U.S. patent application number 11/490962 was filed with the patent office on 2006-11-16 for system for triggering the control plane in an asynchronous connection-oriented transmission network.
Invention is credited to Claude Basso, Philippe Damon, Guy Menanteau.
Application Number | 20060256795 11/490962 |
Document ID | / |
Family ID | 36951857 |
Filed Date | 2006-11-16 |
United States Patent
Application |
20060256795 |
Kind Code |
A1 |
Basso; Claude ; et
al. |
November 16, 2006 |
System for triggering the control plane in an asynchronous
connection-oriented transmission network
Abstract
A system and method are disclosed for verifying connection
characteristics of a connection-oriented transmission pathway. A
receiver of a network device is configured to receive a data stream
from a source network device over the pathway. The data stream
including a header portion and a data portion. In response to
detecting the header portion, a processor of the network device
counts a number of units of data received in the data portion and
measures a time span over which the data portion is received. Then
a transmitter of the network device sends a response data stream,
including the count of the number of units received and the
measured time span, to the source network device. The source
network device determines an actual bandwidth of the
connection-oriented transmission pathway using these values.
Inventors: |
Basso; Claude; (Nice,
FR) ; Damon; Philippe; (Cagnes-sur-mer, FR) ;
Menanteau; Guy; (Cagnes-sur-mer, FR) |
Correspondence
Address: |
CESARI AND MCKENNA, LLP
88 BLACK FALCON AVENUE
BOSTON
MA
02210
US
|
Family ID: |
36951857 |
Appl. No.: |
11/490962 |
Filed: |
July 21, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09334415 |
Jun 16, 1999 |
7106698 |
|
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11490962 |
Jul 21, 2006 |
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Current U.S.
Class: |
370/395.1 |
Current CPC
Class: |
H04L 45/10 20130101 |
Class at
Publication: |
370/395.1 |
International
Class: |
H04L 12/56 20060101
H04L012/56 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 16, 1998 |
EP |
98480063.1 |
Claims
1. A network device for verifying connection characteristics of a
connection-oriented transmission pathway, the network device
comprising: a receiver configured to receive a data stream from a
source network device, the data stream transmitted along the
connection-oriented transmission pathway, the data stream including
a header portion and a data portion; a processor configured to, in
response to detection of the header portion of the data stream,
count a number of units of data received in the data portion and
further configured to measure a time span over which the data
portion is received; and a transmitter configured to send a
response data stream to the source network device, the response
data stream including the count of the number of units received and
the measured time span, to permit the source network device to
determine an actual bandwidth of the connection-oriented
transmission pathway.
2. The network device of claim 1, wherein the data stream is an
Asynchronous Transfer Mode (ATM) data stream.
3. The network device of claim 2, wherein the processor implements
a Deamon Asynchronous Transfer Mode (ATM) Test Application that
controls the receiver and transmitter.
4. The network device of claim 1, wherein the data stream and the
response data stream have substantially identical data
portions.
5. The network device of claim 1, wherein the receiver is further
configured to receive a call setup message and the processor is
further configured to, in response to the call setup message, send
an acknowledgement message to the source network device to
establish the a connection-oriented transmission pathway.
6. The network device of claim 5, wherein the call setup message
includes a desired bandwidth parameter, a quality of service
parameter, and a type of connection parameter that specify desired
characteristics for the connection-oriented transmission
pathway.
7. The network device of claim 1, wherein the source network device
is configured to compare the actual bandwidth of the
connection-oriented transmission pathway with a desired bandwidth
for the connection-oriented transmission pathway.
8. The network device of claim 1, wherein the processor is
configured to detect a first time that the data stream is received
at the network device and to detect a second time when the reply
data stream is to be transmitted by the network device, and the
processor is further configured to calculate the difference between
the first time and the second time, and to include the difference
in the response data stream.
9. The network device of claim 8, wherein the the difference is
adapted to be used by the source network device, along with a
transmit time of the data stream and a receipt time of the response
data stream, to calculate an end to end transit delay.
10. A method for verifying connection characteristics of a
connection-oriented transmission pathway, the method comprising the
steps of: receiving a data stream from a source network device, the
data stream transmitted along the connection-oriented transmission
pathway, the data stream including a header portion and a data
portion; detecting the header portion of the data stream and in
response counting a number of units of data received in the data
portion of the data stream; measuring a time span over which the
data portion is received; and sending a response data stream to the
source network device, the response data stream including the count
of the number of units received and the measured time span, to
permit the source network device to determine an actual bandwidth
of the connection-oriented transmission pathway.
11. The method of claim 10 wherein the data stream is an
Asynchronous Transfer Mode (ATM) data stream.
12. The method of claim 11 wherein the steps of detecting and
measuring are performed by a processor executing a Deamon
Asynchronous Transfer Mode (ATM) Test Application.
13. The method of claim 10, wherein the data stream and the
response data stream have substantially identical data
portions.
14. The method of claim 10, further comprising the steps of:
receiving a call setup message; and in response to the call setup
message, sending an acknowledgement message to the source network
device to establish the connection-oriented transmission
pathway.
15. The method of claim 14, wherein the call setup message includes
a bandwidth parameter, a quality of service parameter, and a type
of connection parameter that specify desired characteristics of the
network conneciton.
16. The method of claim 10, further comprising the step of:
comparing the actual bandwidth of the connection-oriented
transmission pathway with a desired bandwidth for the
connection-oriented transmission pathway.
17. The method of claim 10, further comprising the steps of:
detecting a first time when the data stream is received; detecting
a second time when the reply data stream is to be transmitted; and
calculating the difference between the first time and the second
time; and including the difference in the response data stream.
18. The method of claim 17, further comprising the step of:
calculating an end to end transit delay from the difference, a
transmit time of the data stream, and a receipt time of the
response data stream.
19. A network device for verifying connection characteristics of a
connection-oriented transmission pathway, the network device
comprising: means for receiving a data stream from a source network
device, the data stream transmitted along the connection-oriented
transmission pathway, the data stream including a header portion
and a data portion; means for detecting the header portion of the
data stream and in response counting a number of units of data
received in the data portion of the data stream; means for
measuring a time span over which the data portion is received; and
means for sending a response data stream to the source network
device, the response data stream including the count of the number
of units received and the measured time span to permit the source
network device to determine a bandwidth of the connection-oriented
transmission pathway.
20. A computer readable medium containing executable program
instructions for verifying connection characteristics of a
connection-oriented transmission pathway, the executable program
instructions comprising program instructions configure to: receive
a data stream from a source network device, the data stream
transmitted along the connection-oriented transmission pathway, the
data stream including a header portion and a data portion; detect
the header portion of the data stream and in response counting a
number of units of data received in the data portion of the data
stream; measure a time span over which the data portion is
received; and send a response data stream to the source network
device, the response data stream including the count of the number
of units received and the measured time span, to permit the source
network device to determine a bandwidth of the connection-oriented
transmission pathway.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of commonly
assigned copending U.S. patent application Ser. No. 09/334,415,
which was filed on Jun. 16, 1999, by Claude Basso et al. for a
System for Triggering the Control Plane in an Asynchronous
Connection-Oriented Transmission Network, and that is hereby
incorporated by reference. Further, application Ser. No. 09/334,415
itself claims priority to European Patent No. 98480063.1 filed on
Sep. 16, 1998.
TECHNICAL FIELD
[0002] The present invention relates to systems enabling testing
for the availability of connections in an asynchronous
connection-oriented transmission network such as an Asynchronous
Transfer Mode (ATM) network or a Frame Relay network and
particularly to a method for triggering the control plane in such a
network.
BACKGROUND
[0003] Different techniques have been developed for transporting
information over a network, such as packet switching techniques
whereby digitized data is arranged into so-called bit packets, and
circuit switching techniques. In packet switching, the bit packets
may either be of fixed length like in the Asynchronous Transfer
Mode (ATM) where the packets, also called cells, are all of a
conventional fixed length, or be of variable length.
[0004] ATM has been recognized as the common base on which
different types of services and networks can operate. The ATM
technology can efficiently combine the transmission of speech,
video, audio (what is commonly called the multimedia traffic) and
computer data into the wired network. Furthermore, ATM has proven
to scale well from very high speed network infrastructure (the
information highways) to customer premises networks. One of the
great advantages of the ATM technology is the fact that it can
guarantee some level of service when an ATM connection is set up.
Such guarantees can correspond to transmission rate, transmission
latency and information loss. They can be achieved mainly because
the ATM architecture assumes that the transmission media are almost
error free.
[0005] At the beginning of the ATM technology, there were only
Permanent Virtual Connections (PVC). Switched Virtual Connection
(SVC) were soon developed. SVCs supported the growth of ATM by
providing bandwidth on demand, in real time, to any user
destination, with custom-tailored performance to meet the needs of
almost any application. From the beginning, SVCs have been
integrated to ATM specifications and most ATM customer equipment
supports SVCs.
[0006] To establish a SVC connection, a routing procedure takes
place during which the control point of the source node determines
the best route to the destination node. Afterwards, the source
control point sends a call setup message, a copy of which is
delivered to the control point of every switching node on the
route. The call setup message includes all the critical information
needed to define and support a connection, and is based upon
information contained in the request initiated by an end user or an
application. When routing the connection, the network ensures that
the selected path has sufficient resources to support the traffic
descriptor, bearer capability and Quality of Service (QoS)
parameters specified in the call setup message. This is done by the
Connection Admission Control (CAC). Then, when the call setup
message is received at the destination node, a confirmation message
is sent back to the source node which can initiate the exchange of
information between the source node and the destination node.
[0007] All these procedures for establishing a connection are
controlled by the control plane managed by a control point in each
node of the network.
[0008] ATM networks are getting more and more complex and are being
used to handle critical data. Therefore, the control plane is more
and more complex and becomes a critical element of such networks.
Unfortunately, there is currently no tool to test and verify that
the control plane of a network (formed of the control planes of
network nodes used in the connection) works properly in a real
environment (e.g. a production network).
[0009] A solution known as Internet Protocol (IP) "Ping", was been
originally designed to check the availability of a path in the IP
world and whether a destination device could be reached by sending
out an echo ICMP (Internet Control Message Protocol) to the
specified destination device and just waiting for an acknowledgment
sent back by the destination device. This procedure is mainly used
for networks of routers. Even if a "Ping" works, this cannot ensure
that a data stream will actually flow because of the connectionless
nature of IP. There is no control plane insofar as the path is
determined at the time when the data is sent in the network.
Furthermore, there are no Quality of Service parameters.
[0010] One advantage of the ATM is its ability to integrate the IP
protocol. For that, the first step is to define Higher Layer
Protocols (HLP) to emulate the LAN protocols above ATM. Thus, LAN
emulation and classical IP are widely used. The advantage is that
the applications developed on top of an IP stack are still working
transparently. Of course, the "Ping" function is still implemented
when IP is used on top of these HLPs since, due to the
connection-oriented nature of ATM, the connection must be
established prior to the data transmission.
[0011] The problem with the HLPs is that they require an extra
process to actually establish a connection between two users. In
fact, an additional server is necessary to translate the addresses
of HLPs (e.g. IP addresses) into ATM and vice-versa. That is why
each user must first register to the server before doing anything
else and in particular trying to do a "Ping". This is not very
satisfying for testing the connectivity because the "Ping"
procedure may not work for reasons which are unrelated to the
control plane such as when the server has failed. Therefore, the
HLPs do not integrate the full QoS capabilities of ATM.
[0012] Another solution for checking if an ATM connection is
working properly is to use Operation Administration Management
(OAM) cells. OAM cells were designed to test an ATM network through
the user plane. Unfortunately, OAM cells do not trigger the control
plane and in particular the Connection Admission Control (CAC).
Besides, a connection must be established prior to the use of OAM
cells. In fact, OAM cells simply check the physical path but do not
test the establishment of a connection characterized by specific
traffic parameters.
SUMMARY OF THE INVENTION
[0013] Accordingly, the main object of the invention is to provide
a method enabling to test at any time, the connectivity from a
source node to a destination node in an asynchronous
connection-oriented network such as ATM network.
[0014] Another object of the invention is to provide a method for
testing the availability of a network connection characterized by
its traffic parameters.
[0015] Another object of the invention is to provide a method for
triggering the control plane in an asynchronous connection-oriented
network in order to test any connection between two nodes by using
traffic parameters requested by the user.
[0016] The invention relates to an asynchronous connection-oriented
transmission network comprising a plurality of switching nodes
interconnected by connection lines, each switching node being
associated with a control point which is in charge of when a
connection has to be established therebetween by identifying which
of the connection lines are eligible based upon the requirement of
a quality of service. Each switching node comprises a Control ATM
Test Application (CATMTA) and a Deamon ATM Test Application
(DATMTA) so that, at any time, a user interfacing a source node can
test the connectivity of a network connection from the source node
to a destination node by initiating a connection procedure wherein
a call setup message is sent by the CATMTA of the source node to
the destination node and the DATMTA of the destination node sends
back an acknowledgment message to the source node.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The objects, characteristics and advantages of the invention
will become clear from the following description given in reference
to the accompanying drawings wherein:
[0018] FIG. 1 represents a block-diagram of an ATM network wherein
a Control ATM Test Application (CATMTA) of a source node initiates
a connection by sending a call setup message to a Deamon ATM Test
application (DATMTA) of a destination node.
[0019] FIG. 2 represents the same block-diagram of an ATM network
wherein the DATMTA of the destination node sends back an
acknowledge message to the CATMTA of the source node.
[0020] FIG. 3 represents the same block-diagram of an ATM network
showing the data stream exchanges between the CATMTA of the source
node and the DATMTA of the destination node for verifying the
characteristics of the connection.
DETAILED DESCRIPTION OF THE INVENTION
[0021] As shown schematically in FIGS. 1, 2 and 3, an ATM network
10 includes a plurality of switching nodes 12, 14, 16 and 18. In
the present illustration, switching node 12 will be the source node
and switching node 18 will be the destination node.
[0022] Each node of the network includes a control point which are
illustrated only for source node 12 and destination node 18. The
control point 20 of source node 12 comprises a Control ATM Test
Application (CATMTA) 22, a control plane 24, an adaptation ATM
layer (AAL) 26 and an ATM layer 28. CATMTA 22 is connected to
control plane 24 but is also connected to AAL 26 and to ATM layer
28.
[0023] In the same way, the control point 30 of destination node 18
comprises a Deamon ATM Test Application (DATMTA) 32, a control
plane 34, an adaptation ATM layer (AAL) 36 and an ATM layer 38.
DATMTA 32 is connected to control plane 34 but is also connected to
AAL 36 and ATM layer 38.
[0024] Although only a CATMTA has been represented for source node
12 and only a DATMTA has been represented for destination node 18,
each of these two nodes, and in a general way, each node of the
network includes both CATMTA and DATMTA. Indeed, each node could be
used as a source node or a destination node in the procedure
implementing the invention. Note that both CATMTA and DATMTA of the
same node can be used at the same time.
[0025] It must also be noted, that the control point associated
with the source node or with the destination node could be outside
the node, such as an independent station or any Data Terminal
Equipment (DTE).
[0026] The procedure described hereafter in reference to the
Figures illustrates how are used the CATMTA and DATMTA are used
according to the invention.
[0027] First, CATMTA 22 associated with source node 22 receives a
request from an end user or from a higher level application (not
shown) to establish a connection with several parameters. There are
three sets of parameters: general parameters such as the number of
connection establishment retries in the case of failures or the
lifetime of the connection; call setup parameters which will
determine the characteristics of the connection. Among them, the
most important are the destination ATM address (which is the
address of the destination node), the bandwidth parameters, the
Quality of Service (QoS) parameters, the type of the connection;
i.e., point to point or point to multipoint, virtual circuit or
virtual path; and
the data stream parameters such as the data stream format, its
size, its frequency and any kind of measures to perform.
[0028] CATMTA 22 requests the establishment of the connection with
destination node 18 by triggering (signaling and routing) control
plane 24. A call setup message is sent from source node 12 to
destination node 18 through the switching nodes of the network 10
such as switching node 14 as illustrated in FIG. 1. As usual the
control plane of each switching node of the connection is triggered
by the call setup message. Note that, if the network fails to
deliver the call setup message to the destination node, CATMTA 22
of source node 12 is aware of this failure and it notifies to the
requesting end user or application.
[0029] When the call setup message is successfully delivered to
destination node 18, it is actually received by DATMTA 32. DATMTA
accepts the incoming message and sends back an acknowledge message
(connect message) toward source node 12 as illustrated in FIG.
2.
[0030] The acknowledge message being received by CATMTA 22, the
connection is effectively established between source node 12 and
destination node 18. The work of the control plane is completed.
CATMTA notifies the requesting end user or application that the
connection has been successfully established.
[0031] According to another aspect of the invention, the new means
which are CATMTA and DATMTA can be used for verifying the
characteristics of the connection which has just been established
between source node 12 and destination node 18 by exchanging data
streams as illustrated in FIG. 3. It must be noted that such a
verification would not be possible if a classical connection in the
ATM network was normally established without using CATMTA and
DATMTA.
[0032] CATMTA 22 of source node 12 sends a data stream over the
connection. If the connection is actually established, the data
stream is received by DATMTA 32 of destination node 18. DATMTA 32
will decode this data stream and it will respond back with another
data stream. CATMTA 22 receives the response. Everything works so
far. CATMTA 22 notifies the end user or the application. In
addition, CATMTA 22 may perform several retries, statistics, etc. .
. .
[0033] If the connection is not actually established, either the
data stream sent by CATMTA 22 will not be received by DATMTA 32, or
the response sent back by DATMTA 32 will not be received by CATMTA
22. In both cases, CATMTA 22 will never get any response, and it
notifies the end user or the application of this failure.
[0034] This data stream can be used to check the actual
connection's characteristics which has been established by the
control plane. As there are a lot of possible combinations of these
characteristics, it is impossible to make an exhaustive list of all
tests.
[0035] For each individual test, a specific initial data stream is
sent by the CATMTA. The DATMTA recognizes the nature data stream
and can act differently.
[0036] Here is a simple example to check the end to end transit
delay of the connection. The end to end transit delay is the
maximum acceptable time for an ATM cell to flow from the source
node the destination node. This value is specified in the call
setup message at the creation time of the connection. If the
control plane works properly, the actual value of the end to end
transit delay must be lower than the one given in the call setup
message.
[0037] With the following data stream format, it is possible to
measure the actual end to end transit delay of the connection:
[0038] The data stream sent by the CATMTA includes the time T1 at
which the data stream is sent. The data stream is received by the
DATMTA at time T2. The DATMTA sends back the answer at time T3. The
overhead of the DATMTA is T3-T2. This value is put in the response
data stream. The response data stream is received by the CATMTA at
time T4. So, the end to end transit delay is given by the formula:
T=(T4-(T3-T2)-T1)/2. This value can be compared with the one
requested by the user or the application.
[0039] To check whether the bandwidth BW requested by the user or
the above application has been actually allocated for a constant
bit rate connection, a specific data stream has to be sent at the
rate BW by the CATAMTA during an amount of time T. The DATMTA which
receives the data steam recognizes the header and starts to count
the received data (the bytes for example) and the time during which
the data are received. When it doesn't receive any more data, it
sends back a response data stream in which it puts the amount of
received data and the measured time. The CATMTA can then compare
the values and it may detect that some data have been lost (cell
discarded in the network) for example.
[0040] While the above description has been made by considering an
ATM network, it is clear that the invention could be implemented in
any other asynchronous transmission network of the ATM network type
such as a Frame Relay network wherein the packets has a variable
length.
* * * * *