http://oss.oetiker.ch/mrtg/
MRTG traffic example
MRTG evolved into RRDTool, a round-robin database tool. RRDTool can be developed into various applications such as cacti, JFFNms and many others.