Multiplex communications – Pathfinding or routing – Switching a message which includes an address header
Reexamination Certificate
1997-04-02
2002-04-02
Nguyen, Chau (Department: 2663)
Multiplex communications
Pathfinding or routing
Switching a message which includes an address header
Reexamination Certificate
active
06366581
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to telecommunication switching equipment in general and more specifically to a method and apparatus for creating a permanent connection from one side of the telecommunications switch to the other side of telecommunications switch.
2. Description of the Related Art
Telecommunication networks are often classified into the type of information transmitted thereon. For example, there are voice, video and data networks. Some telecommunication networks are capable of accommodating different types of data. Broad band switching systems, such as those using asynchronous transfer mode (ATM) packets are an example of systems which may be able to transmit several types of information.
FIG. 1
shows a typical ATM network. In
FIG. 1
, LEC represents local exchange carrier. Each local exchange carrier includes at least one switch. An example of an ATM switch in a local exchange carrier is the Fujitsu FETEX 150 ESP Broadband Switching System. TE represents terminal equipment. Terminal equipment is the equipment belonging to the customer or user of the network. The circles enclosing multiple local exchange carriers represents different operating companies. IC is an inter-exchange carrier, a carrier which connects one operating company to another operating company. The connections within the network are denoted by the UNI or NNI, depending on what the connection is between. A UNI is a user-network interface, and this indicates that the connection is between a network and a user. NNI represents network node interface, a connection between a switching node and another switch, rather than a user. Of the NNIs, there are two types. An NNI between two switches belonging to the same operating company is referred to as an intraNNI, and an NNI between two switches belonging to different operating companies is referred to as an interNNI. Billing is a main reason why it is important to differentiate between intraNNIs and interNNIs.
A permanent virtual connection is a connection from one side of a switch to the other side of the switch. For example, it is possible that the entity owning terminal equipment A would run connectivity to operating company A so this entity can communicate with the entity owning terminal equipment D. In the switch of local exchange carrier
1
, one side of the switch would have the node permanently connected to terminal equipment A. With a permanent virtual connection, this node would be connected to a node on the other side of the local exchange carrier
1
switch, which in turn would be permanently connected to local exchange carrier
3
. Although the term “permanent” is used, it is possible that the connection will change dynamically. For example, at some time during the day, one branch of a financial institution may need to transfer back-up data to another branch of the financial institution. In this case, the permanent virtual connection may be established every business day, at a particular time of the day. Perhaps at a different time of the day different users would use the same connection.
A permanent virtual connection can be compared to a “nailed-up” connection in conventional telephone equipment. In a nailed-up connection, two parties who need to communicate often, can avoid per-call toll charges. In this case, every time the dedicated telephone equipment is used, the only user who can be reached is the other party. On the other hand, a permanent virtual connection and a nailed-up connection can both be contrasted with a “switched virtual connection,” which is comparable to the standard dialed-in connection used in conventional telephone equipment. In a switched virtual connection, the telephone user decides who to call every time the telephone is picked up. The parameters which determine routing and connections from one side of a switch to the other side of the switch are determined separately for every call, based on the number dialed by the user.
There are at least two ways to establish a permanent virtual connection between two sides of a switch. First, the permanent virtual connection can be established remotely at a central location within the operating company. Second, the permanent virtual connection can be done on-site at the local exchange carrier. On-site permanent virtual connections are done, for example, when performing maintenance on a switch or testing a new route.
For both the centralized approach and the on-location approach, establishing a permanent virtual connection in the past has been a very laborious two-step procedure performed by highly trained workers. The first step is usually performed by a translations engineer who consults manuals, her education and experience. The translations engineer would assess the needs of the permanent virtual connection and determine how the network can satisfy those needs. The second step involves incorporating the translations engineer's decisions into a connection. The second step is usually performed by a technician (a person different than the translations engineer). The second step is performed at the switch (local exchange carrier) or at a central location for the operating company. The technician who performs the second step must understand, based on the connection outlined by the translations engineer, what information the switch will need. Further, the technician who performs, the second step must know how to provide this information to the switch. For example, the switch may require certain of the information to be provided in a specified order.
In the second step, the switch is controlled using a language called Transaction Language 1. Transaction Language 1 (TL1) is a language developed specifically for controlling telecommunications equipment and uses ASCII characters. TL1 standards are described in BellCore References TA-NWT-000199, TA-NWT-000831 and TA-NWT-000833. TL1 was designed to have abbreviated commands which represent the words for which they stand. For example, the word route is represented by “RT”. TL1 is difficult to understand, and other, newer languages have been proposed, such as a language known by the acronym CMISE (common management information service elements). CMIP (common management information protocol) is the protocol to implement CMISE. Although newer languages are proposed, the more difficult TL1 language is still being used. Should the protocol ever change from TL1, the change will clearly make the second more difficult, at least in the short term.
The syntax and structure of a TL1 command is as follows:
>VERB-NOUN:AID:P1-Pxx;
In the above, > is a command prompt, VERB-NOUN represents a command code, AID is an access identifier, P1-Pxx is the parameter block, and; (semicolon) is a command terminator. An example of a TL1 control command for assigning a route to telephone calls which need to go to the city of Morgantown, is as follows:
>ENT-RT:RTN=0001:OFLOCN-VPCI=MORGANTOWN-1,TEST=Y;
In the above, after the prompt >, ENT-RT: is the command code. It includes a verb (ENT for “enter”) and a direct object (RT for “route”) separated by a hyphen. The command code ends with a colon. RTN=0001: is the access identifier. For identification within the switch, the access identifier gives a name and a number to the command. The access identifier also ends in a colon. In the above, “OFLOCN-VPCI=MORGANTOWN-1,TEST=Y” is the parameter block and includes the parameters describing the connection. Each parameter includes a parameter name (for example OFLOCN-VPCI for the virtual path connection identifier at the office location) and a parameter value (for example MORGANTOWN-1 for a VPCI of 1 and an office location of Morgantown). The parameter name and the parameter value are connected with an equal sign. Note that the hyphens show the correlation between the two parts of the parameter name and the two parts of the parameter value. Commas are used to string together parameters. Finally, the command includes a semicolon indicating that the command is
Baker & Botts L.L.P.
Fujitsu Network Communications, Inc.
Kwoh Jasper
Nguyen Chau
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