Checking communication-path data in MPLS communication scheme

Details Checking communication-path data in MPLS communication scheme Checking communication-path data in MPLS communication scheme

2000-07-26

2004-08-10

Vanderpuye, Kenneth (Department: 2732)

Multiplex communications

Diagnostic testing

Path check

C370S249000, C370S250000

Reexamination Certificate

active

06775239

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a method of checking communication-path data in an MPLS (multi protocol label switching) communication scheme, and relates to a router a switch, and a communication system operating based on such a method. The present invention particularly relates to a method of checking communication-path data in an MPLS communication scheme for the purpose of checking integrity of label data controlled by a MPLS router and switch data controlled by a trunk switch, and relates to a router, a switch, and a communication system operating based on such a method.
2. Description of the Related Art
In the MPLS communication system that uses ATM (asynchronous transfer mode) switches as trunk switches, data for communication control purposes are maintained as label data controlled by an MPLS router and switch data controlled by an ATM switch.
FIG. 1
is an illustrative drawing showing a system based on the MPLS communication scheme.
An MPLS router
11
converts an IP packet
12
into an ATM cell
21
when the IP packet
12
is supplied from an IP (internet protocol) network
10
, and supplies the ATM cell
21
to an ATM network
20
. The ATM cell
21
is transferred to an MPLS router
31
via ATM switches
22
and
24
and the like through ATM switching based on PVC (permanent virtual circuit).
The MPLS, router
31
extracts an IP packet
32
from an ATM cell
25
supplied from the ATM network
20
, and supplies the IP packet
32
to an IP network
30
.
The MPLS communication scheme will be described further in detail in the following.
FIG. 2
is an illustrative drawing for explaining a principle of the MPLS communication system.
In
FIG. 2
, an MPLS router
40
is provided with label data
41
, which indicates correspondences between destination IP addresses and VPI/VCI (virtual path identifier/virtual channel identifier). An ATM switch
50
is provided with switch data
51
that is used for ATM switching.
The MPLS router
40
converts IP packets
42
and
43
supplied from the IP network into ATM cells
44
and
45
by utilizing the label data
41
, and supplies the ATM cells
44
and
45
to the ATM switch
50
. For example, when the IP packet
42
is supplied, the MPLS router
40
refers to a destination IP address “164.69.15.2” of the IP header, and reads VPI/VCI “1/10” from the label data
41
that corresponds to this destination IP address. Then, the MPLS router
40
generates the ATM cell
44
by using the obtained VPI/VCI and the IP packet
42
.
The ATM switch
50
performs ATM switching on the ATM cells
44
and
45
supplied from the MPLS router
40
where the switch data
51
is used for such ATM switching. By switching, the ATM switch
50
transfers the ATM-cells
44
and
45
to an MPLS router
60
or an MPLS router
61
. For example, when the ATM cell
44
is supplied, the ATM switch
50
refers to the VPI/VCI “1/10”, and reads VPI/VCI “2/15” and an output-communication-line number
1
from the switch data
51
as they correspond to the VPI/VCI “1/10”. Then, the ATM switch
50
generates an ATM cell
52
by utilizing the obtained VPI/VCI, and outputs the ATM cell
52
to the communication line of the output-communication-line number
1
.
The MPLS router
60
extracts an IP packet
62
from the ATM cell
52
supplied from the ATM switch
50
, and outputs the IP packet
62
to an IP network.
In this manner, data necessary for communication control in the MPLS communication scheme are kept in storage as the label data
41
controlled by the MPLS router and the switch data
51
controlled by the trunk switch.
When there is a need to identify a fault point during a setup of communication or upon detection of communication fault, the label data
41
and the switch data
51
have to be checked as to their contents. Further, in such a situation, the ATM communication lines need to be monitored to check whether the MPLS router
40
is operating normally to perform ATM-cell conversion as well as to check whether the ATM switch is receiving ATM cells without trouble.
In order to check the label data controlled by the MPLS router and the switch data controlled by the trunk switch, a visual inspection of the data is necessary. When the MPLS router and the trunk switch are located at physically distanced places or maintained by different administrators, such a visual inspection may be difficult.
Namely, in such cases, a check on the label data and the switch data cannot be made promptly, thereby making it difficult to promptly identify a fault point.
Further, apart from monitoring the communication lines, there is no other way of checking whether the MPLS router is correctly converting protocol data for the trunk switch and checking whether the protocol data converted by the MPLS router is correctly supplied to the trunk switch.
Accordingly, there is a need for a method for checking communication-path data in the MPLS communication system where the method can help to identify a fault point promptly and easily and help to make a prompt recovery.
SUMMARY OF THE INVENTION
It is a general object of the present invention to provide a method for checking communication-path data that substantially obviates one or more of the problems caused by the limitations and disadvantages of the related art.
Features and advantages of the present invention will be set forth in the description which follows, and in part will become apparent from the description and the accompanying drawings, or may be learned by practice of the invention according to the teachings provided in the description. Objects as well as other features and advantages of the present invention will be realized and attained by a method, a router, and a switch particularly pointed out in the specification in such full, clear, concise, and exact terms as to enable a person having ordinary skill in the art to practice the invention.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a method of checking communication-path data in a system in which a router connecting first and second networks operating on different protocols is connected to a switch of the second network. The method includes the steps of changing the router and the switch from a normal mode to a test mode, checking consistency between router communication-path data controlled by the router and switch communication-path data controlled by the switch by sending the router communication-path data to the switch during the test mode, and checking communication between the router and the switch by sending cells from the router to the switch and returning the cells from the switch to the router during the test mode.
In the method described above, the communication-path data controlled by the router and the communication-path data controlled by the switch are checked as to whether they are consistent with each other, and cells transmitted from the router to the switch are returned from the switch to the router so as to allow a check to be made as to communication between the router and the switch, so that a consistency check of the communication-path data, a cell-transparency check, and a connection check between the router and the switch can be easily made.
Accordingly, the method of checking communication-path data according to the present invention can help to identify a fault point easily and promptly in the communication system. In other words, when the communication system suffers a fault, it is possible to decide which one of the trunk switch and the router is suffering the fault, thereby separating the fault point from the rest of the system.
According to another aspect of the present invention, test signals are used for reporting results of the consistency check and results of the communication check. Therefore, the check results can be promptly and easily collected, which allows a fault point to be readily identified in a short time period.


REFERENCES:
patent: 4710769 (1987-12-01)

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