Table of Contents  

Table of Contents *

Introduction *

Document Conventions *

Getting Help *

Credits *

1. Overview *

2. ASExplorer *

Main Window *

Real-Time Graphs *

Table of Current Flapping Prefixes *

3. NetNowd *

Synopsis *

Options *

Description *

Sample Configuration File *

Configuration Commands *

Interactive Interface Commands *

Viewing the Results *

Related Documents *

 

Introduction

Document Conventions

Getting Help

Credits

1. Overview

2. ASExplorer

Main Window

Real-Time Graphs

Table of Current Flapping Prefixes

3. NetNowd

Synopsis

Options

Description

NetNowd collects network performance statistics information and reports real-time results to one or more Statistics servers (SalServer). In turn, reporting tools and Java clients can connect to a statistics server to generate real-time and historical reports of network performance. NetNowd is the back-end tool for a number of visualization clients, including ASExplorer, FlapGraph and TopologyNow. See the IPMA web site (http://www.merit.edu/ipma) for more information about the visualization tools.

This release of NetNowd includes support for the following network measurements:

• One-way latency (IETF IPPM working group)
• One-way loss (IETF IPPM working group)
• ICMP pings
• Bulk file transfer
  

NetNowd first reads its configuration file (by default /etc/netnowd.config) to configure security controls, plink streams and other measurements. If a configuration file does not exist on disk, NetNowd will create a default configuration in volatile memory. The configuration file strongly resembles the files used by Cisco Systems.

After reading the configuration file, NetNowd will begin network measurement tests and report the results to the one or more configured statistics servers. NetNowd will also listen on the UII port for user telnet connections (specified in /etc/services as the TCP port for "netnowd").

The daemon has been set up to run in a default configuration "out of the box". You should simply be able to download the binary and run it. If you want more control over what the daemon does (such as which machines it peers with, how it outputs error and diagnostic information, and security features) you will need to edit the configuration file. By default, the daemon participates in an "Alpha" community of NetNowd testers and publishes performance data to a public statistics server (currently based at Merit Network, Inc.).

Note that if you want to specify the next hop of a plink packet, or if you want to do a local (subnet) plink, you will need to run the NetNow daemon as root.

Below is an example of starting the NetNowd daemon from the command line:

Notice in the above example that we did not run NetNowd as root, and the daemon could not obtain access to the ethernet (hme) interface. Lacking this access, the NetNowd probe will only be able to send UDP packets via the default route.

Sample Configuration File

A sample NewNowd configuration file is shown on the next page.

!####################################################################
! NetNowd—MRT version 1.4.1 ALPHA December 17, 1997
!####################################################################
!
debug all /var/tmp/netnowd.log 1000
!
password blechy 1
!
source_ip 192.41.177.169 /dev/le ethernet
!
! The sites we plink and accept plinks from
!
community alpha
!
! Salamander Server
salserver zounds.merit.net 123456
!
allow unconfigured-peers
!
!
plink_subnet 192.41.177.181 tag 3561 # MCI
plink_subnet 192.41.177.80 tag 5000 # IOSnet
plink_subnet 192.41.177.87 tag 4969 # NetAxs
!
access-list 1 198.108.60.0 permit
access-list 1 141.213.8.0 permit
!###################################################################

Configuration Commands

Configuration commands are used to configure NetNowd; interactive interface (telnet) commands are used to show and modify the status of various metrics, such as packet latency and loss.

A WARNING – Most, but not all, configuration commands may be issued even through the interactive, telnet interface. In this alpha release of NetNowd, the modification of volatile memory occasionally may have unintended side effects. In rare instances, the alteration of some volatile memory setting may crash the application. We recommend most configuration changes be made directly to the configuration file on disk. The program must be restarted, or rebooted, to reread the changed configuration file. Improved support for configuration management will be available with the next release of NetNowd.

uii—configures the user interface (by telnet)

debug—controls debug options

		 .... info, norm, trace, parse, packet, state, timer, all
		 .... filename or "stdout". 
		                             Some applications also support "syslog"
			

access-list—defines a filter

!—comment and separator

redirect—allows shell-like redirection of output (> or >>).

plink—define a remote plink host

community—define a community

salserver—specify the Statistics server

packet_size—specify the packet size of all plink packets

interval—specify the inter-transmission time of plink packets

Interactive Interface Commands

NetNowd provides an interactive telnet user interface for configuration and display/management of various statistics and measurement parameters.

The port number can be specified in the configuration file, or in /etc/services ("netnowd"). The default port is 5674. If a password is specified in the configuration, it must be supplied on logging in.

Unix shell-like redirection ( or filename) is available for output. To edit a line, emacs-like line editing including ^b, ^f, ^d, ^k, ^u and ^c is available. To reuse a previous line, tcsh-line history function is available by typing ^p and ^n.

The following commands are available from the user interface.

• show community—Show community of machines in statistics mesh
• show config—Display current configuration
• show plink—Show machines we are plinking
• show stats—Show netnow statistics
• show timers—Show status of NetNow timers

Below is an example of several netnowd user interface commands:

Viewing the Results

A number of client applications are available for viewing and monitoring NetNow performance data. NetNowGraph is a Java application that graphs latency/loss information between a given source probe and destination over the course of a day. NetNowReport is a Perl program that shows the latency/loss information from a given source to all destinations over the course of a day. Both tools are distributed with the IPMA Internet Performance Toolkit at http://www.merit.edu/ipma/tools. A version of NetNowReport is also distributed with the NetNowd source code.