Classifications

• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F11/00—Error detection; Error correction; Monitoring
  • G06F11/07—Responding to the occurrence of a fault, e.g. fault tolerance
  • G06F11/14—Error detection or correction of the data by redundancy in operation
  • G06F11/1402—Saving, restoring, recovering or retrying
  • G06F11/1415—Saving, restoring, recovering or retrying at system level
  • G06F11/1417—Boot up procedures
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F11/00—Error detection; Error correction; Monitoring
  • G06F11/07—Responding to the occurrence of a fault, e.g. fault tolerance
  • G06F11/14—Error detection or correction of the data by redundancy in operation
  • G06F11/1402—Saving, restoring, recovering or retrying
  • G06F11/1446—Point-in-time backing up or restoration of persistent data
  • G06F11/1456—Hardware arrangements for backup
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F11/00—Error detection; Error correction; Monitoring
  • G06F11/07—Responding to the occurrence of a fault, e.g. fault tolerance
  • G06F11/14—Error detection or correction of the data by redundancy in operation
  • G06F11/1402—Saving, restoring, recovering or retrying
  • G06F11/1446—Point-in-time backing up or restoration of persistent data
  • G06F11/1458—Management of the backup or restore process
  • G06F11/1466—Management of the backup or restore process to make the backup process non-disruptive

Definitions

• the invention relates to a back-up method for equipment settings in accordance with the preamble of the attached claim 1.
• the preferred range of use of the invention is to back up equipment settings of node equipments in a digital telecommunications system under all operating conditions, but in principle, the solution of the invention is applicable to backing up equipment settings of any similar electronic equipment, e.g. to backing up a database of a telephone exchange or switch.
• a telecommunications system comprises a plura ⁇ lity of nodes communicating with each other via trans ⁇ mission paths.
• a node is constituted by a telecommunica- tions equipment, e.g.
• a cross-connection equipment com ⁇ prising in a manner known per se several board units, which implement one or several telecommunication func ⁇ tions, such as the very cross-connection.
• telecommunications equipment are stored a lot of various settings and parameters, the values of which depend on how the equipment in question controls or conveys traf ⁇ fic of the network and how the equipment is supposed to behave in different special situations, such as fault, alarm, emergency service etc.
• These set values/parame- ters are stored in the equipment at the commissioning thereof.
• the object of the present invention is to elim ⁇ inate the above-described problem and to provide a solu ⁇ tion, through which a telecommunications equipment, and thus the whole telecommunications system, can be started quickly and reliably in association with a change of board unit.
• This is achieved by means of the method of the invention, the method being characterized in what is set forth in the characterizing portion of claim 1.
• the idea of the invention is to add such infor ⁇ mation to the settings that makes the equipment capable of utilizing back-up copies stored inside the equipment independently and quickly in failure and other change situations, in order to return the correct operating copy to the board unit and to bring the equipment as well as the whole network quickly into an operating condition.
• the equipment shall be capable, also during its normal operation, of writing all changes made in the actual operating copy into the back-up copies, which are at least one, but preferably two, and of checking whether the copying was successful.
• Preferred embodiments of the invention concern primarily additional information to be stored in the settings, by means of which information it is possible to speed up further a correct starting of the equipment in predetermined situations.
• Figure 1 shows a typical mechanical configura ⁇ tion of a telecommunications equipment and illustrates simultaneously an input of set values
• FIGS 2a to 2d illustrate an operational block diagram of the equipment shown in Figure 1
• FIGS 3a to 3c show schematically measures to be taken according to the invention in the telecom- munications equipment in various situations.
• Figure 1 is a front view of a subrack SR of a telecommunications equipment 10.
• Six board units Bl...B6 are in this case mounted at board locations of the sub ⁇ rack, the units comprising various connectors CN for connecting external devices to the telecommunications equipment and for connecting the telecommunications equipment to a telecommunications network.
• the above- mentioned input of set values is performed e.g. by con ⁇ necting a service terminal 11 and a microcomputer 12 via a separate interface device 13 to a board unit in the telecommunications equipment. Subsequently, parameters are inputted from the microcomputer or the service ter ⁇ minal to the equipment 10.
• Figures 2a to 2d show various architectural models of a typical telecommunications equipment, in this case comprising a cross-connection device.
• a con ⁇ trol portion of the equipment is indicated in the fig ⁇ ures by reference mark CU, and additionally, the units performing cross-connection are provided by reference marks DCC (Digital Cross-Connect).
• DCC Digital Cross-Connect
• a node is connected to the network through interface units IU [each inter ⁇ face (not shown in the figures) may be e.g. a 2 Mbit/s PCM interface, which conforms to the CCITT recommenda ⁇ tions G.703 and G.704.]. If there are interfaces in other units than in the actual interface units IU, the unit in question is provided by reference mark IU in brackets.
• the units of a node are connected to two dif ⁇ ferent buses CBUS and DBUS, the former being a command bus, along which the units of the node communicate with each other, and the latter being a fast data bus inside the node, intended for transmitting data, coming (from the other nodes of the network) to the cross-connection device, between the different units.
• the internal data bus of the node also acts as a transmission path for set data.
• control portion CU is a separate unit and the actual cross-connection is decentralized to parallel interface units IU (each of them consisting of its own board unit) . All interface units are connected to the same fast DBUS and receive all incoming data, from which they select their own outgoing data.
• the control unit CU in a mother board of the node is connected to the interface units IU only via the CBUS.
• control unit CU is parallel with the interface units IU and connected to both buses.
• the control unit may then also comprise interfaces to the network and cross-con- nection functions, but it is, however, the only unit capable of controlling the node.
• the cross-connection is centralized in a separate board unit 71, which is parallel with the interface units IU and connected to both buses of the node.
• This unit receives all incoming data from the DBUS and forms the outgoing data from the node to the bus ready for the interface units.
• the control unit is separate also in this case and manages the node via the CBUS in the same way as in the case of Figure 2a.
• all units 72 comprise both interfaces and cross-connection functions and each of them can also function as a con- trol unit of the equipment, but only one at a time.
• the functional configuration of a node may vary accord ⁇ ing to which functions are built for each board unit.
• the equipment comprises a plurality of parallel board units as in Figure 1 and that the equip ⁇ ment comprises a control unit CU or the like, capable of reading and processing information stored in the board units.
• the purpose of the figures 2a...2d is only to make it clear how the different parts of the equip ⁇ ment are connected to each other, in other words, that the equipment typically comprises one control unit CU, which reads set data contained in the board units via the bus (CBUS) and processes them and controls the copy- ing of the data from one board unit to another.
• the control unit may be duplicated to improve the back-up.
• Communication on the command bus is implemented in practice in a manner known per se, e.g. by the use of a bus server in each board unit connected to the bus.
• the control unit CU desires to send a command and possibly also data to one or several interface units IU, it writes the number of the command and the possible data in its buffer, calls the command bus server and gives it an information of where to find the buffer con- taining said message and to whom the message shall be sent (either to all or only predetermined board units, each board unit having a separate address in the sub ⁇ rack).
• the command bus server assembles the data, writes this data packet in the buffer and sends it to the com- mand bus servers of the desired interface units.
• the command bus server of the interface unit performs an error check, disassembles the packet, writes the received commands in the buffer and calls then a message processing portion, which reads the received command and the possible data from the buffer and processes it.
• the command bus server of the control unit polls board or interface units in succession. If these need services of the con ⁇ trol unit, they switch on a desired service request bit in their response.
• the interface units are thus not al ⁇ lowed to send anything spontaneously to the command bus, but they perform a transmission only when they respond to a polling or a request command or when they receive a right to transmit information, which right was applied for in association with polling. In this way, no colli ⁇ sions can occur on the command bus either.
• bus servers can be used e.g. a Motorola 68HC11 processor comprising a built-in serial port connectable to the bus.
• Figures 3a...3c show measures according to the invention in different operating conditions of a tele ⁇ communications equipment schematically.
• the subrack SR comprises (only) four neighbour board units B1...B4. From each board unit are shown three separate storage areas indicated by refer ⁇ ence marks A, B and C.
• the storage areas are preferably implemented by an EEPROM, whereby the data remains stored in the memory in spite of power failures.
• the equipment is shown at the commissioning or installation stage thereof.
• each board unit e.g. storage area A
• the memory of each board unit contains the settings of the respective board unit, which set- tings comprise (besides other settings) addresses of two other board units in the equipment, preferably neighbour board units (the former and the latter) .
• One of these other board units is a board unit comprising a back-up copy of the set values of the board unit in question and the other one is a board unit a back-up copy of the set values of which is stored in the board unit in question.
• Each board location of the subrack does not necessarily comprise a board unit, due to which said other board units are not necessarily physically at directly neigh- bouring board locations with respect to the board unit in question.
• one neighbour board unit is the board unit which is the last one at the opposite end of the subrack, whereby a closed back-up loop according to the invention is generated.
• the set values of each board unit addi ⁇ tionally comprise a first identification number identi ⁇ fying the type of said board unit.
• Board units perform- ing the same task have the same identification number.
• the first identification number is not absolutely neces ⁇ sary, but in practice, it is very important, however.
• a second identification number is added to the set values, by which number different equipment configurations are distinguished from each other.
• Equip ⁇ ment configuration means how the equipment is configur ⁇ ed, in other words, how many board units there are in the equipment and at which board locations they are positioned.
• the time and date informing when the equipment configuration was made can be stored in connection with the second identification number.
• the address of a board unit in the equipment will also be stored in that board unit. This address is determined directly according to the physical location of the board unit in the subrack (at which board location the board unit is positioned). Advantages to be achieved by stor ⁇ ing the address will be described below.
• the set values of each board unit addi ⁇ tionally comprise a checksum calculated from the set values.
• Checksum is not quite necessary either, but sig ⁇ nificant advantages (to be described below) will be achieved, however, if a checksum is used.
• the first identification number is a board- specific identification number stored in the EEPROM of the board unit at the manufacture of the board unit already.
• the purpose of the identification number is to prevent a board unit of wrong type from being mounted in the equipment (i.e. copying back-up copy data of wrong type to a board unit mounted in the equipment) .
• the first identification number does not change at re ⁇ configuration of the equipment.
• the second identification number is preferably a random number to be generated by a random number gen ⁇ erator, which number is stored by the software of the equipment in the memory of each board unit belonging to the equipment configuration in connection with each configuration process, also re-configuration process.
• the purpose of the second indentification number is to inform in connection with a change of board unit, whether the new board unit positioned in the equipment is the same as was in the equipment earlier.
• the sig ⁇ nificance of the random number will be described more accurately below.
• the control unit CU of the equipment copies the set data of each board unit to a storage area of "external" set ⁇ tings in the memory of a neighbour board unit. This operation is indicated by dashed line arrows Al in Fig- ure 3a and the storage area of "external" settings by reference mark C.
• the data of the last board unit (B4) of the subrack are copied to the first board unit (Bl) of the subrack, in order to create a closed back-up loop as described above.
• the data are trans- ferred along the internal transmission bus CBUS ( Figures
• the set data are also copied to an ⁇ other storage area B of the own board unit.
• This opera- tion is described in Figure 3a by dashed line arrows A2.
• the memory of the equipment contains three copies of the settings of each board; the actual operat ⁇ ing copy in the very board unit (storage area A), the first back-up copy in a neighbour board unit (storage area C) and the second back-up copy in the same board unit (storage area B) .
• the advantage of using the third copy is that if e.g. some bit happens to change in the actual operating copy or back-up copy, it is possible to discover more reliably, by comparing the three copies, which one is the faulty one.
• the third copy can be stored also elsewhere than in the very board unit, e.g. in a microcomputer connected to the equipment (cf. Fig ⁇ ure 1) .
• a microcomputer connected to the equipment cf. Fig ⁇ ure 1
• the equipment is ready for use and can start operating normally as is described in Figure 3b.
• the control unit CU of the equipment performs a checking of the copies at regular intervals, comparing all three copies with each other.
• the comparison can be performed as a comparison bit by bit or by calculating a checksum from the set data and by comparing those with each other.
• the comparison is shown in the figure by two-way arrows A3. If it is discovered as a result of comparison that a fault has arisen e.g. in the actual operating copy in the storage area A of a board unit, the fault ⁇ less data are copied either from the storage area B or C to the storage area A.
• checksum functions as an additional back-up also e.g. in such a case when two copies are similar but erroneous. If this would be the case, checksums taken from said two storage areas (being wrong) inform that the right ver ⁇ sion is the (third) version having the right checksum.
• a need to change the settings of a board unit may also occur. The reason can be e.g. that the client desires to transmit his traffic e.g. in the night-time to another location than in the daytime. Then the concerned parameter of the board unit in question is changed and the same change is made auto ⁇ matically, as a response to the first change command, in all three copies.
• An observation of a change made in the operating copy may in principle be achieved also by the above comparison function, but an updating of data occurs then more slowly than if it were made automati ⁇ cally in all three copies.
• a change of a faulty board unit is described in Figure 3c. If one or more board units of the equip ⁇ ment are damaged, it (e.g. board unit B2 in Figure 3c) has to be removed from the equipment configuration and a new board unit has to be mounted in place thereof. Then the control unit of the equipment first reads the first identification number (board type) of the new board unit and compares it with the identification num- ber in the memory of another board unit of similar type (e.g. neighbour board unit) already existing in the equipment. If the new board unit is provided with cor ⁇ rect identification number, it is known to be of correct type and can be accepted to belong to the equipment con- figuration.
• first identification number board type
• the new board unit is provided with cor ⁇ rect identification number, it is known to be of correct type and can be accepted to belong to the equipment con- figuration.
• the control unit CU may also have a list of acceptable identification numbers in its memory, due to which the identification number of the other board unit needs not be used for the comparison. This list may be board location specific, informing which type of board unit can be accepted for which board location. In any case, a comparison of the identification number of a new board unit with the identification number stored in the memory of the other board unit presupposes that it is known that said two board locations should comprise a board unit of the same type.
• the control unit Upon acceptance of the first identification number, the control unit reads next the random number (specific number for each equipment configuration) stored in the new board unit and compares it with the random number stored in another, e.g. neighbour board unit. If these differ from each other, the settings of the neighbour board unit are copied to the new board unit. This is indicated by dashed line arrows A4 in Figure 3c. Additionally, a second back-up copy is taken of the settings for the storage area B (dashed line arrow A5) of the own board unit. Subsequently, the equipment may continue its normal operation again.
• the control unit knows that the same board unit has been positioned in the equipment again, due to which it is not necessary to copy the settings and the equip ⁇ ment may continue its operation immediately. Such a situation may arise if a board unit requires only little maintenance, e.g. resetting a jumper.
• the second configuration-specific identification number random number
• the equipment is capable of giving an error information to the mounter, if this mounts a board unit having been in the equipment already earlier by mistake into a wrong, e.g. neighbour board location.
• a new equipment configuration is made, e.g. a new board unit is added to an empty board location, a new back-up loop is always formed on the principle set forth above, in which loop the back-up copy of the set data of the board unit is always found in another, pre- ferably neighbour board unit.
• a new random number is also calculated a new random number, which is written over the old random numbers in order to know that the equipment configuration has changed. Accordingly, the random number is an identification number identifying the back-up loop as well. If date and time are used as additional back-up, these new data are written over the old date and time in each board unit.
• the control unit recreates, by using above data, a back-up loop for settings, in which loop the back-up copy of the set data of the board unit is always found in another, preferably neighbour board unit. If the control unit discovers at start-up that the set data in the board unit are different, it compares the copies with the copy in the neighbour board unit. If two of these copies are identical, they are accepted to be correct, supposing that the checksum is correct, and the correct data are copied to necessary storage areas. It is not absolutely necessary to store the back-up copy expressly in a neighbour board unit, but it can be stored in any other board unit in principle.
• neighbour board unit e.g. the advantage is achieved, however, that the re-configuring mounter knows a very simple rule, according to which two neighbour board units never must be simultaneously ab ⁇ sent from the equipment. Accordingly, the use of neigh ⁇ bour board unit (e.g. the right-hand one seen from the front of the subrack) as a storage location of the back- up copy of each board unit offers a very clear rule for the mounter.
• neigh ⁇ bour board unit e.g. the right-hand one seen from the front of the subrack
• the equipment thus comprises board units implementing telecommunications functions of very dif ⁇ ferent kinds, all board units have the common feature that they comprise a mutually identical storage area for storing back-up copies. In this sense they all seem to be similar outwards (to the control unit).
• EPROM any type of memory may be used in which it is possible to write during the operation of the equipment and which keeps the data stored in spite of a power failure (e.g. withdrawal of board unit).
• types of memories are e.g. battery back-up memories and flash-type memories. All above-mentioned data, e.g. address data of back-up copies, need not be located absolutely in the very board units either, if only the equipment contains said data for each board unit.
• the first and second iden ⁇ tification number have to be included in each board unit in order to make it possible to bring these data from the new board unit to the control unit.

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• Engineering & Computer Science (AREA)
• Theoretical Computer Science (AREA)
• Quality & Reliability (AREA)
• Physics & Mathematics (AREA)
• General Engineering & Computer Science (AREA)
• General Physics & Mathematics (AREA)
• Hardware Redundancy (AREA)
• Multi Processors (AREA)
• Maintenance And Management Of Digital Transmission (AREA)
• Techniques For Improving Reliability Of Storages (AREA)
• Exchange Systems With Centralized Control (AREA)
• Lock And Its Accessories (AREA)

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• 1994
  • 1994-02-14 FI FI940688A patent/FI99238C/fi active
• 1995
  • 1995-02-13 JP JP52099495A patent/JP3744537B2/ja not_active Expired - Lifetime
  • 1995-02-13 EP EP95907680A patent/EP0796460B1/en not_active Expired - Lifetime
  • 1995-02-13 WO PCT/FI1995/000061 patent/WO1995022105A1/en active IP Right Grant
  • 1995-02-13 AU AU15800/95A patent/AU1580095A/en not_active Abandoned
  • 1995-02-13 US US08/693,199 patent/US5796933A/en not_active Expired - Lifetime
  • 1995-02-13 DE DE69520841T patent/DE69520841T2/de not_active Expired - Lifetime

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