Download DSU / CSU NETWORK DESIGN LAB INTRODUCTION

Lab
1
CSU / DSU CONFIGURATION
F A 2 4
Exercise
T S E C
0 0 1 - 0 8
LAB OBJECTIVE
The objective of this lab is to gain an understanding of the functionality of a Channel Service Unit /
Data Service Unit (CSU/DSU) system employed within an Internet Protocol (IP) communications
network.
INTRODUCTION (Students read prior to attending lab session)
The CSU is a device that performs protective and diagnostic functions for a telecommunications
line while the DSU is used to connect a terminal to a digital line. Typically, the two devices are
packaged as a single unit and are required at both ends of a T-1 or T-3 connection.
One option for connecting a company’s data network between two geographically distant offices is
to use a serial connection. Some of the popular serial connections have T1, Frame Relay and 56
kbps / 64 kbps data rates. To establish the data network link, a high-speed connection (such as a
T1 or Digital Data Service (DDS) 56/64 kbps line), is leased from your local carrier (e.g.
AT&T/Sprint/MCI) and terminated into a CSU at the customer premise location. A DSU would
normally be used to terminate the slower 56/64 kbps DDS line. In most cases, the digital line will
terminate into a single device that has the DSU/CSU functionality, although, DSUs and CSUs can
be acquired separately.
Receive Pair
User
Interface
V.35 or RS-449
DSU
CSU
Telco
Transmit Pair
Figure 1
The primary function of the DSU is to convert the user generated signals such as RS-232 or V.35
into the form needed for transmission over the line provided by the local carrier. This conversion
conditions the user-input signal into the appropriate line code and framing format. The DSU
interconnects Data Terminal Equipment (DTE) for the public switched telephone network, acting
like a short-haul, synchronous-data line driver. It is normally installed at a customer’s location and
connects a user's synchronous equipment, via a 4-wire circuit, to a servicing Dial Central Office
(DCO). This service can be for point-to-point or multi-point operation in a Digital Data Network
(DDN).
The primary function of the CSU is to protect the local carrier’s network from the users’ network. It
also tracks statistics, provides loop-back testing for the local carrier, provides signal conversion
and maintains the local loop's electrical characteristics. It is a line-bridging device that is the last
signal regeneration point before a multiplexer or the DTE. The CSU also may perform bit stuffing;
providing a framing and formatting pattern compatible with the network. Figure 1 shows the basic
CSU/DSU functional diagram.
MATERIALS
Item
Cray DCP 3552 CSU/DSU
Satellite 651 T1 DSU
2600 Series Router
FA24 TSEC 01-08
Qty
1 ea.
1 ea.
1 ea.
CSU/DSU Configuration Lab
1
RJ48S T1 Cross Cable
Console Cable
HS Serial to V.35
V.35 to RS422 DTE
HS Serial to RS449 DTE
Four-port Hub
Cat-5 Patch Cable
1 ea.
1 ea.
1 ea.
1 ea.
1 ea.
1 ea.
1 ea.
PROCEDURES
Students will configure the Cray DCP3552 CSU/DSU System and the Satellite 651 T1 DSU
System to connect two geographically distant customer sites via a 1536 kbps WAN / serial link.
The WAN link between two CSU/DSU Systems will replicate a commercial carrier WAN link. This
practical exercise is designed to reinforce the instructional blocks that have been presented in the
Data Communications classes.
This lab assignment will require you to work in two teams. You will need to identify, configure and
install the equipment and networking components that are needed for each portion of the networks.
The actual commands for configuring the CSU/DSUs will be provided.
The major tasks associated with this lab are:
1. Cable the network components/devices up correctly IAW the CSU/DSU network
diagrams (Figures 2, 3 and 4, in that order). (15 points)
2. Configure the Cray DCP3552 CSU/DSU systems. (5 points)
3. Configure the Satellite 651 T1 DSU systems. (5 points)
4. Configure the Cisco 2600 series routers IAW the network diagram. (20 points)
5. Configure and connect computer laptops to the network. (5 points)
6. Verify end-to-end network (component) connectivity. (5 points)
7. Perform troubleshooting as appropriate. (5 points)
Install the Cray DCP3552 CSU/DSU/Router Network (Figure 2)
Install the CSU/DSU Lab network IAW diagram Figure 2. All of the required equipment that you
need is on the lab benches. Remember to identify the equipment by nomenclature and vendor
name to insure that you are using the correct items. You should already be broken down into your
two teams to complete the remainder of this lab. Team #1 will install the left portion of the network
and Team #2 will install the right portion of the network. You should install the network from the
CSU/DSU components outward to the laptops.
STEP 1 – Install and configure the T1 communications link between the two Cray DCP3552
CSU/DSUs.
A. Connect the two Cray Communications CSU/DSU together via the NI LINE interface
(RJ48S 8-Pin modular connection). You will use the RJ48S T1 Crossover cable to facilitate this
connection. [The cable will be connected to the NI LINE ports on the back of the Cray
Communications CSU.]
B. Configure the Cray CSU for network operation. Use the up and down arrows on the
front panel of the CSU to view and select your configuration options. Use the up or down arrow to
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CSU/DSU Configuration Lab
2
get to System Configuration and press ENTER to select and view the options. The selected
configuration option(s) will be displayed on the 32-digit Alphanumeric Display. Use the following
settings:
DTE Rate
Format
Mode
Interface
Audible Alarm
Front Panel
Density Mode
Unit Address
Timing
Keep Alive Type
Remote Unit
Line Build Out
Remote Loop Out
Sync Date Mode
Sync Clocking
Sync DSR
Sync CTS
Sync LSD
Sync Diagnostic
1536
306 to ESF (sync unframed)
Bipolar w/ 8 Zero Substitution (B8ZS)
RS422 (or V.35) – based on connection
Disabled
Enable
FCC Part 68
000
Internal
Type 1 – All Ones
Compatible
0
Enable
Normal
Give Both
On
On
On
Off
C. The “TIMING” configuration option will be determined by the network function that is
required.]
D. Once you have completed the configuration settings, select Return to MAIN MENU.
You have now configured your CSU systems for network operation. Have the Lab instructor verify
your configuration settings.
STEP 2 – Install and Configure the Cisco 2600 Routers for DTE Operation with the Cray
CSUs.
A. Configure the required interfaces IAW Figure 1, to support DTE to NI operations.
B. Use the CISCO High Speed Serial to V.35 (CAB-SS-V35MT) cables or the Cisco 7207901-01 V.35  RS422 DTE Interface cables to connect the Cisco router high speed serial port
to the V.35 interface on the back of the CSU.
C. Configure the routers and PCs to support Ethernet LAN clients IAW Figure 2 network
diagram. Verify by pinging the distant end router. Turn in the router configurations with
your lab questions.
D. Verify network connectivity via executing PINGs across the network from each PC
LAN client. Have the Lab instructor verify your non-secure network operability.
Install the Satellite 651 T1 DSU CSU/DSU Network (Figure 3)
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CSU/DSU Configuration Lab
3
STEP 1 – Install and configure the T1 communications link between the two Satellite 651 T1
DSUs (See Figure 2).
A. Connect the two Satellite 651 T1 DSUs together via the NI LINE interface (RJ48S 8-Pin
modular connection). You will use the RJ48S T1 Cross cable to facilitate this connection. [The
cable will be connected to the NI LINE ports on the back of the DSUs.]
B. Configure the DSU for network operation. Use the following to configure the Satellite
651 T1 DSU.
Note 1: The configurations will be similar to the ones used in the Cray Communications CSU/DSU
system.
Note 2: Holding the Next or Previous button down will scroll rapidly through the available choices.
Using the buttons on the front of the unit, configure the NI framing format.
1. Push escape until SYSTEM STATUS appears in the display.
2. Push Next or Previous until NETWORK CFG appears in the display.
3. Push Select. FRAMING FORMAT appears in the display.
4. Push Select. SF ESF appears in the display. The currently selected format is
blinking.
5. Push Next or Previous until the format you want (ESF) is blinking. A question
mark appears meaning the blinking value is not yet configured.
6. When the format you want is blinking, push Select. The question mark
disappears.
Using the buttons on the front of the unit, specify the NI line coding.
1. Push Escape until SYSTEM STATUS appears in the display.
2. Push Next or Previous until NETWORKL CFG appears in the display.
3. Push Select. FRAMING FORMAT appears in the display.
4. Push Next or Previous until LINE CODING appears in the display.
5. Push Select. AMI B8ZS appears in the display. The currently selectred value
blinks.
6. Push Next or Previous until the line coding you want (B8ZS) is blinking. A
question mark appears meaning the blinking value is not yet configured.
7. When the line coding you want is blinking, push Select. The question mark
disappears.
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CSU/DSU Configuration Lab
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Step 2 - Install and Configure the Cisco 2600 Routers (if necessary) for DTE Operation with
the Satellite 651 T1 DSUs.
Configure the routers, DSUs and PCs to support Ethernet LAN clients. Use the CISCO High
Speed Serial to V.35 (CAB-SS-V35MT) cables or the Cisco 72-07901-01 V.35  422 DTE
Interface cables to connect the Cisco router high speed serial port to the V.35 interface on the
back of the DSU. Once you have completed your configurations, verify connectivity by
executing a ping to the distant end router and PCs.
Note: Make sure you turn in the router configurations with your lab discussion questions.
Install the Network that uses the Cray CSU/DSU and Satellite DSU (Figure 4)
Replace one of the Satellite 651 T1 DSUs with a Cray Communications CSU/DSUs and reestablish communications. Have your lab instructor verify connectivity. This is to demonstrate
that devices manufactured by different companies will work as long as they adhere to the same
standards and are configured properly.
Discussion Questions
Please type all questions and answers.
[Q1, 5 points] What are the primary functions of a CSU?
[Q2, 5 points] What are the primary functions of a DSU?
[Q3, 3 points] Describe the difference(s) between a CSU and a DSU?
[Q4, 3 points] – There are two choices for timing when configuring the CSU/DSU. What are they?
Explain the differences between the two. In your answer make sure you address where timing is
drawn from.
[Q5, 5 points] – The synchronization settings of the CSU/DSUs used in this lab were “Internal” and
“loop” respectively. Explain why this worked. In theory, should the network work if both
CSU/DSUs are set to the same timing source? Will they work if both are set to Loop? Will they
work if both are set to Internal?
[Q6, 2 points] The device that normally provides clocking in the network is considered to be the
DTE or DCE? Which device provided timing in our lab network?
[Q7, 2 points] If you wanted to connect the two routers in our lab in a point-to-point configuration,
without the CSU/DSUs, how would you do it? What cables would you require?
[Q8, 5 points] – Name the 3 types of timing used in telecommunication networking. Which is used
in the U.S. telephone network? Explain.
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CSU/DSU Configuration Lab
5
[Q9, 5 points] - What LINE CODING can be implemented between the two CSU/DSUs for you to
communicate across the network? What are the differences between the two? What FRAMING
can be implemented between the two CSU/DSUs?
[Q10, 5 points] – What framing can be implemented between the two CSU/DSUs in the lab?
What causes a frame slip? Define the two types of frame slips.
REFERENCES
Books/Manuals/Websites
 Cisco Systems, Inc. - http://www.cisco.com
 T1-ESF Channel Service Unit Installation and Operations Manual
 Satellite 651 T1 DSU Installation Guide
 Cisco Certified Network Associate Study Guide
 Comer, Douglas E. Internetworking With TCP/IP Volume One
 Huitema, Christian, Routing in the Internet
 Kessler, Andrew. Integrated Systems Testing for Network, Student Seminar Presentation,
Spring 1996
 Newton, Harry. Newton’ s Telecom Dictionary
 Steinke, Steve. “Getting Data Over the Telephone Line, Lesson 92: CSUs and DSUs.” LAN,
Apr 96.
APPARATUS
REQUIRED EQUIPMENT
QTY
COMMENTS
Cray Communications DCP3552
CSU/DSU and Installation and Operation
Manual
2
Laptop / PC with Hyper-terminal
application
Network Interface Cable: RJ48S 
RJ48S TELCO Cross cable
Network cables: Cisco 72-07950-01
RS449 DTE Cable  RS422 DTE
Interface cable (serial port).
Network cables: Ethernet strait
4
Cisco 2500 or 2600 Series Router
4
Netgear 4 port hub
Satellite 651 T1 DSU and lab manual
Network cables: Cisco 72-07901-01 V.35
Cable  422 DTE Interface cable (serial
port).
CISCO High Speed Serial to V.35 (CABSS-V35MT) cables
4
2
2
Provide the network / power cables along
with the Cray Communication CSU/DSU
and Installation and Operation Manual for
the lab session.
For configuring the Cisco Routers and to
serve as the network clients.
This will facilitate the T1 Network Interface
between the two CSU/DSU units.
Two sets of each may be required to
facilitate the CSU/DSU  Router
connection / interface.
Two sets of each will be required for to
support the Ethernet host and network
connections.
With the required Cisco 72-07950-01
RS449 DTE HSSI cable (listed above)
To simulate client network
Power Cables and
Two may be required to facilitate the
CSU/DSU  Router connection / interface
FA24 TSEC 01-08
2
2
6
2
Two may be required to facilitate the
CSU/DSU  Router connection / interface
CSU/DSU Configuration Lab
6
Addendum: Router Notes
NotesNotes
The Cisco Router Interface
All Cisco routers have at least a console port, a 25-pin female serial port or an 8 pin RJ45 female
port. To access the router, you need to connect a serial cable between the console port of a router
and a PC’s serial port. Then you can access the router through a terminal emulation program that
emulates VT-100. When you first get a new router, none of the other ports are configured. The only
way to access and configure a new router is through the console port. Once the router is
configured, access is available over other interfaces with the standard Telnet program.
Attach one end of the console cable to the serial port on the PC and the other end to the
console port on the selected router. To talk to the router, use a terminal emulation program such
as Microsoft’s Hyperterminal. It can usually be found Start > Programs > Accessories >
Hyperterminal. Use the following communication settings for the COM port connected to the
router:
9600bps
8 bit
1 stop
No Parity.
No flow control
INTERNETWORK OPERATING SYSTEM (IOS)
IOS Levels
As mentioned before, a router is just a specialized computer. Like any computer, the router needs
an operating system. Cisco calls their operating system IOS – Internetwork operating system.
Cisco IOS provides two levels of access security to a router, referred to as user and enable level.
User level and enable level have different prompts:
User level prompt >
Enable level prompt #
Only user level commands can be executed at the > prompt. User level commands are mainly the
show commands. As you will see later, these are very useful in troubleshooting a routing problem.
Configuration changes must be made at enable level; they will not work at user level. The enable
level allows you to actually change the configuration settings on the router, including set-up of
interfaces and configuring IP addresses. To enter enable level, you must type enable at the user
level prompt >.
Help
To access help for commands that can be entered, type a ? at the prompt and hit enter. Not all of
the available commands will show up in user level help.
Configuration Mode
Configuration mode offers interface-specific as well as global commands. To enter configuration
mode, you must first go to the enable level. The command config terminal enters configuration
mode.
Global commands consist of router name, security commands, routing protocols, and
network management commands. Global commands need to be entered at the prompt config>.
FA24 TSEC 01-08
CSU/DSU Configuration Lab
7
Interface commands are commands specific to an interface. Some examples of interface
commands are ip address, novell network, access lists, dialer commands, etc. To enter interface
commands, the interface must first be specified. Entering a command in the form
interface <name of interface> <interface number>
allows commands to be entered for the specified interface. For example, the command interface
ethernet 0 will allow commands to be entered to configure the interface ethernet 0. The prompt
becomes config-if>. To get back to the global prompt, type exit. Configuration commands can now
be entered.
Interface names
Interfaces have to be specified for configuration and show commands. The names are listed below.
Interface
Token Ring
Ethernet
FDDI
Serial
BRI
Name
token[interface
number]
e[interface #]
FDDI[interface #]
Serial[interface #]
BRI[interface #]
Saving and Displaying Configuration
The write command will save the current configuration to memory; the router will maintain the
configuration settings even if the power is shut off. The enable level command, write terminal,
allows one to view the configuration. Write terminal will not save your configuration; it only displays
the current configuration.
FA24 TSEC 01-08
CSU/DSU Configuration Lab
8
FA24 TELECOM SYSTEMS ENGINEERING COURSE
LAB #1 – CSU/DSU Network Diagram
Simulated T1
Telco Network
200.65.35.8/30
FA24_R1
CISCO
2514
E0/.73
(SLAVE)
S0/.10 DTE-1 DSU / CSU
199.57.7.72/29
B8ZS
TELCO
CROSS
CABLE
(MASTER)
DTE-1
CSU / DSU
E-Hub
PC1
BVTC
.76
FA24_R2
S1/.9
CISCO
2514
192.46.57.8/29
E1/.12
E-Hub
Cray DCP3552
T1 ESF Channel Service Unit
PC2
BVTC
.9
Figure 2
FA24 TSEC 01-08
CSU/DSU Configuration Lab
9
FA24 TELECOM SYSTEMS ENGINEERING COURSE
LAB #1 – CSU/DSU Network Diagram
Simulated T1
Telco Network
200.65.35.8/30
FA24_R1
CISCO
2514
E0/.73
(SLAVE)
S0/.10 DTE-1
DSU /CSU
199.57.7.72/29
B8ZS
TELCO
CROSS
CABLE
(MASTER)
DTE-1
CSU /DSU
E-Hub
PC1
BVTC
.76
FA24_R2
S1/.9
CISCO
2514
192.46.57.8/29
E1/.12
E-Hub
Satellite 651 T1 DSU
PC2
BVTC
.9
Figure 3
FA24 TSEC 01-08
CSU/DSU Configuration Lab
10
FA24 TELECOM SYSTEMS ENGINEERING COURSE
LAB #1 – CSU/DSU Network Diagram
Simulated T1
Telco Network
200.65.35.8/30
FA24_R1
CISCO
2514
E0/.73
(SLAVE)
S0/.10 DTE-1 DSU /CSU
199.57.7.72/29
B8ZS
TELCO
CROSS
CABLE
(MASTER)
DTE-1
CSU /DSU
E-Hub
PC1
BVTC
.76
FA24_R2
S1/.9
CISCO
2514
192.46.57.8/29
E1/.12
E-Hub
Satellite 651 T1 DSU
Cray DCP3552
T1 ESF Channel Service
Unit
PC2
BVTC
.9
Figure 4
FA24 TSEC 01-08
CSU/DSU Configuration Lab
11