Method for allocating internet protocol addresses to clients of a network and corresponding apparatus
An access device and an extender access device, forming a network for network client devices. A single IP address attribution server in the network attributes IP addresses to network devices based on their MAC address. The access device providing access in a first coverage zone. The extender access device providing access in a second coverage zone. The extender access device implements MAC address translation for representing network client devices in the second zone before the access device. When a network client device roams from the second zone to the first zone, the client device keeps its IP address that was attributed to it by the IP address attribution server via the extender access device even if the client device requests an IP address with its real, non-translated MAC address.
1. A method for allocation of Internet Protocol addresses to network devices in a communication network to avoid Internet Protocol session discontinuity for the network devices, wherein said communication network comprises an Internet Protocol address server and a memory and said method is implemented by said Internet Protocol address server, said method comprising:
receiving, from a first network device of said network devices in said communication network, a request for attribution of an Internet Protocol address to a Media Access Control address, the request comprising said Media Access Control address;
retrieving information from the memory to determine if an Internet Protocol address is attributed to the Media Access Control address;
if an Internet Protocol address is not attributed to the Media Access Control address, applying a Media Access Control address translation to the Media Access Control address, to obtain a translated Media Access Control address;
retrieving information from the memory to determine if an Internet Protocol address is attributed to the translated Media Access Control address; and
if an Internet Protocol address is attributed to the translated Media Access Control address, retrieving from the memory the Internet Protocol address attributed to the translated Media Access Control address and transmitting, to said first network device, the Internet Protocol address attributed to the translated Media Access Control address.
2. The method according to claim 1 , wherein the method further comprises verifying if the translated Media Access Control address is not used by any of said network devices, said verifying comprising:
transmitting a message to said translated Media Access Control address; and
checking that no reply is received to said message.
3. The method according to claim 2 , wherein said message is an Internet Protocol PING message.
4. The method according to claim 2 , wherein said message is an Address Resolution Protocol probe packet.
5. The method according to claim 1 , wherein the Media Access Control address translation comprises toggling of a globally unique/locally administered bit comprised in the most significant byte of the Organizationally Unique Identifier of the Media Access Control address comprised in said request.
6. The method according to claim 5 , wherein said toggling is a logical exclusive logical Boolean OR operation with a bit mask applied to said Media Access Control address comprised in said request.
7. The method according to claim 1 , further comprising a transmission of an announcement message over said communication network to inform said network devices of a correspondence between the Media Access Control address of said first network device and of said Internet Protocol address transmitted to said first network device.
8. The method according to claim 1 , further comprising:
verifying if said translated Media Access Control address is on a list of allowable Media Access Control addresses for Media Access Control address filtering; and
if said translated Media Access Control address is on a list of allowable Media Access Control addresses for Media Access Control address filtering, updating of said list of allowable Media Access Control addresses for Media Access Control address filtering with said Media Access Control address of said first network device.
9. An Internet Protocol address server for allocation of Internet Protocol addresses to network devices in a communication network to avoid Internet Protocol session discontinuity for the network devices, wherein the Internet Protocol address server comprises:
a network interface, configured to receive, from a first network device of said network devices, a request for attribution of an Internet Protocol address to a Media Access Control address, the request comprising said Media Access Control address;
a processor in communication with a memory;
the processor configured to retrieve from the memory information from the memory to determine if an Internet Protocol address is attributed to the Media Access Control address;
the processor configured to apply a Media Access Control address translation to the Media Access Control address, to obtain a translated Media Access Control address if an Internet Protocol address is not attributed to the Media Access Control address;
the processor configured to retrieve from the memory information from the memory to determine if an Internet Protocol address is attributed to the translated Media Access Control address; and
said network interface being further configured to transmit, to the first network device, an Internet Protocol address, retrieved by the processor from the memory, attributed to the translated Media Access Control address if an Internet Protocol address is attributed to the translated Media Access Control address.
10. The Internet Protocol address server according to claim 9 , wherein the processor is further configured to verify if the translated Media Access Control address is not used by any of said network devices, and said network interface being further configured, if it is verified by said processor that the translated Media Access control address is not used by any of said network devices, to transmit a message to said translated Media Access Control address; and to check that no reply is received to said message.
11. The Internet Protocol address server according to claim 10 , wherein said message is an Internet Protocol PING message and said network interface is further configured to transmit said Internet Protocol PING message.
12. The Internet Protocol address server according to claim 10 , wherein said message is an Address Resolution Protocol probe packet and said network interface is further configured to transmit said Address Resolution Protocol probe packet.
13. The Internet Protocol address server according to claim 9 , wherein the processor is further configured to execute said Media Access Control address translation by toggling a globally unique/locally administered bit comprised in the most significant byte of the Organizationally Unique Identifier of the Media Access Control address comprised in said request.
14. The Internet Protocol address server according to claim 13 , wherein said processor is further configured to execute said toggling by applying a logical exclusive logical Boolean OR operation with a bit mask applied to said Media Access Control address in said request.
15. The Internet Protocol address server according to claim 9 , wherein said network interface is further configured to transmit an announcement message over said communication network to inform said network devices of a correspondence between the Medium Access Control address of said first network device and of said Internet Protocol address transmitted to said first network device.
16. The Internet Protocol address server according to claim 9 , wherein said Internet Protocol address server is implemented in a gateway.