Patent Application
20050141504
The present invention relates to communication networks, and, more particularly, to multiprotocol label switching (MPLS) communication networks.
Multiprotocol label switching (MPLS) provides a technique for routing packet data based on a label field rather than a destination address. An MPLS network comprises a set of nodes, which are called label switched routers (LSRs), that switch/route packets based on a label that has been added to each packet. Labels are used to define a flow of packets between two nodes or, if packets are being broadcast in a multicast operation, between a source node and multiple destination nodes. A specific path through the LSRs, which is called a label switched path (LSP), is defined for each distinct flow, which is called a forwarding equivalence class (FEC). At intervening nodes in an LSP, an LSR may route the packet based on the MPLS label value, remove the MPLS label (pop a label), and/or impose an additional label (push a label). The label may be removed at the node from the packet at a node that is just prior to the destination node in a particular LSP. This process is sometimes referred to as “penultimate hop popping.”
Referring now to
Customers of telecommunications services may request higher bandwidth service at key sites, such as data centers and/or headquarters locations, but may not wish to make changes at their numerous branch or spoke sites. More specifically, customers may desire layer two data services that aggregate or interwork their diverse access technologies (e.g., Ethernet, frame relay, ATM, DSL, private lines, etc.) where the aggregation is at layer two or frame layer for efficiency and the wide area network (WAN)/metro area network (MAN) connectivity is across the WAN, not just within a metro region or local access and transport area (LATA). Existing RFC 2547bis and other IP-Virtual Private Network (VPN) technologies may provide layer three VPN services, but, unfortunately, these technologies do not address layer two VPN services. Currently layer two VPN proposals do not provide for multiple layer one and layer two technology aggregation capability on the same interface using MPLS and the option of static LSP provisioning and signaling over a RFC2547bis VPN.
According to some embodiments of the present invention, a multiprotocol label switching (MPLS) network is operated by establishing a label switched path (LSP) that connects a first provider edge (PE) label switched router (LSR) a second PE LSR, and a customer edge (CE) LSR. The packet traffic that is associated with a plurality of different layer two technologies is encapsulated with an MPLS label. The encapsulated traffic is securely routed from the first PE LSR through the second PE LSR to the CE LSR using the LSP.
In other embodiments of the present invention, the layer two technologies comprise asynchronous transfer mode (ATM) technology, frame relay technology, point-to-point protocol/high level data link control (HDLC) technology, private line time division multiplexing (TDM), and/or Ethernet technology.
In still other embodiments of the present invention, the MPLS label is signaled between the first PE LSR and the CE LSR and the second PE LSR uses an internal service provider IP-virtual private network to maintain a securely partitioned network for customers.
In further embodiments of the present invention, the MPLS label is statically provisioned from the second PE LSR to the CE LSR and stitched to a signaled LSP in a service provider network that connects the first and second PE LSRs.
In still further embodiments of the present invention, a pseudo wire virtual circuit is provisioned within the LSP for each one of a plurality of attachment circuits at the first PE LSR.
In still further embodiments of the present invention, the LSP and/or pseudo wires, which are terminated via signaling at the second PE LSR, transit on to the CE LSR.
In still further embodiments of the present invention, each of the packets comprising the packet traffic comprises a control word that identifies one of the plurality of different layer two technologies that the respective packet is associated with.
Other systems, methods, and/or computer program products according to embodiments of the invention will be or become apparent to one with skill in the art upon review of the following drawings and detailed description. It is intended that all such additional systems, methods, and/or computer program products be included within this description, be within the scope of the present invention, and be protected by the accompanying claims.
Other features of the present invention will be more readily understood from the following detailed description of specific embodiments thereof when read in conjunction with the accompanying drawings, in which:
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the claims. Like reference numbers signify like elements throughout the description of the figures.
The present invention may be embodied as systems, methods, and/or computer program products. Accordingly, the present invention may be embodied in hardware and/or in software (including firmware, resident software, micro-code, etc.). Furthermore, the present invention may take the form of a computer program product on a computer-usable or computer-readable storage medium having computer-usable or computer-readable program code embodied in the medium for use by or in connection with an instruction execution system. In the context of this document, a computer-usable or computer-readable medium may be any medium that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device.
The computer-usable or computer-readable medium may be, for example but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium. More specific examples (a nonexhaustive list) of the computer-readable medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, and a portable compact disc read-only memory (CD-ROM). Note that the computer-usable or computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via, for instance, optical scanning of the paper or other medium, then compiled, interpreted, or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory.
As used herein, the term “protocol” refers to a defined set of rules that govern the exchange of data or information between two or more entities. In addition, a “protocol layer” refers to the hierarchical protocol structure represented by the open systems interconnection (OSI) model developed by the International Organization for Standardization in which layer one corresponds to the physical layer, layer two corresponds to the data link layer, layer three corresponds to the network layer, layer four corresponds to the transport layer, layer five corresponds to the session layer, layer six corresponds to the presentation layer, and layer seven corresponds to the application layer.
Referring now to
The first PE LSR 205 comprises a layer two aggregation and LSP signaling module 250. The second PE LSR 210 comprises an LSP signaling and static provisioning module 255. In accordance with some embodiments of the present invention, the layer two aggregation and LSP signaling module 250 may be configured to aggregate packet traffic that is associated with multiple types of layer two technologies by encapsulating that traffic with one or more MPLS labels. As shown in
The second LSR 210 may establish label switched paths (LSPs) with a hub site 240 associated with a customer. In accordance with some embodiments of the present invention, the pseudo wire virtual circuits may be provisioned within the LSPs at CE LSR 245 for each attachment circuit that is associated with the layer one and two technologies that the customer is using at the spoke locations. For example, the customer may establish a permanent virtual circuit through the ATM/FR network 215 to the PE LSR 205, which may be represented as a pseudo wire virtual circuit at the CE LSR 245. Moreover, the customer may establish a virtual local area network (VLAN) connection through the Ethernet network 220 to the PE LER 205, which may be represented as a pseudo wire virtual circuit at the CE LSR 245. In accordance with further embodiments of the present invention, the LSP between the PE LSR 205 and CE LSR 245 may be signaled up to the second PE LSR 210 from which point it may be statically provisioned or signaled to the CE LSR 245. This is because the first PE LSR 205 terminates traffic from a customer spoke site, which means traffic from multiple customers terminates at the first PE LSR 205. Only the customer that is associated with the hub site 240 is aware of the static label associated with the LSP that connects to the hub site 240 and so that customer is now aware of any other customer or SP LSP labels. Provisioning may effectively stitch the LSP in the SP network statically to a LSP between the PE LSR and the CE LSR. The PE may be required to disintermediate (i.e., interwork) between the SP and the MPLS UNI labels. If the LSP is signaled, then the SP network may support an internal IP-VPN partition for each customer upon which the LSPs will be encapsulated. This is to prevent other customers from accessing the hub site 240 or spoke sites, which are associated with a particular customer, or from potentially interfering with the operation of the SP network. Thus, according to some embodiments of the present invention, signaling options may be provided as part of service provider IP-VPNs (e.g., RFC-2547bis) that are not exposed to the customer for security partitioning.
The service provider network 200 is associated with encapsulation of traffic for multiple layer one and two technologies, which may be considered an enhanced service because it uses computer-based processing applications to provide the customer with value-added telecommunications services, such as protocol conversion.
Although
The present invention is described hereinafter with reference to flowchart and/or block diagram illustrations of methods, systems, and computer program products in accordance with exemplary embodiments of the invention. It will be understood that each block of the flowchart and/or block diagram illustrations, and combinations of blocks in the flowchart and/or block diagram illustrations, may be implemented by computer program instructions and/or hardware operations. These computer program instructions may be provided to a processor of a general purpose computer, a special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer usable or computer-readable memory that may direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer usable or computer-readable memory produce an article of manufacture including instructions that implement the function specified in the flowchart and/or block diagram block or blocks.
The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions that execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart and/or block diagram block or blocks.
Operations for encapsulating packet traffic that is associated with multiple layer two technologies in accordance with some embodiments of the present invention will now be described with reference to
Advantageously, the present invention may allow traffic from multiple types of layer two technologies to be aggregated without regard to the layer three protocol used in a way that provides protocol conversion and may meet regulatory constraints, for example, for regulated service providers that wish to provide service across local access and transport area (LATA) boundaries.
The flowchart of
Many variations and modifications can be made to the embodiments described herein without substantially departing from the principles of the present invention. All such variations and modifications are intended to be included herein within the scope of the present invention, as set forth in the following claims.
