This invention relates to packet switched networks, and more particularly to systems and method whereby a service provider can migrate a range of existing services over a consolidated MPLS core.
Packet switched networks in general have the potential to reduce the complexity of a service provider's infrastructure by allowing virtually any existing service to be supported over a single networking infrastructure.
Packet switched networks, unlike circuit switched networks, configure data into packets which are switched through shared transmission resources. One of the packet switched mechanisms receiving considerable attention at the present time is multi-protocol label switching (MPLS). MPLS was originally developed to provide faster packet forwarding than traditional IP routing and its flexibility has led to it becoming the default way for modern networks to achieve the quality of service and next generation VPN services.
Traditional IP networks are connectionless: when a packet is received the router determines the next hop using the destination IP address on the packet alongside information from its own forwarding table. The router's forwarding tables contain information on the network topology. They use an IP routing protocol or static configuration to keep their information synchronized with changes in the network. MPLS also uses IP addresses to identify end points and intermediate switches and routers. This makes MPLS networks IP-compatible and easily integrated with traditional IP networks. However, unlike a traditional IP, MPLS flows are connection-oriented and their packets are routed along preconfigured label switched paths (LSPs).
MPLS works by tagging packets with an identifier or a label to distinguish the LSP. When a packet is received, the router reuses this label and sometimes also the link over which it was received to identify the LSP. It then looks up the LSP in its own forwarding table to determine the best link over which to forward the packet, and the label to use on this next hop. A different label is used for each hop and is chosen by the router or switch performing the forwarding operation. This allows the use of very fast and simple forwarding engines as the router can select the label to minimize processing.
Although MPLS core networks represent promise for the future as they dramatically lower the per bit transport cost for carriers while insuring that quality of service capabilities are maintained introduction of this new layer and technology into the network poses new operational challenges. Significant network management capabilities are needed to complement the introduction of MPLS if operational cost reductions are to be achieved and if the full technological benefits of MPLS are to be realized. MPLS enabled network management systems are needed to deliver the operational savings expected from the transition to the new network infrastructure. These management solutions need to provide capabilities to extend the quality of service based end-to-end provisioning and assurance capabilities of frame relay/asynchronous transfer mode (FR/ATM) to the new IP/MPLS fabrics.
Network management systems such as the Alcatel 5620 IP/MPLS data network management architecture is an important tool in broadband management and in particular for multi services networks in which an MPLS core is used to provide end-to-end connection through provider edge routers. The provider edge routers typically implement ATM, frame relay or ethernet technologies, for example.
A pseudo wire is a point-to-point connection between pairs of provider edge routers. Its primary function is to emulate service like ATM or ethernet over an underlying core MPLS network through encapsulation into a common MPLS format. By encapsulating services into common MPLS format a pseudo wire allows carrier to converge their services to an MPLS network.
A prior art system such as that described above is illustrated in
Accordingly, there is a need for a management entity which will overcome these limitations.
The present invention allows a provider to migrate existing ATM networks, for example, over a consolidated MPLS core without undue difficulty.
Therefore, in accordance with a first aspect of the present invention there is provided a networking infrastructure for logically connecting edge devices over a multi-protocol label switching (MPLS) core to migrate multiple network services employing a packet switch network link (PSNL) and a management entity to provide end-to-end management of the edge devices and the PSNL.
In accordance with the second aspect of the invention there is provided a method of managing an end-to-end connection between edge devices for transporting multiple network services over a MPLS core, the method comprising: providing a packet switch network link PSNL between the edge devices, the PSNL emulating physical connectivity; and providing a management entity for managing both the PSNL and the multiple network services.
In accordance with the further aspect of the invention there is provided a system for implementing and managing services between service networks at opposite ends of a network infrastructure having a multi protocol label switching (MPLS) core the system comprising a packet switch network link acting as an abstraction of the MPLS core and hiding layer-3 specific configuration associated with the service network; and a layer-2 network manager to provide end-to-end management across the service network and the MPLS core.
The invention will now be described in greater detail with reference to the attached drawings wherein:
The basic architecture of the present invention is illustrated in
Since the PSNL appears as a basic layer-2 connectivity it allows a customer call to ride over it in the same manner as it would a physical link.
More importantly, however, connections that ride the PSNL have the full end-to-end management that is available to pure ATM calls namely statistics connection, rerouting, optimization, automatic recovery, diagnostic and maintenance operations.
As shown in
As PSNL acts as a layer-2 connectivity, the ATM Pseudo-Wire endpoint configuration on the MPLS edge [endpoints of the PSNL] will appear as an ATM connection [where VPI/VCI represent the Pseudo Wire Identifier].
Through the use of the present invention convergence/migration of ATM networks to MPLS core networks is achieved. This results in easy migration procedures for calls on networks, such as ATM core networks, to MPLS core networks with minimum effort. Most importantly, no special training is required as the PSNL looks and behaves like any other ATM physical link.
While particular embodiments of the invention have been described and illustrated it will be apparent to one skilled in the art that numerous changes can be made without departing from the basic concepts. It is to be understood, however, that such changes will fall within the full scope of the invention as defined by the appended claims.