Classifications

• • 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
  • 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
  • H04L1/0075—Transmission of coding parameters to receiver
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
  • H04L69/40—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
  • H04L9/40—Network security protocols
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
  • H04L69/24—Negotiation of communication capabilities

Definitions

• Connection-oriented communication protocols are considered, in which each packet contains a checksum.
• the algorithm used to form the checksum is not relevant here. However, if this algorithm is changed and replaced by one or more new ones, then during a transition period it can be expected that both the old and the new algorithm will be used within a communication network. Furthermore, since a packet with an incorrect checksum is normally discarded by the receiver, it must be determined for each traffic relationship which algorithm is used to form the checksum.
• the first solution is not acceptable in a transition phase.
• the second solution requires the manufacturer of the switching systems or network nodes, on the one hand, additional development effort for the administration of the selection of the algorithm for forming the checksum, but on the other hand the network operator must make and configure this selection for each traffic relationship. This can be very time-consuming and costly and is highly prone to errors.
• the object on which the present invention is based is to specify a method for supporting a plurality of checksum algorithms in a network node which avoids the disadvantages of the prior art. This object is achieved by a method for supporting a number of checksum algorithms in a network node in accordance with the features of claims 1 or 2.
• a method for supporting a plurality of checksum algorithms is provided in a first network node A, according to which a communication relationship is established between the first network node A and a second network node B, the initialization of which is carried out by the first network node A, in a first step a first checksum algorithm is selected by the first network node A, in a second step the selected checksum algorithm is signaled by the first network node A to the second network node B, in a third step the communication relationship is established using the selected checksum algorithm if the initialization of the communication relationship with the selected checksum algorithm is accepted by the second network node B or, in the third step, a further checksum algorithm is selected by the first network node A, if by the second network node B the initialization of the communication relationship with the selected checksum algorithm is rejected or ignored, the second and third steps then being repeated with the newly selected checksum algorithm.
• a method for supporting a plurality of checksum algorithms in a first network node (A) for an existing communication relationship between the first network node (A) and a second is also implemented Network node (B), for which a first checksum algorithm is used, is provided, accordingly in a first step a second checksum algorithm is selected by the first network node (A), in a second step the selected checksum algorithm by the first network node (A) to the second Network node (B) is signaled, in a third step the selected checksum algorithm for the communication relationship is determined if the use of the selected checksum algorithm is accepted by the second network node (B) or in the third step another checksum algorithm is selected by the first network node (A) If the selected checksum algorithm is rejected or ignored by the second network node (B), the second and third steps are then repeated with the newly selected checksum algorithm.
• the selected checksum algorithm is signaled indirectly from the first network node A to the second network node B by sending an initialization message which is coded by means of the checksum algorithm to be signaled.
• An important advantage of the method according to the invention is that the administrative configuration or the administrative specification of the checksum algorithm is dispensed with. This eliminates, for example, the disadvantages mentioned for the network operator when introducing a new algorithm for forming the checksum.
• the manufacturer of the switching centers or network nodes implements a method that allows to work with all implemented algorithms in a transparent manner. The development effort is no greater than the provision of the administration option.
• An end point or network node which uses the method according to the invention can advantageously communicate with other end points or network nodes which either master the method according to the invention or only the old checksum algorithm or only the new checksum algorithm.
• Both communication partners or network nodes use the same algorithm for forming the checksum for a connection in both directions.
• the active end point or network node selects a checksum algorithm and starts the normal procedure for establishing a connection.
• the checksum algorithm once selected for a connection to a specific communication partner or network node is also used when receiving packets or messages from this partner or network node.
• the passive end point or network node uses all the checksum algorithms known to it to check whether the message or the packet has been transmitted correctly. If this test was only successful with a checksum, the corresponding checksum algorithm is selected for this connection.
• connection request is not answered even after repeated repetition, the active end point or network node waits for a certain amount of time, depending on the coincidence, and starts the connection request again, but with a different checksum algorithm.
• FIG. 1 shows schematically the process of initializing a connection between two nodes, both of which are based on conventional only support the previous checksum algorithm ADLER32
• FIG. 2 shows schematically the procedure for initializing a connection between two nodes, both of which only support the new checksum algorithm CRC32 in a conventional manner
• FIG. 3 shows schematically the procedure for initializing a connection between a node , which uses the method according to the invention and supports two checksum algorithms ADLER32 and CRC32 and a node which in the conventional manner only supports the previous checksum algorithm ADLER32
• FIG. 1 shows schematically the process of initializing a connection between two nodes, both of which are based on conventional only support the previous checksum algorithm ADLER32
• FIG. 2 shows schematically the procedure for initializing a connection between two nodes, both of which only support the new checksum algorithm CRC32 in a conventional manner
• FIG. 3 shows schematically the procedure for initializing a connection between a node , which uses the method according to the invention and supports two checksum
• FIG. 4 shows schematically the sequence of the initialization of a connection between two nodes, both of which are methods according to the invention use and support two checksum algorithms ADLER32 and CRC32, one node preferably using ADLER32 and the other node preferably using CRC32 and a collision of the connection requests occurs.
• the Stream Control Transmission Protocol which is defined in RFC 2960, is considered as the transport protocol.
• SCTP Stream Control Transmission Protocol
• ADLER32 an algorithm for the creation of the checksum
• CRC32 a new algorithm for the creation of the checksum
• the method according to the invention can also be used to introduce several new algorithms for forming the checksum, which are intended to replace the previous algorithm ADLER32.
• FIG. 1 shows the connection setup with the conventional method, in which both the first network node A and the second network node B each only have the new algorithm. Support CRC32 to create the checksum. This means that two endpoints that use different algorithms to generate the checksum cannot communicate with each other.
• connection setup for SCTP is briefly explained at this point with reference to FIGS. 1 and 2. For the sake of simplicity, it is assumed that the connection requests originate from the first network node A.
• an SCTP packet with an INIT chunk is sent from the first network node A to the other network node B.
• the checksum for this SCTP packet is formed with the checksum algorithm implemented in the first network node A, ie ADLER32 in FIG. 1 and CRC32 in FIG.
• the second network node B which uses the same checksum algorithm as the first network node A due to administrative requirements, recognizes the received SCTP packets as valid or corrupted on the basis of the checksum.
• Transmission errors are indicated by a discrepancy between the checksum formed in accordance with the respective checksum algorithm and the content of the SCTP packet over which the checksum was formed. If such a corrupted SCTP packet is recognized by the second network node B, it is discarded by the second network node. If there is no response from the second network node B after a retransmit with timer T1, the first network node A will repeat the transmission of the corresponding SCTP packet. If the SCTP packet received by the second network node B is recognized as valid, which in principle can only occur if there are no transmission errors and the same checksum algorithm ADLER32, CRC32 is used in both network nodes A, B, an SCTP packet is also used by the second network node B. an INIT ACK chunk.
• This INIT ACK chunk contains a cookie parameter which is sent back from the first network node A in a COOKIE ECHO chunk in a further SCTP packet to the second network node B.
• the second network node B confirms receipt of this COOKIE ECHO chunk by sending a COOKIE ACK chunk in an SCTP packet, and the
• the connection between the network nodes A, B is established using the checksum algorithm ADLER32 (FIG. 1) or CRC32 (FIG. 2) and can be used to transmit the useful information.
• connection data block in which all connection-specific data of a connection is stored and which is stored in a network node A, is expanded by a field in which information about the checksum algorithm used can be stored, for example one
• Checksum_algorithm This always has a value. If a network node A working with the method according to the invention receives an SCTP packet, a search for the connection data block is initiated. If the connection data block is found, the one specified in the "checksum_algorithm" field
• Algorithm used to verify the packet Further treatment is carried out as provided in the standard. However, if no connection data block is found, all available algorithms are used. In the event that only one algorithm recognizes the packet as valid, it is assumed that this algorithm was used, otherwise the packet is discarded. A response that is sent on the basis of this packet is provided with the checksum of the algorithm found. Furthermore, a connection data block is generated whose field "checksum_algorithm" is set to a value representing this algorithm.
• connection data block is also called the Transmission Control Block (TCB).
• TCP Transmission Control Block
• a connection establishment with a first checksum method CRC32 is unsuccessful, the initiating first network node A must wait a random time (random delay) and can then try again with another checksum method ADLER32.
• the second end point or network node B only has implemented the ADLER32 checksum algorithm.
• the first end point or network node A has implemented the method according to the invention.
• the first network node A attempts to establish the connection using the checksum algorithm CRC32.
• the connection establishment is initiated with the checksum algorithm ADLER32, whereupon the second network node B answers as described above, and the communication relationship can be established using the checksum algorithm.
• SCTP is a peer to peer protocol, i.e. both
• Pages can be active at the same time, and collisions of the initialization messages can occur.
• the random distance (random delay) between the connection attempts of the two endpoints which is very likely to be different for neighboring network nodes A and B because it is random, serves to avoid synchronization (and thus a permanent failure to establish the connection), which would occur, for example, if - the neighboring network nodes A, B both support the method according to the invention, the network nodes A, B have different preferred checksum algorithms (in FIG. 4 the algorithm ADLER32 is preferred by the first network node A and the algorithm by the second network node B) CRC32), and the switchover to the other algorithm would take place at the same times both in the first network node A and in the second network node B.
• network node network elements which Have connections with several other network elements
• end point network element
• end point network element
• end point network node
• end point network node
• protocols can certainly communicate across these SCTP endpoints and thus an SCTP endpoint for a higher-level protocol can be a network node.
• the present invention is not limited to the exemplary embodiment.
• communication networks that are based on other connection-oriented communication protocols, several checksum methods can be operated in parallel using the teaching of the present invention.

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• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Computer Security & Cryptography (AREA)
• Detection And Prevention Of Errors In Transmission (AREA)
• Data Exchanges In Wide-Area Networks (AREA)
• Error Detection And Correction (AREA)
• Mobile Radio Communication Systems (AREA)

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• 2002
  • 2002-05-06 EP EP02726087A patent/EP1413114A1/de not_active Withdrawn
  • 2002-05-06 BR BR0211568-9A patent/BR0211568A/pt not_active IP Right Cessation
  • 2002-05-06 JP JP2003518148A patent/JP2004537241A/ja active Pending
  • 2002-05-06 US US10/343,153 patent/US20030162541A1/en not_active Abandoned
  • 2002-05-06 CA CA002455122A patent/CA2455122A1/en not_active Abandoned
  • 2002-05-06 WO PCT/DE2002/001626 patent/WO2003013098A1/de active Application Filing
  • 2002-05-06 KR KR10-2004-7001468A patent/KR20040017364A/ko not_active Application Discontinuation
  • 2002-05-06 CN CNA028192893A patent/CN1561623A/zh active Pending

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