CSU / DSU CONFIGURATION

bugqueenNetworking and Communications

Oct 26, 2013 (3 years and 9 months ago)

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CSU/DSU Configuration Lab

1




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 (
Student
s read prior to attending lab session)

The CSU is a device that performs protective and diagnostic functions for a telecommunications
line while t
he DSU is
used to
connect a terminal to a digital line. Typically, the two devices are
packaged as a single u
nit

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 th
e 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
pre
mise 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.








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
appropr
iate

line code and framing format. The DSU
interconnect
s

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 use
r'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
track
s

statistics
,
provide
s

loop
-
back testing for the local carrier
, pro
vides signal conversion
and maintains the local loop's electrical characteristics. It is a line
-
bridging device that is the last
signal reg
eneration point before a multiplexer or the DTE.

T
he 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





Qty

Cray DCP 3552 CSU/
DSU




1 ea.

Satellite 651 T1 DSU




1 ea.

2600 Series Router




1 ea.


1

Lab

Exercise

CSU / DSU CONFIGURATION

F A 2 4 T S E C 0
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DSU





CSU

User
Interface

V.35

or RS
-
449

Receive Pair

Telco

Transmit Pair

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CSU/DSU Configuration Lab

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RJ48S T1 Cross Cable




1 ea.

Console Cable




1 ea.

HS Serial to V.35




1 ea.

V.35 to RS422 DTE




1 ea.

HS Serial to RS449 DTE



1 ea.

Four
-
port Hub





1 ea.

Cat
-
5 Patch Cabl
e




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 repl
icate 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
l
ab assignment will require you to work in two teams
.

You will need to ident
ify, 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 compo
nents/devices up correctly IAW the CSU/DSU network
diagram
s

(Figure
s

2
, 3 and 4
, in that order
).

(
1
5 points)

2.

Configure
the Cray DCP3552 CSU/DSU
s
ystem
s
.

(5 points)

3.

Configure the
S
atellite 651 T1 DSU

systems
.

(5 points)

4.

Configure the Cisco 2
6
00 series route
rs 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)





I
nstall the CSU/DSU Lab netwo
rk 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
tw
o 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



I
nstall 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
Cross
over

cable
to faci
litate this
connection.
[The cable will be connected to the
NI LINE port
s

on the back of the Cray
Comm
unications

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 conf
iguration options. Use the
up
or
down arrow
to
Install the
Cray DCP3552 CSU/DSU
/Router

Network (Figure 2)

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CSU/DSU Configuration Lab

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get to
System Configuration
and press
ENTER
to select and view the options.
The selected
configuration option(s) will be displayed on the 3
2
-
digit Alphanumeric Display.
Use the following
settings:


DTE Rate


1536

Format


306 to ESF (sync unframed)

Mode



Bipolar w/ 8 Zero Substitution

(B8ZS)

Interface


RS422 (or V.35)


based on connection

Audible Alarm

Disabled

Front Panel


Enable

Density Mode


FCC Part 68

Unit Address


000

Timing


Internal

Keep Alive Type

Ty
pe 1


All Ones

Remote Unit


Compatible

Line Build Out

0

Remote Loop Out

Enable

Sync Date Mode

Normal

Sync Clocking

Give Both

Sync DSR


On

Sync CTS


On

Sync LSD


On

Sync Diagnostic

Off


C.
The
“TIMING”
configuration option will be determined by the networ
k 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



Ins
tall 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
72
-
07901
-
01

V.35


RS㐲㈠䑔E

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 dista
nt 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

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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
D
SUs together via the
NI LINE

interface (RJ48S 8
-
Pin
modular connection). You will use t
he
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.

Us
e
the following to
configure the
Satellite
651 T1
DSU.


Note

1
:

The

configurat
ions
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 fo
rmat
.


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 Esca
pe 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 un
til 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
, DSU
s

a
nd 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
D
SU.


Once
you have
complete
d your configurations
,

ve
rify connectivity by
executing a ping to the distant end router

and PCs
.


Note: Make sure you t
urn in the router configurations with your lab

discussion questions
.






Replace one of the Satellite 651
T1 DSUs with a
Cray Communications CSU/DSU
s

and re
-
establish 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.





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 th
e 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 poi
nt
-
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.


Discussion Questions

Install the Network that
uses the Cray CSU/DSU and Satellite DSU (Figure 4)

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CSU/DSU Configuration Lab

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[Q9, 5 poin
ts]

-

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 imp
lemented 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 I
nstallation 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.”
LA
N,
Apr 96.


APPARATUS

REQUIRED EQUIPMENT

QTY

COMMENTS

Cray Comm
unications DCP3552
CSU/DSU and Installation and Operation
Manual

2

Provide the network / power cables along
with the Cray Communication CSU/DSU
and Installation and Operation Manual for
the lab session.

Laptop / PC with Hyper
-
terminal
application

4

For co
nfiguring the Cisco Routers and to
serve as the network clients.

Network Interface Cable: RJ48S


RJ48S TELCO Cross cable

2

This will facilitate the T1 Network Interface
between the two CSU/DSU units.

Network cables: Cisco 72
-
07950
-
01
RS449 DTE Cable


RS422 DTE
Interface cable

(serial port)
.

2

Two sets of each
may

be required to
facilitate the CSU/DSU


R潵ter
捯c湥捴i潮 / i湴nrfa捥c

Network cables: Ethernet strait

6

Two sets of each will be required for to
support the Ethernet host and network
conne
ctions.

Cisco 2500
or 2600
Series Router

4

With the required
Cisco 72
-
07950
-
01
RS449 DTE HSSI

cable (listed above)

Netgear 4 port hub

4

To simulate client network

Satellite 651 T1 DSU and lab manual

2

Power Cables and

Network cables: Cisco 72
-
079
01
-
0
1
V.35
Cable


422 DTE Interface cable

(serial
port)
.

2

Two
may

be required to facilitate the
CSU/DSU


R潵ter 捯c湥捴i潮 / i湴nrf慣a

CISCO High Speed Serial to V.35 (CAB
-
SS
-
V35MT)
cables

2

Two
may

be required to facilitate the
CSU/DSU


R潵ter 捯c湥捴i潮

/ i湴nrf慣a

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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 route
r, 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 Parit
y.

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 syste
m.
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 actua
lly 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 c
ommand 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>.

Addendum: Router Notes
NotesNotes

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Interface commands are commands spec
ific 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 p
rompt, 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

Name

Token Ring

token[interface
number]

Ethernet

e[interface #]

FD
DI

FDDI[interface #]

Serial

Serial[interface #]

BRI

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.
























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