Multiplex communications – Pathfinding or routing – Switching a message which includes an address header
Reexamination Certificate
2003-02-27
2004-10-12
Chin, Wellington (Department: 2664)
Multiplex communications
Pathfinding or routing
Switching a message which includes an address header
Reexamination Certificate
active
06804235
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a communication system (“network”) that transparently maps and operates in one domain of addressing that may be different from the addressing domain interfacing with the network. More specifically, the invention provides mapping between an addressing domain outside the network with an addressing domain inside the network at end nodes of the network, the latter addressing domain not being constrained to a particular bit size and being used to supplant addresses outside the network that, but for this invention, would be used inside the network as well.
2. Description of the Related Art
A communication network is generally regarded as an interconnected set of subnetworks or subnets. The network can extend over localized subnets as an intranet, or can extend globally as an internet between one or more intranets. A communication network can therefore forward data within a localized network between termination devices extending to almost anywhere around the world. The termination devices include any data entry/retrieval system (e.g., telephone or computer), and a network includes a local and/or global interconnection of termination devices configured on one or more subnets.
The basic underpinnings of network operation is the various protocols used to communicate across the network. A popular foundation for those protocols is the Open System Interconnect (“OSI”) model of the International Standards Organization. Using that model or a derivative thereof, protocols can be developed which work in concert with each other. A popular communication protocol includes the Transmission Control Protocol (“TCP”) and the Internet Protocol (“IP”). TCP/IP are used in networks that are known as packet-switched networks. The advent of asynchronous transfer mode (“ATM”) has brought about a divergence from packet-based standards to one using a cell-switched network. Packet-switched and cell-switched networks are in contrast with circuit-switched networks, such as the telephone system. As opposed to maintaining a fixed routing connection for the transmitted message, packet or cell switching evenly allocates or “switches” packet or cell portions of the message across dissimilar routes of the network. The term packet switching henceforth refers generically to switching message portions, regardless of whether that portion is a cell or packet.
In a packet-switched network, each packet of a particular message may be sent across different routes of the network at the same time and then reassembled at the proper termination device. In order to ensure the packets are properly received, certain layers of the OSI protocol stack will wrap the data before the data is sent across the network. For example, TCP can divide data into segments which are then placed into, for example, IP datagrams having a header which includes the IP address of the originating and receiving termination devices. It is not until the IP has been wrapped possibly several times will the TCP be forwarded across the network.
The IP datagram can be further wrapped using a Point-to-Point Protocol (“PPP”), a popular such protocol being that which follows the Ethernet specification at the physical or data transport layer of the OSI model. As the datagram is transferred across the network, the addressing header contains both the source and destination address. The source address and destination address can be represented in different domains. For example, the termination device which transmits the datagram can be considered the source, whereby the source can be represented with possibly numerous source addresses. At the network or internet layer, the source address can be represented as an IP address, whereas at the physical or data transport layer, the source address can also be represented as an Ethernet or Token Ring address. The same applies for the destination address. Depending on whether the source and destination are in an Ethernet network or a Token Ring network, their addresses follow the protocol used by those networks.
The various networks of an internet can be connected in different ways. For example, dedicated telephone lines can transmit data between networks, or a satellite link can be employed. In addition, routers, satellites, fiber-optic cables, and special ISDN telephone lines, or high-speed DSL connections are used to pass information between networks. Regional networks are connected to one another via high-speed backbones, i.e., connections that can send data from one regional network to another. The regional networks can be configured either as Token Ring networks or as an Ethernet server/host (with clients coupled thereto).
Routers are used to direct traffic across the internet and between regional networks. Routers function to open the IP addressed packet and read the IP destination address. Routers can then calculate the best route, and send the packet toward that final destination. The mechanism for determining the best route involves comparing the destination addresses against an internal database called the routing table. Routing tables are generally dynamic in nature and can accommodate multiplicity of nodes and/or forwarding modules of a rather large internet or intranet having IP identification numbers and Ethernet identification numbers (addresses) that can change as the modules are reconfigured with new routers, bridges, switches, and/or gateways. In this manner, conventional networks purposely rely upon the internal modules or nodes having a non-structured identification numbers or addresses. In this manner, the multiple subnetworks which form the internet can be updated and varied with new modules and corresponding addresses not knowing necessarily the addresses of the other modules or nodes. All that is required is that the routing tables within the routers be updated or periodically programmed. However, one router on the network will not necessarily know the location of the physically closest router or its placement within the network. The router will simply route based on its existing routing table and the resulting look-up outcome. Such a system can be considered a non-relative or non-deterministic router topography. Non deterministic routers tend to rely on the number of hops (i.e., the number of routers or gateways) when determining the optimal routing path. Thus, while a router may know the number of additional routers on a given path, it does not necessarily know or have a link to the identity and relative placement of those routers.
As a precept to the routing function of a router, each node of a regional network and the multiplicity of nodes across numerous regional networks, have a common identifier. That is, each node across an intranet or internet between a source termination device and a destination termination device has an identification number to allow a router to route data across a plurality of nodes and eventually to a destination node, or termination device. While the identifier can dynamically change, it is important that the identifiers be unique to their corresponding nodes so that addressing can be specific from one node to another throughout the routing process. Regardless of whether the nodes and termination devices use high speed Ethernet, or even higher speed, for example, Synchronous Optical Networks (“SONETs”), a singular (or common) addressing domain is needed across all nodes of an interlinked set of regional networks which form an intranet or internet.
Using a common addressing domain for each and every node of an internet or intranet having possibly numerous subnets, poses several problems. For instance, a 32-bit address domain is well-known and typically used in IP networking. To access the Internet spread across the global environment of termination devices, every access point (or interface) needs to have a unique IP address in the same 32-bit domain. 32-bit addressing provides for four gigabit IP addresses. However, four-gigabit addressing may soon be insufficient in the ever growing world of inte
Chin Wellington
Conley & Rose, P.C.
Daffer Kevin L.
Dunti LLC
Schultz William
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