Patent Application
20090296737
The present disclosure generally relates to communication networks, and more particularly, the disclosed embodiments relate to a system and method for combining a plurality of communication links into a virtual link between two nodes.
The rapid evolution of communication networks has created a significant demand for bandwidth consumption—a demand that has been placed on the shoulders of the service providers to meet. A service provider can be a cellular carrier, a Public Switched Telephone Network (PSTN) carrier, data network carrier an access network service provider, an Internet Service Provider (ISP), etc. A common network of a service provider can include a central premises, a plurality of intermediate nodes and a plurality of subscribers. In a common network, one side of the intermediate nodes is connected to the customer equipment and the other side is connected to the central premises either directly or through one or more other intermediate nodes. The network that connects the central premises and the intermediate nodes can be referred to as the infrastructure of the service provider or as the fixed network of the service provider. Typically, changes in the fixed network are quite expensive for a service provider because the intermediate nodes are spread over a wide geographic region (such as the country of operation) and each intermediate node is connected using a wide bandwidth communication link.
An exemplary service provider can be a carrier of wireless communication networks for mobile communications such as but not limited to Global System for Mobile communications (GSM) networks, 3G networks, etc. A common fixed network of a cellular carrier can include a Radio Network Controller (RNC) located in a central premises and a plurality of node base stations (Nb), which are spread over a large geographic region (such as the country of operation), as intermediate nodes.
Henceforth, the description, drawings and claims of the present disclosure may use the terms RNC as a representative term for a central node and Nb as a representative term for an intermediate node. Exemplary mobile terminals (MT) can be a cellular telephone, a PDA with cellular capabilities, or any other computerized device that can generate and/or receive media such as audio, video, data or any combination of those via a communication network such as, but not limited to a cellular network.
Usually an RNC is used as an aggregation point for different types of data transferred to and from a plurality of MTs. The RNC can receive circuit switch telephony traffic as well as packet switched traffic traveling to and from the Internet, for example. Usually, a communication line between a central point and an intermediate node can carry a plurality of communication sessions, each potentially composed of a different type of media, between one or more other intermediate nodes and/or one or more terminals. Different types of networks and protocols can be used over the communication lines. The communication lines can comply with different types of data link layer protocols, such as but not limited to: Time Division Multiplexing Access (TDMA), Asynchronous Transfer Mode (ATM), Ethernet, etc.
A common evolution process starts with adding similar resources in parallel. Later, a technology evolution (changing protocols, new and advance equipments, new technologies, etc.) occurs and creates a breakthrough in the performance. Usually such an evolution requires changes in the fixed network of a service provider. Such changes may include adding new or changing physical lines to respond to the extra bandwidth requirements. In some cases, the new equipment cannot work with the current infrastructure of a service provider. Upgrading the fixed network is expensive and if at all possible, service providers would prefer an alternative solution. Thus there is a need in the art for a communication multiplexer that alleviates the cost and or necessity of upgrading fixed networks as technology continues to grow and migrate. Such a need could be addressed by a system and method that can inverse multiplex a high-speed data stream from one physical link connecting two nodes, into a plurality of physical low-speed communication links that connect the two nodes. Each communication link can have a different bandwidth and can comply with different communication protocols and be carried over different networks.
Exemplary embodiments of a communications multiplexer seek to provide a novel apparatus and method for inverse multiplexing media communication traffic from a high-speed communication link into a plurality of low-speed communication links, wherein each low-speed link can use a different physical line, having different speeds, and wherein the communication over each link can comply with different communication protocols and can be connected on different networks. Exemplary one or more low-speed communication links can be connected to an Internet Protocol (IP) network, ATM networks, Ethernet networks, etc. Some of the communication links can be based on physical layer technologies such as, but not limited to, Single pair High-speed Digital Subscriber Line (SHDSL), Symmetric Digital Subscriber Line (SDSL), Asymmetric Digital Subscriber Line (ADSL) and Very high data rate Digital Subscriber Line (VDSL). The physical lines can be a twisted-pair, a bundle of a plurality of twisted-pairs, a point to point wireless link, a fiber optics line, etc.
A physical layer and a data link layer are the two lowest layers of the OSI model. The OSI (Open System Interconnection) is a seven layer communication system. Each layer in the OSI model is a collection of related functions that provide services to the layer above it and receives services from the layer below it. The layers in the OSI model include (1) the Physical Layer in which the information is presented in a bits binary format; (2) the Data link Layer in which the bits from the Physical layer are arranged in logical sequences called frames; (3) the Network Layer which fragments the above frames into packets; (4) the Transport Layer which segments the above packets to segments; (5) the Session Layer; (6) the Presentation Layer and (7) the Application Layer. The Session Layer, the Presentation Layer and the Application Layer is often collectively referred to as the User layer.
One of the described embodiments defines a new type of Transport Layer protocol. The flow control of this new type of Transport Layer protocol enables the allocation of media traffic from one high-speed communication link into two or more low-speed communication links of a service provider. The low-speed communication links can differ from each other in at least one of the communication protocols that are used over each link. For instance, one low-speed communication link can be based on the internet protocol (IP) while the other can be based on ATM or ISDN, etc. The low-speed communication links can be carried over various Physical Layers. For instance, one low-speed communication link can be carried over a microwave link, while the other can be carried over copper or fiber-optic cable, etc.
An exemplary system can comprise two devices: a transmitting inverse multiplexing module (TIMM) and a receiving multiplexing module (RMM). The TIMM can be connected to an egress of one of the nodes as the high-speed communication link. The RMM can be connected to ingress of a second node as the other side of the high-speed communication link. The transmitting and the receiving modules can communicate over a plurality of communication links. Each communication link can be connected to a different network using a different physical line. In an alternate exemplary embodiment, two combined inverse multiplexing modules (CIMM) can be used, one in located at each side of the high-speed communication link. Each CIMM can include elements of a TIMM and elements of a RMM. Yet in an alternate embodiment, an exemplary TIMM and/or RMM can be embedded within an intermediate node.
The exemplary TIMM can be adapted to receive a stream of groups of bits. In one embodiment, the stream of group of bits can be a stream of bits that comply with the Physical Layer protocol used over the high-speed connection. In an alternate embodiment, the stream of groups of bits can be a stream of ATM cells carried over the high-speed communication link. Yet in another embodiment, the stream of groups of bits can be a stream of packets carried over the high-speed communication link, etc. The received stream of groups of bits can be handled by the TIMM as a stream of groups of bits of a “network independent message interchange”. The sequential stream of groups of bits which is received as the data of the high-speed communication link is converted into a new type of transport layer by an exemplary transmitting “Inverse Multiplexing Transport Protocol (IMTP)” module (TIMTPM). An exemplary new type of transport layer protocol is disclosed below. The output from the TIMTPM can be inverse multiplexed by a switch to a plurality of FIFOs (first in first out) buffers. In an exemplary embodiment, flow control criterion can be used for controlling the switch. Each FIFO can be associated with a low-speed output interface module (LSOIFM).
Each LSOIFM is connected to one of the low-speed communication links. Each LSOIFM can be adapted to (a) receive a plurality of data segments which were processed according to the IMTP, and (b) process the received IMTP segments according to: the Network Layer protocol, Data link Layer protocol and the Physical Layer protocol that are used by the low-speed communication link that is associated with the LSOIFM. The processed data is transmitted over the associated low-speed communication link toward the receiving module.
Inverse multiplexing decisions made by an exemplary TIMTPM can be based on the obligations or contractual requirements of the service provider to its subscribers. For instance, the service provider's obligations or requirements may include defining or establishing parameters, such as performance parameters, that can establish minimum criteria required to ensure a particular level of experience by the user. One parameter can define the maximum latency that is contributed by the operator (Lmax). Another parameter can define the maximum jitter between consecutive segments (Jmax). Yet another parameter can establish the percentage of dropped calls or disconnections, etc. In order to comply with the obligations of the service provider, an exemplary TIMTPM can consecutively calculate, per each low-speed communication link, the delay time (Tdn) that a next IMPT segment of data will stay in its associated FIFO before being transferred to the FIFO. The ‘n’ in Tdn can reflect the serial number of the low-speed path ‘n’, wherein the low-speed path can include the FIFO, its associated LSOIFM and the low-speed communication link. The Tdn value can be used as an indication for the current load over the low-speed communication link number ‘n’. A jitter can be defined as unwanted variation between two consecutive intervals of time between successive segments of data that are currently transferred.
An exemplary inverse multiplexing process can route a plurality of consecutive IMTP data segments toward one of the FIFOs (FIFO ‘n’, for example), until Tdn becomes equal or greater than a portion of Lmax minus Jmax, [Tdn>(Lmax−Jmax)]*(a factor), wherein the factor is smaller than one. Exemplary values of the factor can be 0.95; 0.90; 0.8; etc. The value of the portion of the difference of Lmax minus Jmax can be referred as Tdmax. At this point the IMPTM can search for a FIFO that its current Td is smaller than Jmax. For example, the Tdm of FIFO ‘m’ is smaller than Jmax. Then, the next IMTP data segments are routed toward FIFOm to be transmitted over its associated low-speed communication line ‘m’, while FIFOn is drained by its associated LSOIFM, and so on. The above exemplary embodiment uses the Lmax and Jmax as flow control criteria. Other embodiments may use other flow control criteria.
An exemplary TIMTPM can add control information to each IMTP data segment, such as a sequence number, for example. For each block of consecutive IMTP data segments that is routed toward one of the FIFOs, a CRC data segment can be calculated and added to the end of the blocks. Each block can have a different number of IMTP data segments depending on the current situation of the low-speed path via which the block is transmitted. One or more control IMTP segments can be added to the beginning and the end of each block. An exemplary control IMTP segment at the beginning of a block of segments can point the low-speed path that carried the previous transmitted block of IMTP data segments. Another one or more control IMTP segments can be added to the end of the current block of IMTP segments. Those control segments can reflect the number of segments that were included in the current block and the low-speed communication path that will carry the next block of IMTP data segments, for example. In an exemplary embodiment, a block is considered as the group of IMTP segments sent over a low-speed communication link and bounded by Previous-Path or First-Path IMTP control segment to Next-Path IMTP control segment.
On the other end of the plurality of low-speed communication links, a mating RMM may receive a plurality of streams of data. Each stream can be received over a low-speed communication link that is associated with a low-speed input interfacing module (LSIIFM). The mating RMM may process the plurality of streams and multiplex them into a single stream of IMTP data segments. The single stream of IMTP data segments can be further processed according to the IMTP and be rearranged to create a stream of groups of bits that complies with or is compatible with the groups of bits carried over the high-speed communication link and that are handled by the mating TIMM. In one embodiment, the stream of groups of bits can be a stream of bits that comply with the Physical Layer protocol used over the high-speed connection. In an alternate embodiment, the stream of groups of bits can be a stream of ATM cells carried over the high-speed communication link. Yet in another embodiment, the stream of groups of bits can be a stream of IP packets carried over the high-speed communication link, etc. The stream of groups of bits is processed according to the relevant protocol of the high-speed communication link and can be sent over the high-speed communication link toward the second intermediate node.
An exemplary LSIIFM can process the received data according to the protocols used by the first three layers of the associated low-speed communication link (the Physical Layer, the Data link Layer and the Network Layer, for example). The output of each LSIIFM, which can be in a format of IMTP data segments, can be stored in a buffer. The output of the buffer is processed according to the IMTP by a receiving IMTP module (RMTPM). The IMTP data segments are organized according to their sequential number and are grouped into blocks of IMTP data segments. Each block can start with a control IMTP segment that indicates a communication path on which the previous block of IMTP data segments was received. Each block can be terminated with several control IMTP segments. For instance, one can point to the next communication path in which the next block of IMTP segments would be sent. Other control IMTP segments can include the number of IMTP data segments that were sent in the current block (the block size). Another control IMTP segment can be a CRC.
An exemplary RMTPM can verify that the number of the received IMTP data segments in the block matches the number of segments that were sent. If not, an error indication can be sent to an administrator of the service provider. The error indication can point the low-speed communication link on which the error happened. A CRC check can be executed on the received block. If it happens that a mistake that cannot be corrected is disclosed, an error indication can be sent. The CRC segment and the control segment that includes the number of segments that were sent can be removed and the received block of IMTP segments can be stored in a FIFO. The control IMTP segment with an indication on the communication path that carried the previous block is the first to be stored in the FIFO, then the IMTP data segments according to their sequential number and finally the control IMTP segment that indicated the communication path the would carry the next block.
The plurality of FIFOs, one per each receiving communication path, is connected to a MUX module. During the initiation of the mating RMM, an exemplary MUX module can be adapted to scan the group of FIFOs, looking for a ‘Starting IMTP control segment”. The FIFO that has the “Starting IMTP control segment” stores the first block of IMTP data segments that was sent. The MUX model starts draining the FIFO, removing the control information that was added as part of the IMTP and creates a stream of group of bits that are transferred toward the high-speed output interface. When the NUX module identifies a control IMTP segment that points the next communication path (a next FIFO), then the first segment from the next FIFO is fetched. This segment is checked to verify that it is a control segment that points to the previous path. If both segments comply, then the MUX module can proceed and retrieving the data from the next path. If not, an error indication can be sent. The stream of group of bits at the output of the MUX module is processed according to the relevant protocol of the high-speed communication link and sent over the high-speed communication link toward the second intermediate node.
Some exemplary embodiments may process the error mistakes and may determine whether to cancel one of the low-speed communication links that is creating or causing the problem.
The foregoing summary is not intended to summarize each potential embodiment or every aspect of the present disclosure, and other features and advantages of the present disclosure will become apparent upon reading the following detailed description of the embodiments with the accompanying drawings and appended claims.
Furthermore, although specific exemplary embodiments are described in detail to illustrate the inventive concepts to a person skilled in the art, such embodiments can be modified to various modifications and alternative forms. Accordingly, the figures and written description are not intended to limit the scope of the inventive concepts in any manner.
Exemplary embodiments of the present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:
Turning now to the figures in which like numerals represent like elements throughout the several views, exemplary embodiments of solutions are presented. For convenience, only some elements of the same group may be labeled with numerals. The purpose of the drawings is to describe exemplary embodiments and is not for production purpose. Therefore features shown in the figures were chosen only for convenience and clarity of presentation.
In the example of
An exemplary TIMM 120 can be capable of receiving high-speed data from communication link 112a and inverse multiplex the data into two or more different low-speed links (152, 140, and 132). The inverse multiplexing decisions are controlled by a flow control mechanism that keeps true to the obligation of the service provider. Obligations, such as but not limited to, the maximum latency (Lmax) and the maximum jitter (Jmax) that the service provider is obligated to provide to its subscribers. More information on the operation of the TIMM 120 is disclosed below in conjunction with
An exemplary RMM 160 is capable of receiving data from the different low-speed links (154, 140, and 134) and multiplex the data into a single data stream that is transmitted over high-speed link 112b toward Nb 170. In addition the RMM 160 is capable of detecting errors and informing the TIMM 120 about the errors. More information on the operation of the RMM 160 is disclosed below in conjunction with
For a bi-directional high-speed communication link between the two nodes, an exemplary embodiment can use an RMM and a TIMM in association with each one of the nodes (Nb 170 and RNC 110) instead of just a TIMM 120 or just an RMM 160. Another exemplary embodiment can use one module that combines elements of a TIMM and an RMM. Such a combined module can be referred to as a CIMM. A CIMM can be installed in association with each node. Yet in an alternate embodiment of the present invention an exemplary TIMM 120 and/or RMM 160 can be embedded within an intermediate node 110 and 170, respectively. In such embodiment high-speed communication link 112a-b can be eliminated.
In another embodiment, the Inverse Multiplexing Transport Protocol may handle streams of groups of ATM cells carried over the high-speed communication link 112a. In such embodiments, an exemplary HSIF can be adapted to also process the data link layer according to ATM protocols. Yet in another embodiment, the stream of groups of bits can be a stream of IP packets carried over the high-speed communication link 112a. In such embodiment, an exemplary HSIF can be adapted to process also the network layer according to internet protocols, etc.
The TIMTPM 220 receives the stream of bits from HSIF 210 and rearranges them according to a new “Inverse Multiplexing Transport Protocol (IMTP)”. An exemplary TIMTPM 220 can divide the stream of bits into IMTP segments and adds a header to each segment. The header, for example can include an indication on the type of the segment, whether the segment is a control segment or data segment. If the segment is a control segment, the header may also include information on the previous path, sequence number of each segment, number of segments, CRC, next path, etc., depending on the type of the control segment. The sequence number and the CRC can be calculated by TIMTPM 220. An exemplary CRC algorithm can create a payload in which each bit is the sum of equivalent bits of the payloads that were sent from the last calculated CRC. If the IMTP segment is a data segment, it will include in addition to the data, a sequence number that is associated to the segment.
In other embodiments, in which an exemplary TIMTPM gets streams of groups of bits from the relevant HSIF, wherein each group comprises a plurality of bits, the TIMTPM can be adapted to process the stream the groups of bits into IMTP segments. Each IMTP segment can include an integer number of groups of bits. An integer number of ATM cells, for example. Or a portion of a group of bits, a portion of IP packet, for example.
The TIMTPM 220 is also responsible for the flow control over a low-speed communication path that will carry the data toward the RMM 160 (
An exemplary IMTP data segment can include one byte of header and a few bytes of payload, one to over a hundred bytes, for example. The payload is required to be small enough in order to meet the Lmax requirements, on one hand. On the other hand, the payload needs to be long enough to reduce the overhead between the payload and header.
An exemplary header can be implemented such that the first three bits, of the header's byte, define the type of the IMTP segment: Data; Initialization; First path; Previous path; Next path; Block size; CRC; etc. The last five bits of the header's byte can be the value of a sequential counter. The number of bytes of the payload of a control IMTP segment can differ for each type of control segment, for example, one byte for the Previous path control IMTP segment or Next path control IMTP segment; payload of the Initialization control IMTP segment can be zero for example. The length of the data IMTP segment can be a fixed size, a fix number of bytes (padding bits can be added if needed).
The output of the TIMTPM 220 can be connected to two or more paths. Each path is associated with a FIFO and Monitoring Module 240a-c and a low-speed output interface module (LSOIM) 250a-c respectively. It will be appreciated by those skilled in the art that depending upon its configuration and the needs, any number other than three paths can also be included in TIMM 200. However, for purposes of simplicity of understanding, three paths are shown.
An exemplary flow control and inverse multiplexing method that can be implemented by TIMTPM 220 can include two phases, an initialization phase and ongoing phase. During the initialization phase TIMTPM 220 determines which of the paths will be the first one to carry data toward RMM 160 (
Once the TIMTPM 220 determines that a first path is available, then the ongoing phase begins. The TIMTPM 220 can create and send a first path IMTP control segment toward the FIFO and monitoring module 240a-c of the first path. TIMTPM 220 starts sending a chain of IMTP data segments toward the first path by dividing the data into payloads of data-segment, incrementing the sequential counter and adding an appropriated data header including the sequential number to each payload.
As a result, the volume used in the FIFO and Monitoring Module 240 of the first path is increased thus the Td of the first path increases. Once the current Td of the path is larger than Lmax minus Jmax (Tdmax), the TIMTPM 220 searches for an alternative path, a path with a current Td smaller than Jmax.
Once an alternative path has been chosen as the next path, TIMTPM 220 starts terminating the transmission of IMTP data segments block by creating and sending few control IMTP segments such as Block Size segment with the number of data segments in the block; a CRC segment with the calculated CRC; and the Next path segment with information on the next path. At this point the current path can be referred to as a previous path. Then, TIMTPM 220 can start transmitting a new block of data segments through the next path, which will now be referred to as the current path. The new block can start by sending a Previous path IMTP segment with the information on the previous path and the CRC processor and the block size counter are reset. The TIMTPM 220 starts sending a chain of IMTP data segments toward the new current path, incrementing the sequential counter, updating the CRC value and adding an appropriate data header including the sequential number to each payload. The sequential counter is not reset when changing paths, rather it is reset in the initialization phase.
As a result the current path's Td starts to increase with each IMTP data segment sent through it, while the Td of the other paths decreases. Once the Td of the current path reaches the value of Tdmax, the TIMTPM 220 starts the procedure of searching and changing to an alternative path as disclosed above, and so on and so forth.
Exemplary FIFO and Monitoring Modules 240a-c can include a FIFO (first in first out) memory device that can be loaded and drained by different clocks and speeds. Each module includes a monitoring unit that measures the draining rate. An exemplary unit can count the number of bytes that are retrieved from the FIFO in a certain unit of time. In addition, the monitoring unit can measure the current used volume of the FIFO. Indication from the FIFO and Monitoring Module 240a-c regarding the size of the memory in use and the draining rate are transmitted toward TIMTPM 220.
In an alternate embodiment, an exemplary FIFO and Monitoring Module 240a-c may use other methods for monitoring the load over its associated low-speed path. An exemplary monitoring module may receive a dropping indication from its mating RMM 160. The dropping indication can be used to prompt the TIMTPM 220 to switch to another low-speed path.
Each low-speed Interface Module (LSOIM) 250a-c is a module or component that converts the IMTP segments to Network Layer, Data Link Layer and Physical Layer according to its associated communication links 152, 140, and 132 (respectively).
Another exemplary embodiment of the TIMM 200 can be embedded in an intermediate Node (such as Nb 170 and\or RNC or Nb 110). In such an embodiment, the high-speed data bit stream of the node is directly entered into the TIMTPM 220 and the HSIF 210 interfaces and converts the signals from the Physical Layer format used over a backbone of the intermediate node to bits stream. In such an embodiment, the high-speed communication link 112a is eliminated.
In another exemplary embodiment, if the value of Td of two or more paths is smaller than Jmax, the Management and Communication Module 260 can force the TIMTPM 220 to select a certain path even if another path has a shorter Td, the decision can be cost oriented, reliability based, or the like.
The RMTPM 320a-c receives blocks of Inverse Multiplexing Transport Layer segments. For each segment, the RMTPM 320a-c determines the type of the IMTP segment. Data IMTP segments are sorted according to their sequence number and are then stored in a jitter buffer; the CRC value is updated; and a receiving block size counter is incremented by one. In parallel, segments from the jitter buffer can be transferred to a FIFO 330 in the following order: (1) first a First path segment or a Previous path segment (depends if it's the initiation or on-going phase); (2) next, after removing their headers, the data segments are forward from the jitter buffer according to their sequence number.
Upon identifying the control segment “Block size” and the control segment “CRC” their values are compared to the calculated received CRC and block size counter. When RMTPM 320a-c notices a CRC error or the actual number of received segments is different from the number specified in the “block size” control segment, then RMTPM 320a-c notifies the Receiver Management and Communication Module RMCM 360. When the Next-path control segment is received, indicating the end of the block, the next-path segment is transferred to the FIFO 330. In some embodiments, the block size can be limited to a certain number of segments. Therefore, at the mating TIMM 200, when a block size reaches the limit, the block can be terminated and the next path can point to the same path.
The output of each FIFO 330 is connected to a Selecting and Multiplexing Module (SMM) 340. In the initiation phase, an exemplary SMM 340 can scan all FIFOs 330 looking for the first-path segment. Once the first-path segment is found, the SMM 340 starts draining the FIFO storing the first-path segment and rearranges each IMTP segment into bits in an orderly manner. These bits are transferred to a High-speed Output Interface Module (HSOIF) 350. In this exemplary embodiment SMM 340 delivers a stream of bits that comply with the physical layer protocol used over the high-speed connection 112a.
In another embodiment, the SMM may deliver a stream of groups of bits such as ATM cells. In such an embodiment, an exemplary HSOIF can be adapted to also process the Data Link Layer according to ATM protocols. Yet in another embodiment, the stream of groups of bits can be a stream of IP packets carried over the high-speed communication link 112a. In such an embodiment, an exemplary HSIF can be adapted to process also the network layer according to IP, etc.
This procedure continues until the SMM 340 encounters the next-path control segment. The next-path control segment is parsed by the SMM 340 for decoding which is the next FIFO to be drained. Then the SMM 340 starts drawing the segments from the specified FIFO according to the Next-path segment. For the first segment received in next FIFO, the control segment is examined to identify the Previous-path. The SMM 340 can verify that the value of the previous-path segment matches the FIFO previously used. If not, the SMM 340 informs the RMCM 360. If the value matches, then the SMM 340 starts drawing data segments from the next FIFO, dividing each segment into bits in an orderly manner and transferring said bits to the HSOIF 350 and so on and so forth.
The HSOIF 350 receives a stream of bits and converts them to a stream of high-speed signals (RF, Analog or optic, for example) depending on the physical layer of the high-speed communication link 112b. In another exemplary embodiment, the RMM 300 is embedded in the intermediate node (Nb 170,
The MCM 260 (
During the ongoing phase, the management and communication modules MCM 260 and RMCM 360 are responsible to exchange information such as errors detected by one of them. Exemplary errors can be missing segments, CRC errors, dropping indication, synchronization problems detected, etc. In addition, they may receive requests and new demands or changes in the demands of a service provider. Exemplary changes can be a demand to abandon a certain low-speed communication link, a request to start an initialization phase or restart an initialization phase, giving precedence to certain links (for economic reasons for example), information on changes in the hardware or software or firmware in the nodes or in one of the layers protocols or in TIMM 200 or RMM 300, changes in the maximum Jitter and maximum latency, etc. The management and communication modules can inform the service provider or its administrators on the different errors and the actions that were made to overcome the error, for example. More information on the operation of the RMM 300 is disclosed below in conjunction with
An Exemplary method 400 may be initiated by MCM 260 (
The initialization phase begins by creating and sending 406 few IMTP Initiation-Control segments toward all the low-speed paths of TIMTPM 220 in parallel. The IMTP Initiation-Control segments can include the appropriate header followed by a stream of ‘1’, for example. TIMTPM 220 transfers theses IMTP Initiation-Control segments at the high-speed rate of its input high-speed link 112a (
Next, a decision is made 410 as to whether the Tds is smaller than the Tdmax. If not, TIMTPM 220 may start dropping high-speed input data bits and an error indication 412 can be sent to the MCM 260 (
If it happens that one of the low-speed communication paths has a problem, its monitored Td value will be higher than Tdmax, as long as the problem exists. Such a low-speed path will be passed over while the problem persists but, may share the load when the problem is resolved or alleviated.
Next method 400 may run in a loop between step 416 and 420. At step 416 the high-speed bits in the input of the TIMTPM 220 are arranged into IMTP data segments. Appropriate headers and sequential numbers are added to each segment, and the values of Scnt and BScnt are incremented accordingly. Additionally, the CRC value is calculated and updated. These IMTP data segments are transferred to the FIFO and Monitoring module 240 in the current path. Then a decision is made 420 as to whether Td of the current path (Tdcurrent) is smaller than Tdmax. If the Tdcurrent is smaller, then method 400 returns to step 416. If Tdcurrent is longer than Tdmax, then method 400 proceeds to step 422 for terminating the first block of IMPT data segments. The block size and the CRC are calculated and a block size and a CRC IMTP control segments are created and sent 422 to the FIFO and Monitoring module 240 of the current path (the first path). Method 400 proceeds to step 424 in
In step 424 in
In case that one of the low-speed communication paths has a problem, thus its monitored Td value will be higher than Tdmax, as long as the problem exists. Such a low-speed path will be passed over during the existing of the problem and may share the load when the problem disappears.
At step 436 the current path is defined as the “Previous Path”, and the selected next path is defined as the “Current-Path”. The BScnt and the CRC engine are reset. A “Previous-Path” IMTP control segment is created and sent through the current path. Next an internal loop may be initiated between step 438 and 440. In step 438 the high-speed bits in the input of the TIMTPM 220 are arranged into IMTP data segments. Appropriate data headers and sequential numbers are added to each segment, and the values of Scnt and BScnt are incremented accordingly. In addition, the CRC value is calculated and updated. These IMTP data segments are transferred to the FIFO and Monitoring module 240 of the Current-Path. Then a decision is made 440 as to whether the Td of the Current-Path (Tdcurrent) is smaller than Tdmax. If the Tdcurrent is smaller, then method 400 returns to step 438. If 440 the Tdcurrent is longer than the Tdmax, then method 400 proceeds to step 442 thus terminating the current block.
An IMTP “Block-Size” control segment is created 442 and sent through the Current Path. The CRC is calculated and sent as an IMTP control segment through the Current Path and Method 400 returns to step 424.
Method 500a can be initiated 502 during power on. After initiation in process 504 all the resources associated to RMM 300 can be reset. Resources can be such as but not limited to: Sequence counter (Scnt), Jitter Buffer (JB) (explained in more detail in conjunction with
If 510 the Tr value is bigger than the Di value then there is probably a problem in the low-speed communication link, therefore a “Connection-Error” can be sent 512 to RMCM 360 and process 500a ends. If 510 the Tr value is smaller than the Di value, then method 500a checks if 514 any IMTP segments have been received. If 514 no IMTP segments have been received, then method 500a returns to step 510. If an IMTP segment has been received, then method 500a proceeds to step 520. In step 520, the received segment is parsed and examined whether it is an Initialization IMTP segment or not.
If 520 the received segment is not an Initialization IMTP segment, the Tr value is compared 522 to the Di value. If 522 the Tr value is smaller than the Di value, method 500a returns to step 520. If 522 the Tr value is bigger than the Di value, method 500a sends a “No-Initialization-Segment” error 524 to the RMCM 360 process 500a ends.
Returning now to step 520, if the received segment is an Initialization IMTP segment, then the Tr is stopped and the Jitter buffer (JB) is reset 526. Next method 500a waits for an IMTP segment 530. Upon receiving an IMTP segment, method 500a inspects whether 532 it is a “First-Path” or a “Previous-Path” IMTP segment. If the IMTP segment is neither, then the segment is loaded into the JB (Jitter Buffer) in memory-address number corresponding or related to the segment's sequence number 536 and method 500a returns to step 530. Each memory-location in the JB has a “Read-Me” indication bit. The Read-Me indication bit indicates that data in the cell can be loaded into FIFO 330 (
At step 554 the “Read-Me” indication bit of the JB memory at the address that is equal to the value of RAcnt is parsed. The state of the “Read-Me” indication is examined 560 to determine whether it is true or false. If the “Read-Me” indication is false 560, then the Tr value is compared 562 to the Jitter delay (Dj). If the Tr value is smaller than the Dj, then method 550b returns to step 560. If 562 the Tr value is larger than the Dj, then a “Missing Segment” indication is sent 564 to the RMCM 360 (
Returning now to step 560, if the Read-Me indication is true, then the data stored is fetched from the JB 566. Next, the method 550b examines whether the stored data is an IMTP data segment 570. If the stored data is an IMTP data segment, then the CRC of the current received block is calculated and updated; the IMTP data segment is stored in FIFO 330; and the RAcnt and RBScnt are incremented by one 572 and Tr is reset. The “Read-Me” indication bit is then converted to false. Next method 500b returns to step 554.
If 570 the data in relevant address (RAcnt) JB is not an IMTP data segment, then the IMTP segment is fetched and parsed 574 in order to determine its type. In step 576 the segment type is determined. Three possible types of non-data segments include: Next-Path, Block-Size or CRC. If the IMTP segment type is Next-Path, then it is stored 578 in FIFO 330 and method 500b ends 590. If the IMTP segment type is Block-Size, then the payload of the segment (the block size) is compared to the RBScnt value 580. If the block size is equal to RBScnt value, then method 500b returns to step 554. If block size is not equal to RBScnt value then a “Block-Size Error” indication is sent 582 to RMCM 360 (
If the segment type is CRC, then its payload (CRC value) is compared to the calculated CRC 584. If they are equal, then method 500b returns to step 554. If they are not equal, a “CRC-Error” is sent 586 to (RMCM) 360 (
The Tsmm value is compared 614 to the value of a configurable Initiation Duration (Di2) parameter. If 614 Tsmm value is smaller than Di2 then all the FIFOs output are scanned 616 looking for a “First-Path” segment. Each segment is examined to determine if 620 it is the “First-Path” segment. If no First-Path segments are found, then the Tsmm is compared 622 to the Di. Initiation delay Di value is a configurable parameter. The Di depends on the type of the low-speed communication links. If the Tsmm value is smaller than the Di value, then method 600 returns to step 616. If the Tsmm value is bigger than the Di value, then method 600 sends 624 No-First-Path error indication to (RMCM) 360 and method 600 ends. If a First-Path segment is found at step 620, then the FIFO 330 that stores the First Path segment is defined as the Current FIFO 626, and the First-Path segment is released. Next SMM 340 starts fetching and parsing 628 the segments from the current FIFO.
Each IMTP segment is examined. If 630 the segment is identified as a data segment, then its header is removed and the payload of the data segment is stripped into bits. The bits are then transferred 632 as a bit stream at a high-speed rate toward the HSOIF 350 illustrated in
In the description and claims of the present application, each of the verbs, “comprise”, “include” and “have”, and conjugates thereof, are used to indicate that the object or objects of the verb are not necessarily a complete listing of members, components, elements, or parts of the subject or subjects of the verb.
In this application the words “unit” and “module” are used interchangeably. Anything designated as a unit or module may be a stand-alone unit or a specialized module. A unit or a module may be modular or have modular aspects allowing it to be easily removed and replaced with another similar unit or module. Each unit or module may be any one of, or any combination of, software, hardware, and/or firmware. Software of a logical module can be embodied on a computer readable medium such as a read/write hard disc, CDROM, Flash memory, ROM, etc. In order to execute a certain task a software program can be loaded to an appropriate processor as needed.
Various aspects, features and embodiments of the present invention have been described using detailed descriptions of embodiments thereof that are provided by way of example and are not intended to limit the scope of the invention. The described embodiments comprise different features, not all of which are required in all embodiments of the invention. Some embodiments of the present invention utilize only some of the features or possible combinations of the features. Many other ramification and variations are possible within the teaching of the embodiments comprising different combinations of features noted in the described embodiments.
It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described herein above. Rather the scope of the invention is defined by the claims that follow.
This application is being filed under 35 USC 111 and 37 CFR 1.53(b) and claims the benefit of the filing dates of the U.S. Provisional Application for Patent that was filed on Jun. 3, 2008 and assigned Ser. No. 61/058,471 and the U.S. Provisional Application for Patent that was filed on Jul. 10, 2008 and assigned Ser. No. 61/079,792, both of which are herein incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61058471 | Jun 2008 | US | |
| 61079792 | Jul 2008 | US |
