Electrical computers and digital processing systems: multicomput – Computer network managing
Reexamination Certificate
1997-12-10
2002-08-13
Harrell, Robert B. (Department: 2152)
Electrical computers and digital processing systems: multicomput
Computer network managing
C709S223000
Reexamination Certificate
active
06434612
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to the management of network nodes and more particularly to a mechanism for allowing communication and control of a multiservice switch in a network.
BACKGROUND OF THE INVENTION
Multiservice network switches such as the BPX™ sold by Cisco Systems, Inc. of San Jose, Calif., are used to provide a data path, or interface, between multiple networks, each of which may operate according to a different networking standard protocol. Examples of the networking protocols supported by these multiservice switches include, but are not limited to, frame relay, voice, circuit emulation, T
1
channelized, T
3
channelized, and Asynchronous Transfer Mode (ATM).
FIG. 1
is a prior art network
1500
of switches comprising connection control processes on the switches communicating with each other and then setting up connections through the switches. This network
1500
comprises a number of switches
1502
-
1508
that are connected using port cards
1532
-
1546
and trunks
1548
-
1554
. Each switch comprises a control card
1512
-
1518
, and each control card comprises a connection routing processor
1522
-
1528
, respectively. A connection routing protocol communicates between connection routing processors
1522
-
1528
. A command line interface is used to input a request for an end-to-end connection in one switch. Different connections may be requested in different switches. Connection routing processors on different switches communicate with each other to set up an end-to-end connection by building the connection out of virtual circuits on the trunks
1548
-
1554
and cross-connects on the switches
1502
-
1508
.
FIG. 2
shows a prior art network switch
100
that is a node of a network. Network switch
100
generally comprises a data path
125
and command bus
127
to which a controller
105
, a trunk module
110
, or port, and service modules
115
and
120
, or ports, may be coupled. Trunk module
110
connects network switch
100
to other switches, or nodes, of the network.
Service modules
115
and
120
are coupled to customer premise equipment (CPE) B and CPE C, respectively. The trunk and service modules may be configured in a number of different ways to allow communication between trunk A, CPE B, and CPE C via data path
125
.
Controller
105
generally performs control functions for a single network switch
100
using command bus
127
. Controller
105
controls the switch
100
using a configuration database
106
comprising switch control code, a connection routing protocol
107
, and switch resource management software
108
. The configuration database
106
contains information regarding each of the trunk and service modules, including the configuration and capabilities of each trunk and service module. Controller
105
also provides a user interface
135
that allows a user access to and control of network switch
100
. The configuration database
106
runs on the controller
105
and the user interface
135
writes to the configuration database
106
. The user interface
135
is also used to configure the switch
100
and the connection routing protocol
107
.
The switch resource management function
108
establishes and deestablishes switch connections under the control of the controller
105
.
Controller
105
treats network switch
100
as a single network node, addressing all communications destined for network switch
100
to the network address of network switch
100
. Controller
105
receives and processes connection routing protocol messages and determines which local resources are affected by the protocol message. If the protocol message affects a resource of network switch
100
that is not present on controller
105
, controller
105
translates the configuration information originally contained in the protocol message to a format suitable for use by the target trunk or service module.
Controller
105
then transfers the translated configuration information to the target trunk or service module using command bus
127
. The target trunk or service module receives and processes the configuration information, and the target trunk or service module indicates completion of configuration operations to controller
105
using command bus
127
.
In this prior art switch and controller arrangement, only a single controller, also referred to as a master, supporting a single network software layer is allowed control of the resources of the switch. A major disadvantage of this prior art switch and controller arrangement is that the single controller is limited to supporting a single network connection routing protocol which limits the control of all of the resources of the switch to the single configuration supported by the connection routing protocol.
There was also a disadvantage in the typical prior art switch and controller arrangement in that the controller typically could not be isolated from the switch. The prior art controller was tied to the particular parameters for a particular interface and the way the switch represented those parameters internally. As these parameters typically varied from switch to switch, this would typically mean that the controller was tied to or associated with particular parameters for an interface making the controller software specific to a switch and the representation by the switch of Quality of Service (QoS) and interface parameters. Therefore, there was no way to have the same controller software, and thus the same controller, support other switches as these other switches had a completely different set of QoS and interface parameters. Furthermore, a prior art controller designed to support a particular switch having particular interface types could not support a different switch with different interface types; for example, a controller designed for a switch having only ATM interfaces could not support a switch with frame relay interfaces. Thus, a disadvantage of the prior art is that there is no clear separation between standard QoS parameters and switch specific parameters for the way the QoS is represented in the switch.
The Quality of Service (QoS) associated with a network switch defines the user-oriented end-to-end performance of ATM networks, and is defined using particular parameters and reference configurations. The switch manufacturer or network provider state the QoS performance objectives in terms of a particular type or class of QoS. A network connection may be requested by a controller using a particular available service class, along with the parameters corresponding to that class. Another major disadvantage of prior art switch and controller arrangements is that prior art connection control methods each allowed the QoS for connections to be specified only in a narrow set of ways. For example, QoS can be specified in terms of one of the following classes of service: ATM Forum Service Categories; priority fields or Internet Protocol (IP) Type of Service; or, service types that are proprietary to a switch manufacturer.
Furthermore, a major disadvantage of the prior art switch and controller arrangements is that there is no reliably fast way to check for errors in connections between the controller and a switch. Prior art switch connection control protocols maintain synchronization between the controller's expectations of the connections present on a switch, and what is actually on the switch. One prior art synchronization technique involves the controller requesting details of each connection on the switch individually, checking each connection with the controller records of the connection, and correcting each discrepancy. Another prior art synchronization technique involves each connection on the switch timing out every 20 minutes, thereby forcing the controller to re-download all switch connections every 20 minutes.
Moreover, a disadvantage of the prior art switch and controller arrangement is that prior art connection protocols do not support distributed processing thereby requiring connection control messages to be sent to a single point on the ass
Buckley William P.
Choi Isaac P.
Fernandes Neufito L.
Hughes David A.
Lawrence Jeremy R
Blakely , Sokoloff, Taylor & Zafman LLP
Cisco Technology Inc.
Harrell Robert B.
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