Preallocation of client network address translation addresses for client-server networks

• US 7,072,981 B1
• Filed: 02/08/2001
• Issued: 07/04/2006
• Est. Priority Date: 12/21/2000
• Status: Expired due to Fees

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: O'Rourke, Chris, Batz, Robert M, Housel, Barron C, Klein, Steven C
• Primary Examiner(s): Dharia, Rupal
• Assistant Examiner(s): Shingles, Kristie D.
• Application Number:
  US09/780,755
• Time in Patent Office: 1,972 Days
• Field of Search: 709/225, 709/228, 709/245, 711/207, 711/202, 370/392, 370/401, 713/201, 712/13
• US Class Current: 709/245
• CPC Class Codes: H04L 61/00 Network arrangements, protocols or services for addressing or naming
• CPC Class Codes: H04L 61/2514 between local and global IP addresses
• CPC Class Codes: H04L 61/255 Maintenance or indexing of mapping tables
• CPC Class Codes: H04L 61/50 Address allocation
• CPC Class Codes: H04L 61/5061 Pools of addresses

Abstract

An improved client network address translation (“NAT”) system is provided. Methods are provided for initializing connection control blocks with the client NAT addresses when a storage pool of connection control blocks are allocated. This avoids the costly overhead as connections are created and destroyed. Unlike the prior art solutions, once the connection control blocks of the present invention are allocated, they remain in effect until the storage subpool is deleted. Secondly, in order to provide as large a pool of client NAT addresses as possible, methods are provided for using intervals to allocate and reclaim client NAT addresses as subpools are allocated and freed.

Claims

1. A method of allocating memory for a client network address translation (NAT) pool, said method comprising the steps of:

creating a control block that represents a client NAT address range, said control block identifying client NAT addresses for a computer system;

creating a memory pool having a main pool header, said main pool header having an address referenced in said control block;

allocating at least one subpool header having a subpool memory block containing one or more fixed-length connection blocks that are allocated within said subpool memory block, said connection blocks containing particular ones of said client NAT addresses, said subpool header being referenced by said main pool header;

wherein each connection block may be either free or allocated, said particular ones of said client NAT addresses remain allocated within said subpool memory until all connection blocks in said subpool memory are free.

2. A method as in claim 1, wherein said control block has a pool name property.

3. A method as in claim 1, wherein said control block has a first IP address property.

4. A method as in claim 1, wherein said control block has a last IP address property.

5. A method as in claim 1, wherein said control block has a net mask property.

6. A method as in claim 1, wherein said control block has a memory pool address property.

7. A method as in claim 1, wherein said control block has an initial number of connection blocks property.

8. A method as in claim 1, wherein said control block has a maximum number of connection blocks property.

9. A method as in claim 1, wherein said control block has an interval list address.

10. A method of allocating memory for a client network address translation (NAT) pool, said method comprising the steps of:

configuring a client network address translation (NAT) address range having a plurality of client NAT addresses;

allocating said client NAT address range;

allocating memory for a memory pool;

creating said memory pool;

creating a subpool within said memory pool, said subpool containing a subpool memory block containing one or more connection blocks that are allocated within said subpool, said subpool constructed and arranged to contain connection blocks with particular ones of said plurality of client NAT addresses within said client NAT address range;

wherein each connection block is either free or allocated, said particular ones of said plurality of client NAT addresses remain allocated within said subpool until all of said connection blocks are free.

11. The method according to claim 10, wherein said step of creating a subpool further comprises the steps of:

initializing said subpool;

allocating an interval within said subpool with at least one block; and

initializing said at least one block with client NAT addresses.

12. The method according to claim 10, wherein said method further comprising the step of:

allocating a new connection block in said memory pool;

allocating said new connection block to subpool.

13. A method of allocating memory in software for a client network address translation (NAT) pool, said method comprising the steps of:

creating an internal control block that represents said client NAT address range, said control block identifying client NAT addresses for the computer system;

creating a main pool header;

allocating at least one subpool header having a subpool memory block containing one or more fixed-length connection blocks that are allocated within said subpool memory block, said connection blocks containing particular ones of said client NAT addresses, said subpool header being referenced by said main pool header;

wherein each connection block is either allocated or free, said particular ones of said client NAT addresses remain allocated within said subpool memory until all of said connection blocks are free.