Single address prefix allocation within computer networks

• US 8,681,695 B1
• Filed: 10/14/2009
• Issued: 03/25/2014
• Est. Priority Date: 10/14/2009
• Status: Active Grant

• Current Assignee: Juniper Networks Incorporated
• Original Assignee: Juniper Networks Incorporated
• Inventors: Krishnan, Suhir
• Primary Examiner(s): Lee, Jay Y
• Application Number:
  US12/578,935
• Time in Patent Office: 1,623 Days
• Field of Search: None
• US Class Current: 370/328
• CPC Class Codes: H04L 2101/659 Internet protocol version 6 [IPv6] addresses
• CPC Class Codes: H04L 2101/668 Internet protocol [IP] address subnets
• CPC Class Codes: H04L 61/00 Network arrangements, protocols or services for addressing or naming
• CPC Class Codes: H04L 61/5014 using dynamic host configuration protocol [DHCP] or bootstrap protocol [BOOTP]

Abstract

In general, techniques are described for single prefix address allocation within computer networks. Typically, a network device that allocates addresses within a computer network implements the techniques. The network device comprises an interface and a control unit. The interface receives first and second messages from a subscriber network. The first message requests at least one address be allocated to the subscriber network according to a first address allocation mechanism. The second message requests at least one address be allocated to the subscriber network in accordance with a second address allocation mechanism. The control unit automatically determines a topology of the subscriber network based on the second message. Based on the determined topology, the control unit selectively allocates either a single network address prefix or one or more addresses of the network address prefix in response to the second message without allocating an address in response to the first message.

Claims

1. A method of address allocation within a computer network, the method comprising:

receiving, with a network device of the computer network, a message from a subscriber network,

in response to determining that the message includes a request that a network address be allocated to the subscriber network in accordance with a stateful address allocation mechanism without the message including any other requests that a single network address prefix be allocated to the subscriber network, allocating a network address of a single network address prefix associated with the subscriber network to the subscriber network with the network device;

in response to determining that the message includes the request that the single network address prefix be allocated to the subscriber network in accordance with the stateful address allocation mechanism without the message including any other requests that the network address be allocated to the subscriber network, allocating the entire single network address prefix with the network device to the subscriber network; and

in response to determining that the message includes the request that the network address be allocated to the subscriber network in accordance with the stateful address allocation mechanism and the message includes the request that the single network address prefix be allocated to the subscriber network in accordance with the stateful address allocation mechanism, allocating, with the network device, the entire single network address prefix to the subscriber network in response to the request that the single network address prefix be allocated to the subscriber network so as to avoid allocating one or more addresses from another network address prefix different from the single network address prefix.

2. The method of claim 1,

wherein the request that a network address be allocated to the subscriber network includes only option fields of type identity association temporary address (IA_TA) or identity association non-temporary address (IA_NA) and not of type identity association prefix delegation (IA_PD),

wherein the request that the single network address prefix be allocated to the subscriber network includes an identity association prefix delegation (IA_PD) option field, and

wherein the method further comprises:

determining that the message includes a request that a network address be allocated to the subscriber network in accordance with a stateful address allocation mechanism without including any other requests that a single network address prefix be allocated to the subscriber network when the message includes the option fields of type IA_TA or IA_NA without including other option fields of type IA_PD,

determining that the message includes the request that the single network address prefix be allocated to the subscriber network in accordance with the stateful address allocation mechanism without including any other requests that the network address be allocated to the subscriber network when the message the message includes the option fields of type IA_PD without including other option fields of type IA_TA or IA_NA, and

determining that the message includes both the request that the network address be allocated to the subscriber network in accordance with the stateful address allocation mechanism and the request that the single network address prefix be allocated to the subscriber network in accordance with the stateful address allocation mechanism when the message includes the option fields of type IA_PD and at least one of the option fields of type IA_TA and IA_NA.

3. The method of claim 1,

receiving a message comprises receiving, with the network device, the message from a residential gateway device, wherein the message includes a request that the network address prefix be allocated to the residential gateway device in accordance with the stateful address allocation mechanism so as to enable the residential gateway device to allocate the one or more addresses of the requested network address prefix to one or more subscriber network devices located within the subscriber network, and

allocating, with the network device, the entire single network address prefix to the residential gateway device in response to the request of the second message that the network address prefix be allocated to the residential gateway device without allocating an address in response to any request in another message for a network address using a stateless address allocation mechanism or the any other request in the second message for a network address so as to avoid allocating the one or more addresses from another network address prefix different form the single network address prefix to an interface of the residential gateway device facing the network device.

4. The method of claim 1, further comprising receiving, with the network device, a neighbor discover router solicitation (ND/RS) message from the subscriber network prior to receiving the message, wherein the ND/RS message requests allocation of the network address to the subscriber network in accordance with a stateless address auto-configuration address allocation mechanism, and

wherein receiving a message comprises receiving, with the network device, a dynamic host configuration protocol version 6 (DHCPv6) solicit message from the subscriber network, wherein DHCPv6 solicit message includes a first request that network address be allocated to the subscriber network in accordance with the stateful address allocation mechanism and a second request that a network address prefix be allocated to the subscriber network in accordance with the stateful address configuration address allocation mechanism.

5. The method of claim 4, further comprising generating and forwarding a neighbor discover routing advertisement (ND/RA) message in response to the ND/RS message, wherein the ND/RA message does not allocate any network addresses.

6. The method of claim 4,

wherein the first request of the DHCPv6 solicit message that a network address be allocated to the subscriber network includes a first option field and the second request of the DHCPv6 solicit message includes a second option field different from the first option field, wherein the first option field designates a first scope of the address allocation request, and wherein the second option field designates a second scope of the address allocation request that is different from the first scope of the address allocation request,

wherein the first scope of the address allocation request is for either a single temporary address (TA) or a single non-temporary address (NA),

wherein the second scope of the address allocation request is for a prefix delegation (PD),

wherein allocating the single network address prefix in response to determining that the message includes both the request that the network address be allocated to the subscriber network in accordance with the stateful address allocation mechanism and the request that the single network address prefix be allocated to the subscriber network in accordance with the stateful address allocation mechanism comprises allocating, with the network device, the entire single network address prefix to the residential gateway device in response to the determination that the DHCPv6 solicit message includes both the first option field and the second option field.

7. The method of claim 1, further comprising storing data that defines a single address prefix policy within the network device, wherein the single address prefix policy provisions only the single network address prefix for use by the subscriber network to prevent allocation of two or more network address prefixes for use by the subscriber network.

8. The method of claim 1,

wherein the computer network comprises an access network of a service provider network that enables one or more subscriber devices of the subscriber network to access a public computer network, and

wherein the network device comprises an edge router located at the edge of the service provider network.

9. A network device that allocates addresses within a computer network, the network device comprising:

at least one interface that receives a message from a subscriber network connected to the computer network; and

a control unit comprising a processor configured to;

in response to determining that the message includes a request that a network address be allocated to the subscriber network in accordance with a stateful address allocation mechanism without including any other requests that a single network address prefix be allocated to the subscriber network, allocate a network address of a single network address prefix associated with the subscriber network to the subscriber network with the network device;

in response to determining that the message includes the request that the single network address prefix be allocated to the subscriber network in accordance with the stateful address allocation mechanism without including any other requests that the network address be allocated to the subscriber network, allocate the entire single network address prefix with the network device to the subscriber network; and

in response to determining that the message includes both the request that the network address be allocated to the subscriber network in accordance with the stateful address allocation mechanism and the request that the single network address prefix be allocated to the subscriber network in accordance with the stateful address allocation mechanism, allocate, with the network device, the entire single network address prefix to the subscriber network the request that the single network address prefix be allocated to the subscriber network so as to avoid allocating one or more addresses from another network address prefix different from the single network address prefix.

10. The network device of claim 9,

wherein the request that a network address be allocated to the subscriber network includes only option fields of type identity association temporary_address (IA_TA) or identity association non-temporary address (IA NA) and not of type identity association prefix delegation (IA PD),

wherein the request that the single network address prefix be allocated to the subscriber network includes an identity association prefix delegation (IA_PD) option field, and wherein the processor further determines that 1) the message includes a request that a network address be allocated to the subscriber network in accordance with a stateful address allocation mechanism without including any other requests that a single network address prefix be allocated to the subscriber network when the message includes the option fields of type IATA or IA NA without including˜

other option fields of type IAPD,

     2) the message includes the request that the single network address prefix be allocated to the subscriber network in accordance with the stateful address allocation mechanism without including any other requests that the network address be allocated to the subscriber network when the message the message includes the option fields of type IA_PD without including other option fields of type IA_TA or IA_NA, and

3) the message includes both the request that the network address be allocated to the subscriber network in accordance with the stateful address allocation mechanism and the request that the single network address prefix be allocated to the subscriber network in accordance with the stateful address allocation mechanism when the message includes the option fields of type IA PD and at least one of the option fields of type IA TA and IA NA.

11. The network device of claim 9,

wherein the at least one interface receives the message from the residential gateway device, wherein the message includes the request that the network address prefix be allocated to the residential gateway device in accordance with the stateful address allocation mechanism so as to enable the residential gateway device to allocate the one or more addresses of the requested network address prefix to one or more subscriber network devices located within the subscriber network, and

wherein the processor allocates the entire single network address prefix to the residential gateway device in response to the request of the second message that the network address prefix be allocated to the residential gateway device without allocating an address in response to any request in another message for a network address using a stateless address allocation mechanism or any other request in the second message for a network address so as to avoid allocating the one or more addresses from another network address prefix different form the single network address prefix to an interface of the residential gateway device facing the network device.

12. The network device of claim 9,

wherein the at least one interface receives a neighbor discover router solicitation (ND/RS) message from the subscriber network prior to receiving the message, wherein the ND/RS message requests the network address be allocated to the subscriber network in accordance with an stateless address auto-configuration address allocation mechanism, and

wherein the at least one interface receives the message as a dynamic host configuration protocol version 6 (DHCPv6) solicit message from the subscriber network, wherein DHCPv6 solicit message includes a first request that a network address be allocated to the subscriber network in accordance with a stateful address allocation mechanism and a second request that a network address prefix be allocated to the subscriber network in accordance with the stateful address configuration address allocation mechanism.

13. The network device of claim 12, wherein the processor includes an Internet protocol version 6 (IPv6) module comprising a neighbor discover (ND) module that generates and forwards a neighbor discover routing advertisement (ND/RA) message in response to the ND/RS message, wherein the ND/RA message does not allocate any network addresses.

14. The network device of claim 12,

wherein the first request of the DHCPv6 solicit message includes a first option field and the second request of the DHCPv6 solicit message includes a second option field different from the first option field, wherein the first option field designates a first scope of the address allocation request, and wherein the second option field designates a second scope of the address allocation request that is different from the first scope of the address allocation request,

wherein the first scope of the address allocation request is for either a single temporary address (TA) or a single non-temporary address (NA),

wherein the second scope of the address allocation request is for a prefix delegation (PD),

wherein the processor includes a DHCPv6 module that allocates the entire single network address prefix to the residential gateway device in response to the determination the DHCPv6 solicit message includes both the first option field and the second option field.

15. The network device of claim 9, wherein the processor further stores data that defines a single address prefix policy within the network device, wherein the single address prefix policy provisions only the single network address prefix for use by the subscriber network to prevent allocation of two or more network address prefixes for use by the subscriber network.

16. The network device of claim 9,

wherein the computer network comprises an access network of a service provider network that enables one or more subscriber devices of the subscriber network to access a public computer network, and

wherein the network device comprises an edge router located at the edge of the service provider network.

17. A non-transitory computer-readable storage medium comprising instructions for causing a programmable processor to:

receive a message from a subscriber network;

in response to determining that the message includes a request that a network address be allocated to the subscriber network in accordance with a stateful address allocation mechanism without including any other requests that a single network address prefix be allocated to the subscriber network, allocate a network address of a single network address prefix associated with the subscriber network to the subscriber network;

in response to determining that the message includes the request that the single network address prefix be allocated to the subscriber network in accordance with the stateful address allocation mechanism without including any other requests that the network address be allocated to the subscriber network, allocate the entire single network address prefix to the subscriber network; and

in response to determining that the message includes both the request that the network address be allocated to the subscriber network in accordance with the stateful address allocation mechanism and the request that the single network address prefix be allocated to the subscriber network in accordance with the stateful address allocation mechanism, allocate, with the network device, the entire single network address prefix to the subscriber network the request that the single network address prefix be allocated to the subscriber network so as to avoid allocating one or more addresses from another network address prefix different from the single network address prefix.

18. A network system comprising:

a public network;

a subscriber network that includes a residential gateway device; and

a service provider network comprising a network device that interfaces with the residential gateway device to enable the subscriber network to access the public network,

wherein the network device comprises;

at least one interface that receives a message from the subscriber network connected to the service provider network; and

a control unit comprising a processor that, in response to determining that the message includes a request that a network address be allocated to the subscriber network in accordance with a stateful address allocation mechanism without including any other requests that a single network address prefix be allocated to the subscriber network, allocates a network address of a single network address prefix associated with the subscriber network to the subscriber network with the network device, in response to determining that the message includes the request that the single network address prefix be allocated to the subscriber network in accordance with the stateful address allocation mechanism without including any other requests that the network address be allocated to the subscriber network, allocates the entire single network address prefix with the network device to the subscriber network, and, in response to determining that the message includes both the request that the network address be allocated to the subscriber network in accordance with the stateful address allocation mechanism and the request that the single network address prefix be allocated to the subscriber network in accordance with the stateful address allocation mechanism, allocates, with the network device, the entire single network address prefix to the subscriber network the request that the single network address prefix be allocated to the subscriber network so as to avoid allocating one or more addresses from another network address prefix different from the single network address prefix.

19. A network system comprising:

a public network;

a subscriber network that includes a residential gateway device;

a service provider network that provides access to the public network, wherein the service provider network comprises;

an authentication server that authenticates the one or more subscriber networks before allowing the subscriber networks to gain access to the service provider network; and

a network device that interfaces with the residential gateway device to enable the subscriber network to access the public network, wherein the network device comprises;

at least one interface that receives a message from the subscriber network connected to the service provider network;

a control unit comprising a processor that communicates with the authentication server to authenticate the subscriber network as permitted to interface with the service provider network to access the public network, receives a single network address prefix from the authentication server in response to successfully authenticating the subscriber network, in response to determining that the message includes a request that a network address be allocated to the subscriber network in accordance with a stateful address allocation mechanism without including any other requests that a single network address prefix be allocated to the subscriber network, allocates a network address of a single network address prefix associated with the subscriber network to the subscriber network with the network device, in response to determining that the message includes the request that the single network address prefix be allocated to the subscriber network in accordance with the stateful address allocation mechanism without including any other requests that the network address be allocated to the subscriber network, allocates the entire single network address prefix with the network device to the subscriber network, and, in response to determining that the message includes both the request that the network address be allocated to the subscriber network in accordance with the stateful address allocation mechanism and the request that the single network address prefix be allocated to the subscriber network in accordance with the stateful address allocation mechanism, allocates, with the network device, the entire single network address prefix to the subscriber network the request that the single network address prefix be allocated to the subscriber network so as to avoid allocating one or more addresses from another network address prefix different from the single network address prefix.

20. A network system comprising:

a public network;

a subscriber network that includes a residential gateway device;

a service provider network that provides access to the public network, wherein the service provider network includes;

a network device that interfaces with the residential gateway device to enable the subscriber network to access the public network;

a dynamic host configuration protocol version six (DHCPv6) server positioned intermediate to the network device and the authentication server that allocates network addresses in accordance with DHCPv6,

wherein the network device comprises;

at least one interface that receives a message from the subscriber network connected to the service provider network, wherein the message includes a first request that a network address be allocated to the subscriber network in accordance with a stateful address allocation mechanism and a second request that a network address prefix be allocated to the subscriber network in accordance with the stateful address allocation mechanism; and

a control unit comprising a processor that parses the message in accordance with a single prefix allocation policy to selectively remove one or more options related to the scope of the address allocation request to generate an updated message, forwards the updated message to the DHCPv6 server, receives a response message from the DHCPv6 server allocating a single network address prefix in response to the second request of the updated message without allocating one or more network addresses in response to the first request of the message so as to avoid allocating one or more addresses from another network address prefix different from the single network address prefix.