Ethernet Communications and IP
addresses
Field Bulletin
Date: 12/7/99
Products: SC-3, RMS
Subject: Ethernet Communications and IP addresses
Author: Greg Campbell / Randy Rose
SC-3 System Controller and RMS software
The SC-3 System Controller, Router Management System
(RMS) software and SCP control panels are used together
to control and manage routers. The RMS software runs
on a Windows NT platform and provides the user with
a graphical user interface (GUI) for configuring routers,
control panels and also for the status displays for
numerous operational statistics regarding the routers
and control panels.
Communications
The RMS software that runs on a PC (see field bulletin
fb11112 for specifications) which communicates with
the SC-3 over a 10 BaseT Ethernet link. The link between
the SC-3 and the RMS computer can be configured in
a couple of different ways but must follow certain
specifications to ensure that reliable communications
exist.
SC-3 to RMS Computer Cabling
The two basic configurations for the Ethernet link
between the SC-3 and the computer running the RMS
software are stand alone and networked. Both are described
below with the differences in cabling requirements.
Stand Alone
In a stand alone configuration the Windows NT PC
running the RMS software is linked directly to the
SC-3 with a single cable and the PC is not tied to
a network as shown in figure 1. The cable used for
this type of connection is a non-standard Ethernet
cable commonly called a "loop through" or "crossover"
cable. The pin out for this cable is depicted below
in figure 5. Although the SC-3 and the RMS computer
may be in a stand alone configuration, it is recommended
that a hub be used to connect the two, which eliminates
the need for the non-standard Ethernet cable. In this
case two standard Ethernet cables would be used to
connect both the PC and the SC-3 to the hub as shown
in figure 2. A cable pin out for the standard Ethernet
cable or "straight-through" cable is shown below in
figure 4. As shown in figures 5 and 6, the pairs that
actually carry the Ethernet signal are pair 3 and
pair 2. In both straight-through and crossover configurations,
the four pair Ethernet cable must be category 5 grade
and be unshielded twisted pair (UTP) cable.
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Figure
1 - Stand Alone Direct Connect |
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Figure
2 - Stand Alone HUB |
Figure 3 - RJ-45
Jack
Figure 4 - Standard
Ethernet Cable Pairs
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Figure
5 - Crossover Cable |
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Figure
6 - Straight Through Cable |
Figure 4 shows the standard wiring diagram for a
standard "straight-through" Ethernet cable. Figures
5 and 6 specify only those wires that are actually
used in Ethernet communications. The remaining wires
are not used in the actual communications for 10Base
T but may be connected in a straight-through manner
in both cases.
Note: It is imperative
that wires in each of the pairs, 3 and 2, remain in
that pair to retain the balance properties of the
cable. In other words, pair 2, which resides on pins
1 and 2 of the RJ-45, jack should occupy the white/orange
and orange/white wires of the cable. Pair 3, which
resides on pins 3 and 6, should occupy the white/green
and green/white wires. Category 5 UTP cable should
be used as the cable grade. Failure to adhere to these
guidelines will result in faulty communications.
Networked
In a networked configuration the Windows NT PC running
the RMS software is on a local or wide area network
and must plug into a hub to access the network. The
SC-3 would also plug into a hub on the network as
shown in figure 7. The cable used to link the SC-3
to the network hub is a standard off-the-shelf 10Base
T network cable with the pin out as shown above in
figures 4 and 6.
Figure 7- Networked
Configuration
Note: Although
more than one computer can run the RMS software on
a network, only one RMS computer should attempt to
access the SC-3 at a time.
Communications Between RMS and SC-3
This portion of the document assumes that you have
a functional PC meeting the RMS PC specifications.
(fb11112) This PC must be running Windows NT and have
a functional network interface card installed and
operational. If you need assistance on these requirements,
contact your system administrator. The SC-3 control
cards each have their own unique assigned IP address.
RMS uses the IP address of the SC-3 boards to establish
communications with the proper board or SC-3. The
SC-3 boards are shipped to the end user with factory
default addresses for stand-alone operation. The IP
assigned to the master card is 192.168.221.21 and
the one assigned to the redundant (slave) card is
192.168.221.22. (These may be different upon shipment
only if specific request from the end user has been
made). There should be no reason to change these numbers
unless specific addresses are needed, would be the
case if the SC-3 and RMS computer are to be placed
on a LAN/WAN .
Note: The IP
addresses for the Master and Slave boards should never
be assigned the same number.
Stand Alone
If you plan to run the RMS in a stand alone setting,
the only IP address that you will need to set is the
one located within the computer that will be running
the RMS application. To do this, locate the Network
Neighborhood icon on the NT workstation desktop and
right click on it. Click on "Properties" and then
click on the tab at the top of the screen labeled
"Protocols". Find the item in the menu labeled "TCP/IP
Protocol" and click it. (If TCP/IP is not loaded,
you must add it as a protocol. Contact your systems
administrator for assistance). Click "Properties"
and then click the button labeled "Specify an IP address".
To the right of the IP Address type 192.168.221.23
and next to the Subnet Mask type 255.255.255.0. Click
on "Apply" and then the "OK" button.
Networked
If the SC-3 will be used on a company network then
the IP addresses assigned to the control cards as
well as the computer that will be running the RMS
application will need to be changed. (You will need
to contact a member of your MIS department for assistance
in assigning these IP addresses, as they will be unique
to your network). Note:
Any network (LAN/WAN) configurations or PC settings
are the responsibility of the customer and should
be handled by the appropriate MIS persons.
To change the computer IP address, use the same procedure
as above in the stand alone operation, entering a
specific and unique IP address assigned by your MIS
person. The SC-3 cards will need to have their IP
addresses changed also, and to do this will require
a cable connected from the SC-3 Comm 0 port to a computer
Comm port using HyperTerminal or a similar emulator,
and then accessing the diagnostics menu where this
change is made from. (This may also be done via Telnet.
See below).
The pins for this cable are as follows:
| SC-3
Comm 0 (25 pin port) |
PC Comm
Port (9 pin) |
PC Comm
Port (25 pin) |
| 2 (TX) |
2 (RX) |
3 (RX) |
| 3 (RX) |
3 (TX) |
2 (TX) |
| 7 (Gnd) |
5 (Gnd) |
7 (Gnd) |
The settings that need to be used for directly connecting
a terminal to Comm 0 are:
| Baud Rate |
38400 |
| Parity Settings |
8 data bits / no parity / 1 stop bit |
| Emulation |
VT-100 or Auto mode. |
With these settings in place and the diagnostics
cable attached, there will appear an arrow like cursor
on the screen. Type "help" to get the menu on screen
and then type "setipaddr" and press enter. Type the
new IP address that was assigned to the SC-3 card
from your MIS person and then press enter. Push the
black reset button on the Master card to reset the
new IP address into the card. To verify the new address,
type "getipaddr" and press enter. If there is a redundant
SC-3 card, then its address will also need to be changed.
Push the changeover switch on the Master SC-3 card
to place the redundant card into the Master position
and then perform the same steps as above. Be sure
to give the second board an IP address different from
the one assigned to the first board.
Gateways
If there are any RMS computers that reside on a
different subnet other than the one in which the SC-3
resides, then a gateway will need to be set up on
your LAN/WAN to bridge these subnets. This gateway
information will need to be entered into the RMS computer
and the SC-3 control cards. The gateway address for
the RMS computer should be assigned and installed
by an MIS person. The gateway address to be used by
the SC-3 cards is entered through the diagnostics
port (Comm 0) on the SC-3 by going into the menu and
typing "setgatewayaddr" followed by the "enter" key
and then the gateway address.
Using Diagnostics Menu via Telnet
The SC-3 diagnostics menu can be accessed through
a Telnet session as well as the diagnostics port on
the SC-3. In order to use this program however, there
are two requirements. Your SC-3 cards must have version
2.0 or newer firmware installed (U62, U63 and U64).
You will need to know the IP address of the card you
are accessing, which will be the card with the "master"
led on. If you run Telnet to view the menu, you need
to type "quit" when exiting the menu rather than just
closing the session. If you fail to do this, the RMS
will transfer to the redundant card and lose communication
to the SC-3.
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