Multiplex communications – Pathfinding or routing – Switching a message which includes an address header
Reexamination Certificate
1998-08-25
2002-05-14
Ton, Dang (Department: 2661)
Multiplex communications
Pathfinding or routing
Switching a message which includes an address header
Reexamination Certificate
active
06389027
ABSTRACT:
FIELD OF INVENTION
The present invention is generally directed to an IP multicast interface used in network connections with gateway devices.
BACKGROUND OF THE INVENTION
Personal computers are gaining widespread popularity as the state of technology is improving. Over the past few decades, their utilization has proliferated both for personal purposes and for use in business and scientific communities. Establishing good computing communications have become a necessity as individual users try to connect to one another for exchange of information, and to larger computers to take advantage of their higher processing capabilities. This need to communicate between different computing hosts or nodes have evolved into the creation of distributed networks. A distributed network is an aggregate of individual systems that are connected to one another electronically. Distributed networks can be organized in a number of ways, either remotely extending over great distances using wide area networks or WANs, or locally through the use of a Local Area Network, better known as a LAN.
A LAN usually consists of a number of nodes or hosts located within an office, a building or at other close proximations. Being a type of a distributed network, a LAN loosely couples processors and workstations. Generally, workstations on a LAN do not share a central memory but do share common servers. In this way a LAN increases the power and flexibility of workstations by enabling them to access shared data without jeopardizing the security of each individual resource.
A LAN system that has been in wide use in recent years is produced by Novell, Inc. of Provo, Utah. In a Novell system, a LAN device driver is implemented on top of the local operating systems to be coupled and device driver commands at the LAN workstations are directed to and from the workstations onto the LAN to the target servers.
As networks have grown and particularly as LANs have come into widespread use, many businesses and organizations have faced the necessity of interconnecting and managing a confederation of networks and LANs. Each network itself can in turn comprises of a plurality of logical networks which in turn run independent and different networking protocols. The challenge has not become only to interconnect local area networks to one another, but to do so and still provide remote server access through WANs or other devices.
Three basic methods are now available to interconnect both local and remote area networks to one another as to provide wide used access and remote information exchange capabilities. These three methods are 1) bridges or data-link devices that connect similar networks together; 2) routers that perform routing services by maintaining a routing table in each host; and 3) gateway devices that carry out protocol conversions and other connectivity functions. Typically, a device driver for the gateway is provided with modems or other physical ports that can be linked to switched communication WANs.
A gateway facility allows the interconnection of multiple independently controlled communication networks to one another in a way that logical units in the network can communicate with one another without any changes to the network. A logical network runs a single networking protocol, but a processing organization can be composed of a dozen of logical networks running six or seven networking protocols. A gateway provides transparent interconnection of these single networking protocols, so that a single multiport transport network is formed.
In the existing mechanisms, gateway devices are implemented on top of the LAN device drivers as a switched communications device interface. The user initialization of the communication link-up procedure redirects the user hardware commands to the gateway. The communications interface in the gateway driver then institutes and maintains the swithched communications link, diverting hardware resources of the driver to do so. The connection and access procedures are then executed using the gateway ports and modems in order to lick the user's system with the switched communications network. A remote connection is established through the LAN/WAN which sets up a point to point configuration through the port along the communication line between the user and the communications device in use.
The procedure described above have many complexities associated with it. The complexities connected with the configuration assessment of gateway divices is an on-going concern of the disigners of such divices today. These configuration concerns contributes to many limitations that exist with today's gateway devices. These limitations often make the interconnection of networks running different protocols non-transparent. Because many of the present gateways are transport layer protocol-specific, it is possible that a gateway cannot interconnect a network running for example a TCP/IP protocol and a network running the SNA protocol. Furthermore, a variety of gateway devices have been developed which connect TCP/IP to different operating system and give connectivity to the LAN/WAN environments, but each time the configuration has to be redefined and reassessed before connectivity is accomplished successfully. Furthermore, each gateway device can usually implement only a subset of the TCP/IP functions. Most currently existing gateway devices do not support many of the TCP/IP functions and performance problems have been encountered due to increased bandwidth of the LAN/WAN arenas. One of the communication protocols used to communicate with the gateway is LCS or LAN Channel Station. A control command interface exists in the LCS protocol that requires all the configuration information to be set prior to the TCP/IP connect sequence. Nonetheless, the control interface does not have a command sequence to enable the use of the TCP/IP functions which have been implemented in the gateway devices. To reduce the complexity of configuring gateway devices, an expanded control command interface is needed.
This application incorporates by reference pending application, Ser. No. 08/921,432, now U.S. Pat. No. 5,999,974 issued Dec. 7, 1999.
This application is being filed with the following related applications on the same date—Ser. Nos. 09/140,180; 09/139,948 and 09/139,684.
SUMMARY OF THE INVENTION
A computer program product for use with a computer system having a host and a plurality of clients coupled to one another via a local area network (LAN), to provide a multicasting of messages using a special command set. First computer readable code means is generated for issuing a first special command to add a new IP multicast address providing a group multicast address and an IP multicast address. Then computer readable code means is created for entering said special control command in a multicast routing table, one entry per connection request received. Computer readable code means is then provided for a use count mechanism for keeping track of numbers of communication stacks which have registered with a certain IP multicast address. Also computer readable code means is generated for comparing all inbound IP packets destined for an IP multicast address with said entries in said table and routing all matches to their appropriate communication stacks.
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Lee Chin
Ratcliff Bruce H.
Valley Stephen R.
Gonzalez Floyd A.
International Business Machines - Corporation
Neff Lily
Ton Dang
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