WO2001069834A1 - Mecanisme hybride de transport de donnees sur des reseaux optiques - Google Patents

Mecanisme hybride de transport de donnees sur des reseaux optiques Download PDF

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Publication number
WO2001069834A1
WO2001069834A1 PCT/US2001/007780 US0107780W WO0169834A1 WO 2001069834 A1 WO2001069834 A1 WO 2001069834A1 US 0107780 W US0107780 W US 0107780W WO 0169834 A1 WO0169834 A1 WO 0169834A1
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WIPO (PCT)
Prior art keywords
packet
packets
data
sonet
frame
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PCT/US2001/007780
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English (en)
Inventor
Pankaj K. Jha
Original Assignee
Cypress Semiconductor Corp.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US09/523,576 external-priority patent/US6778561B1/en
Priority claimed from US09/523,476 external-priority patent/US6771663B1/en
Priority claimed from US09/535,889 external-priority patent/US6847644B1/en
Priority claimed from US09/535,717 external-priority patent/US6973084B1/en
Priority claimed from US09/535,890 external-priority patent/US7006525B1/en
Application filed by Cypress Semiconductor Corp. filed Critical Cypress Semiconductor Corp.
Priority to EP01916564A priority Critical patent/EP1266476A4/fr
Priority to AU2001243574A priority patent/AU2001243574A1/en
Publication of WO2001069834A1 publication Critical patent/WO2001069834A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
    • H04L1/0056—Systems characterized by the type of code used
    • H04L1/0061—Error detection codes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/16—Time-division multiplex systems in which the time allocation to individual channels within a transmission cycle is variable, e.g. to accommodate varying complexity of signals, to vary number of channels transmitted
    • H04J3/1605—Fixed allocated frame structures
    • H04J3/1611—Synchronous digital hierarchy [SDH] or SONET
    • H04J3/1617—Synchronous digital hierarchy [SDH] or SONET carrying packets or ATM cells
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/0078—Avoidance of errors by organising the transmitted data in a format specifically designed to deal with errors, e.g. location
    • H04L1/0083—Formatting with frames or packets; Protocol or part of protocol for error control
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0062—Network aspects
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0062—Network aspects
    • H04Q11/0071—Provisions for the electrical-optical layer interface
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J2203/00—Aspects of optical multiplex systems other than those covered by H04J14/05 and H04J14/07
    • H04J2203/0001—Provisions for broadband connections in integrated services digital network using frames of the Optical Transport Network [OTN] or using synchronous transfer mode [STM], e.g. SONET, SDH
    • H04J2203/0073—Services, e.g. multimedia, GOS, QOS
    • H04J2203/0082—Interaction of SDH with non-ATM protocols
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J2203/00—Aspects of optical multiplex systems other than those covered by H04J14/05 and H04J14/07
    • H04J2203/0001—Provisions for broadband connections in integrated services digital network using frames of the Optical Transport Network [OTN] or using synchronous transfer mode [STM], e.g. SONET, SDH
    • H04J2203/0089—Multiplexing, e.g. coding, scrambling, SONET
    • H04J2203/0094—Virtual Concatenation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0062—Network aspects
    • H04Q11/0066—Provisions for optical burst or packet networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0062—Network aspects
    • H04Q2011/0064—Arbitration, scheduling or medium access control aspects
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0062—Network aspects
    • H04Q2011/0077—Labelling aspects, e.g. multiprotocol label switching [MPLS], G-MPLS, MPAS
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0062—Network aspects
    • H04Q2011/0086—Network resource allocation, dimensioning or optimisation

Definitions

  • the present invention relates to a method and/or architecture for hybrid data transportation generally and, more particularly, to sending a mix of different data types over a fiber optic network running
  • SONET was designed to efficiently carry telephony Plesiochronous Digital Hierarchy (PDH) channels such as T1/T3. This was easily achieved by dividing the payload area in fixed slots called virtual tributaries (VT). These virtual tributaries are then grouped together to form higher-rate channels. These fixed slots are efficient for carrying fixed-bandwidth telephony channels because any one or more channels can be added or removed from a bundle without processing an entire payload of channels. Because SONET frames repeat at fixed intervals, these virtual tributaries have fixed locations and time intervals, and it is easy to extract T1/T3 or fractions of Tl without processing the entire SONET payload.
  • PDH Digital Hierarchy
  • a set of time-division- multiplexed (TDM) packets 12a-12n, a set of ATM packets 14a-14n and a set of POS packets 16a-16n are shown in connection with a SONET fiber line 18.
  • TDM time-division- multiplexed
  • ATM ATM
  • POS POS
  • 16a-16n POS packets 16a-16n
  • PSL path signal label
  • inverse multiplexing suffers from one or more of the following disadvantages :
  • ATM VP multiplexing encodes packets in ATM cells and then inserts the cells inside a SONET SPE.
  • the ATM VP multiplexing typically utilizes CES to carry DSO/1 PDH traffic.
  • SONET/SDH rings As more and more data is being transported on SONET/SDH rings, there is a need to send variable-length packets on pre-existing SONET/SDH networks. These packets originate out of routers and other data access devices. While SONET/SDH networks must transport these data packets, they must also continue to support TDM-style fixed length packets for telephony and leased line applications.
  • VT channels while other VT channels may be under-utilized.
  • VT channels Once a VT channel is dedicated for a particular traffic and is put on a specific circuit-switched path, the topology does not change, even if traffic conditions change.
  • Conventional approaches have the following disadvantages (i) ATM and Packets are implemented on different rings because of QoS and timing issues; (ii) very high cost for new fiber and SONET equipment for Telco/ISP/MAN; (iii) only one type of packet goes inside a SONET SPE at one time (the remaining bytes of the frame with conventional SONET are wasted) (SONET packets go around the entire SONET ring, limiting bandwidth); and or (iv) the only way to support telephony channels along with data packets is to allocated part of SONET frame for packet data transmissions (which results in an inefficient bandwidth usage).
  • FIG. 18 is a flow chart illustrating an operation of the present invention.
  • FIG. 19 is a flow chart illustrating an operation of the present invention.
  • FIG. 21 is a block diagram, illustrating an operation of the present invention.
  • the present invention may provide spatial reuse of bandwidth, allocation of PDH bandwidth in 64Kbps increments, protocol-independent MPLS (Multi-Protocol Label Switching) support, and/or seamless operation over point-to-point and ring networks with SONET/SDH, direct data-over-fiber configurations or other network configurations.
  • the present invention may also be applicable to Synchronous Digital Hierarchy (SDH).
  • SDH Synchronous Digital Hierarchy
  • SONET is used as a general description for SONET/SDH networks with similar implementation for SDH networks. Additional details of the operation of the HDT protocol are also described in connection with direct data-over-fiber networks.
  • FIG. 9 a block diagram of a system 100 is shown in accordance with a preferred embodiment of the present invention.
  • the system 100 may comprise a number of devices 102a-102n connected to a network backbone 104.
  • FIG. 10 illustrates the addition of a number of chips 106a-106n.
  • the devices 102a- 102n may receive T1/T3 signals, ATM signals, and POS signals.
  • the devices 102a- 102n may receive data in one or more of the following data transmission media: SONET, SDH, direct data over fiber (e.g., both in point-to-point or ring configuration) with or without SONET/SDH framing and other transmission methods needed to meet the design criteria of a particular implementation.
  • SONET SONET
  • SDH direct data over fiber
  • the system 100 may provide an increase in the data traffic handling capabilities of SONET/SDH networks.
  • the system 100 may implement a design of a SONET/SDH add drop multiplexer
  • the present invention may embed a header (and/or footer) 202 (e.g., a 32-bit packet header) to create a deterministic packet transport protocol.
  • the packet header may comprise a 32-bit payload header 204a-204n that may precede each frame, regardless of the particular packet type stored within the frame.
  • the protocol identification may be implemented as a few header bits configured to denote the particular type of packet (e.g., ATM, IP , PPP, Frame Relay, etc.) embedded within the payload portion of a particular frame.
  • Bandwidth maximization may be implemented with another bit in the header 202 that may specify whether the packet may be reused by the intermediate SONET nodes 102a- 102n.
  • the SONET framing may be left unchanged by implementing a single PSL (Path Signal Label) value 206 in a SONET Path Over Head (POH) 208 that is generally able to specify the various types of packets embedded within the payload of a particular frame.
  • PSL Pulth Signal Label
  • POH SONET Path Over Head
  • the system 100 may be directly applicable to WDM/DWDM Fiber because individual packet framing is independent of SONET.
  • the system 100 may be also used in IP-over-Fiber networks.
  • FIG. 12 a more detailed example of the frame 200 is shown illustrating packet fragmentation across fixed bandwidth channels in accordance with the present invention.
  • the frame 200 leverages the fact that SONET/SDH frames are normally synchronous in nature and that frame bytes are normally transferred in a single sequence within a timed window.
  • An optical node may receive bytes from a synchronous frame (e.g., the frame 200) and generally have access to all the bytes in the particular SONET/SDH frame.
  • the particular frame is generally of a fixed size (e.g., for a given SONET/SDH speed and type).
  • the frames may be clearly marked and are normally accessible in a definitive manner using path overhead and line overhead markers.
  • the system 100 may have different types of packets to span over available spaces inside particular SONET/SDH frame.
  • the system 100 may provide an encapsulation 210 around the payload 212 that generally contains additional information about the packet.
  • the HDT protocol may allow dynamic management of packets to maximize bandwidth.
  • the system 100 may allow the transport of different types of data over a single fiber link. With the system 100, IP (or other protocol) packets, Packet-Over-SONET (POS), ATM cells, G.702-based PDH (T1/T3), SRP, Frame Relay, and other types of data may be mixed inside a SONET payload and dynamically and sent on a single fiber (as shown in FIGS. 9 and 10).
  • the system 100 may provide robust scrambling and unified packet transport over ring and point-to-point networks and may be well suited for non-SONET configurations such as point-to-point WDM networks.
  • An offset locator operation 230 for a next packet fragment location is shown.
  • An offset pointer 232 may point to a header location 234 in the frame where the next portion of the packet is stored.
  • a packet may have a number of offset pointers if the packet is stored in a number of locations.
  • the HDT is generally able to extend data identification beyond PSL-based SPE-level data typing and put multiple data types inside a SONET SPE.
  • a value of 0000 may indicate the packet area (e.g., the length of the packet area is given by the length value in the outside SDL framing) that does not generally contain any useful data and can be reused for storing new data.
  • HDT may easily support traditional PDH and other guaranteed bandwidth channels.
  • a frame repeats every 125 ⁇ S, resulting in abandwidth of 64KHz for every byte in the payload.
  • the SONET SPE 200 may comprise anumber of packets 220a-220n and anumber of empty packets 222a-222n.
  • the packet payload header 204a of the packet 220a may identify the packet/protocol.
  • the packet payload header 204a may identify a packet type of the packet 220a stored (or transported).
  • the payload header 204a may tell what kind of packet/protocol (such as Ethernet, PPP, IP, Frame Relay, ATM cells, Tl, etc.) is inside a payload of the packet 220a.
  • packet/protocol such as Ethernet, PPP, IP, Frame Relay, ATM cells, Tl, etc.
  • Different protocols may be supported at two ends (e.g., the devices 102a-l 02n) of a network without the need for provisioning in advance.
  • conventional approaches use a protocol over WAN which is usually negotiated between two parties at the ends devices 102a-102n of the WAN link.
  • the payload header 204a maybe used to tell whether one or more of the empty packets 222a-
  • a receiver may mark the SONET SPE 200 as reusable. Nodes on the fiber network 100 may mark different sections of the SONET SPE 200 as reusable by the other nodes 102a-102n. Provisioning of TDM channels may provide the ability to mark a portion (or many portions) of a SONET SPE payload area as non-reusable. With a non-reusable area, even when a receiver receives the packet, another receiver cannot reuse the packet area. However, the same receiver may reuse the non- reusable area.
  • Any packet may be marked in any fashion to support, for example, a dynamic mix of data and voice (TDM) traffic on a
  • SONET/SDH network Such an implementation is not possible with current technologies.
  • the present invention may solve the problem of mixed value and data transmissions faced by telephone carriers and data providers.
  • intermediate nodes may detect these packets (e.g., the reusability bit is reset), note the offsets of these packets, and preserve the respective offsets when recreating the frame (e.g., after adding packets from local input ports) for outbound traffic.
  • An SDL framing 262 may be in the first 16 bits and may contain the length of the entire payload, including SDL framing bytes.
  • a 16 bits of CRC-16 264 may be provided on the length field (e.g., xl6 + xl2 + x5 + 1).
  • a next fragment offset 270 may be a 16-bit value showing the location offset of a next packet fragment (if any) of the packet. The next fragment offset 270 is generally taken from the start of a current packet.
  • a header CRC 272 may be computed over payload header bytes only, with same scrambling polynomial used for SDL framing.
  • a payload area 274 may contain the actual packet to be transmitted over the WDM or SONET link.
  • the payload area 274 may contain one of a number of types of protocol packets, such as Ethernet, ATM, GR.702, PPP, Frame Relay, etc.
  • a payload CRC 276 may be user-controlled value and may be computed for the payload bytes only.
  • the payload CRC 276 is generally either a 16 or 32-bit value, depending on mutual negotiation between sending and receiving stations. Referring to FIG. 16, various parameters of the packet header 204a are shown. The particular bit width of the payload header 204a may be varied accordingly to meet the design criteria of a particular implementation.
  • a packet identifier 280 (e.g., D3: DO) generally identifies the type of packet in the payload. For example, a value of 0000 may represent a null packet. A null packet may indicate that the payload area may be reused. When a packet is dropped at a node, the length field does not generally need to be modified for the packet, only the D3 : DO bits need to be cleared.
  • a header data area 282 may carry MPLS labels (e.g., outside of payload area). Operation administration and maintenance (OAM) bytes 282 may be used for link management, or any other data separately from the payload.
  • a reusability area 284 (e.g., D7) may be a "1". If a SONET node can reuse a particular packet area, the size of the packet area may be given by the packet length field 264 of the SDL header. If the bit D7 is set to a "0", then a node will not generally mark the packet area as re-usable, even after apacket has been dropped.
  • the particular nodes of the various configuration bits may be varied (e.g., inverted) accordingly to meet the design criteria of a particular implementation.
  • a header length area 286 may include, in one example, a 32-bit payload header.
  • a fragment identifier area 288 (e.g., D17: D16) maybe implemented as a two word value.
  • a value of "00” may indicate that the payload area contains a complete packet.
  • a value of "01 " may indicate the beginning packet of a fragmentation sequence.
  • a value of "10” may indicate a continuation of packets.
  • a value of "11” may mark the last fragment in the series.
  • Other particular bit patterns maybe implemented accordingly to meet the design criteria of a particular implementation.
  • a padding area 290 may indicate a minimum packet length.
  • the minimum packet length may be 4 bytes (e.g., 2 bytes length + 2 bytes CRC). Idle bytes at the end of packets and elsewhere may be marked by a length field of "0000". In instances there may be less than 4 bytes left between packets. In this case, it may be impossible to place a SDL null packet. Such idle bytes are shown as tail-end padding for the preceding packet.
  • An unused area 292 (e.g., D31:20) may be used for additional expansion.
  • a node may receive a frame at a block 300.
  • a block 302 may determine if the received frame is an HDT frame. The block 302 may use the PSL value in the POH to determine the type of protocol carried inside the SPE. If the PSL shows POS, ATM, or PDH traffic, the receive operation may proceed to the block 304. If no HDT packets are present, a block 306 handles the POS/ATM/PDH packet. If in the block 302, the PSL shows the SPE contains HDT frames, the node uses additional logic for HDT processing to detect and route different types of packets embedded in the SONET SPE 200.
  • a block 308 may read the POH.
  • a block 310 may determine a first packet of the SONET SPE 200.
  • a block 312 may read a length and CRC of the first packet.
  • Ablock 314 may determine a match of the length and the CRC. If a non-match of the length and CRC occurs, the receive operation is generally set to ablock 316. The block 316 may read a next word of thepacket from the SONET SPE 318. If amatch occurs, the receive operation may process the packet.
  • hardware e.g., implemented in the system 100
  • ATM cells are generally retrieved by first looking at the PSL value to determine their presence and then reaching the SONET SPE to get fixed byte ATM cells, either with or without HEC-based cell delineation. For example, if the payload header in the HDT shows the payload contains ATM cells, the hardware device generally retrieves payload bytes (up to number of bytes specified in length field) and sends the byte stream to an existing ATM cell processing logic. The ATM cell processing logic may then work on the byte stream using HEC hunting just as if the SPE contained only ATM cells in its payload. Referring to FIG. 18, an example of a processing operation 320 is shown.
  • a device supporting Hybrid Data Transport HDT protocol generally operates much the same as a normal SONET/SDH transport operates.
  • HDT adds a header to packets to allow their mixing within the same SPE 200.
  • Much of the HDT processing is generally related to processing of the header to identify the type of packet and thenpassing the starting address of data bytes to standard logic for handling the individual packet type.
  • Support of PDH-type channel typically requires a fixed starting location for the channel in every frame. If PDH support is not needed, packets of any mix may be put anywhere inside the SPE 200 to achieve excellent bandwidth utilization without much operational complexity. When fixed bandwidth channels are carried, some data packets may need to be fragmented when the packet hits a static location. Fragmentation of a packet, however, is generally easily achieved in SONET networking because all bytes in the SPE 200 are transmitted sequentially. Additionally, recovering fragments and putting the fragment together may be simply accomplished.
  • a device supporting HDT may receive a packet to be transmitted from a system side.
  • a node may take inputs from different sources 402, encapsulate the packets with an SDL length/CRC fields 404, add an HDT header 406 to each of the packets, and then store the packets inside the SPE.
  • the node may not send a fresh frame on the network in order to transmit the packets.
  • a TDM channel check 408 may determine a reusability of the SPE 200.
  • the transmit operation 400 may reuse available space in an incoming SPE (containing HDT frames).
  • the transmit operation 400 may then may proceed to a length check 410 to see if there is any space available to insert the packet to be sent. If there is enough space, the entire packet is stored (with proper SDL framing and HDT header bytes). Any remaining bytes, depending on the size, are generally either (i) filled with a null HDT packet (e.g., the payload header identification bits are 0000), (ii) filled with SDL null packets (e.g., pairs of length/CRC with a null length field), or (iii) accounted for as tail- end padding (e.g., if the size is less than 4 bytes).
  • a null HDT packet e.g., the payload header identification bits are 0000
  • SDL null packets e.g., pairs of length/CRC with a null length field
  • tail- end padding e.g., if the size is less than 4 bytes.
  • the packet is generally fragmented.
  • a portion of the packet may be stored at one place and other fragments may be stored at another free location.
  • the first fragment offset pointer may contain the starting location of second fragment. Because bytes are transmitted sequentially in the SPE 200, reassembling fragments may be easily achieved.
  • the node checks the frame to see if there are unused/reusable areas in the incoming/queued frame that can be used for sending data. If there is enough space available in the frame, the node fills the space with additional data before sending the frame out.
  • PDH channels of any bandwidth may be provisioned anywhere inside the SONET SPE.
  • PDH bytes must begin at the same offset inside the SONET SPE.
  • allocation of PDH channels at different locations inside a SONET SPE may create fragments of unused bytes all over the SONET SPE. For efficient transport of variable-size IP packets, these unused bytes may be utilized for IP data.
  • an operation 500 for CRC error checking is shown. If bit errors occur at an upstream node that receives a packet with a correct CRC, the downstream node will never learn about the bit errors if the upstream node recomputed CRC for the packet before transmission.
  • a node that receives the packet usually swaps the label with a different value, pops the label, or adds a new label to the stack. If MPLS is embedded inside a packet, payload CRC will change at each node.
  • One solution would be to check for CRC for ingress, but not to re-compute the CRC on egress.
  • An efficient way to implement such CRC computation is to separate header CRC from payload CRC. This way, header CRC is recomputed easily and quickly at intermediate nodes while the payload CRC is preserved end-to-end. With HDT, all header labels and other temporary information for the packet may be carried outside of the payload so the payload data/CRC is not modified at any of the intermediate nodes.
  • a SONET node may be a data-aware add/drop multiplexer, a digital cross-connect, or a router/access multiplexer sitting on a SONET ring.
  • Such devices may implement HDT protocol for data encapsulation and transport over SONET and WDM networks.
  • Traditional circuitry for ATM cell delineation, PPP processing and other protocol handling may be implemented similar to conventional approaches, with some additional added circuitry for HDT encapsulation and decapsulation.
  • the path signal label (PSL) value proposed for use with the HDT may be the same as the one for SDL frames. Referring to FIG. 21, an example of spatial reuse with HDT is shown.
  • Spatial reuse of bandwidth across anumber of network nodes may be achieved by permitting full or partial termination of individual packets at any node. Spatial reuse of bandwidth reclaimed from the terminated packet may increase performance. HDT may provide an ideal way to achieve spatial reuse of SONET bandwidth. Using add/drop of hybrid data, nodes can reuse released bandwidth for transmission of any of the various kinds of data.
  • initial bytes may be placed in a small transit buffer.
  • a particular node A, B, C, D may be able to determine whether the packet belongs to the node. If the packet does not belong to the node, the bytes are streamed out of transit buffer to the output port. However, the packet may belong to the node A, B, C, D if, for example, (i) the D7 bit is set in the payload header, (ii) the packet area has been reserved for a fixed bandwidth channel such as a PDH, and/or (iii) in this case, the D3 : DO bits are not cleared.
  • the node may clear the D3: DO field to mark the packets void and reusable, where the bytes belonging to the packet are sent to system.
  • the number of bytes sent to the system may be specified in the length field of the SDL header. If the header shows fragmentation then a packet is received in many fragments and sent out to the system until the last fragment is received. Packets may be added either using a fresh SONET SPE or by reusing bytes inside an incoming or previously queued frame.
  • the decision of which packet to add to a void or reusable packet area inside an SPE can be made on following lines by (a) selecting a packet (or a collection of packets) that will fit inside the reusable area, (b) selecting all packets that can fit inside the reusable space, or (c) selecting a packet based on QoS parameters or packet priority. Since SONET frames repeat at 125ms intervals, packet transmission may be arranged to achieve a desired rate. Once a packet is selected for addition to the SPE, the node creates a payload header by setting payload type, reusability and other bits for the packet. The circuit 100 may then add the header to the payload.
  • the SDL framing mechanism may use length CRC pair information as a header and a frame delimiter.
  • SDL provides a robust scrambling and frame locator technique and may be used for direct data-over- fiber networks where SONET framing may not be used.
  • Implementing OAM packets may eliminate the need for complex SONET framing and link management overheads.
  • the HDT protocol structure may operate unmodified. Point-to-point WDM networks and ring-based SONET networks (or any other network) may easily be mixed and connected to each other. With a powerful support for MPLS (that may be transported independently of payload), networks may be designed that may have alternative LSP (Label Switched Paths) links for a highly robust redundancy.
  • LSP Label Switched Paths
  • nodes on a SONET ring may be connected through another network that may be entirely different from the ring.
  • the backup path could be a high-speed point-to-point link or a ring network that may be geographically quite diverse.
  • the HDT protocol may permit configuration of these networks quite easily without requiring complex protocol translation logic for different network configuration.
  • the present invention may use a packet payload header to identify the kind of packet inside. These identifier bits tell what kind of packet/protocol (e.g., such as Ethernet, PPP, IP, Frame Relay, ATM cells, Tl, etc.) is inside the payload. Using such a technique, different protocols may be supported at two ends without the need for advanced provisioning. Using conventional methods, the use of a single protocol over a WAN needs to be negotiated.
  • the identifier may indicate whether one or more packet areas inside SONET SPE may be reused at an intermediate node. Conventional SONET networks require the SONET frame to travel around the ring until removed by the sender. Even when the receiving node received a packet, the frame went around the network, wasting bandwidth. With the present invention, not only may a receiver mark a SONET SPE as reusable, but differentreceivers on the fiber network may mark different sections of SONET
  • the present invention may provide the ability to mark a portion (or many portions) of a
  • SONET SPE payload area as non-reusable.
  • the packet area is not generally reused by another receiver/transmitter.
  • the same receiver may reuse the markedpayload area for add/drop applications. Allowing the same receiverto re-use apacket may help TDM channels and packet data within a single SPE.
  • bit definitions inside a payload header may change as further research is conducted on the fiber data protocol operation. Such changes in bit definitions are common in data communication protocols and do not change the nature and content of present invention.
  • the present invention often refers specifically to SONET.

Abstract

L'invention concerne une trame configurée de façon à être transmise sur un réseau, et à stocker de paquets de données dans plusieurs canaux. Au moins l'un des canaux peut être configuré de façon à stocker au moins un fragment de paquet de données (1, 2), chaque paquet de données étant séparé et relié par un pointeur de déplacement (232). Chaque paquet peut, également, être de type et de longueur quelconques, et se trouver à un emplacement quelconque de la trame, notamment dans une partie d'erreur (230) et dans des étiquettes de façon à commander l'acheminement d'une charge (234).
PCT/US2001/007780 2000-03-10 2001-03-09 Mecanisme hybride de transport de donnees sur des reseaux optiques WO2001069834A1 (fr)

Priority Applications (2)

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EP01916564A EP1266476A4 (fr) 2000-03-10 2001-03-09 Mecanisme hybride de transport de donnees sur des reseaux optiques
AU2001243574A AU2001243574A1 (en) 2000-03-10 2001-03-09 Hybrid data transport scheme over optical networks

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US09/523,576 US6778561B1 (en) 2000-02-23 2000-03-10 Hybrid data transport scheme over optical networks
US09/523,476 US6771663B1 (en) 2000-02-23 2000-03-10 Hybrid data transport scheme over optical networks
US09/523,576 2000-03-10
US09/523,476 2000-03-10
US09/535,890 2000-03-27
US09/535,717 2000-03-27
US09/535,889 US6847644B1 (en) 2000-02-23 2000-03-27 Hybrid data transport scheme over optical networks
US09/535,889 2000-03-27
US09/535,717 US6973084B1 (en) 2000-02-23 2000-03-27 Hybrid data transport scheme over optical networks
US09/535,890 US7006525B1 (en) 2000-02-23 2000-03-27 Hybrid data transport scheme over optical networks

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EP1349416A1 (fr) * 2002-03-28 2003-10-01 Alcatel Méthode dynamique d'insertion de données aux noeuds d'un réseau de transmission optique
FR2838005A1 (fr) * 2002-03-28 2003-10-03 Cit Alcatel Methode dynamique d'insertion de donnees aux noeuds d'un reseau de transmission optique
WO2003084279A1 (fr) * 2002-03-28 2003-10-09 Alcatel Methode dynamique d'insertion de donnees aux noeuds d'un reseau de transmission optique
US9350653B2 (en) 2002-04-01 2016-05-24 Cisco Technology, Inc. Label switching in fibre channel networks
FR2846185A1 (fr) * 2002-10-21 2004-04-23 Cit Alcatel Routeur perfectionne a insertion et/ou extraction de ressources
WO2004039120A1 (fr) * 2002-10-21 2004-05-06 Alcatel Routeur perfectionne a insertion et/ou extraction de ressources
US7706686B2 (en) 2002-10-21 2010-04-27 Alcatel Router with resource add-drop functionality
CN1305253C (zh) * 2003-04-10 2007-03-14 三星电子株式会社 千兆无源光网络的数据处理方法
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EP1467590A1 (fr) * 2003-04-10 2004-10-13 Samsung Electronics Co., Ltd. Structure d'une trame GEM avec indication du type de charge utile de la trame et méthode de traitement de données de celle-ci
KR100547864B1 (ko) * 2003-08-02 2006-01-31 삼성전자주식회사 Ｇｐｏｎ에서의 데이터 처리 방법
FR2864395A1 (fr) * 2003-12-23 2005-06-24 Cit Alcatel Systeme de commutation de paquets pour noeud de reseau de communication
US7385968B2 (en) 2003-12-23 2008-06-10 Alcatel Packet switching system for a communication network node
EP1549103A3 (fr) * 2003-12-23 2005-07-13 Alcatel Système de communication de paquets pour noeud de reseau de communication
EP1549103A2 (fr) * 2003-12-23 2005-06-29 Alcatel Système de communication de paquets pour noeud de reseau de communication
EP1990939A1 (fr) 2007-05-10 2008-11-12 Nokia Siemens Networks S.p.A. Procédé de transmission à utilisateurs multiples adaptatif en standard, réseau et programme informatique correspondants
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CN102439923B (zh) * 2009-07-20 2014-07-09 华为技术有限公司 传输通用服务传输转变编码的设备和方法
CN102014063A (zh) * 2010-11-30 2011-04-13 北京华环电子股份有限公司 一种实现多路uart复用到tdm的方法及装置

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EP1266476A4 (fr) 2009-08-05
EP1266476A1 (fr) 2002-12-18

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