26 \20

US005966427A
Ulllted States Patent [19]
[11] Patent Number:
Shaffer et al.
[45]
[54]
[75]
Date of Patent:
Oct. 12, 1999
APPARATUS AND METHOD FOR
5,659,684
8/1997 Giovannoni et al. .............. .. 395/2008
TROUBLESHOOTING INTERNET
PROTOCOL TELEPHONY NETWORKS
5,774,524
5,774,640
5,784,558
6/1998 Yang ............................. .. 379/1
6/1998 Kurio ........ ..
395/ 182.02
7/1998 Emerson et al.
.. 395/200.6
Inventors: Joseph
Shmuel Beyda>
Sha?'er,cupemno’
Palo A110;both
William
of Cahf'
5,898,674 lg;
4/1999 Mahwhinney
2353;; ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
et al. ............... .. 370/247
~~
[73] Assignees: Siemens Information;
Primary Examiner—Curtis A. Kuntz
Communications Networks, Inc., both
of Boca Raton, Fla.
Assistant Examiner—ReXford N. Barnie
[57]
ABSTRACT
[21] Appl, No.1 08/941,144
A device and method for IP telephony troubleshooting
_
include multiple alternative input/output members for con
[22]
Flled:
[51]
Int. Cl? .................................................... .. H04M 1/24
[52]
U S C]
Sep‘ 30’ 1997
' l
[58]
5,966,427
necting the troubleshooting device to an IP telephony net
Work at one of multiple Sites Within the IP telephony
379/1_ 379/5_ 379/6_ 379/29_
network. Asystem control connected to one of the connector
3%9/27 579/21,’ 379/906
members transmits and receives digital control messages to
l """"""""""" "
Field of Search
’
379/1 900 5
establish a bidirectional audio communications link over the
18 22’ 23 ’28’
IP telephony network. A system control user interface con
26 29_ 370/249 ’241’ 24’2 2’47 ’250’_ 365/1525 1’
nected to the system control enables a user to direct a call to
379
’
’
’
560 328/181) 19’3 185
’
[56]
’
’
a remote telephonic device. Aconverter, connected to one of
’
the connector members, converts digital audio signals
References Cited
received from the remote telephonic device to analog audio
U8. PATENT DOCUMENTS
microphone to digital audio signals for transmission to the
signals and converts analog audio signals generated by a
5’446’781
5:495:516
5,502,756
_
3223:1600
"""""""""""" "
8/1995 Lindstrom et
379/5
2/1996 Lee et a1_ ___________ __
379/1
3/1996 Cmcker et a1, __
379/29
remote telephonic device. An interface obtains synchroni
Zation With the remote telephonic device to facilitate syn
chronous data communication. In an alternative
embodiment, the IP telephony troubleshooting device is an
IP telephony adaptor for an analog telephony troubleshoot
ing dCViCC.
5,530,367
6/1996 Bottman ......... ..
5,629,931
5/1997
5,636,260
6/1997 Chopping ................................ .. 379/29
I-
_
_
_
_
_
_
_
Kausel
_
_
324/616
.. ... ... .
_
_
-
. . . . . . ..
_
_
_
_
_
_
379/1
_
_
_
20 Claims, 7 Drawing Sheets
_
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ETHERNET
INTERFACE
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SYSTEM CONTROL
USER INTERFACE
_
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U.S. Patent
Oct.12,1999
Sheet 2 of7
mm
\82>
85s8
a/
mm
00
5,966,427
U.S. Patent
Oct.12,1999
Sheet 4 0f 7
CONNECT TO IP
TELEPHONY NETWORK
5,966,427
_I_ 50
I
ATTEMPT TO
OBTAIN SYNCHRONIZATION
f
52
DOES
GATEWAY
SYNCHIRONIZE
TRANSMIT ARQ MESSAGE
FOR LOOPBACK CALL
_/- 58
DETERMINE
BANDWIDTH I62
AVAILABILITY
66 x
TRANSMITAUDIO
TESTSIGNAL
DETERMINE I64
PROTOCOL
COMPATIBILITY
DETERMINE
72-‘- BANDWIDTH
AVAILABILITY
DETERMINE PERFORMANCE
__/— 70
CHARACTERISTICS
FIG. 4
U.S. Patent
Oct. 12,1999
Sheet 5 0f 7
TRANSMIT ARQ MESSAGE
FOR LOOPBACK CALL
DETERMINE
BANDWIDTH
AVAILABILITY
TRANSMIT
VIDEO SEQUENCE
DETERMINE
PROTOCOL
COMPATIBILITY
DETERMINE
BANDWIDTH
AVAILABILITY
DETERMINE PERFORMANCE
CHARACTERISTICS
FIG.
5,966,427
U.S. Patent
Oct.12,1999
ATTEMPT TO
OBTAIN SYNCHRONIZATION
Sheet 6 of7
5,966,427
__/— 9O
DOES
TERMINAL
RESIZOND
TRANsNIIT
_/— 94
SETUP MESSAGE
9s
96
)
DOES
DETERMINE
IRIAIIII
?
INCOMPATIBILITY
EXISTS
Y
TRANSMIT AUDIO
TEST SIGNAL
l
ANALYZE PERFORMANCE
CHARACTERISTICS
FIG. 6
5,966,427
1
2
APPARATUS AND METHOD FOR
TROUBLESHOOTING INTERNET
PROTOCOL TELEPHONY NETWORKS
nication capability of a LAN, it does not test the audio
communication capability of a netWork.
What is needed is a device and method for performing
troubleshooting on an IP telephony netWork at multiple sites
Within the netWork to determine Whether at least a portion of
BACKGROUND OF THE INVENTION
the netWork is capable of supporting bidirectional audio
The invention generally relates to troubleshooting tele
communication.
communications networks and more speci?cally to trouble
shooting Internet protocol (IP) telephony netWorks.
SUMMARY OF THE INVENTION
DESCRIPTION OF THE RELATED ART
A telephony troubleshooting device includes multiple
IP telephony has opened up netWorks such as local area
alternative input/output members for connecting the tele
netWorks (LAN), intranets, internets, and the Internet, Which
Were originally designed for data communication, to be
utiliZed for audio communication as Well. Furthermore, the
promulgation of the H.323 standard for line transmission of
15
non-telephone signals by the International Telecommunica
tions Union (ITU) provides a standard for IP telephony
Which obviates many of the incompatibility problems
betWeen different IP telephonic devices Which previously
hindered utiliZation of IP telephony.
netWork. A system control user interface connected to the
system control enables a user of the telephony troubleshoot
ing device to direct a call to a remote telephonic device. A
IP telephony provides numerous bene?ts to netWork
converter connected to one of the connector members con
users. The high bandWidth available on netWorks such as
LANs and intranets can support such call features as call
forWarding, call Waiting, and caller ID in addition to numer
ous other features. The higher bandWidth also supports
25
parallel transmission of interactive video and images,
enabling video teleconferencing along With telephony capa
bilities. Furthermore, IP telephony provides signi?cant ?eX
verts a ?rst digital audio signal received from the remote
telephonic device to a ?rst analog audio signal and converts
a second analog audio signal to a second digital audio signal
transmitted to the remote telephonic device. A speaker
connected to the converter is responsive to the ?rst analog
audio signal, and a microphone connected to the converter
converts speech into the second analog audio signal.
In another embodiment, the telephony troubleshooting
ibility to accommodate the needs of a user, even as these
needs change over time. For instance, a business might
install a self-contained LAN in its of?ce building. Initially,
the IP telephony connecting the various terminals in the
of?ce building operates essentially as an intercom system. If
the business subsequently desires to connect its IP telephony
phony troubleshooting device to an IP telephony netWork at
one of multiple sites Within the IP telephony netWork. A
system control is con?gured for an electrical association
With any one of the connector members and for transmitting
and receiving digital control messages to establish a bidi
rectional audio communication link over the IP telephony
device is an adaptor connected to an analog telephony
troubleshooting device Which includes, in addition to a
system control and multiple connectors, an electrical circuit
35
for converting an analog DTMF signal generated by the
analog telephony troubleshooting device to a ?rst digital
to a larger netWork, it can connect an ISDN line to a gateWay
associated With its LAN and in this manner gain access to
control message. A converter is connected to a microphone
any other IP telephony netWorks connected to the ISDN.
Alternatively the gateWay of the LAN could be utiliZed to
connect directly to the gateWays of several other LANs,
thereby forming an internet, or the gateWay could be used to
from a remote telephonic device to a ?rst analog audio signal
transmitted to the speaker and for converting a second
and a speaker of the analog telephony troubleshooting
device for converting a ?rst digital audio signal received
analog audio signal generated by the microphone of the
connect the LAN to a T1 carrier or to a private branch
analog telephony troubleshooting device to a second digital
audio signal transmitted to the remote telephonic device.
exchange.
Although the bene?ts and advantages of IP telephony
described above are readily apparent, there eXists no prac
A method for troubleshooting an IP telephony netWork
45
includes connecting a hand-held telephony troubleshooting
tical and effective means for troubleshooting IP telephony
netWorks. For analog telephony netWorks as Well as ISDN,
device to an IP telephony netWork. A ?rst digital telephony
there eXist telephony troubleshooting devices Which enable
device via the IP telephony netWork to a remotely located
a technician to connect to a line on the netWork and, in the
device, the ?rst signal containing information requesting a
return digital telephony signal from the remotely located
device. The signal exchange betWeen the telephony trouble
signal is transmitted from the telephony troubleshooting
case of the analog networks, establish Whether the line has
a dial tone. If a dial tone is obtained, the analog trouble
shooting device can then place and receive calls to verify
shooting device and the remotely located device is necessary
that a line on the netWork can support bidirectional audio
communications. ISDN lines do not have dial tones, so When
to establish a bidirectional audio communication capability
over the IP telephony netWork. The connection betWeen the
the ISDN telephony troubleshooting device is connected to
an ISDN line and turned on, a liquid crystal display (LCD)
55
device is monitored to determine Whether the return tele
shoWs the status of the troubleshooting device as it goes
phony signal is received. If it is determined from the
monitoring step that the return signal is received, a loopback
through a series of line diagnostics. Upon synchroniZing
With the phone company sWitch, the ISDN telephony
call is eXecuted Wherein an audio test signal is transmitted
troubleshooting device can place and take calls over the
ISDN line. At this time there is no telephony troubleshooting
over the IP telephony netWork, the loopback call being
directed to an address assigned to the telephony trouble
shooting device. Adetermination is made Whether the audio
device for IP telephony netWorks equivalent to those pro
vided for analog and ISDN telephony netWorks.
Adevice commonly knoWn as a LAN sniffer is capable of
troubleshooting a LAN to determine data communication
capability of the different connections Within a LAN.
HoWever, although the LAN sniffer tests the data commu
telephony troubleshooting device and the remotely located
test signal is received by the telephony troubleshooting
device. If the audio test signal is received, the received
65
signal is analyZed to determine the performance character
istics of the transmission of the audio test signal over the IP
telephony netWork.
5,966,427
3
4
BRIEF DESCRIPTION OF THE DRAWINGS
verter 22 is connected to both the speaker 24 and the
microphone 26 to convert analog audio signals generated by
FIG. 1 is a block diagram of an IP telephony trouble
the microphone 26 to digital audio signals and to convert
digital audio signals received from a remote IP telephony
device to analog audio signals transmitted to the speaker 24.
shooting device according to the present invention.
FIG. 2 is a block diagram of a video-enabled embodiment
of the IP telephony troubleshooting device illustrated in FIG.
The set of connectors used to connect the IP telephony
troubleshooting device 10 to the LAN enable troubleshoot
ing at multiple sites Within the LAN. The ability to connect
to the LAN at multiple sites is critical to pinpointing the
1.
FIG. 3 is an alternative embodiment of the IP telephony
troubleshooting device of FIG. 1 Wherein the IP telephony
troubleshooting device is an adaptor associated With an
10
analog telephony troubleshooting device.
reference to FIG. 7, if IP telephony terminal 106 is not
functioning properly, any number of causes outside of a
malfunction in the terminal itself could be responsible. The
connection betWeen the terminal 106 and the bus 108 might
FIG. 4 is a flow diagram illustrating the steps of a method
for operating the IP telephony troubleshooting device of
FIG. 1.
FIG. 5 is a flow diagram illustrating a method of using the
15
video-enabled IP telephony troubleshooting device illus
trated in FIG. 2.
FIG. 6 is a flow diagram of a method for utiliZing the IP
a LAN unattached to a gateWay.
FIG. 7 is a diagram of various sites on an IP telephony
netWork in Which the IP telephony troubleshooting devices
114 Within LAN #2 112 is not functioning properly, the IP
of FIG. 1 or 2 operate.
25
FIG. 1 illustrates an IP telephony troubleshooting device
10 according to the claimed invention. The IP telephony
troubleshooting device Will be described by Way of an
telephony troubleshooting device 10 is plugged into the Wall
jack 116. If it is possible to place and receive calls With the
IP telephony troubleshooting device from the Wall jack 116,
then it is clear that a malfunction in terminal 114 is respon
sible for the inability of the terminal to make and receive
calls. If no telephony is accessible from the user Wall jack
116, an alligator clip can be used to connect the trouble
shooting device 10 to the netWork at a site 118 Within the
cable connecting the terminal 114 to the hub 120 of LAN #2
eXample Wherein the IP telephony troubleshooting device
performs troubleshooting operations on an internetWorked
LAN and the speci?cations of the IP telephony troubleshoot
ing device 10 conform to the standards articulated in the
International Telecommunications Union H.323 standards
for Visual Telephone Systems and Equipment for Local Area
be inoperative, the bus 108 itself might be inoperative, or
router #1 110 might be malfunctioning. Connecting the IP
troubleshooting device 10 at various sites betWeen the IP
telephony terminal 106 and the router 110 utiliZing the
different adaptors can isolate the source of the malfunction.
One of the connectors is an RJ45 connector Which is used
to connect the IP troubleshooting device 10 to a Wall jack of
a terminal on the LAN. With reference to FIG. 7, if terminal
telephony troubleshooting device of FIG. 1 to troubleshoot
DETAILED DESCRIPTION
cause of a malfunction Within the LAN. For instance, With
112. If telephony is accessible at site 118, then the Wall jack
35
NetWorks Which Provide a Non-Guaranteed Quality of
Service. The claimed IP telephony troubleshooting device
and methods can be practiced on many different types of
connection is most likely faulty. The RJ45 connector can
also be used to connect the IP telephony troubleshooting
device 10 at the hub 120 to test the connection betWeen the
hub and router #2 122.
Adaptors are provided Which enable the IP telephony
netWorks including the Internet, intranetWorks, and
troubleshooting device 10 to connect to various ports of a
router associated With a LAN. For instance, an RS-449
internetWorks, as Well as a variety of LANs including
Ethernet and Token Ring.
The IP telephony troubleshooting device 10 is preferably
adaptor and an ethernet adaptor enable the IP telephony
troubleshooting device to connect to an RS-449 port of the
router
and an ethernet port of the router, respectively. With
necting the IP telephony troubleshooting device to a LAN.
The connector is one of a set of connectors for connecting 45 reference to FIG. 7, an RS-449 adaptor is used to connect the
IP telephony troubleshooting device to an RS-449 port of
the IP telephony troubleshooting device at a number of
router #2 122 to perform remote troubleshooting of LAN #1
different sites Within the LAN. The set of connectors
a hand-held device that includes a connector 12 for con
104. A call is placed to terminal 106 through router #1.
Assuming router #2 is functioning properly, if router #1 122
includes an R] 45 connection for connecting the IP telephony
troubleshooting device 10 at either a Wall jack of a LAN
does not respond, then either the connection betWeen router
#2 122 and router #1 is faulty, or router #1 110 is malfunc
tioning. If router #1 responds, but is unable to facilitate a
terminal or an ethernet hub. The set of connectors further
includes alligator clips Which can be utiliZed to connect the
IP telephony troubleshooting device to the LAN at any
accessible portion of the LAN cable connecting the various
LAN terminals. An ethernet LAN interface 14, or an equiva
lent such as an RS-232, provides a point of connection for
connection betWeen the IP telephony troubleshooting device
55
one of the set of connectors. A system control 16 is con
nected to the ethernet interface 14 to provide control mes
sages necessary to establish a bidirectional audio commu
nication link over the LAN and to perform various
troubleshooting functions. A system control user interface
18 includes a set of keypads to enable a user of the IP
troubleshooting device to enter an address of a called
endpoint and regulators to control the levels of a speaker 24
and a microphone 26. An audio codec 20 connected via the
ethernet interface to a connector compresses, decompresses, 65
and packetiZes audio signals transmitted and received by the
IP telephony troubleshooting device. An analog/digital con
10 and IP terminal 106, then either the connection betWeen
router #1 110 is faulty, or IP terminal 106 is malfunctioning.
Returning to FIG. 1, the ethernet interface 14 provides a
physical interface betWeen the LAN and the IP telephony
troubleshooting device 10 to conform the signals generated
by the IP telephony troubleshooting device to a standard
common to the various terminals connected to the IP tele
phony netWork. The ethernet interface also causes a remote
IP telephony device, for eXample, a server, to synchroniZe
With the IP telephony troubleshooting device to facilitate
synchronous transmission of signals betWeen the IP tele
phony troubleshooting device 10 and the server.
The system control 16 generates control messages trans
mitted to remotely located IP telephony devices and receives
5,966,427
5
6
control messages from the remotely located devices. For
example, in FIG. 7, to call terminal 106 of LAN #1 104
remote IP telephony terminal. It also packetiZes the signals
using the IP telephony troubleshooting device 10 from the
Wall jack 128 Where terminal 126 is located, the system
nal. Compression of the audio signals is important to mini
miZe the bandWidth occupied by an audio communications
link since, as previously noted, bandWidth scarcity on the
control Will ?rst transmit an Admission Request (ARQ)
message to gateWay #3 130 of LAN #3 124. If gateWay #3
is functioning properly, it Will transmit a responsive control
message of either Admission Con?rmed (ACF) or Admis
sion Rejected
This eXchange of control messages
betWeen the IP telephony troubleshooting device 10 and
for ef?cient transmission to the remote IP telephony termi
LAN can account for failure to establish a link.
The converter 22, positioned betWeen the speaker 24 and
microphone 26 on one side and the audio codec 20 on the
10
other, converts the analog audio signals generated by the
speaker 24 to digital audio signals. This conversion to digital
gateWay #3 130 is necessary to establish a bidirectional
signals is necessary for transmission of the audio signals
communication link betWeen the IP telephony troubleshoot
ing device 10 and terminal 106. If the troubleshooting device
over the IP telephony netWork. The converter 11 also con
10 is utiliZed to call a terminal (not shoWn) on a LAN Which
is not registered to a server, then the system control gener
ates a Setup message for transmission to the terminal. If the
verts incoming digital signals from a remote telephonic
device to analog signals to Which the speaker 26 is respon
15
terminal receives the Setup message and the terminal is
sive.
FIG. 2 illustrates an alternative embodiment of the IP
telephony troubleshooting device Wherein video trouble
shooting capabilities are integrated into the IP telephony
troubleshooting device. The video-enabled IP telephony
functioning properly, the terminal responds by transmitting
a Connect message, Which, if received by the system control
16, establishes a bidirectional audio communications link
betWeen the terminal and the troubleshooting device 10.
The system control 16, in addition to performing call
signaling operations described above, also performs speci?c
troubleshooting device 34 is con?gured in the same manner
as the non-video-enabled embodiment described in FIG. 1
With the exception that a video codec 28 is connected to the
ethernet interface 14 and the A/D-D/A converter 22. The
analysis operations. For instance, When the ethernet inter
video codec compresses and decompresses video signals and
face 14 causes a server to synchroniZe With the IP telephony 25 packetiZes the signals for transmission over the LAN in the
troubleshooting device as described above, the system con
trol determines Whether the troubleshooting device 10 and
the server Were successfully synchroniZed. If the trouble
same manner as the audio codec performs these functions on
audio signals. The video codec is also connected to a
non-volatile random access memory (NVRAM) Which
shooting device 10 and the server Were unable to
stores a video sequence for transmission over the LAN as a
synchroniZe, then an indicator on the troubleshooting device
communicates the failed synchroniZation attempt to a user of
the troubleshooting device 10 as a cause for IP telephony
failure on the LAN. The system control 16 is also able to
video test sequence. Storage of the video sequence in
NVRAM is more economical and ef?cient than attaching a
video camera to generate a video sequence. Avideo monitor
failure on the LAN. For instance, if the system control
30 is connected to the A/D-D/A converter 22 for displaying
the video sequence. The A/D-D/A converter converts digital
video signals received over the LAN to analog video signals
for use by the monitor. Alternatively, a converter may be
transmits an ARQ message to a server Which is equipped
integrally incorporated Within the monitor.
interpret responses to call signaling messages to identify
protocol incompatibility as the source for IP telephony
35
With an H.323 protocol Which is incompatible With the
H.323 protocol on the troubleshooting device 10, then the
system control is able to recogniZe the response from the
server re?ecting an incompatibility of H.323 protocols.
Furthermore, the system control 16 is able to ascertain the
bandWidth availability of a connection in communicating
FIG. 3 illustrates an alternative embodiment of the IP
telephony troubleshooting device Wherein the IP telephony
troubleshooting device is an IP telephony adaptor 36 asso
ciated With an analog troubleshooting device. The IP tele
phony adaptor enables analog telephony troubleshooting
devices to troubleshoot IP telephony netWorks. Similar to
With a server. The system control compares the available
the stand-alone IP telephony troubleshooting embodiment
bandWidth on a connection Within the LAN With the band 45 described above, the adaptor 36 employs multiple connec
Width necessary to support a bidirectional audio communi
tors to connect to a LAN at multiple sites. An ethernet
cations link, and thereby determines Whether suf?cient
interface 14 provides an input/output connection for a con
bandWidth is available to make a particular call. If insuf?
nector 12, and a system control (not shoWn) is connected to
cient bandWidth is available, then the system control causes
the ethernet interface. Also connected With the ethernet
an indicator on the troubleshooting device 10 to communi
interface are an audio codec 20 and a converter 31.
cate this information to the user.
Unlike the stand-alone IP telephony troubleshooting
device embodiment, the adaptor 36 interfaces With an analog
telephony troubleshooting device 40 by Way of the dual tone
Connected to the system control 16 is a system control
user interface 18. Included in the system control user inter
face is a keyboard or set of keypads Which enables the user
to enter the address of an IP telephony terminal to Which the
user Wishes to place a call. Volume adjustment devices for
55
multifrequency (DTMF) converter 31 and the analog-to
digital/digital-to-analog (A/D-D/A) converter 22. The
DTMF converter receives a DTMF signal from a DTMF
the speaker and microphone are also part of the system
generator 44. The DTMF signal is generated When a user
depresses one of the keypads on the keyboard 42 of the
control user interface 18. A display, such as an LCD,
provides a user With messages Which communicate results of
16 discussed above. For instance, if the system control
analog troubleshooting device 40. For instance, When the
key representing digit “9” is depressed, a corresponding
DTMF signal is generated by the DTMF generator. The
determines that the troubleshooting device and the server are
DTMF signal must then be converted to the same signal
unable to communicate because of incompatible versions of
H.323 protocol, then the LCD Would display a message
stand-alone embodiment When a user depresses key “9” on
troubleshooting operations performed by the system control
Which indicates H.323 protocol incompatibility.
The audio codec 20 codes audio signals generated by the
microphone 26 and decodes audio signals received from a
generated by the system control user interface 18 in the
65
the keypad of the system control user interface 18. Thus, the
DTMF generator 44 and keyboard 42 of the analog trouble
shooting device 40 in conjunction With the DTMF converter
5,966,427
8
7
31 of the IP telephony adaptor are the equivalent of the
keyboard of the system control user interface 18 in the
If the gateWay transmits an ACF signal, then the loopback
connection is established and an audio test signal is trans
stand-alone embodiment of FIG. 1. The A/D-D/A converter
22 is structurally and functionally equivalent to the A/D-D/A
converter in the stand-alone embodiment, except that it is
connected to a speaker 46 and microphone 48 of the analog
troubleshooting device.
FIG. 4 illustrates a method of troubleshooting a LAN
according to the claimed invention. Either the stand-alone IP
telephony troubleshooting device 10 of FIG. 1 or the IP
1O
telephony adaptor 36 of FIG. 3 may be utiliZed. HoWever,
for the sake of brevity, the stand-alone embodiment is
discussed beloW. In step 50, the IP telephony troubleshoot
ing device 10 is connected to a LAN utiliZing one of the set
of connectors. In step 52, the ethernet interface 14 is utiliZed
to obtain synchroniZation With a gateWay associated With the
LAN. Synchronization is necessary to facilitate synchronous
data communication. If the gateWay does not synchroniZe,
then either the connection betWeen the IP telephony trouble
shooting device 10 and the gateWay is faulty or the gateWay
15
mission.
FIG. 5 illustrates a method for troubleshooting a LAN
utiliZing the video-enabled IP telephony troubleshooting
is not functioning properly. Instep 56, the IP telephony
device 34. Though not shoWn in FIG. 5, steps 50 through 56
illustrated in FIG. 4 and discussed above are performed by
the video-enabled IP telephony troubleshooting device in the
troubleshooting device makes the determination Whether the
gateWay synchroniZes With the IP telephony troubleshooting
device. If the gateWay responds by signaling that it is unable
to synchroniZe, then it can be deduced that the line connect
mitted by the IP telephony troubleshooting device 10 over
the connection in step 66. In step 68, the IP telephony
troubleshooting device 10 determines Whether the audio test
signal has been received. Failure of the audio test signal to
be transmitted back to the IP telephony troubleshooting
device indicates that the loopback connection is unable to
support bidirectional audio communication. At this point,
the IP telephony troubleshooting device once again ascer
tains Whether insuf?cient bandWidth availability caused the
transmission failure of the audio test signal in step 72.
If the audio test signal transmission is successful, then in
step 70 the received audio test signal is analyZed to deter
mine the performance characteristics of the signal transmis
sion. The frequency and amplitude of the received audio test
signal are compared to the frequency and amplitude of the
transmitted test signal to determine the quality of the trans
same manner as the non-video-enabled embodiment. In step
25
74 the video-enabled IP telephony troubleshooting device
ing the IP telephony troubleshooting device is capable of
transmits an ARQ message to the gateWay to establish a
supporting at least data communication and that the gateWay
loopback call. In step 76, the video-enabled IP telephony
troubleshooting device 34 determines Whether the gateWay
is incapable of facilitating audio communication establish
ment on the LAN. If the gateWay synchronizes, then in step
58 the IP telephony troubleshooting device transmits an
admission request (ARQ) message to the gateWay to estab
lish a loopback call. The loopback call is a call Which the IP
telephony troubleshooting device directs to itself to deter
mine the performance characteristics of audio signal trans
missions over the LAN. The loopback call is particularly
has responded With an ACF message. If the gateWay does
not respond With an ACF message, then in step 78 the
video-enabled IP telephony troubleshooting device deter
35
troubleshooting device is responsible for the failed call
useful When installing a LAN and no terminals are yet
installed on the LAN to call to test the connections of the
LAN.
attempt.
If the gateWay transmits an ACF signal, then the loopback
connection is established and, in step 82, the video-enabled
IP troubleshooting device 34 transmits the video sequence
In step 60, the IP telephony troubleshooting device 10
determines Whether the gateWay has returned an admission
con?rmed (ACF) message or an admission rejected (ARJ)
message. If the gateWay does not transmit an ACF message,
then in steps 62 and 64 the IP telephony troubleshooting
device attempts to determine the cause for the failed attempt
to execute the loopback call. The determination of the cause
for the failed call attempt is important, because the cause of
the failure may lie in some incompatibility betWeen the IP
telephony troubleshooting device and the gateWay or some
transient condition in the LAN rather than some malfunc
45
used to vieW the video sequence to determine the perfor
mance characteristics of the transmission in step 88.
FIG. 6 illustrates a method for troubleshooting a LAN in
Which IP telephony terminals are not registered to a gateWay.
ascertained to determine if insuf?cient bandWidth eXists to
support the call. In step 64, the IP telephony troubleshooting
In step 90, the IP telephony troubleshooting device attempts
55
ing device employs might be incompatible With the version
Which the gateWay employs. If the loopback call fails
because of bandWidth unavailability, then the cause of the
failure is a temporary congestion on the LAN. If the LAN is
and this information greatly affects the interpretation of the
signi?cance of the failed call attempt.
to synchroniZe With an IP telephony terminal. In step 92, the
IP telephony troubleshooting device 10 determines Whether
the terminal has synchroniZed With the troubleshooting
device. If no response is forthcoming, then the connection
betWeen the IP telephony troubleshooting device and the IP
telephony terminal is faulty or the IP telephony terminal is
not functioning properly. If the IP telephony terminal
routinely overloaded, then a recon?guration of the LAN
might be in order. On the other hand, if the loopback call
failure is due to a protocol incompatibility betWeen the IP
telephony troubleshooting device and the gateWay, then the
failure has nothing to do With the LAN or its components
stored in NVRAM 32 over the loopback connection. In step
84, it is determined Whether the video sequence is received.
Failure of the video sequence to be transmitted back to the
video enabled troubleshooting device indicates that the
loopback connection is unable to support video transmis
sion. If the transmission has failed, then in step 86 the
video-enabled troubleshooting device determines Whether
insufficient bandWidth availability is responsible. If the
video sequence is received, then the video monitor 30 is
tioning component of the LAN Which requires repair. In step
62, the bandWidth availability of the loopback connection is
device determines Whether a protocol incompatibility is
responsible for the failed loopback call. For instance, the
H.323 protocol version Which the IP telephony troubleshoot
mines Whether insuf?cient bandWidth is responsible for the
failed attempt to set up the call. In step 80, the video-enabled
troubleshooting device 34 determines Whether a protocol
incompatibility betWeen the gateWay and the video-enabled
responds With a message that it is unable to synchroniZe,
then the connection can support at least data communication
65
and the IP telephony terminal is not functioning properly. A
functioning terminal might be placed at the same location to
determine Whether the connection is capable of supporting
bidirectional audio communication.
5,966,427
9
10
If the IP telephony terminal responds to the clocking
signals by signaling that the IP telephony terminal has
synchronized to the clocking signals, then in step 94 the IP
connected to said connector members, for processing digital
audio signals transmitted and received by said telephony
telephony troubleshooting device 10 transmits a Setup mes
sage to the IP telephony terminal. In step 96, the IP tele
codec for converting a ?rst digital audio signal received
from said remote telephonic device by Way of said at least
phony troubleshooting device determines Whether the IP
telephony terminal has responded to the Setup message. If
one selected connector member to a ?rst analog audio signal
and for converting a second analog audio signal to a second
no Connect response to the Setup message is forthcoming,
digital audio signal transmitted to said remote telephonic
device, said enabling means further including a speaker
troubleshooting device, a converter connected to said audio
then in step 98 the IP telephony troubleshooting device
determines Whether a protocol incompatibility betWeen the
IP telephony troubleshooting device and the IP telephony
terminal is responsible. A protocol incompatibility, as dis
connected to said converter and responsive to said ?rst
analog audio signal and a microphone connected to said
converter for converting speech into said second analog
audio signal.
cussed above, indicates that the failure to establish a bidi
rectional audio communications link is not attributable to
some malfunction in the LAN.
3. The telephony troubleshooting device of claim 1
15
Wherein said IP telephony netWork is one of a local area
If the IP telephony terminal returns a Connect message in
response to the Setup message, then a bidirectional audio
netWork (LAN) and an intranet.
communications link has been established. In step 100, the
IP telephony terminal transmits an audio test signal together
Wherein said connector members include at least one alli
4. The telephony troubleshooting device of claim 1
gator clip for connecting to a cable of said IP telephony
With signaling information directing the IP telephony termi
netWork, a ?rst adaptor for connecting at one of a user Wall
nal to return the audio test signals back to the IP telephony
jack and a HUB connection of said IP telephony netWork,
troubleshooting device. The IP telephony troubleshooting
and a second adaptor for connecting at a router port of said
device monitors the connection to determine Whether the
audio test signal is received. If the audio test signal is not
IP telephony netWork.
5. The telephony troubleshooting device of claim 3
received, then either the IP telephony terminal is unable to
25
return the audio test signal as instructed, or the connection
betWeen the IP telephony terminal and the IP telephony
troubleshooting device is unable to support bidirectional
audio communications. If the audio test signal is received,
then in step 102 the signal is analyZed to determine the
performance characteristics of the transmission. Such
parameters as amplitude and frequency of the received
signal can be measured and compared to the transmitted
6. The telephony troubleshooting device of claim 3
Wherein said digital control messages are transmitted to and
received from a gateWay connected to said LAN, said
transmitted digital control messages include an admission
signal.
The method and device for troubleshooting IP telephony
netWorks described herein enables IP telephony trouble
Wherein said remote telephonic device is a terminal unreg
istered to a gateWay and Within said LAN, said transmitted
digital control messages include a Setup message transmit
ted to said terminal, and said received digital control mes
sages include a Connect message received from said termi
nal.
35
request (ARQ) message, and said received control messages
include one of an admission con?rmation (ACF) message
and an admission reject (ARJ) message.
7. The telephony troubleshooting device of claim 2 further
shooting of a variety of netWorks for Which no effective and
ef?cient troubleshooting techniques have previously been
available. Furthermore, the IP telephony adaptor embodi
comprising:
ment of the invention alloWs technicians familiar With only
a video monitor for displaying a video sequence con
analog telephony technology to employ an analog telephony
nected to said converter;
a video codec connected to said converter for processing
troubleshooting device connected to the IP telephony adap
video signals for transmission by said telephony
tor to troubleshoot IP telephony netWorks.
What is claimed is:
1. A telephony troubleshooting device comprising:
troubleshooting device over said IP telephony netWork
45
and for processing video signals received by said
for connecting said telephony troubleshooting device to
establish connectivity With an Internet protocol (IP)
telephony troubleshooting device over said IF tele
phony netWork to be displayed on said video monitor;
and
telephony netWork at one of a plurality of different sites
non-volatile memory connected to said video codec for
a plurality of alternative input/output connector members
Within said IP telephony netWork;
storing a video sequence for transmission by said
telephony troubleshooting device over said IF tele
a system control, con?gured for an electrical association
phony netWork.
With said connector members, for transmitting and
8. A method for troubleshooting on an IP telephony
receiving digital control messages compatible With
establishing an audio communication link over said IP 55 netWork comprising the steps of:
telephony netWork via at least one selected connector
connecting a telephony troubleshooting device to said IP
member of said plurality of connector members;
telephony netWork;
a system control user interface connected to said system
control to enable a user of said telephony troubleshoot
ing device to direct a call to a remote telephonic device;
transmitting a ?rst digital telephony signal from said
telephony troubleshooting device via said IP telephony
and
means, operatively associated With said connector of said
erating said ?rst digital signal to contain information
requesting a return digital telephony signal from said
connector members, for enabling transmission and
receipt of audio signals over said IP telephony netWork
remotely located device, said digital telephony signal
exchange betWeen said telephony troubleshooting
via said at least one selected connector member.
2. The telephony troubleshooting device of claim 1
Wherein said enabling means includes an audio codec,
netWork to a remotely located device, including gen
65
device and said remotely located device being dedi
cated to establishing bidirectional audio communica
tion capability over said IP telephony netWork; and
5,966,427
11
12
monitoring said connection between said telephony
troubleshooting device and said remotely located
15. The method of claim 12 Wherein said transrnitting step
includes transmitting said ?rst digital telephony signal that
is a Setup message to said remotely located device that is a
terminal unregistered to a gateWay, and Wherein said return
device to determine Whether said return digital tele
phony signal is received.
digital telephony signal is a Connect message.
16. An IP telephony adaptor for an analog telephony
9. The method of claim 8 comprising the further steps of:
if it is determined from said rnonitoring step that said
troubleshooting device comprising:
return digital signal is received, executing a loopback
an electrical circuit connected to said analog telephony
call Wherein an audio test signal is transmitted over said
troubleshooting device for converting an analog DTMF
IP telephony netWork, said loopback call being directed
to an address assigned to said telephony troubleshoot
10
ing device;
determining whether said audio test signal is received by
trical circuit, for transmitting said ?rst digital control
said telephony troubleshooting device; and
if said audio test signal is received by said telephony
troubleshooting device, analyZing said received audio
signal generated by said analog telephony trouble
shooting device to a ?rst digital control message;
a system control, connected and responsive to said elec
message over an IP telephony netWork and for receiv
15
ing a second digital control rnessage, said transmission
and receipt of said ?rst and second digital control
rnessages being necessary to establish a bidirectional
test signal to determine performance characteristics of
said transmission of said audio test signal over said IP
audio communications link betWeen said IP telephony
telephony netWork.
adaptor and a remote telephonic device over said IP
telephony netWork;
10. The method of claim 8 Wherein said transrnitting step
includes attempting to synchroniZe said remotely located
device With said telephony troubleshooting device and said
rnonitoring step includes rnonitoring said connection to
establish Whether said remotely located device has synchro
niZed With said telephony troubleshooting device.
11. The method of claim 8 Wherein said transrnitting step
a converter connected to a microphone and a speaker of
25
includes transmitting said ?rst digital telephony signal to
said analog telephony troubleshooting device for con
verting a ?rst digital audio signal received from said
rernote telephonic device to a ?rst analog audio signal
transmitted to said speaker and for converting a second
analog audio signal generated by said microphone to a
second digital audio signal transmitted to said rernote
telephonic device;
said remotely located device that is a gateWay connected to
a plurality of connectors, each individual connector
said IP telephony netWork and comprising the further step
designed for connecting said IP telephony adaptor to
of:
said IP telephony netWork at a different site on said
after said return digital signal has been received, placing
netWork; and
a call to a remote telephonic device to determine
an audio codec, connected to said converter and one of
Whether at least a portion of said IP telephony netWork
said plurality of connectors, for processing digital
is capable of supporting bidirectional audio communi
audio signals transmitted and received by said IF tele
cation.
12. The method of claim 8 Wherein said connecting step
phony adaptor.
takes place Within a LAN at one of a Wall jack connected to
a cable of said LAN, a hub connection, a router port
connection, and one of a plurality of sites Within said LAN
17. The IP telephony adaptor of claim 16 Wherein said
plurality of connectors includes an alligator clip for con
necting to a cable of said IP telephony netWork, a ?rst
utiliZing an alligator clip to connect said telephony trouble
shooting device to said IP telephony netWork.
13. The method of claim 8 Wherein said rnonitoring step
includes making a determination of bandWidth availability
of said connection betWeen said remotely located device and
connection of said IP telephony based netWork, and a second
adaptor for connecting at a router port of said IP telephony
netWork.
18. The IP telephony adaptor of claim 16 Wherein said IP
said telephony troubleshooting device and determining
adaptor for connecting to one of a user Wall jack and a HUB
45
Whether a protocol incornpatibility is responsible for a
communication failure betWeen said telephony trouble
shooting device and said remotely located device.
14. The method of claim 8 comprising the further steps of:
if it is determined from said rnonitoring step that said
return digital signal is received, executing a loopback
an AR] message and an ACF message.
19. The IP telephony adaptor of claim 16 Wherein one of
said plurality of connectors is utiliZed to connect said IP
telephony adaptor to a LAN, said rernote device is a terminal
on said LAN and is unregistered to a gateWay, said ?rst
digital control rnessage transmitted to said terminal is a
call Wherein a video sequence is transmitted over said
IP telephony netWork, said loopback call being directed
to an address assigned to said telephony troubleshoot
ing device;
determining whether said video sequence is received by
said telephony troubleshooting device; and
telephony netWork includes a LAN, said server is a gateWay
on said LAN, and said ?rst digital control rnessage trans
rnitted to said gateWay is an ARQ message, and said second
digital control message received from said gateWay is one of
55
Setup message, and said second digital control message
received from said terminal is a Connect message.
20. The IP telephony adaptor of claim 16 Wherein one of
said plurality of connectors is enabled to connect said IP
if said video sequence is received by said telephony
telephony adaptor at a site Within a LAN that is one of a Wall
troubleshooting device, analyZing said received
jack connected to a cable of said LAN, a hub connection,
sequence to determine performance characteristics of
and a router port connection.
said transmission of said video sequence over said IP
telephony network.

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