Dynamic soft permanent virtual circuit bulk connection tracing

Details Dynamic soft permanent virtual circuit bulk connection tracing Dynamic soft permanent virtual circuit bulk connection tracing

2002-12-13

2004-08-17

Olms, Douglas (Department: 2661)

Multiplex communications

Diagnostic testing

Determination of communication parameters

C370S395200, C370S355000, C709S224000, C709S238000

Reexamination Certificate

active

06778504

ABSTRACT:

FIELD OF THE INVENTION
The invention relates to communication networks, and in particular to methods and apparatus for tracing soft permanent virtual circuit connections.
BACKGROUND OF THE INVENTION
Asynchronous Transfer Mode (ATM) technologies have been developed to derive combined benefits from packet-switched technologies and circuit-switched technologies. Packet-switched technologies benefit from an efficient utilization of bandwidth. Circuit-switched technologies benefit from a high quality-of-service. ATM technologies employ fixed sized packets, known as cells, which are switched in an ATM network to follow Virtual Circuit (VC) transport paths.
FIG. 1
is representative of an ATM network
100
which includes ATM network nodes
102
and interconnecting links
104
. Legacy ATM cell transport includes the use of pre-established Permanent Virtual Circuits (PVCs)
106
in the ATM network
100
provisioned over selected interconnecting links
104
. The establishment of a PVC
106
is performed by a call manager entity
110
which has access to knowledge regarding: the topology of the managed ATM network, cell processing capacities of each managed network node, transport bandwidth capacities of each: managed interconnecting link, etc. The call manager
110
makes use of a network configuration database
112
to store and track provisioning information about the network
100
.
If a connection is needed between any two ATM network nodes
102
, a request
120
for establishing the connection is provided to the call manager
110
. The request
120
includes a network address specification corresponding to the source network node
102
-S requesting the establishment of the connection and a network address specification corresponding to the destination network node
102
-D. The request may also specify resource utilization requirements including, but not limited to: a required average bandwidth, a maximum transport latency, a maximum jitter, etc.
The call manager
110
, upon receiving the request
120
for establishing a connection, parses the request
120
to extract the source and destination network node addresses, and the resource utilization requirements. Based on the extracted information, and information held in the network configuration database
112
, the call manager
110
attempts to determine
122
a transport path, of network nodes
102
and interconnecting links
104
, which will have enough spare cell processing capacity at the network nodes
102
, and enough transport bandwidth on the interconnecting links
104
, to accommodate the new connection in the network
100
. Once the transport path is determined
122
, various commands are sent, via signaling messages
124
, to the network nodes
102
in the transport path to reserve resources for PVC
106
to be established therebetween. Once all network nodes
102
in the transport path confirm the resource reservations, via return setup complete signaling messages
126
, the PVC
106
is said to be established. The call manager
110
also updates
128
the network configuration database
112
with the particulars of the new PVC transport path.
Via a Network Management System (NMS)
140
, network administrators
130
may be provided with a visual display
132
of all PVCs
106
in use in the network
100
. The provisioning of the visual display
132
is possible due to the fact that all PVC transport path provisioning information is available centrally via the network configuration database
112
. The availability of PVC transport path information stored in the network configuration database
112
enables micro-management of network resources.
Should any network infrastructure failures occur, network nodes
102
connected to the affected failed interconnecting links
104
or failed network nodes
102
, inform the call manager
110
thereof, via signaling messages (not shown). The call manager
110
updates
128
the network configuration database
112
to reflect the failed equipment, determines the PVCs
106
which were provisioned via the failed network infrastructure, and the call manager
110
begins to reprovision (
122
,
124
,
126
,
128
) all the affected PVCs
106
around the failed network infrastructure one-by-one in the same fashion presented above. Besides the deleterious effects of the infrastructure failure, a large amount of bandwidth is needed for the conveyance of signaling messages
124
/
126
/
128
to effect the reprovisioning of the affected PVCs.
A person of ordinary skill in the art understands that ATM technologies were devised to provision a large number of PVCs
106
in order to deliver high transport capacities. An infrastructure failure therefore affects a large number of PVCs
106
which the call manager
110
will have to reroute in a short period of time following the infrastructure failure to reduce cell loss.
There has been a trend towards conveying cells at ever increasing transport bandwidths over the interconnecting links
104
, and employing network nodes
102
of higher and higher cell processing capacities. The processing requirements imposed on the call manager
110
can quickly stress the call manager entity to its processing limits especially when network failures occur. As the call manager
110
is associated with a network node
102
-CM, an abnormal amount of signaling traffic processing is experienced by the network node
102
-CM although the network node
102
-CM may not be closely associated with the failed network infrastructure. The sequential transport path re-determination in healing the affected network
100
is considered very slow and typically leads to excessive cell loss.
In referring to
FIG. 2
, recent developments have brought about intelligent ATM network nodes
202
which led to intelligent networks
200
. Intelligent ATM network nodes
202
use Private Network-Node Interface (PNNI) signaling to perform some of the tasks related to connection establishment, and connection rerouting in response to network failures. The transport path determination and reconfiguration performed by the intelligent network nodes
202
themselves, is enabled via the use of Soft Permanent Virtual Circuits (SPVC)
206
. In the event of a network failure
208
, benefits are derived from parallel transport path rerouting
210
which reduces the probability of cell loss. The use of SPVCs
206
provides connectivity resiliency by distributing SPVC connection re-routing processing overheads over many intelligent network nodes
202
in the network
200
. For this reason SPVCs are also know colloquially as Smart PVCs.
In using SPVCs
206
to provision connectivity, the call manager
110
only keeps track of SPVC connectivity states at a high level—the task of ensuring low level physical SPVC connectivity being performed by the intelligent network nodes
202
themselves. The result is that the call manager
110
is informed
226
of the establishment of SPVCs
206
but not of the transport path used by the SPVCs. Therefore, in using SPVCs
206
, the call manager
110
and the network configuration database
112
, no longer have access to detailed connectivity information. Network administrators
130
can only engage in macro-management of network resources because the visibility of detailed connectivity information is diminished compared to what was previously enjoyed by using PVCs. As a result there is a reluctance to employ SPVCs
206
in provisioning connections over ATM infrastructure.
There is a strong demand to provide SPVC configuration visibility akin to PVC provisioning to enable micro-management of SPVC connections.
An extension to PNNI signaling has been described in af-cs-0141.000, “PNNI Addendum for Path and Connection Trace”, Version 1.0, March 2000, which is incorporated herein by reference. Provisions are made for SPVC path tracing in troubleshooting connection establishment, and for SPVC connection tracing for discovering the transport path used by already established SPVC connections.
The very recent adoption of the af-cs-0141.000 extension to PNNI signaling has only benefit

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