Patent Application
20090257751
1. Field
Embodiments of the invention relate to the field of networking; and more specifically, to optical networks.
2. Background
Optically Switched Networks
An optically switched network is a collection of optically switched network devices interconnected by optical links made up of optical fiber cables. The optically switched network devices that allow traffic to enter and/or exit the optically switched network are referred to as access nodes; in contrast, any optically switched network devices that do not are referred to as pass-thru nodes (an optically switched network need not have any pass-thru nodes). Thus, the pass-thru nodes typically optically switch traffic carried on the optical network. An optical node refers to either an access or pass-thru node. Each optical link interconnects two optically switched network devices and typically includes an optical fiber to carry traffic in both directions. There may be multiple optical links between two optically switched network devices.
A given fiber can carry multiple communication channels simultaneously through a technique called wavelength division multiplexing (WDM), which is a form of frequency division multiplexing (FDM). When implementing WDM, each of multiple carrier wavelengths (or, equivalently, frequencies or colors) is used to provide a communication channel. Thus, a single fiber looks like multiple virtual fibers, with each virtual fiber carrying a different data stream. Each of these data streams may be a single data stream, or may be a time division multiplex (TDM) data stream. Each of the wavelengths used for these channels is often referred to as a lambda.
A lightpath is a one-way path in an optically switched network for which the lambda does not change. For a given lightpath, the optical nodes at which its path begins and ends are respectively called the source node and the destination node; the nodes (if any) on the lightpath in-between the source and destination nodes are called intermediate nodes. An optical circuit is a bi-directional, end-to-end (between the access nodes providing the ingress to and egress from the optically switched network for the traffic carried by that optical circuit) path through the optically switched network. Each of the two directions of an optical circuit is made up of one or more lightpaths. Specifically, when a given direction of the end-to-end path of an optical circuit will use a single wavelength, then a single end-to-end lightpath is provisioned for that direction (the source and destination nodes of that lightpath are access nodes of the optically switched network and are the same as the end nodes of the optical circuit). However, in the case where a single wavelength for a given direction will not be used, wavelength conversion is necessary and two or more concatenated lightpaths are provisioned for that direction of the end-to-end path of the optical circuit. Thus, a lightpath comprises a lambda and a path (the series of optical nodes (and, of course, the interconnecting links) through which traffic is carried with that lambda).
Put another way, when using Generalized Multiprotocol Label Switching (GMPLS) [RFC3471] on an optically switched network, the optically switched network can be thought of as circuit switched, where LSPs are the circuits. Each of these LSPs (unidirectional or bi-directional) forms an end-to-end path where the generalized label(s) are the wavelength(s) of the lightpath(s) used. When wavelength conversion is not used for a given bi-directional LSP, there will be a single end-to-end lightpath in each direction (and thus, a single wavelength; and thus, a single generalized label).
The term disjoint path is used to describe a relationship between a given path and certain other network resources (e.g., nodes, links, etc.). There are various levels of disjointness (e.g., maximally link disjoint, fully link disjoint, maximally node disjoint, and fully node disjoint; and each can additionally be shared risk group (SRG) disjoint). For instance, a first and second path are disjoint if the network resources they use meet the required level of disjointness.
Disjoint paths are formed for a variety of reasons, including to form restricted paths and protection paths. Restricted paths are formed to carry traffic that is not to travel through certain network resources for security reasons. Protection paths are used to provide redundancy; that is, they are used as alternate paths to working paths in case of a network failure of some kind. Protection paths are commonly implemented as either: 1) 1+1 protected; 2) 1:1 protected; or 3) 1:N mesh restored. A 1+1 or 1:1 protected path is a disjoint path from node A to node B in the network where one of the paths is a working path, and the other is a protection path. The working path and the protection path are typically established at the same time. In the case of a 1+1 protected path, the same traffic is carried on both paths, and the receiving node selects the best of the paths (i.e., if the one currently selected by the receiving node degrades or fails, that node will switch to the other). In contrast, in the case of a 1:1 protected path, traffic is transmitted on the working path; when a failure occurs on the working path, traffic is switched to the protection path. A mesh restored path from node A to node B is a pair of shared resource group disjoint paths in the network, where one of the routes is a working path and the other is a backup path. The capacity dedicated on the backup path can be shared with backup paths of other mesh-restored paths.
Connecting Optically and Electrically Switched Networks
As mentioned above, an access node allows traffic to enter and/or exit the optically switched network. When traffic is entering the optically switched network from an electrically switched network, the electrical network traffic must be placed onto a lightpath. The conversion of electrical signal to a light signal is carried out by the access node or any other device interfacing with the access node. An electrically switched network switches packets in the electrical domain typically using traditional packet routers and switches. A typical electrical switching device is represented as a “L2/L3 device” meaning the device switches packets in the electrical domain based on the electrical domain protocol encapsulations as illustrated in
Furthermore, in
In
Currently, traffic is converted between electrically and optically switched networks by two schemes: (i) mapping electrical network ports to wavelengths and (ii) mapping SONET channels to wavelengths.
Typically, access node 300 is deployed with one or more separate Quality of Service (QoS) type devices (such as an L2/L3 device that supports QoS) in front of it as illustrated in
As in
The 1:1 mapping between electrical network ports and wavelengths limits access nodes 300/332 in several ways: (1) traffic entering access nodes 300/332 on a given port cannot but be put on a wavelength other than the one mapped to that port (e.g. traffic entering port 304A cannot be transmitted on a lightpath using 2); (2) access nodes 300/332 cannot classify traffic into separate traffic flows according to the characteristics of access nodes 300/332 cannot classify the data packets carrying the traffic; (3) access nodes 300/332 cannot electrically switch packets to protected optical circuits; (4) access nodes 300/332 cannot associate a traffic flow with a particular optical service level; (5) access nodes 300/332 cannot aggregate traffic flows from multiple L2/L3 devices to the same wavelength, or separate multiple traffic flows from one wavelength to multiple L2/L3 devices; (6) access nodes 300/332 do not represent any visibility of the optically switched network to the electrically switched network; and (7) increasing the number of wavelengths used requires a corresponding increase in the number of access node 300/332 and L2/L3 device ports.
Another scheme used to map electrically switched and optically switched traffic is a 1:1 mapping between SONET channels and optical wavelengths. In
Although access node 350 does not have a strict 1:1 mapping between electrical network ports and wavelengths like access nodes 300 and 332, access node 350 still suffers from problems (1)-(7) above.
A method and apparatus for an electrically switched optically protecting network device is described. One embodiment of the invention establishes pairs of optical circuits between different electrically switched optically protecting network devices acting as access nodes of an optically switched network. The network device communicates different add/drop traffic flows between externally facing ports of different electrically switched optically protecting network devices by transmitting over the optical circuit. In addition, the network device optically switches optical circuits for which the network device is an intermediate node and electrically switches packets between different ones of the network devices' externally facing ports and those of the optical circuits for which the network device is an end node. Furthermore, the network device protects the communication of traffic flows across the optical network by controlling the packet electrical switching to the pairs of optical circuits.
The invention may best be understood by referring to the following description and accompanying drawings that are used to illustrate embodiments of the invention. The numbering scheme for the Figures included herein are such that the leading number for a given element in a Figure is associated with the number of the Figure. For example, access node 300 can be located in
In the following description, numerous specific details are set forth (e.g., such as logic resource partitioning/sharing/duplication implementations, types and interrelationships of system components, and logic partitioning/integration choices). However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known circuits, software instruction sequences, structures and techniques have not been shown in detail in order not to obscure the understanding of this description.
References in the specification to “one embodiment”, “an embodiment”, “an example embodiment”, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.
In the following description and claims, the terms “coupled” and “connected,” along with their derivatives, may be used. It should be understood that these terms are not intended as synonyms for each other. Rather, in particular embodiments, “connected” may be used to indicate that two or more elements are in direct contact with each other (e.g., physically, electrically, optically, etc.). “Coupled” may mean that two or more elements are in direct contact (physically, electrically, optically, etc.). However, “coupled” may also mean that two or more elements are not in direct contact with each other, but yet still co-operate or interact with each other.
According to embodiments of the invention, a group of network devices act as access nodes between an optically switched VDM network and an electrically switched network. The access nodes integrate electrical and optical switching functions by electrically switching packets to/from those optical circuits for which the node is an end node, and by optically switching those optical circuits for which the node acts as an optical circuit intermediate node. According to another aspect of the invention, an access node provides electrically switched optical protection by controlling the electrical switching of the packets to/from optical circuits pairs to protect the communication of the traffic flows. According to another aspect of the invention, an access node electrically switches to aggregate multiple traffic flows onto a single wavelength. Conversely, the access node electrically switches to separate aggregated traffic flows carried on the single wavelength. According to another aspect of the invention, optical circuits terminated by the access nodes are represented in the forwarding databases of electrically switched devices as single hops between access node endpoints of the optical networks.
Since each of the above aspects is independent, different embodiments may implement different ones, different combinations, or all of the above aspects of the invention. For example, certain embodiments of the invention include an access node that integrates electrical and optical switching with electronically switched optical protection. In addition to the switch integration and optical protection, the access node further aggregates multiple traffic flows from multiple L2/L3 devices onto a variety of WDM wavelengths including aggregating multiple traffic flows onto a single WDM wavelength. Furthermore, the access node includes a mapping of optical circuits comprising the WDM network and the access nodes terminating the optical circuits. The access node represents this mapping to L2/L3 devices in the electrically switched network as a collection of single hops between the access nodes endpoints. The L2/L3 devices use this representation in there forwarding database to make decision on forwarding packets.
Of course, one or more parts of an embodiment of the invention may be implemented using any combination of software, firmware, and/or hardware. Such software and/or firmware can be stored and communicated (internally and with other access nodes over the network) using machine-readable media, such as magnetic disks; optical disks; random access memory; read only memory; flash memory devices; electrical, optical, acoustical or other form of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.); etc.
Each DTSP 402A-D acts an access node by bridging the optically switched 416 and electrically switched 420 networks. Each DTSP 402A-D comprises an optical transport part 404A-D that couples to optical network 418. Furthermore, each DTSP 402A-D comprises packet electrical switching part (414A-414C for DTSP 402B-D and 406A-N for DTSP 402A) and an optically aware aggregation switch 410A-D. The packet electrical switching part (414A-C for DTSP 402B-D and 406A-N for DTSP 402A) may electrically switch traffic between electrically switched network 420 and optically switched network 416. In addition, packet electrical switching part (414A-C for DTSP 402B-D and 406A-N for DTSP 402A) electrically switches traffic in-between L2/L3 devices 408A-F in electrically switched network 420 without traffic being part of the optical domain. Optically aware aggregation switch 410A-D aggregates traffic into traffic flows from the electrically switched network 420 onto wavelengths transmitted by optical transport 404A-D. Conversely, optically aware aggregation switch separates aggregated traffic flows carried on the wavelengths from the optically switched network 416 to the electrically switched network 420. Each optically aware aggregation switch can support one or more packet electrical switches (414A-414C for DTSP 402B-D and 406A-N for DTSP 402A). In an exemplary embodiment, each optically aware aggregation switch 410A-D supports up to eight packet electrical switches (414A-C for DTSP 402B-D and 406A-N for DTSP 402A). In addition, each packet electrical switch 406A-N switch may couple to multiple L2/L3 devices 408A-F. Furthermore, each optically aware aggregation switch 410A-D includes a protection unit 412 that controls electrically switched optical platform for traffic flows using one or more of the traffic protection schemes outlined above. For example, protection unit could provide protection for a traffic flow such as, but not limited to, 1+1, 1:1, 1:N, etc.
Optical transport parts 404A-D participate in provisioning of optical circuits in the optical network 418. Provisioning the optical network 418 may be implemented differently in different embodiments. By way of example, and not limitation, it may be completed as described in (Ser. No. 10/455,933, filed Jun. 6, 2003; Ser. No. 10/626,055, filed Jul. 23, 2003; Ser. No. 10/626,363, filed Jul. 23, 2003; and Ser. No. 10/862,142, filed Jun. 3, 2004).
As in
Different embodiments may generate map 406A-D in different ways; by way of example, several embodiments immediately follow. In one embodiment, an operator manually generates map 406A-D on each DTSP 404A-D by entering values for the other boundary DTSPs. For example, and by way of illustration, the operator manually enters in each DTSP 404A-D that DTSP 404A is connected with L2/L3 device 104, DTSP 404B is connected with L2/L3 device 130, DTSP 404C is connected with L2/L3 device 106. Because DTSP 404D is not connected to any L2/L3 device in this example, DTSP 404D is not an entry in the map. In one embodiment, map 406A-D is as illustrated in Table 1. Alternatively, map 406A-D contains addresses of DTSP 404A-C and L2/L3 devices (104, 106 and 130). In a further embodiment, map 406A-D contains address(es) of DTSP 404A-C and networks accessible by L2/L3 devices 104-106 and 130.
In another embodiment, the operator enters the addresses for L2/L3 device 104-108 and 130 connected to each boundary DTSP 404A-D and DTSP 404A-D automatically exchanges with other DTSP 404A-D the L2/L3 device (104-108 and 130) connection information. For example, and by way of illustration, the operator: enters at DTSP 404A that DTSP 404A is connected to L2/L3 device 104; enters at DTSP 404B that DTSP 404B is connected to L2/L3 device 130; and enters at DTSP 404C that DTSP 404C is connected to L2/L3 device 106. Typically, once the operator completes entering of the local connection information at each DTSP, DTSPs 404A-D automatically exchanges the connection information. Automatically exchanging the connection information creates the map 406A-D as illustrated in Table 1. This embodiment lessons the need for operator involvement as compared with the fully manual embodiment above.
In another embodiment, each DTSP 404A-D discovers the L2/L3 devices (104-108 and 130) connected to it and automatically exchanges the connection information with the other DTSPs in the optically switched network 402. For example and by way of illustration, DTSP 404A discovers that it is connected to L2/L3 device 104, DTSP 404B discovers that it is connected to L2/L3 device 130, and DTSP 404C discovers that it is connected to L2/L3 device 106. The DTSPs automatically exchange the connection information with other DTSPs. As above, exchanging of the connection information creates map 406A-D.
As in
Because DTSP 510A-D expose map 512A-D to the neighboring L2/L3 devices 504, 506 and 516, neighboring devices L2/3 504, 506 and 516 device may discover new routes to inaccessible L2/L3 devices and/or associated networks. For example and by way of illustration, in
Each DTSP 604A-D contains map 612A-D and routing protocol 614A-D. Map 612A-D comprises similar DTSP 604A-D and L2/L3 device (104-108 and 130) connection information as illustrated in
Each connection in this table represents one or more optical circuits between the DTSP pair. Thus, the routing protocol connection table represents an abstraction of optically switched network 602 to the electrically switched network 102.
Furthermore, DTSP 604A-D acts as a L2/L3 device in the electrically switched network 102. Routing protocol 614A-D exposes the packet electrical switch part of DTSP 604A-D to electrically switched network 102 via map 612A-D and routing protocol connection table 614A-D, so that each DTSP 604A-D appears as a node in electrically switched network 102. Thus, packet electrical switch part causes each DTSP 604A-D to act as an L2/L3 device in electrically switched network 102. Thus,
However, optically switched network 602 is not exposed to network 102. Instead, DTSP 604A-D are represented in the electrically switched network 102 as connected in a single hop mesh, regardless of the optical circuits interconnecting each DTSP 604A-D (e.g., as represented in routing protocol connection table (Table 2)). For example and by way of illustration, in the electrically switched domain, DTSP 604A connects to DTSP 604B-D with one hop. Furthermore, DTSP 604B-D are similarly interconnected in electrically switched network 102. Thus,
In addition and similar to
Thus, different embodiments may be implemented to operate in one or more different levels of network visibility (e.g., one or more of the exemplary network visibility levels from
DTSP 802A-D comprises an electrical switch part 804A-D and an optical transport part 806A-D. The electrical switch part 804A-D comprises three parts: packet line card(s) 814A-D, packet electrical switch module 808A-D and WDM transmit/receive modules (WTR) 810A-H. The packet line card(s) 814A-D transmit and receive packets with the electrically switched network (such as electrically switched network 102 in
Packet electrical switch module 808A-D processes the received packets from packet line card(s) into traffic flows and electrically switches the traffic flows to the appropriate WTR 810A-H for transmission onto wavelengths in the optically switched network. Traffic flows are groups of packets with similar characteristics. Examples of packet characteristics are, but not limited to, IP source, IP destination, IP source port, IP destination port, MPLS tag, VLAN tag, MAC source address, MAC destination address, DSCP bit, ATM virtual circuit information (VCI)/virtual path information (VPI), etc. or combinations thereof. Conversely, the packet electrical switch module 808A-D processes the received packets from the WTR 810A-H into traffic flows and electrically switches the traffic flows to the appropriate packet line card(s) 814A-D for transmission to the electrically switched network.
WTR 810A-H receives traffic flows from packet electrical switch module 808A-D and adapts the packets in the traffic flow for transmission on a wavelength. In one embodiment, WTR 810A-H encapsulates each packet with a DWDM 200 protocol layer. Alternatively, WTR 810A-H encapsulates each packet with OTN 202 and DWDM 200 protocol layers. With a properly encapsulated packet, WTR 810A-H transmits each packet in a traffic flow on a corresponding DWDM wavelength. Furthermore, each WTR 810A-H can receive multiple traffic flows and transmit these traffic flows on different DWDM wavelengths.
Furthermore, WTR 810A-H receives packets on multiple DWDM wavelengths from the optically switched network. In addition, WTR 810A-H coverts the packets to be ready for electrical switching with packet electrical switch module 808A-D by decapsulating the DWDM protocol layer 200 or and possibly OTN 202 protocol layers from packets carried on the DWDM wavelength. WTR 810A-H forwards the deencapsulated packets to packet electrical switch module 808A-D.
Referring back to
Returning to
Thus, different embodiments may be implemented to perform one or more different applications combinations of applications (e.g., one or more of the exemplary applications or from
Returning to
In one embodiment, NPU(s) 912B aggregates traffic flows with the same packet classification and forwards the aggregated traffic flows to corresponding WTR 916A-D. Specifically in
In addition, each WTR 916A-C may be a beginninglend point of an optical circuit, and thus encapsulate/decapsulate to/from a DWDM wavelength. Thus, WTR 916A-C encapsulates packets in traffic flows 906A-B and transmits the traffic flow on DWDM wavelengths. Specifically, WTR 916A transmits traffic flows 922A-B on wavelength λ1 924A; WTR 916B transmits traffic flows 922C-D on wavelength λ2 924B; and WTR 916C transmits traffic flows 922E-G on wavelength λ3. WTR 916A-C provides DWDM wavelengths to the optical switch module, which optically switches and multiplexes DWDM wavelengths onto different of the optical ports 918A-D. In turn, optical ports 918A-C forward the wavelengths λ1, λ2 and λ3 924A-C, respectively, on connected DWDM fibers. Alternatively, optical switch module 904 multiplexes wavelengths λ1 924A and λ2 924B onto the fiber coupled to optical port 918A.
In this embodiment and by way of illustration, traffic flows with the same packet classification are transmitted on the same wavelength. Alternatively, other embodiments can aggregate traffic flows with different packet classification transmitted on the same wavelength. Each traffic flow 922A-G is illustrated as unprotected working traffic flows. A working traffic flow is the main traffic flow used to transmit packets over the optical circuit.
Traffic flows 920A-C entering DTSP 900 on optical ports 918A-C are processed in a reciprocal fashion as traffic flows 906A-B entering on packet ports 910A-B. Traffic flows 920A-C entering optical ports 918A-C, respectively, are demultiplexed and optically switched by optical switch module 904 to the corresponding WTR 916A-C. WTR 916A-C converts the packets in traffic flows 920A-C into packets ready for processing by NPU(s) 912A-B. Specifically, WTR 916A-C deencapsulate and forward the converted packets in traffic flows 920A-C to NPU(s) 912B. Packet network processor(s) 912B separates traffic flows 920A-C into individual traffic flows 922A-G. In addition, NPU(s) 912B adds a node internal mark to each packet that signals to the electrical switch module 902 how to switch the packet. Electrical switch module 902 switches the individual traffic flows to NPU(s) 912A based on the marks added to the traffic flow packets by NPU(s) 912B. Packet network processor(s) 912A removes the node internal mark from each packet added by NPU(s) 912B and the traffic flow mark from each packet added by the source DTSP. Packet marking and removal of marks is further described in
In
However,
However, unlike in
In
In
In
Thus, different embodiments may be implemented to process traffic one or more different ways or combinations of ways (e.g., one or more of the exemplary ways in
In
Each queue 1008A-L manages the corresponding individual traffic flow by draining queues at a rate configured for each traffic flow. Each queue 1008A-L performs the traffic flow management using techniques known in the art and/or developed in the future, such as rate limiting, policing, etc.
DTSP 1000 processes the packets in the individual traffic flows in much the same manner as DTSP 900. For example and by way of illustration, electrical switch module 1010 switches packets in individual traffic flows (e.g., based on node internal marks added by classifiers 1006A-C). Packet network processor(s) 1012 aggregate traffic flows to corresponding WTR 1014A-C. Specifically, NPU(s) 1012 aggregate and forward the following traffic flows: (1) traffic flows (PC1, C1), (PC1, C2), (PC2, C2), (PC1, C3), (PC2, C3), and (PC2, C4) to WTR 1014A; (2) traffic flows (PC3, C1), (PC3, C2), and (PC3, C2) to WTR 1014B; and (3) protecting traffic flows (when necessary) for traffic flows (PC1, C2), (PC2, C3), and (PC3, C4) to WTR 1014C.
In turn, WTR 1014A transmits individual traffic flows (PC1, C1), PC1, C2), (PC2, C2), (PC, C3), (PC2, C3), and (PC2, C4) on wavelength λ1 to optical circuit 1022A via optical port 1018A and optical switch module 1016. Similarly, WTR 1014B transmits individual traffic flows PC3, C1), (PC3, C2), and (PC3, C2) on wavelength λ2 to optical circuit 1022B via optical port 1018B and optical switch module 1016. In addition, WTR 1014C transmits protecting traffic flows for traffic flows (PC1, C2), (PC2, C3), and (PC3, C4) (when necessary) on wavelength 3 to optical circuit 1022C via optical port 1018C and optical switch module 1016.
While embodiments are described in which traffic flows are handled individually (e.g., one per queue), alternative embodiments may handle them differently (e.g., by having one or more queue handle more than one traffic flow, by having multiple queues for a single traffic flow, etc.)
Forwarding engines 1104A-C separate the individual traffic flows 1106A-G and forward these traffic flows 1106A-G to corresponding optical circuits 1110A-G based on the destination of the individual traffic flow, the individual traffic flow packet classification and available bandwidth on the optical circuit. For example and by way of illustration, seven optical circuits 1110A-G are destined for three different destination nodes 1112A-C. Optical circuits 1110A-C are destined for destination D1 1112A, whereas optical circuits 1110D-F are destined for destination D2 1112B. Finally only one optical circuit 1110G is destined for destination D3.
In
However, unlike in
As illustrated in
However, added to
In one embodiment, optical circuit selection is performed as illustrated in
Unlike in
In
In addition, optically aware aggregation switch 1206 protects calls 1210A-B. For example and by way of illustration, call 1210A and call 1210B are respectively 1+1 and 1:1 protected. Specifically, optically aware aggregation switch 1206 switches working call 1210A to optical circuit 1216A using call working flow 1212A. In addition, optically aware aggregation switch 1206 protects call 1210A by also switching in call 1210A to optical circuit 1216C using call 1+1 protecting flow 1212B. Because optically aware aggregation switch 1206 protects call 1210A using 1+1 protection, optically aware aggregation switch 1206 duplicates the traffic flows contained in call 1210A and forwards these flows to optical circuit 1216C. Furthermore, optically aware aggregation switch 1206 switches call 1210B to optical circuit 1216B (call working flow 1212A) and protects call 1210B using 1:1 protection with optical circuit 1216A (call 1+1 protecting flow 1212A). Thus, as illustrated, optically aware aggregation switch 1206 uses optical circuit 1216A for call working and protecting flows.
Consequently, optically aware aggregation switch 1206 aggregates call working flow 1212A and call protecting traffic flows 1214B to optical circuit 1216A. As illustrated, optical circuit 1216A carries five connections. Optical circuit 1216A bandwidth allocation 1220 illustrates an exemplary partition of the bandwidth by call and connection. At the call level, optical circuit 1216A bandwidth allocation 1220 shows an allocation for call 1210A bandwidth 1222A, call 1210B bandwidth 1222B, and unallocated bandwidth 1222C. At the connection level, call 1210A bandwidth 1222A is split between connection 1208A bandwidth 1224A, connection 1208C bandwidth 1224B, and connection 1208D bandwidth 1224C, with unused bandwidth 1224D allocated for call 1210A. Similarly, call 1210B bandwidth is split between connection 1208B bandwidth 1224A and connection 1208E bandwidth 1224B, with unused bandwidth 1226C allocated for call 1210B. While
However,
In this embodiment, optically aware aggregation switch 1206 provides protection at the call level, not the connection level. This provides an extra level of flexibility because groups of connections (such as traffic flows) may be protected under one scheme by mapping groups of connections to one call. Alternatively, optically aware aggregation switch 1206 may protect a connection separately by mapping that connection to a unique call.
While embodiments are described illustrating exemplary ways of organizing the mapping of traffic flows onto optical circuits and providing traffic flow protection (e.g., traffic flows are mapped into connections, connections mapped into calls, calls mapped into optical circuits, and protection is at the call level), alternative embodiments may handle them differently (mapping traffic flows into calls and/or optical circuits, protecting at the connection level, protecting the optical circuits, etc.).
As mentioned above, DTSPs add and remove node internal and traffic flow marks to packets processed by the DTSP in certain embodiments of the invention.
In
In addition to the node internal mark 1316A, NPU(s) 1302A adds traffic flow mark 1312 to each received packet destined for optical circuit 1308. The traffic flow mark 1312 uniquely identifies each packet as part of a particular traffic flow (or equivalently, belonging to a connection in embodiments described) in the optically switched network. While in one embodiment NPU(s) 1302A adds a GMPLS label to each packet (with the GMPLS label corresponding to the traffic flow associated with the packet), alternate embodiments, may employ different marks (e.g. address associated with NPU(s) 1302D, IP address associated DTSP 1300B, client interface module (CIM) IP address, etc.) and/or combinations thereof.
Furthermore, NPU(s) 1302A adds additional parameters 1314A to each packet destined for optical circuit 1308. Examples of the parameters added by NPU(s) 1302A are, but not limited to, working egress client interface module port, working ingress WTR port, protect egress client interface, other control parameters as required, etc. These parameters are added so that when the traffic flows into WTR 1306B, the packet is marked with the proper destination CIM port(s).
ESM switches each packet based on node internal mark(s) 1316A, and NPU(s) 1302B removes node internal mark 1316A. Thus, node internal mark 1316A exists on the packet between NPUs 1302A and 1302B in timeline 1322A. Traffic flow mark 1312 remains on the packet. In addition, NPU(s) 1306B marks the packet with destination WTR 1318A. In this case, the mark added is associated with WTR 1306B. WTR 1306A transmits the packet with marks 1310B on optical circuit 1308 with WTR 1306B receiving this packet.
NPU(s) 1302C adds node internal mark(s) 1316B to packets received from WTR 1306B. Similar to above, node internal mark(s) can be, but not limited to, a hardware dependent C6 mark or some alternate mark used by ESM 1304B to properly switch the packets. Although in one embodiment ingress/egress ESM port addresses, the CIM address and WTR address are part of the node internal mark, alternate embodiments may have more, less and/or different marks (e.g. any additional control parameters) In addition, NPU(s) 1302C removes destination WTR mark 1318A from the packets. Finally, NPU(s) 1302D removes node internal mark(s) 1316B and traffic flow mark 1312. Thus, traffic flow mark 1312 exists on the packet between NPUs 1302A and 1302D as illustrated in timeline 1320; while node internal mark 1316B exists on the packet between NPUs 1302C and 1302D as illustrated in timeline 1322B. Although in one embodiment, NPU(s) 1302D adds parameters 1314B such as, but not limited to, CIM port, alternate embodiments have NPU(s) 1302D performing more, less and/or different operation (e.g., not adding the additional parameters, converting the traffic flow mark to an MPLS label, etc.). Conversely, node internal and traffic flow marks are added/removed in a similar fashion for packets traveling from NPU(s) 1302D to NPU(s) 1302A.
While embodiments are described in which packets in traffic flows are marked with node internal and traffic flow marks, alternative embodiments may mark packets in traffic flows differently (e.g., use traffic flow mark, but not node internal mark; use existing packet marks, etc.).
A source external to DTSP 1400A transmits a traffic flow to a destination external to DTSP 1400B over optical circuits 1410A and 1410B (if necessary) between DTSPs 1400A-B.
In
DTSPs 1400A-B offer three basic realms of protections for traffic flows: electrically switched electrical protection, electrically switched optical protection, and optically switched optical protection. Electrically switched electrical protections protects traffic flows in the electrically switched domain using connection working and protecting flows at source and destination DTSPs 1400A-B, respectively. As shown below, electrically switched electrical protection may employ the same or different protection schemes at the source and destination DTSPs 1400A-B (i.e., 1+1 protection scheme at both DTSP 1400A-B; 1:N protection scheme at both DTSP 1400A-B; 1+1 protection scheme at source DTSP 1400A, 1:N protection scheme at DTSP 1400B, or visa versa; etc.). Electrically switched electrical protection runs between the ports receiving/transmitting the traffic flows and the NPUs adjacent to the ports (e.g. source electrically switched electrically protection 1436 is between ports 1402A-B and NPUs 1404A, 1404E, while destination electrically switched electrically protection 1440 is between ports 1402A-B and NPUs 1404D, 1404H).
Electrically switched optical protection protects traffic flows on working optical circuits in the optical domain by electrically switching the traffic flows to different protecting optical circuits. Electrically switched optical protection runs between the NPUs in the source/destination DTSP 1400A-B that are adjacent to the ports. For example, electrically switched optical protection 1438 runs between NPU pairs 1404A, 1404E and 1404D, 1404H. Electrically switched optical protection may employ one of the know protection schemes in the art (e.g., 1+1, 1:1, 1:N, optical re-routable, unprotected, etc.). While in one embodiment, DTSPs 1400A-B protect traffic flows using electrically switched optical protection by organizing connections into calls and protecting at the call level, alternate embodiments may protect traffic flows with different granularity (e.g. protect at the connection level, optical circuit level, etc.).
Not shown in
Source connection working flow 1412 comprises the traffic flow received on port 1402A. NPU 1404A processes source connection working flow 1412 and ESM 1406A switches source connection working flow 1412 to NPU 1404B. NPU 1404B maps source connection working flow 1412 to call working flow 1414. WTR 1408A transmits call working flow 1414 on optical circuit 1410A, which is received by WTR 1408B. NPU 1404C processes the traffic flow in call working flow 1414 and ESM 1406B switches the traffic flow to NPU 1404D. NPU 1404D separates destination connection working flow 1416 from call working flow 1414 and forwards destination connection working flow 1416 to port 1402C.
In
In addition, DTSPs 1400A-B protects call working flow 1414 with call 1+1 protecting flow 1420. Through receipt of either source connection working flow 1412 or source connection 1+1 protection flow 1418 by NPU 1404F, WTR 1408C transmits call 1+1 protecting flow 1420 over optical circuit 1410B to WTR 1408D. NPU 1404G receives the flow in call 1+1 protecting flow 1420 and either drops the duplicated flow or forwards the flow to NPU 1404D and 1404A via ESM 1406B. The decision to drop or forward the duplicated flow depends on the availability of call working flow 1414. If call working flow 1414 is available, NPU 1404G drops the duplicated flow. However, if call working flow 1414 is unavailable, NPU 1404G forwards the duplicated flow via ESM 1406B to NPU 1404D.
Furthermore, system 1400 protects working destination connection working flow 1416 with destination connection 1+1 protecting flow 1422. With this scheme, if call working flow 1414 is available, NPU 1404C duplicates the traffic flow in call working flow 1414, where ESM 1406B switches the duplicated flow to NPU 1404H. If call working flow 1414 is not available, NPU 1404G duplicates the traffic flow in call 1+1 protecting flow 1420, where ESM 1406 switches the duplicated traffic flow to both NPU 1404D and 1404H; NPU 1404D and 1404H forward the duplicated flow in destination connection 1+1 protecting flow to ports 1402C and 1402D, respectively. In either case, NPU 1404D and 1404H forwards the received flows in destination connection 1+1 protecting flow 1422 to ports 1404C and 1402D, respectively.
In
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While embodiments are described illustrating connections and calls protected with l+1/1:N protection schemes, alternative embodiments may offer connections/calls different, some and/or no protection (e.g., offer connections/calls different protection schemes, protecting the call but not the connections, protecting the connections but not the call, protecting one or none of the connections, etc.).
Profile ID 1506 is the traffic shaping parameters associated with the connection. In an exemplary embodiment, profile ID identifies traffic policing parameters that are well known in the art and/or developed in the future. Referring back to
Returning back to
CIM working and protection parameters 1512 identify the working/protecting source and destination client interface module (CIM). Each connection has a source and destination CIM on the corresponding source/destination DTSP. Furthermore, a connection may be protected at the source and/or destination DTSP using the appropriate CIM. For example and by the way of illustration, referring to
Finally, traffic flow mark 1514 is the traffic flow mark added to each packet in the connection as illustrated in
By way of example according to one embodiment,
Call ID 1502 is a network-wide unique ID assigned to each call, where the ID is unique throughout the optically switched network. Thus, a call has the same call ID on both the source 1524 and destination 1526 DTSP nodes. Within each source 1524 and destination 1526 DTSP node, a call is mapped to a source 1528 and destination 1530 CIM, respectively. In addition, a call is assigned to a source 1540 and destination 1544 working WTRs, where the source 1540 and destination 1544 working WTRs terminate the optical circuit the call uses for the call working flow. Similarly, if the call is protected, the call is associated with a source 1542 and destination 1546 protecting WTR terminate the optical circuit the call uses for the call protecting flow.
As mentioned above, each call is associated with a working optical circuit, and possibly, a protecting optical circuit. These optical circuits are identified in the call configuration table with working optical circuit ID 1536 and protecting circuit ID 1538. Furthermore, each call is associated to an optical service level 1526. While in one embodiment, the optical service level contains the minimum bit error rate and bit rate desired for the call, alternate embodiments may have additional, less and/or different optical service level parameters. In addition, for example and by way of illustration, two calls sharing the same optical circuit have the same optical service level. Furthermore, each call has a maximum bandwidth 1532. The call's maximum bandwidth 1532 represents the maximum amount of connection bandwidth that can be allocated from the call. The maximum bandwidth 1532 is allocated from each optical circuit (working and protecting) as illustrated in
By way of example and according to one embodiment,
Finally,
While embodiments are described in which configuration data is organized in a particular arrangement of tables, alternative embodiments may organize the same or different configuration data in the same or different tables (e.g., organized service name and parameters into a separate table, organize profile ID parameters into a separate table, etc.).
At block 1604, method 1600 determines if one or more of the existing calls has the same destination as the requested traffic flow. If there are existing calls that have the same destination, at block 1606, method determines if one or more of these calls can support the characteristics of the requested traffic flow. For example and by way of illustration, does the call have enough bandwidth for the traffic flow, the correct protection type, and/or use an optical circuit with the correct optical service level? If so, method 1600 selects one of these calls for the traffic flow at block 1608 and control passes to block 1610. If not, control passes from block 1606 to block 1616.
Returning to block 1604, if there is not a call having the same destination as the traffic flow, at block 1616, method 1600 determines is there are one or more optical circuits having the same destination as the traffic flow. If so, at block 1626, method 1600 determines if one or more of the optical circuits having the same destination have enough bandwidth to support the traffic flow. If there are optical circuit(s) with enough bandwidth to support the traffic flow, at block 1622, method 1600 sets up a call on the selected optical circuit(s) for the traffic flow on the source and destination DTSP nodes. Method 1600 sets up the call by adding an entry in table 1520 as illustrated in
Returning to block 1616, if there are no optical circuits with the same destination as the traffic flow, at block 1618, method 1600 provisions optical circuit(s) for the traffic flow. While in one embodiment provisioning an optical circuit adds an entry in table 1550 as illustrated in
At block 1610, method 1600 setups up the connections on the source and destination DTSP nodes. In one embodiment, method 1600 sets up the connection by adding an entry to table 1500 as illustrated in
Returning to block 1706, if method 1700 does not delete the optical circuit(s) associated with the call (e.g., there are one or more calls mapped to the optical circuit(s), etc.), method 1700 recovers the optical circuit(s) bandwidth used by the call. For example and by way of illustration, method 1700 updates table 1550 by subtracting the bandwidth allocated to the call (maximum bandwidth 1532) from the bandwidth allocated 1556 and adds call bandwidth allocated to optical circuit bandwidth availability 1558. At block 1710, method 1700 deletes the call from the call table. For example and by way of illustration, method 1700 deletes the corresponding entry from call table 1520. Control passes to block 1712.
Returning to block 1704, if method 1700 does not delete the call associated with the connection (e.g., there are one or more connections mapped to the call, etc.), method 1700 recovers the call bandwidth allocated to the connection. For example and by way of illustration, method 1700 updates table 1520 by decrementing the call utilized bandwidth 1534 by the connection bandwidth. Control passes to block 1712.
At block 1712, method 1700 deletes the connection from the connection table. For example and by way of illustration, method deletes the entry associated with the connection from the table 1500.
At block 1806, based on the traffic flow classification, method 1800 forwards the traffic flows to the selected WTR(s) of the provisioned optical circuit(s). Forwarding the traffic flows is further described in
In
In one direction ESM(s) 2104 switches packets from CIM 2102A-N to WTR 2106A-M based on the packet markings added by CIM 2102A-N, while in the other direction ESM(s) 2104 switches packets from WTR 2106A-M to CIM 2102A-N.
SCM(s) 2114 configures and updates CIM 2102A-N and VVR 2106A-M by forwarding configuration information and status events to CIM 2102A-N and WTR 2106A-M. While in one embodiment, SCM(s) 2114 forwards status events such as, but not limited to, CIM Up/Down and WTR Up/Down events to CIM 2102A-N and WTR 2106A-M, other embodiments may send more, less and/or different events to CIM 2102A-N and WTR 2106A-M. Based on the events received by the CIM 2102A-N, CIM 2102A-N programs NPU(s) associated with CIM 2102A-N. Similarly, WTR 2106A-M programs NPU(s) on WTR 2106A-M based on the events received by WTR 2106A-M. CIM 2102A-N and WTR 2106A-M NPU(s) programming is further described in
In addition, in
CIM IFM 2202 couples to CIM NPUIFM 2204, CPM 2208, CAC 2212, CALM 2216, WTR NPUIFM 2222, and ECM 2218. CIM NPUIFM further couples to the respective CIM NPU 2206, WTR IFM 2210, and ECM 2218. In addition, WTR IFM 2210 further couples to WTR NPUIFM 2222 and CAC 2212. WTR NPUIFM couples to ECM 2218 and the respective WTR NPU 2224. Furthermore, CALM 2216 couples to CAC 2212, ECM 2218, and RSVP 2220.
In the control plane architecture 2200, CIM NPUIFM 2204 and WTR NPUIFM 2222 which both manage the NPUs on the respective cards. CIM IFM 2202 receives status of WTR ports involved in the connection from WTR IFM 2210 and status of CIM ports involved in the connection from CPM 2208. For example and by way of illustration, the various managers signal status of the ports involved/participating in the connection. As an additional example and by way of illustration, the status of the optical circuit can be determined by the status of the WTR operational state. An up/down WTR participating as optical circuit endpoints maps to an up/down optical circuit. If a fiber is cut, the receive end of WTR detects a loss of signal (LOS), will go operationally down and WTR IFM receives this operational down message. In addition, ECM 2218 sends/reports NPU configuration information to CIM NPUIFM 2204, such as, but not limited to, traffic flow configuration (i.e. traffic flow comprised of particular packet characteristics, bandwidth, etc.), connection/call configuration (e.g. configurations as illustrated in
WTR NPUIFM 2222 functions in a similar way as CIM NPUIFM 2204. WTR NPUIFM receives call configuration information from ECM 2218 and WTR status information from WTR IFM 2210. For example, and by way of illustration, ECM 2218 sends/reports NPU status information, such as, but not limited to, traffic flow configuration (i.e. traffic flow comprised of particular packet characteristics, bandwidth, etc.), connection/call configuration (e.g. configurations as illustrated in
CAC 2212 maintains the bandwidth information for the CIM and WTR ports. It monitors the bandwidth utilization on the CIM/WTR ports. CAC 2212 acts as a gatekeeper for reserving and committing bandwidth. CALM 2216 makes a request to CAC 2212 for bandwidth before creating any call at the source and destination nodes of the call. If there is bandwidth available, CAC 2212 gives a go ahead to CALM 2216 to create a call and updates the port bandwidth information.
CPM 2208 maintains user provided protection information for the CIM ports and provides the port-based protection to the CIM(s). Port-based protection enables the user to designate which port on one CIM protects which other port on another CIM. CPM 2208 maintains the co-relation and the type of protection. CIM IFM 2202 reports any port specific events (e.g., port up/down) to CPM 2208. CPM 2208 signals CIM events such as, but not limited to, working CIM up, working CIM down, protecting CIM up, protecting CIM down, etc., to CIM NPUFIM 2204 and/or WTR NPUIFM 2224.
CALM 2216 is a call manager for alien and non-alien calls and is responsible for creation, updates and deletion of both types of calls. While in one embodiment, an alien call is used to carry an alien wavelength and a non-alien calls carries non-alien wavelength, other embodiments may have different organization of alien/non-alien calls (e.g., non-alien calls carried on alien wavelength, etc.). For example and by way of illustration, a non-alien call is a call as illustrated in FIGS. 12AB and 15A. Alien calls create call records on the source and destination nodes. RSVP 2220 creates optical connections for alien connection requests. RSVP is a GMPLS recommended signaling protocol. RSVP 2220 assists in physically creating optical connections from source to destination. On the other hand, non-alien calls create and/or trigger optical connections and as well as creating call records at the source and destinations nodes. For a non-alien call, CALM 2216 triggers RSVP 2220 to create optical cross-connects from source to destination.
While in one embodiment, CIM IFM 2202, WTR IFM 2210, CPM 2208, CAC 2212, CALM 2216, ECM 2218, and RSVP 2220 reside on the SCM(s) 2114, while CIM NPU(s) 2206 and CIM NPUIFM 2204 on CIM 2102A-N and WTR NPU(s) 2222 and WTR NPUIFM 2224 on WTR 2102A-M, alternate embodiment may have different arrangement of components (e.g., CIM NPUIFM 2204 on SCM(s) 2114, WTR NPUIFM 2222 on SCM(s) 2114, CIM IFM 2202 on CIM 2102A-N, etc.) or other embodiments may be described in which the functionality of control plane architecture 2200 is present.
One end of ESM-NPU(s) 2300 interfaces the DTSP node with the electrically switched network (e.g., end designated by framer/MAC 2302A), while the other end of ESM-NPU(s) 2300 interfaces with WTR(s) (not shown). Framer/MAC 2302A receives the framed packets from the electronically switched networks, collects traffic flow(s) statistics and separates the packets into traffic flow(s). NPU 2304A processes the traffic flow(s) by adding marks to each packet in the traffic flow(s) (e.g. adding the node internal and traffic flow marks as illustrated in
Switch fabric 2310 switches the traffic flow(s) based on the packets characteristics. While in one embodiment switch fabric 2310 switches the traffic flow(s) based on the hardware dependent C6 node internal mark contained in the packets of the traffic flow(s), other embodiments may switch the traffic flow(s) based on other marks or packet characteristics (e.g., another node internal mark known in the art and/or developed in the future, etc.). Switch fabric 2310 switches the traffic flow to the appropriate destination via serializer/deserializer 2306B and switch interface 2306B. NPU 2304B aggregates the received traffic flow(s) and forwards the received traffic flow(s) to the WTR corresponding to NPU 2304B. In addition, if the packets in the traffic flow(s) processed by NPU 2304B contained a node internal mark, NPU 2304B removes the node internal marks. NPU 2304B forwards the aggregated traffic flows to framer/MAC 2302B, where WTR transmits the traffic flow(s) to the optically switched network. In addition, framer/MAC 2302B collects statistics on the traffic flow(s).
The above description illustrates processing by ESM-NPU(s) 2300 of packets received from the electrically switched network to transmission of traffic flow(s) to the optically switched network. In a reciprocal fashion, aggregated traffic flow(s) coming from optically switched network enter ESM-NPU(s) 2300 via framer/MAC 2302B. Framer/MAC 2302B collects statistics, separates the aggregated traffic flow(s) into separate traffic flow(s) and forwards the aggregated traffic flow(s) to NPU 2304B. NPU 2304B marks the packets in the traffic flow(s) with a node internal mark (as illustrated in
Switch fabric 2310 switches the traffic flow(s) to the appropriate electrically switch packet port based on the packets characteristics. While in one embodiment switch fabric 2310 switches the traffic flow(s) based on the hardware dependent C6 node internal mark contained in the packets of the traffic flow(s), other embodiments may switch the traffic flow(s) based on other marks or packet characteristics (e.g., another node internal mark known in the art and/or developed in the future, etc.). Switch fabric 2310 switches the traffic flow to the appropriate destination via serializer/deserializer 2306A and switch interface 2306A.
NPU 2304A removes the node internal mark (if used) and optionally removes the traffic flow mark. Furthermore, NPU 2304A forwards the traffic flow(s) to the appropriate electrically switched packet port via framer/MAC 2302A. In addition, framer/MAC 2302A collects statistics on the traffic flow(s).
While in one embodiment, ESM-NPU(s) 2300 architecture are as illustrated, alternate embodiments may be described in which the functionality of ESM-NPU(s) 2300 architecture is present (e.g., multicasting via Switch fabric 2310 instead of using NPU 2304A-B, etc.).
In
Protecting Up” event from WTR IFM 2210, WTR 2502A-B & WTR 2504A-B change there state to reflect
Table 5 lists the possible events, WTR types, working WTR status, CIM types, CIM modes, CIM status and NPU modes according to one embodiment of the invention. Possible events listed in Table 5 include events from CPM 2208: CPM Working CIM Up; CPM Protecting CIM Up; CPM Working CIM Down; and CPM Protecting CIM Down. These events signal that the working/protecting CIM is up or down. Furthermore, Table includes events from WTR IFM 2210: IPM Working CIM Up; IFM Protecting CIM Up; IFM Working CIM Down; and IFM Protecting CIM Down. The WTR IFM 2210 events signal that the working/protecting WTR is up or down. Alternate embodiments may list more, less or different events.
In addition, Table 5 lists the WTR and CIM protection types. While in one embodiment, WTR/CIM protection types are None (unprotected), 1+1, 1:1, and 1:N, alternate embodiments may have more, less and/or different protection schemes (e.g., fast reroutable, etc.). Furthermore, Table 5 illustrates the WTR and CIM modes can either be working or protecting, with each mode being active or inactive.
As listed in Table 5, the NPU modes for each traffic flow are: normal, protect, multicast, and discard according to one embodiment of the invention. An NPU in normal mode forwards the traffic flow to the working CIM WTR, while an NPU in the protect mode forwards the traffic flow to the protecting CIM/WTR. If a CIM/WTR needs to forwards two copies of the same traffic flow to a working and protecting WTR/CIM, a multicast NPU mode is used. Lastly, an NPU can discard packets in the traffic flow (discard mode). In alternate embodiments, the NPU mode can have more, less and/or different modes (e.g., mark and forward, etc.).
Table 6 lists the status of a CIM WTR with a corresponding CPM/WTR IFM event for a working CIM according to one embodiment of the invention.
Table 7 lists CIM modes, NPU modes for Working CIM NPUIFM for different CIM and/or WTfR protection schemes according to one embodiment of the invention. For example and by way of illustration, if the CIM or WTR has no protection scheme, a CPM Working CIM Up/Down event leaves the NPU mode for the working CIM as normal. As another example, for a WTR 1:1 protection scheme, an IFM Working WTR Down event causes the CIM working NPU mode to be in protect mode, as the CIM forwards the traffic flow the protecting WTR. An IFM Working WTR Up event causes the CIM working NPU mode to be in normal mode, with the CIM forwarding the traffic flow to the working WTR.
In addition, Table 7 lists scenarios when the working CIM participates in both CIM and WTR protection schemes. For example, and by way of illustration, if the working CIM participates in both a CIM 1+1 and WTR 1+1 protection scheme, a CPM
Working CIM Up event causes the CIM Working NPU mode to be multicast, because the working CIM forwards the traffic flow to the working and protecting WTR. Conversely, a Working CIM Down event puts the CIM Working NPU mode into the discard state.
Although only a few protection schemes are described above, Table 7 lists additional CIM and/or WTR protection schemes and the affect on the CIM mode, status and CIM NPU mode. Alternate embodiments may have more, less and/or different table entries.
Table 8 lists the WTR involved in a 1:1 protection scheme according to one embodiment of the invention. If the WTR is active, the CIM status is active with the CIM NPU mode as normal. On the other hand, if the WTR status is inactive, the CIM status can be either active (with the NPU mode protecting) or inactive (with the NPU mode of discard).
Table 9 lists the status of a CIM WTR with a corresponding CPM/WTR IFM event for a protecting CIM according to one embodiment of the invention.
Table 10 lists CIM modes, NPU modes for the protecting CIM NPUIFM for different CIM and/or WTR protection schemes according to one embodiment of the invention. For example and by way of illustration, in a CIM 1+1 protection scheme, a CPM event of working CIM Up causes the protecting CIM mode to be protect, with a CIM status of inactive and NPU mode of discard. This is because the protecting CIM does not forwards the traffic flow as illustrated in
Although only a few protection schemes are described above, Table 10 lists additional CIM and/or WTR protection schemes and the affect on the CIM mode, status and CIM NPU mode. Alternate embodiments may have more, less and/or different table entries.
Table 11 lists WTR modes, NPU modes for the working WTR NPUIFM for different CIM and/or WTR protection schemes according to one embodiment of the invention. For example and by way of illustration, in a CIM 1+1 protection scheme, a CPM event of protecting CIM Up causes the working WTR to be active with the NPU in multicast mode, because the WTR forwards the traffic flow to both the working and protecting CIM (as illustrated in
As in the preceding tables, the working WTR can participate in both CIM and WTR protection schemes. For example, and by way of illustration, for a working WTR involved in both a CIM 1:1 and WTR 1+1 protection schemes, an IFM working WTR
Up event causes the working WTR to be active with the corresponding NPU to be normal. Conversely, an IFM working WTR Down event causes the working WTR to be inactive with the NPU in the discard mode.
Although only a few protection schemes are described above, Table 10 lists additional CIM and/or WTR protection schemes and the affect on the WTR mode, status and WTR NPU mode. Alternate embodiments may have more, less and/or different table entries.
In
In
Working WTR 2702A-B and protecting WTR 2702A-B change between the active and inactive based on events from WTR IFM 2210. While in one embodiment, working WTR 2700A-B receives events listed in Table 11 (under the sub-heading “CIM 1+1 and DTM 1+1 protection”), other embodiments may have more, less, and/or different events that change the active/inactive state of working WTR 2700A-B and protecting WTR 2702A-B.
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Working WTR 2800A-B, protecting WTR 2802A-B, working CIM 2804A-B, and protecting CIM 2806A-B change between the active and inactive based on events from WTR IFM 2210 and CPM manager 2208. While in one embodiment, working CIM 2804A-B receives events listed in Table 9, protecting CIM 2806A-B receives events listed in Table 10, and working WTR 2800A-B receives events listed in Table 11 (each events listed in the tables under the sub-heading “CIM 1+1 and DTM 1+1 protection”), other embodiments may have more, less, and/or different events that change the active/inactive state of working WTR 2800A-B, protecting WTR 2802A-B, working CIM 2804A-B, and/or protecting CIM 2806A-B.
In
Working WTR 2900A-B and protecting WTR 2902A-B change between the active and inactive based on events from WTR IFM 2210. While in one embodiment, working WTR 2900A-B receives events listed in Table 11 (under the sub-headings “WTR 1+1 protection only”, “CIM 1:1 and WTR 1:1 protecting”, and “CIM 1+1 and WTR 1:1 protecting”), other embodiments may have more, less, and/or different events that change the active/inactive state of working WTR 2900A-B and protecting WTR 2902A-B.
While various embodiments of the invention have been described, alternative embodiments of the invention can operate differently. For instance, while the flow diagrams in the figures show a particular order of operations performed by certain embodiments of the invention, it should be understood that such order is exemplary (e.g., alternative embodiments may perform the operations in a different order, combine certain operations, overlap certain operations, etc.).
While the invention has been described in terms of several embodiments, those skilled in the art will recognize that the invention is not limited to the embodiments described, can be practiced with modification and alteration within the spirit and scope of the appended claims. The description is thus to be regarded as illustrative instead of limiting.
This application claims the benefit of U.S. Provisional Application No. 60/688,203 filed Jun. 6, 2005, which is hereby incorporated by reference.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US06/21990 | 6/6/2006 | WO | 00 | 4/24/2009 |
| Number | Date | Country | |
|---|---|---|---|
| 60688203 | Jun 2005 | US |
