1. Field of the Invention
The present invention relates generally to the subnets of a dynamic host configuration protocol server. More particularly, the present invention relates to dynamically updating the subnets of a dynamic host configuration protocol server.
2. Description of the Related Art
Dynamic host configuration protocol (dynamic host configuration protocol) is a protocol for assigning dynamic Internet Protocol (IP) addresses to devices on a network. With dynamic addressing, a device may have a different IP address every time it connects to the network. In some systems, the device's IP address may even change while it is still connected. Dynamic host configuration protocol also supports a mix of static and dynamic IP addresses.
Dynamic addressing simplifies network administration because the software keeps track of IP addresses rather than requiring an administrator to manage the task. This means that a new computer may be added to a network without the hassle of manually assigning it a unique IP address. Dynamic host configuration protocol adds the capability of automatically allocating reusable network addresses and distributing additional host configuration options.
When the dynamic host configuration protocol server is active, it can have thousands of clients distributed over multiple subnets. Whether an administrator decides to add a new subnet, redistribute a subnet, or modify the server in any way, the administrator must alter the configuration file and then refresh the server. The reason for refreshing the server is that the server must save what it currently has in memory to disk, reread the configuration file, load saved client records, and then invalidate those clients that are no longer valid. This delay may be extensive depending on the number of clients. Additionally, when the server is busy loading the configuration and client records, the server is unable to answer awaiting clients.
The present invention provides a method, data processing system, and computer usable code for dynamically updating a set of subnets. The present invention receives subnet configuration updates from a user or administrator and determines the subnets affected by the configuration updates. The clients associated with the subnets are saved off to storage and the subnet configuration updates are loaded. Once configuration updates are loaded, the clients associated with the newly updated subnets are reloaded.
The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:
The present invention provides a method, data processing system and computer usable code for dynamically updating the subnets of a Dynamic Host Configuration Protocol server.
With reference now to the figures,
In the depicted example, server 104 and server 106 connect to network 102 along with storage unit 108. In addition, clients 110, 112, and 114 connect to network 102. These clients 110, 112, and 114 may be, for example, personal computers or network computers. In the depicted example, server 104 provides data, such as boot files, operating system images, and applications to clients 110, 112, and 114. Clients 110, 112, and 114 are clients to server 104 in this example. Network data processing system 100 may include additional servers, clients, and other devices not shown.
In the depicted example, network data processing system 100 is the Internet with network 102 representing a worldwide collection of networks and gateways that use the Transmission Control Protocol/Internet Protocol (TCP/IP) suite of protocols to communicate with one another. At the heart of the Internet is a backbone of high-speed data communication lines between major nodes or host computers, consisting of thousands of commercial, government, educational and other computer systems that route data and messages. Of course, network data processing system 100 also may be implemented as a number of different types of networks, such as for example, an intranet, a local area network (LAN), or a wide area network (WAN).
With reference now to
In the depicted example, data processing system 200 employs a hub architecture including north bridge and memory controller hub (MCH) 202 and south bridge and input/output (I/O) controller hub (ICH) 204. Processing unit 206, main memory 208, and graphics processor 210 are connected to north bridge and memory controller hub 202. Graphics processor 210 may be connected to north bridge and memory controller hub 202 through an accelerated graphics port (AGP).
In the depicted example, local area network (LAN) adapter 212 connects to south bridge and I/O controller hub 204. Audio adapter 216, keyboard and mouse adapter 220, modem 222, read only memory (ROM) 224, hard disk drive (HDD) 226, CD-ROM drive 230, universal serial bus (USB) ports and other communications ports 232, and PCI/PCIe devices 234 connect to south bridge and I/O controller hub 204 through bus 238 and bus 240. PCI/PCIe devices may include, for example, Ethernet adapters, add-in cards and PC cards for notebook computers. PCI uses a card bus controller, while PCIe does not. ROM 224 may be, for example, a flash binary input/output system (BIOS).
Hard disk drive 226 and CD-ROM drive 230 connect to south bridge and I/O controller hub 204 through bus 240. Hard disk drive 226 and CD-ROM drive 230 may use, for example, an integrated drive electronics (IDE) or serial advanced technology attachment (SATA) interface. Super I/O (SIO) device 236 may be connected to south bridge and I/O controller hub 204.
An operating system runs on processing unit 206 and coordinates and provides control of various components within data processing system 200 in
As a server, data processing system 200 may be, for example, an IBM eServer™ pSeries® computer system, running the Advanced Interactive Executive (AIX®) operating system or Linux™ operating system (eserver, pseries and AIX are trademarks of International Business Machines Corporation in the United States, other countries, or both while Linux is a trademark of Linus Torvalds in the United States, other countries, or both). Data processing system 200 may be a symmetric multiprocessor (SMP) system including a plurality of processors in processing unit 206. Alternatively, a single processor system may be employed.
Instructions for the operating system, the object-oriented programming system, and applications or programs are located on storage devices, such as hard disk drive 226, and may be loaded into main memory 208 for execution by processing unit 206. The processes for embodiments of the present invention are performed by processing unit 206 using computer usable program code, which may be located in a memory such as, for example, main memory 208, read only memory 224, or in one or more peripheral devices 226 and 230.
Those of ordinary skill in the art will appreciate that the hardware in
In some illustrative examples, data processing system 200 may be a personal digital assistant (PDA), which is configured with flash memory to provide non-volatile memory for storing operating system files and/or user-generated data.
A bus system may be comprised of one or more buses, such as bus 238 or bus 240 as shown in
The exemplary aspects of the present invention provide a method to dynamically update the subnets of a dynamic host configuration protocol server. Subnet configuration updates are received from a user or administrator and the subnets affected by the configuration updates are determined. The clients associated with the subnets are saved to storage and the subnet configuration updates are loaded. Once the subnet configuration updates are loaded, the clients associated with the newly updated subnets are reloaded.
Dynamic host configuration protocol server 302 dispenses and manages network IP addresses. Dynamic host configuration protocol server 302 assigns IP addresses to dynamic host configuration protocol clients 310, 312, 314, 316, 318, 320, and 322 that are connecting to the network for the first time. When one of dynamic host configuration protocol clients 310, 312, 314, 316, 318, 320, and 322 connects to the network, dynamic host configuration protocol server 302 automatically assigns it an IP address from an appropriate pool of addresses.
Although it is possible to have multiple dynamic host configuration protocol servers on a network, the subnet pools of the dynamic host configuration protocol servers may not overlap. However, it is recommended that only one dynamic host configuration protocol server is used for an entire network. Dynamic host configuration protocol server 302 is responsible for a pool of IP addresses. This server can give out an IP address to a dynamic host configuration protocol client requesting a new configuration from the pool of IP addresses for which it is responsible. When a dynamic host configuration protocol client asks for confirmation of its existing configuration, dynamic host configuration protocol server 302 confirms the configuration.
Dynamic host configuration protocol server 302 supplies dynamic host configuration protocol clients 310, 312, 314, 316, 318, 320, and 322 with sufficient information to establish an endpoint for network communications. Dynamic host configuration protocol server 302 also supplies other parameters needed by system-level and application-level software. Dynamic host configuration protocol clients 310, 312, 314, 316, 318, 320, and 322 may include TCP/IP network printers, X terminals, and Microsoft Windows machines.
Dynamic host configuration protocol server 302 has control of the IP address block. Dynamic host configuration protocol server 302 grants dynamic host configuration protocol clients 310, 312, 314, 316, 318, 320, and 322 permission to use IP addresses on a lease basis. The IP address is “leased” to the dynamic host configuration protocol client for a fixed amount of time. The administrator sets the lease time, which can last from 120 seconds to infinity. During the lease, dynamic host configuration protocol guarantees that the IP address assigned to the dynamic host configuration protocol client will not be re-assigned to another dynamic host configuration protocol client. Before the lease time expires, dynamic host configuration protocol clients 310, 312, 314, 316, 318, 320, and 322 automatically requests an extension on its lease. As long as dynamic host configuration protocol clients 310, 312, 314, 316, 318, 320, and 322 can contact the dynamic host configuration protocol server 302, the server will renew the lease.
For example, when dynamic host configuration protocol client 310 reboots, it attempts to renew the lease it had before being powered off. If dynamic host configuration protocol client 310 was powered off when the renewal time elapsed, it can be assigned a different IP address. If the IP address is still unassigned when dynamic host configuration protocol client 310 comes back online, dynamic host configuration protocol server 302 can assign the same IP address to dynamic host configuration protocol client 310. But if dynamic host configuration protocol server 302 assigned the IP address to dynamic host configuration protocol client 320 while dynamic host configuration protocol client 310 was off-line, dynamic host configuration protocol client 310 will be assigned a different IP address.
A dynamic host configuration protocol transaction begins when a dynamic host configuration protocol client, such as dynamic host configuration protocol client 310, sends out a DHCPDISCOVER packet. This transmission is usually in the form of a broadcast packet. At minimum, the packet will contain only the dynamic host configuration protocol client's 310 hardware address. Dynamic host configuration protocol server 302 receives the DHCPDISCOVER packet. If an IP address on the dynamic host configuration protocol client 310 subnet is available and dynamic host configuration protocol server 302 is willing to grant a lease, it makes an offer by sending a DHCPOFFER packet to dynamic host configuration protocol client 310. The offer packet contains the: proposed IP address for dynamic host configuration protocol client 310, dynamic host configuration protocol server's 302 name, dynamic host configuration protocol server's 302 IP address, and other configuration information. Dynamic host configuration protocol client 310 receives the DHCPOFFER packet. Dynamic host configuration protocol client 310 might receive more than one offer if more than one dynamic host configuration protocol server is present on the network. If dynamic host configuration protocol client 310 likes the offer, this client sends a DHCPREQUEST packet to dynamic host configuration protocol server 302. This packet indicates a formal request to lease the IP address offered by dynamic host configuration protocol server 302.
Dynamic host configuration protocol server 302 receives the DHCPREQUEST packet and grants dynamic host configuration protocol client 310 its request to lease the IP address. Dynamic host configuration protocol server 302 sends a DHCPACK packet to dynamic host configuration protocol client 310. This packet is the official notification that the address has been granted. Before the lease time expires, dynamic host configuration protocol client 310 requests to extend the lease by sending a DHCPREQUEST packet to dynamic host configuration protocol server 302. Dynamic host configuration protocol server 302 then updates and extends the lease time. Dynamic host configuration protocol server 302 sends a DHCPACK to dynamic host configuration protocol client 310 to notify dynamic host configuration protocol client 310 that the lease has been extended. These updates and lease extensions continue as long as dynamic host configuration protocol client 310 is powered on. If the lease expires and dynamic host configuration protocol client 310 is not powered on, and not able to request an extension on the lease, the IP address is recycled.
Subnets 406 and configuration file 412 may be stored on storage unit 404 of dynamic host configuration protocol server 402. Subnets 406 may be subnets, such as subnets 304, 306, 308 of
When a dynamic host configuration protocol server is active, it can have thousands of clients distributed over multiple subnets, such as subnet 502. Whether an administrator decides to add a new subnet, redistribute a subnet, or modify the server in any way, the administrator must alter the configuration file and then refresh the dynamic host configuration protocol server. The reason for refreshing the dynamic host configuration protocol server is that the server must save what the server currently has in memory to disk, reread the configuration file, load saved client records, and then invalidate those clients that are no loner valid. This delay may be extensive depending on the number of clients. Additionally, when the dynamic host configuration protocol server is busy refreshing the configuration and client records, the dynamic host configuration protocol server is not able to answer awaiting clients.
The clients associated with the one or more subnets that are being updated are then saved off (step 614). The client may be saved to any data structure such as storage 404 of
A determination is then made as to whether there are additional clients to validate (step 624). If there are additional clients, then the operation returns to step 620, otherwise the operation ends. Returning to step 620, if the invalid client is no longer part of the newly configured subnet container, then the client is informed of their IP address being terminated (step 626), the client deleted from the subnet (step 628), and the operation proceeds to step 624.
Thus, the illustrative aspects of the present invention provide a method, apparatus, and computer usable code to dynamically update the subnets of a dynamic host configuration protocol server. Subnet configuration updates are received from a user or administrator and the subnets affected by the configuration updates are determined. The clients associated with the subnets are saved to storage and the subnet configuration updates are loaded. Once the subnet configuration updates are loaded, the clients associated with the newly updated subnets are reloaded.
The invention can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment containing both hardware and software elements. In a preferred embodiment, the invention is implemented in software, which includes but is not limited to firmware, resident software, microcode, etc.
Furthermore, the invention can take the form of a computer program product accessible from a computer-usable or computer-readable medium providing program code for use by or in connection with a computer or any instruction execution system. For the purposes of this description, a computer-usable or computer readable medium can be any apparatus that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device.
The medium can be an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system (or apparatus or device) or a propagation medium. Examples of a computer-readable medium include a semiconductor or solid state memory, magnetic tape, a removable computer diskette, a random access memory (RAM), a read-only memory (ROM), a rigid magnetic disk and an optical disk. Current examples of optical disks include compact disk—read only memory (CD-ROM), compact disk—read/write (CD-R/W) and DVD.
A data processing system suitable for storing and/or executing program code will include at least one processor coupled directly or indirectly to memory elements through a system bus. The memory elements can include local memory employed during actual execution of the program code, bulk storage, and cache memories which provide temporary storage of at least some program code in order to reduce the number of times code must be retrieved from bulk storage during execution.
Input/output or I/O devices (including but not limited to keyboards, displays, pointing devices, etc.) can be coupled to the system either directly or through intervening I/O controllers.
Network adapters may also be coupled to the system to enable the data processing system to become coupled to other data processing systems or remote printers or storage devices through intervening private or public networks. Modems, cable modem and Ethernet cards are just a few of the currently available types of network adapters.
The description of the present invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to best explain the principles of the invention, the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.