Patent Application
20060013231
A network may be characterized by several factors, such as who can use the network, the type of traffic the network carries, the medium carrying the traffic, the typical nature of the network's connections, and the transmission technology the network uses. For example, one network may be public and carry circuit-switched voice traffic while another may be private and carry packet-switched data traffic. Whatever the make-up, most networks facilitate the communication of information between at least two nodes, and as such act as communications networks.
At a physical level, a communication network may include a series of nodes interconnected by communication paths. Whether a network operates as a local area network (LAN), a metropolitan area networks (MAN), a wide are network (WAN) or some other network type, the act of designing the network becomes more difficult as the size and complexity of the network grows. When designing a given network, an operator or provider may decide where to physically locate various network nodes, may develop an interconnection strategy for those nodes, and may prepare a list of deployed and/or necessary networking components.
It will be appreciated that for- simplicity and clarity of illustration, elements illustrated in the Figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements are exaggerated relative to other elements. Embodiments incorporating teachings of the present disclosure are shown and described with respect to the drawings presented herein, in which:
Given the relative complexity of some communication networks, designers may invest substantial time and money to develop a feasible design for a given network. A feasible design may be one that satisfies design objectives like network coverage, network availability, and traffic demands, while considering that design limiters prefer defined limitations on equipment and/or interconnection topology.
In one form of the present disclosure, one or more core layer node and aggregator nodes are combined within the same node to reduce the number of physical nodes/locations required to employ a network. Such an embodiment displays several advantages over conventional networks that utilize separate nodes locations to access each layer. For example, the overall number of nodes or network elements required within a network may be reduced through the use of multiple-layer access nodes or elements and, as a result, the costs associated with cabling and electronics may be reduced. In other words, providing a multiple-layer node may assist in limiting the amount of hardware needed to deploy a desired network thereby reducing the overall cost of the network without sacrificing network performance.
Larger networks are often designed in layers. Each layer has its own roles and responsibilities. The goal of many network designers is to create a network that delivers high performance while maintaining a high degree of manageability. The following disclosure focuses on a layered design consisting of three layers, including a core layer, an aggregation layer, and an access layer.
From a high level, the core layer of a network may perform the backbone-like functions and may need to be both high speed and redundant. The aggregation layer may contain intermediate switches and routers, such as those used to route between subnets or VLANs. And, the access layer may be the point at which users actually plug into their local switch.
In practice, each layer in the model may have a primary responsibility and may be tasked with performing specific functions. As such, nodes of a given layer may need to have specific capabilities unique to that node's assigned layer. For example, the core layer may need to act as a high-speed switched backbone. A typical core layer node, therefore, does not perform routing functions. Core layer nodes may instead be expected to focus on switching traffic. Asking a core layer node to route traffic may reduce overall network performance, because each frame typically must be recreated as it passes through a router. In the core layer, the traffic tends to stay at OSI Layers 1 and 2 instead of having to be considered at Layer 3.
Unlike the core layer, the aggregation layer is the layer at which the routing functions are likely to be performed. The aggregation layer may also represent the point at which various traffic policies are implemented. This may be accomplished with the assistance of access lists maintained in network repositories.
As mentioned above, the access layer may act as the point at which end stations connect to the network. A typical interface into the layered network may involve plugging into a Layer 2 switch or hub. As such, one of the primary responsibilities at the access layer is management of network collision domains. The access layer may also be used to define additional network security policies and filtering.
In an MPLS-based network, a network operator may enjoy greater flexibility when routing traffic around link failures, congestion, and bottlenecks. From a Quality of Service (QoS) perspective, MPLS-based networks may also allow network operators to better manage different kinds of data streams based on priority and/or service plans.
In operation, a packet entering an MPLS network may be given a “label” by a Label Edge Router (LER). The label may contain information based on routing table entry information, Internet Protocol (IP) header information, Layer 4 socket number information, differentiated service information, etc. As such, different packets may be given different Labeled Switch Paths (LSPs), which may “allow” network operators to make better decisions when routing traffic based on data-stream type.
An EON like network 20, as illustrated in
As shown, EON 20 also includes a core node 24 coupled to PE-POP 23 via communication ports 26, which may be operable to communicate information between nodes within EON 20. Core node 24 may serve core layer functions and may enable the high speed switching of traffic that is communicated between different aggregation layer nodes or PE-POP nodes.
PE-POP node 23 and core node 24 are typically provided as separate nodes having different physical locations within a network. As shown in
In embodiments where multiple-layer node 29 also performs core layer switching, node 29 facilitates a reduction in the amount of network nodes. Depending upon the complexity of the network topology, data may be communicated upstream/downstream from multiple-layer node 29, to another core node, to a different aggregation node, to another multiple-layer node, to access layer nodes, etc.
As such, EON 33 presents several advantages over typical networks that may employ discrete boxes to perform aggregation layer and core layer processing. For example, the overall number of fibers needed within EON 33 may be reduced, the overall number of routers and switches may be reduced, the amount of common equipment may be reduced, the number of repeaters between each node or network element may be reduced, a reduction in the number of remote test heads may be provided, the amount of supporting test equipment may be reduced, and a reduction in network traffic may be realized. One or more of these advantages should enable a network operator to increase a network's efficiency, reduce network latency, and lower the amount of power needed to operate the network.
Depending upon implementation detail, one or more elements within EON 33 may be configured with encoded logic to assist with accessing and/or processing one or more layers of the OSI stack. Such encoded logic may be provided as computer-readable mediums having computer-readable instructions capable of instructing a network node to perform aggregation layer functions, to perform core layer functions, and/or to perform access layer functions, as needed. For example, multiple-layer node 29 may include encoded logic operable to allow for switching traffic at Layer 2 and routing traffic at Layer 3.
Several techniques may be used to provide for such a capability. Node 29 may employ a parallel processing schemas that make use of a multi-tasking processing engine. Node 29 may make use of discrete computing platforms—one dedicated to Layer 2 operations and another dedicated to Layer 3 operations. Node 29 may also elect to have both an internal core layer engine and an internal aggregation layer engine. Other techniques may also be utilized without departing from the teachings disclosed herein, and a choice of which technique to utilize may be determined by network design details, implementation details, and/or cost concerns.
At step 312, a type of processing needed is determined and access to an appropriate mechanism is provided at step 314. If aggregation layer capability is needed, traffic from one or more sources may be routed for aggregation layer treatment at step 316 and an aggregation layer processing routine may be deployed at step 318 to properly work on the traffic. For example, an originating node or address for the data traffic may be communicatively-coupled to the multiple-layer node via an aggregation layer port, and the multiple-layer node may recognize that traffic arriving via the port needs to be internally routed to a module capable of handling aggregation layer functionality.
Similarly, if some core layer capability is needed, traffic from one or more sources may be routed for core layer treatment at step 320 and a core layer processing routine may be deployed at step 322 to properly work on the traffic. As indicated above, the mechanism used to distinguish between traffic needing core layer processing and aggregation layer processing may be as simple as hard-wiring specific ports to specific modules. The mechanism may also involve actually looking at and/or sniffing information contained in the packet being received by the multiple-layer node. The node may look at information contained in a packet header, for example, and make a determination based on that information. The node may also use other technologies like VLAN tagging and/or MPLS to assist in making a proper determination.
However accomplished, traffic received at step 312 may be properly processed and communicated to the next node in the network chain at step 324. The method may then proceed to step 26 where the method is repeated based on access and/or required processing. As such, a single node or network element may be used to combine processing of both core layers and aggregation layers thereby increasing the efficiency of an EON system. It should be understood that
EON 70 illustrates specific layers for handling network traffic based on access privileges and functionality that is specific to each node within EON 70. For example, each CPE element may communicate information to and from an access layer node. Aggregation processing modules 53 and 56 may be configured to manage aggregation layer functions, and core layer processing module 54 may be configured to manage core layer functions. Each node or element may be aligned with a specific layer to enable efficient management of network traffic within EON 70. However, multiple-layer node 55 may straddle the aggregation layer and the core layer paradigms, and allow for aggregation layer and core layer processing of network traffic.
In one embodiment, aggregation layer processing modules 53 and 56, core layer processing module 54, and combined processing module 55 may be included within a single device configured to perform the functionality of two or more network layers. For example, a network designer may elect to utilize a Cisco 7609 IP/MPLS switch to perform multiple-layer functionalities.
Within network 70, the communication of network traffic may be provided by fiber optic interconnects, fibers, etc.—facilitating metropolitan Ethernet services. As such, additional components, such as repeaters, may be utilized based on network complexity, size, cable distance, db loss, etc. Redundancy of communication mediums may also be provided via EoMPLS-VC 60 and backup VC 59 connections.
During operation, network traffic may be communicated from CPE sites 50 and 51 using aggregation node 53. Similarly, network traffic for CPE sites 57 and 61 may be consolidated using aggregation node 56. Core node 54 may support aggregation nodes 53 and 56 by enabling switched communication with other core layer nodes. Network traffic for each of aggregation nodes 53 and 56 may further be routed to multiple-layer node 55, which may be operable to access both the aggregation layer and the core layer. As shown, multiple-layer node 55 is coupled to CPE sites 52 and 58, and provides efficient processing of data by reducing the number of nodes required to access both aggregation and core layers. In this manner, processing of data associated with CPE sites 52 and 58 may be reduced thereby limiting the level of network complexity and overall network traffic within EON 70.
Many of the above techniques may be provided by a computing device executing one or more software applications or engines. The software may be executing on a single system, node, more than one, etc. It will be apparent to those skilled in the art that the disclosed embodiments may be modified in numerous ways and may assume many embodiments other than the particular forms specifically set out and described herein.
Accordingly, the above-disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments that fall within the true spirit and scope of the present invention. Thus, to the maximum extent allowed by law, the scope of the present invention is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.
