Classifications

• • 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
  • H04L69/16—Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
  • H04L69/167—Adaptation for transition between two IP versions, e.g. between IPv4 and IPv6
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L61/00—Network arrangements, protocols or services for addressing or naming
  • H04L61/50—Address allocation
  • H04L61/5007—Internet protocol [IP] addresses
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L61/00—Network arrangements, protocols or services for addressing or naming
  • H04L61/50—Address allocation
  • H04L61/5061—Pools of addresses
• • 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
  • H04L69/16—Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]

Definitions

• the present invention relates to internet type communication networks, and more precisely those based on the IPv ⁇ protocol stack (Internet Protocol - version 6). It relates more particularly to the automatic configuration of such a network.
• a network of this type consists of a set of equipment, generally called “routers", the role of which is to route data traffic between a sender and a recipient.
• Each network device has one or more interfaces and each of these interfaces enables it to communicate with one or more other network devices.
• the equipment R A has two interfaces l A1 and l A2 .
• the interface l A2 allows it to communicate with a single device R D , via its interface l D
• the interface l A1 allows it to communicate with two devices connected to the same link, R B and R ç , via their respective interfaces l B and l c .
• a device or router has at least 2 or 3 interfaces.
• each network device has at its disposal a so-called routing table which maps a set of addresses and an output interface: thus, a device receiving a packet data intended for such address, will be able to determine to which of its interfaces it must send it.
• IPv ⁇ IP version 6
• An address of this type is mainly composed of two parts, a first part (typically on 64 bits), and second a part (typically on 64 bits; the global address then being on 1 28 bits in total).
• the second part consists of a unique identifier for the interface.
• the way in which this part is constituted is specified in paragraph 2.5.1 of the document "IP Version 6 Addressing Architecture". It can be formed from a universal identifier, for example of the type defined by the standard "IEEE 802 MAC" (for "Media Access Control") or "IEEE EUI-64" (for "Extended Universal Identifier). This second part can be easily determined by each network equipment autonomously and automatically.
• network number there is no automatic method allowing network equipment to determine the first part, generally called "network number”.
• this part is determined manually by an operator in charge of configuring the network. This connects to each network device in order to assign it a global address for each interface, ideally according to an optimized addressing plan.
• Such an addressing plan may conform to the methodology described in RFC 31 77 entitled "IAB / IESG Recommendations on IPv IP Address Allocations to Sites”.
• This manual allocation of global addresses has many drawbacks. In particular, it requires significant time and the occupation of a team of specialized technicians. It also does not easily allow a reconfiguration of the network topology or the addition of new equipment in a pre-existing network. Above all, it is likely to cause errors because technicians as competent as they are, are subject to human error. These errors are all the more numerous as the network is large, and therefore difficult to detect and then to correct.
• IPv ⁇ Internet Protocol Version 6
• J. Haberman and J. Martin draft-haberman-ipngwg-auto-prefix- 02.txt
• Hierarchical Prefix Dissegation Protocol for Internet Protocol Version 6 IPv ⁇
• the invention relates to communication equipment for an internet communication network, in particular IPv ⁇ , comprising a set of interfaces, each of these being connected to one or more other communication equipment,
• the equipment or router
• the equipment has means for receiving an address prefix from a first other communication device on a first interface (l 2a ).
• the communication equipment according to the invention is characterized in that it also has an allocation means for assigning to each of these interfaces, a global address determined in particular from the address prefix.
• the allocation means determines the global address of one of these interfaces by concatenating a network number and an interface identifier, the network number containing the address prefix and forming an address subspace of that formed by the address prefix.
• the allocation means can moreover assign to the first interface, the same network number as that assigned by this first communication equipment to the interface connected to the first interface.
• one and only one network number is assigned per link.
• Network equipment is therefore capable of configuring its interfaces with a single global address, that is to say unique for the entire communication network.
• This configuration is automatic for each network device and the network can therefore be configured fully automatically recursively, from an initial prefix which can be assigned to it automatically or not.
• FIG. 1 already commented, schematizes a communication network formed by 4 pieces of equipment .
• FIG. 2 illustrates the format of a global interface address according to the invention.
• Figure 3 shows a diagram of a communication network, and the process described on this network.
• a global interface address is composed of 4 parts, as illustrated in FIG. 2.
• the total size of this global address is 128 bits.
• the rightmost part U is formed from a universal identifier as is known from the state of the art and as has been explained previously.
• the size of this U field is 64 bits.
• the leftmost part is a prefix P which is provided by other equipment in the communication network. As we will see later, the size of this prefix is variable and depends on the position of the equipment in the topology of the communication network, during the address delegation process.
• the part referenced N is a number, allowing the derivation of the single resource P into several smaller resources.
• the next part, referenced Z can consist, for example, of "0". Its size is imposed by the size of the other fields and can, at the limit, be reduced to 0 bit.
• a network device transmits a request on all of its interfaces in order to obtain a prefix with address P. As long as it does not receive this prefix , it waits because it cannot determine the global addresses of its interfaces. Once it has received a prefix, it can resume the process of assigning global interface addresses. If it receives several prefixes from several other devices connected via its interfaces, arbitration can be performed. It can for example be chosen to take the first prefix obtained, and to consider the equipment from which it comes as "delegator" for him following the process.
• the network equipment can determine a global address for all of its interfaces, except - according to a preferred implementation of the invention - that of the "delegator", that is to say the one connected to the network equipment which supplied it with the prefix.
• this interface can be judiciously configured with the value of the prefix received, which guarantees good route aggregation properties in the equipment upstream of the delegator.
• These global addresses are determined according to the diagram above, that is to say by using the prefix received to construct the field P, and the universal identifier to construct the field U. According to an embodiment of the invention , the equipment does not determine the global address of the interface by which the prefix was transmitted to it.
• the equipment determines a set of sub-prefixes SP defining as much more limited address space as that defined by the prefix P. These sub-prefixes SP therefore contain the prefix P, and concatenate it by the right a certain number bits (part N). These sub-prefixes SP, and the associated address spaces, can be used by the equipment for its own use or else to be delegated to other communication equipment. There can be different ways to determine these SP sub-prefixes from P prefixes.
• the table below lists the SP sub-prefixes that can be formed from a P prefix. In this example, it has was chosen to concatenate 3 additional bits to the left of the prefix to form the sub-prefixes.
• log 2 (n) bits are needed to represent this number of devices, where log 2 represents the logarithm in binary base.
• an implementation of the invention proposes to number a given interface as a function of the prefix assigned to it from by this neighboring equipment. For example, in FIG. 1, the equipment R A assigns the same number to its l A2 interface as the prefix that has been assigned to the R D equipment. With regard to the l A1 interface, arbitration can be carried out between the numbers assigned to the R B and Rc equipment, since these are connected to this same l A1 interface.
• This method thus makes it possible to determine at least the same global address for the interfaces of equipment connected together, in accordance with what is required by the IPv ⁇ protocol.
• the additional property of determining at most one is very interesting since it saves addressing resources. Indeed, the same network number is thus used for 3 interfaces, which saves two network numbers which can thus be used for other uses.
• the network numbers (ie the most significant 64 bits of the global addresses) of the interfaces l A] , l B and l c are the same.
• FIG. 3 illustrates the progress of the method according to the invention on a small network.
• the R equipment has acquired an initial prefix worth 2001: db8: l: 0000:: 0/48. The meaning of this format is explained in the documents previously cited on address formats in the IPv ⁇ protocol. It is however important to note here that the “/ 48” indicates the length in bits of this prefix and that this one is on 64 bits at most. Subsequently, for global interface addresses we will not mention the U part of the universal identifier.
• This initial prefix is used by the equipment R, to determine the sub-prefixes which it will transmit to its neighboring equipment as a delegator.
• a first subspace is therefore assigned to the equipment R 2 , for example “001” and to the equipment R 5 a second subspace, for example “010”.
• the sub-prefixes transmitted to the equipment R 2 and R 5 are respectively 2001: db8: l: 2000 :: 0/51 and 2001: db8: l: 4000 :: 0/51.
• the R equipment assigns network numbers to its interfaces according to the sub-prefixes assigned to the equipment connected to these interfaces.
• the network number 2001: db8: l: 2000 :: 0/64 is therefore obtained for the interface l la .
• this 64-bit network number can be completed with - for example - the universal identifier to obtain the 1 28 bits of the global IPv ⁇ interface address.
• the equipment R 2 and R 5 then proceed in the same way, for example as soon as they are in possession of the prefix transmitted by the delegator R,.
• the processes can therefore partly be executed in parallel on the various devices.
• the equipment R 2 assigns as network number to the interface l 2a , the same network number as that assigned to the interface l la by the equipment.
• the equipment R 2 allocates 3 additional bits to split into 8 its address space determined by the prefix provided by the delegating equipment R,.
• the equipment R 5 is provided with a sub-prefix by the equipment R,. It is sort of on the same level in the delegation tree as R 2 equipment. Consequently, it is not considered by the equipment R 2 for the assignment of a sub-prefix.
• the equipment R 2 therefore allocates a first subspace to the equipment R 4 , for example determined by “001” in binary (bits of the field N) and a second subspace to the equipment R 5 determined for example by "010".
• the sub-prefixes transmitted to them are therefore respectively
• the R 5 equipment therefore allocates 3 additional bits (in this example) to divide its address space into 8 parts. It therefore allocates a first subspace determined for example by the value “001” for the interface l 5a and a second subspace determined for example by the value “010” for the interface l 5c .
• the network numbers of these two interfaces are then 2001: db8: l: 4400 :: 0/64 for the l 5o interface and 2001: db8: l: 4800:: 0/64 for the l 5c interface.
• the situation is different since there is here a delegation relationship between the equipment R 2 on the one hand and the equipment R 3 and R 4 on the other hand .
• a negotiation can take place in order to determine whether it is the sub-prefix assigned to the equipment R 3 or that assigned to the equipment R 4 which should be used.
• This negotiation allows to use only one network prefix for all interfaces, but another implementation could be to choose different network addresses according to another negotiation mechanism or else without negotiation.
• the sub-prefix assigned to the equipment R 4 has been chosen.
• the network number of these three interfaces l 2b , l 3b and l 4 is therefore 2001: db8: l: 2400 :: 0/64.
• An additional advantage of the invention is that, since the method is tree-like, each item of equipment on the network assigns global addresses to its interfaces which are formed from a prefix provided by the delegator.
• all the network numbers and therefore all the global addresses of the interfaces of the equipment to which it has supplied a prefix are “aggregatable” addresses of this prefix.
• aggregatable addresses is meant addresses formed from the same prefix.
• these “aggregatable” addresses can be stored in the form of a single entry in the routing table of the delegating equipment. This results in a saving of storage space in the network equipment, and a saving of time to search for the correct entry in this routing table, when the equipment has to route data packets.

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• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Computer Security & Cryptography (AREA)
• Data Exchanges In Wide-Area Networks (AREA)

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• 2004
  • 2004-01-30 FR FR0450176A patent/FR2865878B1/fr not_active Expired - Fee Related
• 2005
  • 2005-01-26 WO PCT/FR2005/000153 patent/WO2005083986A1/fr active Application Filing
  • 2005-01-26 EP EP05717477A patent/EP1714467A1/de not_active Withdrawn
  • 2005-01-26 CN CN200580003169.1A patent/CN1914886A/zh active Pending

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