TABLE OF CONTENTS
There are different ways to monitor and graph the data from the SDM300a Satellite Modem. In our case, there are three different implementations that we did to come up with the same goal, to monitor and graph the data from SDM300a Satellite. Modem.
In monitoring the SDM300a satellite modem, we used the following softwares to come up with the final graph outputs.
OVERVIEW OF SNMP
by Mel Brinkley,
UCNS Telecommunications Systems Analyst
Chances are that when you load TCP/IP
on your PC, you will see the term "SNMP" and the system will ask you for
certain information. SNMP is Simple Network Management Protocol and is
widely used in the
management of IP networks. In this
article we'll foc us on answering the question: How does SNMP work?
Managing contemporary computer networks
requires an approach that simplifies the potentially complex problems of
communication and coordination. The prevailing approach, and the one adopted
by SNMP, is to
view the network as a collection
of cooperative c ommunicating entities.
There are basically two types of entities: management nodes (managers) and managed nodes (agents).
MANAGERS
A manager is a node that actively
participates in network management. It solicits and interprets data about
network devices and network traffic, and typically interacts with users
to achieve their intentions. A manager
can also trigger changes in an agent
by changing the value of a variable on the agent node. Managers are frequently
implemented as network management applications.
UCNS uses a RISC 6000 computer running AIX for NetView as a network management station.
AGENTS
An SNMP agent is software that resides
on a network node and is responsible for communicating with managers regarding
that node. The node is represented as a managed object having various fields
or variables that
are defined in the appropriate MIB.
The agent has two purposes:
1.To respond to
requests from managers, supplying or changing the values of the object's
variables as requested.
2.To generate
traps to alert managers of noteworthy events occurring at the node, such
as a component failure.
Not all devices support SNMP directly. Devices that do not can have a proxy agent that translates between SNMP and itself.
If you load SNMP with your TCP/IP package, then your computer could be considered as having an SNMP agent on it.
Many nodes do not have SNMP agents
on them and are considered unmanaged. However, a network management application
such as NetView is aware of their presence, obtains as much information
about them as it
can from the domain name server,
and can monitor their up and down status with the ICMP echo.
MANAGER and AGENT INTERACTION
The manager communicates with the
agent by SNMP messages which are in the form of requests. Managers do not
need to know any internal details about the object managed by an agent.
Likewise, an SNMP agent
can service requests from many SNMP
managers. The agent does not need to know the context of the request or
the structure of the manager making the request. The agent validates the
request, services it, and enters
its passive state--awaiting the
next request. This division of responsibilities simplifies network management
solutions.
TRAPS
Generally, the manager requests information
from the agent and the agent then responds. However, it is possible for
an agent to issue messages without a corresponding request. Such a message
is known as a trap.
Traps exist to handle special conditions.
For example, if an interface on our main router goes down, the router agent
will notify the network management station.
MANAGEMENT INFORMATION BASE (MIB)
The MIB is a method of describing
managed objects by specifying the names, types, and order of the fields
(or variables) that make up the object. The MIB can either be a standard
one or can be what is known as an
enterprise MIB.
Enterprise MIBs are those written
by vendors for their particular object. The managed object can furnish
both standard MIB and enterprise MIB information if there is an enterprise
MIB written for it. There are many
enterprise MIBs. CISCO systems,
Cabletron, and IBM, for example, all have MIBs for their equipment.
The Internet MIB-II is one of many
standard MIBs. The purpose of the MIB-II is to define common objects for
managing TCP/IP networks. When you activate SNMP and are asked for information
such as
SysContact, SysName and SysLocation,
you are loading values for the MIB-II. It is quite common.
HOW DOES IT ALL WORK?
As an example, UCNS monitors traffic
coming into the campus-wide broadband network from the building bridges
as well as traffic on the bridge LAN, which could consist of several local
LANs. Each of the 123
bridges has two interfaces, one
on the local side and one on the broadband side.
Traffic going in and out of the interfaces needs to be monitored. To do this, two MIB-II variables--ifOutOctets and ifInOctets--were chosen. (An octet is an eight bit measurement.)
The manager is set up to sample the
count every 5 minutes, 24 hours a day. Every five minutes a request is
made of the bridge agent for the information. The agent responds and the
information is stored in collection files.
In addition, thresholds are set
for certain levels and the manager responds when these levels are exceeded.
If traffic in one particular area
is of concern, the manager can request the traffic at greater frequency
to get a more minute picture of traffic flow. Finally, if the traffic flow
is such that data is being impeded, management
efforts such as re- engineering
can begin.
There is a tendency to believe that slow network response time is due to network traffic volume. Unfortunately, there are many reasons why the response time could be slow. Future articles will focus on some of them.
WHAT IS MULTI ROUTER TRAFFIC
GRAPHER
by Tobias Oetiker
The Multi Router Traffic Grapher (MRTG) is a tool to monitor the traffic load on network-links. MRTG generates HTML pages containing GIF images which provide a LIVE visual representation of this traffic. Check http://www.ee.ethz.ch/stats/mrtg/ for an example. MRTG is based on Perl and C and works under UNIX and Windows NT. MRTG is being successfully used on many sites around the net. Check the MRTG-Site-Map.
MRTG consists of a Perl script which uses SNMP to read the traffic counters of your routers and a fast C program which logs the traffic data and creates beautiful graphs representing the traffic on the monitored network connection. These graphs are embedded into webpages which can be viewed from any modern Web-browser.
In addition to a detailed daily view, MRTG also creates visual representations of the traffic seen during the last seven days, the last four weeks and the last twelve months. This is possible because MRTG keeps a log of all the data it has pulled from the router. This log is automatically consolidated, so that it does not grow over time, but still contains all the relevant data for all the traffic seen over the last two years. This is all performed in an efficient manner. Therefore you can monitor 50 or more network links from any halfway decent UNIX box.
MRTG is not limited to monitoring traffic though, it is possible to monitor any SNMP variable you choose. You can even use an external program to gather the data which should be monitored via MRTG. People are using MRTG, to monitor things such as System Load, Login Sessions, Modem availability and more. MRTG even allows you to accumulate two or more data sources into a single graph.
Some sample graphs from http://www.ee.ethz.ch/stats/mrtg/:
ABOUT RRDTOOL
by Tobias Oetiker
If you know MRTG, you can think of RRDtool as a reimplementation of MRTGs graphing and logging features. Magnitudes faster and more flexible than you ever thought possible
RRD is the Acronym for Round Robin Database. RRD is a system to store and display time-series data (i.e. network bandwidth, machine-room temperature, server load average). It stores the data in a very compact way that will not expand over time, and it presents useful graphs by processing the data to enforce a certain data density. It can be used either via simple wrapper scripts (from shell or Perl) or via frontends that poll network devices and put a friendly user interface on it.
RRDtool is available for download from this site. Currently it compiles on a number of different Unix platforms as well as on NT. No binaries are officially provided at this point in time.
RRDtool is free software and comes with a GNU license. Nevertheless you can do something to show your gratitude for RRDtool: Check it out!
RRDtool is not a full replacement for MRTG, as it does not implement all the frontend and data aquisition features of MRTG. But it is an excellent base for building tools which work much like MRTG only better. Eventually, MRTG-3 will be built on top of RRDtool. You do not have to wait though. If you can program yourselfe you can use RRDtool right out of the box or if you don't program you can use one of several frontends which use RRDtool.
If you want to stay with MRTG-2 go into the contrib folder of the latest release and take a close look at 14all.
RRDtool does not have a GUI or anything presentable like this yet, but you can use RRDtool to create GIF images visualizing the data collected with it. Here are two sample images. They do not represent any sensible data, they simply show some of the features of RRDtool. Most of the visual aspects of the graphs are auto configured, but can be overridden when needed.
INSTALLATION PROCESS
UCD-SNMP v4.1.1
Download UCD-SNMP-4.1.1 at ftp://ucd-snmp.ucdavis.edu/ucd-snmp-4.1.1.tar.gz, put the file in /usr/local/ directory then follow the following procedures:
NOTE: You can get an sample snmpd.conf
by copying the file 'EXAMPLE.conf' from the directory /usr/local/ucd-snmp-4.1.1/
then rename it to 'snmpd.conf'.
| snmpd | - daemon to respond to SNMP request |
| snmptrapd | - receive and log snmp trap messages |
| snmpbulkget | - communicates with a network entity using SNMP BULK Requests |
| snmpbulkwalk | - communicates with a network entity using SNMP BULK requests |
| snmpdelta | - monitor deltas of integer valued SNMP variables |
| snmpget | - communicates with a network entity using SNMP GET Requests |
| snmpgetnext | - communicates with a network entity using SNMP GET NEXT Requests |
| snmpnetstat | - show network status using SNMP |
| snmpset | - communicates with a network entity using SNMP SET Requests |
| snmpstatus | - retrieves important information from a network entity |
| snmptable | - obtain and print an SNMP table |
| snmptest | - communicates with a network entity using SNMP Requests |
| snmptranslate | - translate SNMP objects into more useful information |
| snmptrap | - sends an SNMP trap to a manager |
| snmpusm | - creates and maintains SNMPv3 user's on a remote entity |
| snmpwalk | - communicates with a network entity using SNMP GET Next Requests |
Download MRTG from http://ee-staff.ethz.ch/~oetiker/webtools/mrtg/mrtg.html then put the file in /usr/local/ directory.
Note: Before you install MRTG, be sure you have a web server installed in your system (ie. apache web server) so that the web pages created by MRTG can be viewed from another workstation or network.
Workdir: /usr/local/www/data/mrtg
(location on html created files)
(refer to doc/config.txt)
Note: When you start MRTG for the
very first time, rateup will complain that it can not find any logfiles
and the graphs generated will look rather empty. Just ignore the complaints.
If you remove the empty graphs, and run MRTG again, rateup will create
new graphs which look better.
0,5,10,15,20,25,30,35,40,45,50,55
* * * * \
/usr/local/bin/mrtg /usr/local/bin/mrtg.cfg
Download the file rrdtool-1.0.16 and put it in /usr/local/.
GRAPHS OF SDM300a
SATELLITE MODEM