Using the Shipboard Network

This page describes steps in configuring and managing the shipboard network for use by scientific parties. The steps involved are relatively simple, but must be followed carefully so as to not create network havoc.

What Scientific Parties Need to Know

There are several important network configuration values that scientific parties should know about to set up their machines.

Domain Name = HMSC.ORST.EDU

This is the name of the network that the ship and ship ops's computers reside in. For example, appending the domain name to oldman gives us oldman's full address: oldman.HSMC.ORST.EDU.

Gateway Address = 128.193.170.1

This is the address of the local network's gateway system. To connect outside of the domain, a computer must go through the gateway machine. This machine (128.193.170.1) is located in HMSC and is not available while the ship is at sea.

Network Mask = 255.255.254.0 (FF.FF.FE.00)

This is a number used as a mask for network addresses. It helps simplify network addressing for machines within the local domain.

Domain Name Server (DNS) = 128.193.128.3 (beasley.CS.ORST.EDU)

This is the machine that is contacted by systems on the net to convert an address referred by name to a numerical IP address. For example, if the DNS is asked for the address of otis.OCE.ORST.EDU, it will answer with 128.193.64.11. Note that oldman, or any other UNIX workstation will first look in the file /etc/hosts to see if it contains a match for the system name. If no match is found, then the computer will connect to the DNS to try and find a name match.

Oldman's Network Configuration

The main network configuration file that needs to be modified on oldman is the /etc/hosts file. This file contains a list of system names followed by numeric IP addresses. It may be worth while to put the names and addresses of systems brought on board by scientific parties into the hosts file. This will allow you and scientists to more easily FTP to and from oldman and scientific systems.

The /etc/hosts file is a text file and may be edited with VI or the textedit tool. Note that you must be logged in as the super user to edit this file. Scientists may find a copy of the hosts file useful in setting up their own network. Here is a simple hosts file for oldman... 

	#
	# Internet host table
	#

	# Main WECOMA systems
	127.0.0.1       localhost loghost
	128.193.170.230 oldman  # Sparc 10/30
	128.193.170.231 dudley  # NCD 15" Color X Terminal
	128.193.170.232 snidely # NCD 19" Monochrome X Terminal
 
	# Miscellaneous off ship systems
	128.193.64.52   lubber.oce.orst.edu lubber
	128.193.64.11   otis.oce.orst.edu otis
	128.193.128.3   mailhost nameserver beasley.cs.orst.edu beasley

	# ---------------------------------------
	# W9406A hosts info
	# ---------------------------------------
	128.193.170.244	quakes  # Trehu's Sparc
	128.193.170.234	indigo  # Sparc 1+, 4.1.3
	128.193.170.235	alpamayo# Sparc LX, 5.1
	128.193.170.236	bailycs # NEC 386, DOS 5.0
	128.193.170.237	obs     # 486, DOS 6.2
	128.193.170.238	panhead # Masscomp
	128.193.170.239	obh2    # NEC 386, DOS 5.0

Monitoring Network Traffic

It may be useful to monitor network traffic at times to get a feel for how active things are, judge performance, and look for troubles. There are several tools that can help with this.
Solaris Perfmeter
The perfmeter program (available in the "Programs" popup menu) can display, amongst other things, network collisions. These are basically network packets that run into each other because of excessive traffic. If a high traffic load job such as tape reading or backup from one machine to another is going on, you may see a rise in collisions. Normally there should be none. Don't be alarmed by collisions, unless there is no apparent reason for them. Collisions can also be a sign that some line is failing somewhere in the network.
Hub Activity LED
The activity lights on the hub will flicker with network activity. When the XMidas system is running, you will see a flicker on about a 1 second interval as data is passed, parsed, etc. When a Chart or Nav program is drawing or active, you will see an increase in network traffic. If an FTP transfer or other cross network transfer is occurring, the light will be on much more solid. Note that when in port, the light is always flickering, as it is also showing HMSC's network traffic.
Etherman Program
An interesting and enlightening program for visually displaying network traffic is the program etherman. It is located in /export/home/holtt/Applications/etherman-1.1a. You must log in as root to run the program. When running it from oldman, run the program with the command ./etherman -mono. The -mono switch tells it to run in black and white. You can run it in color on dudley, the ship's color X terminal.

Network Management In Port

When the ship is in port, and the dockside network connection is made, then the ship's net becomes part of the HMSC domain network. As such, it is very important that the ship's network "behave" and not adversely affect HMSC. It is very, very possible for a system or systems on the ship to trash the HMSC net. Good ways to trash a net are... In agreement with HMSC, we will limit this kind of network intensive stuff to after hours and weekends. It is very, very important to keep an eye out for this kind of network activity by the scientists. They may wish to do tape backups, or file transfers when they come in to port, so be sure that they are aware of the agreement to limit network intense traffic to after hours. If it is necessary to do network intensive work that is between systems on the ship, there are several ways to keep down the effect... Note that it is impossible to make network traffic to and from the ship behave. This must be limited to after hours.

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