Patent Application
20070008974
1. Field of the Invention
The present invention concerns providing network services, and, more particularly, concerns providing such network services in a way that disassociates from a network requester the physical addresses of devices that provide the services and that is responsive to performance of such service-providing devices.
2. Background Art
The Transmission Control Protocol/Internet Protocol (TCP/IP) suite (also referred to as “Internet protocol suite”) is a set of communication protocols for computer networking procedures of the Internet. TCP/IP is also widely used to facilitate communication within intranets. TCP/IP requires addresses and configuration settings to be defined on each host or peripheral connected to an intranet. For instance, to function correctly, the IP protocol of TCP/IP needs to know IP addresses of the source/recipient host, default router, etc.
Dynamic Host Configuration Protocol (DHCP) is a communication protocol that automates assignment of IP addresses for TCP/IP configurations. Workstations commonly use DHCP to automatically obtain such addresses and configurations. However, for application servers this is conventionally done manually, particularly for application servers connected to an intranet. That is, it is common to manually configure application servers connected to an intranet with the IP addresses of required IP services (e.g. Domain Name System [DNS], Network Time Protocol [NTP] and Simple Mail Transfer Protocol [SMTP]). One reason application servers are conventionally configured manually, rather than using DHCP, is that DHCP presents a security issue. A further problem with using DHCP on application servers is that DHCP does not retrieve NTP or SMTP server definitions.
Because the process of manually configuring application servers on a network can be time consuming, and because such a network may have numerous application servers, it can be a resource problem to maintain application servers on a network. This, in turn, can present an obstacle to providing high availability network services. For at least these reasons, a need exists to improve ways for accessing network services.
The foregoing need is addressed in the present invention. According to one form of the invention, a method for accessing network services includes receiving a datagram by a router. The datagram requests a certain network-delivered service and includes a virtual address for the service. A router selects a physical address for a certain server from among a number of a physical addresses of respective servers associated by the router with the virtual address. Performance of the respective servers is ranked so that the physical IP address are selected responsive to the performance ranks. The router forwards the datagram, which includes the selected physical address for directing the datagram to the certain server.
In another aspect, the ranking of performance includes detecting levels of service for listed servers of the router. The detecting includes sending polling datagrams to the respective listed servers and measuring response times based upon responses received for the polling datagrams.
In another aspect, the polling datagrams poll applications running on the respective listed servers. The polling of such an application is at an application level, so as to ensure that the application is actually working.
In another aspect, the ranking of performance includes detecting, for listed servers of the router, availability of the listed servers. The detecting includes sending polling datagrams to the respective listed servers. Nonresponse indications are stored based upon lack of responses within a certain interval for the polling datagrams.
In another aspect, the ranking of performance includes computing products for the respective servers' predetermined weights and measured response times and ranking the servers according to these products. That is, a lowest product is ranked first and a highest product is ranked last.
In another aspect, the selecting of the physical network address for the certain server includes checking whether the virtual address of the received datagram matches a virtual address among pre-configured virtual addresses listed in an address translation table. The selecting also includes selecting a highest performance rank in the router's address translation table for the matching virtual address and selecting a certain physical network address in the address translation table. The certain physical network address is associated with the highest rank.
Variations, objects, advantages, and forms of the invention will become apparent upon reading the following detailed description and upon reference to the accompanying drawings.
The foregoing and other objects, aspects and advantages will be better understood from the following detailed description of a preferred embodiment(s) of the invention with reference to the drawings, in which:
In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings illustrating embodiments in which the invention may be practiced. It should be understood that other embodiments may be utilized and changes may be made without departing from the scope of the present invention. The drawings and detailed description are not intended to limit the invention to the particular form disclosed. On the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. Headings herein are not intended to limit the subject matter in any way.
General Overview
One embodiment of the present invention includes a network services access system. The following description provides an broad overview of the network services access system, followed by a more detailed discussion of the hardware architecture of the system and operations performed therein.
According to the network services access system, intranet hosts collaborate with a router. The intranet hosts, which are typically servers deployed in a data center, are pre-configured with virtual IP addresses, and the router includes a dynamic address translation table that provides an adaptable reservoir of available IP services. The router includes dynamic network address translation (NAT) logic for mapping the virtual address of an IP service into a physical IP address.
More specifically, the intranet hosts (also known as “customer servers”) are preconfigured with virtual server IP addresses for respective IP services that they access, e.g. a virtual DNS server IP address, a virtual NTP server IP address, a virtual SMTP server IP address, etc. In practice, an intranet for an entire enterprise can use a single set of virtual servers to represent the IP services required enterprise-wide. Alternatively, the enterprise may use multiple sets of virtual servers, such as, for example, to isolate different organizations within the enterprise.
The virtual server addresses are independent of the physical addresses of the actual servers hosting the corresponding IP services, so that the virtual addresses need not change merely due to physical changes. Thus, physical addresses of devices that provide network services (servers) are disassociated from a network service requester. In one sense, the physical addresses of servers are disassociated from the network, more generally because the arrangement of the present invention permits IP service servers to be added, removed or displaced from a network without impacting the configuration of the customer servers. As a result, an IP service can be deployed locally in the same intranet as the customer servers, or remotely in another intranet, extranet, or the Internet.
The dynamic address translation table associated with the router links the virtual IP address of an IP service request from a customer server to a physical IP address of an IP service server best suited to provide the required service.
Hardware Architecture
Referring now to
For example,
The listing of the required IP services 18, virtual addresses 20, physical addresses of candidate IP service servers 22 and weights 24 are static. However, the dynamic address translation table 16 also contains dynamically adaptable information, namely ranks 26 and response times 28 of candidate IP service servers 22.
In particular, candidate IP service servers 22 are accorded a rank 26 depending on their response time 28, weight 24 and availability. The ranks 26 are used to determine the IP service server best suited to respond to an IP service request. The ranks 26 are updated when router 14 periodically rechecks availability and response time of IP service servers 22.
For example, the candidate IP service servers 22, which are PA11, PA12, PA13 in the present example of a DNS service request, have weights 24, which are λ11, λ12 and λ13, respectively, and response times 28, which are τ11, τ12 and τ13, respectively. Performance logic of a router 14 (
Referring again to
In use, a customer server 10 transmits an IP service request datagram to router 14 in order to request a particular service. The destination address of the IP service request datagram is one of the virtual addresses with which the customer server 10 has been pre-configured. The particularly requested service is indicated by the (virtual) destination address of the IP service request datagram. NAT logic of router 14 selects the physical IP address of the IP service server having the highest ranked performance for the particularly requested service. Router 14 then forwards the resulting IP datagram through public network 30, second router 32 and second intranet 34 to IP service server 36 having the selected the physical IP address.
Virtual Address Translation
Referring to
The above described NAT logic also is operable in reverse, namely when returning an IP datagram from an IP service server in response to an IP service request from a customer server. In particular, on receipt of an IP service datagram from an IP service server, NAT logic of the router converts the datagram's source IP address (i.e. of the IP service server) into the appropriate virtual IP address used by the customer servers.
Updating Ranking of Candidate IP Service Servers
According to an embodiment of the invention, from time to time (e.g., at periods known as the trigger period (Ttrig)), performance logic of a router monitors each of the IP service servers listed in its dynamic address translation table to ensure and maintain quality of service (QoS). In particular, the router monitors the IP services servers for a fixed time interval known as the monitoring interval (Tmon) wherein Tmon<Ttrig. This monitoring not only detects availability of the servers hosting the relevant IP services, but also detects levels of performance of respective IP services.
Referring to
On receipt of the polling datagram, each IP service server 52 returns a response 54 to the router. On receipt of a response 54, the router's performance logic calculates 56 the response time of the relevant IP service server and stores 58 the response time in its dynamic address translation table.
When the monitoring interval Tmon has elapsed 60, the router's performance logic marks 62 any IP service servers that did not respond to the polling datagram as being non-available. The performance logic ranks the remaining IP service servers according to their weights (stored in the router's dynamic address translation table) and the servers' response times. In particular, performance logic ranks the remaining IP service servers so that the server with the smallest weight and smallest response time attains the highest rank.
More specifically, according to an embodiment of the present invention, the performance logic computes products for the respective servers' predetermined weights 124 and measured response times 128, and ranks the servers according to these products, with the lowest product ranked first (i.e., highest rank) and the highest product ranked last. According to one embodiment of the present invention, in the case of ties servers having smaller weights are ranked higher than servers having associated larger weights. In another variation, in the case of ties servers having larger weights are ranked higher than servers having associated smaller weights. In still another variation, in the case of ties servers are assigned the same rank.
Then the performance logic stores the ranks of the IP service servers in the router's dynamic address translation table and restarts its internal timer. The internal timer issues another trigger to restart the performance logic's monitoring operations after the trigger period (Ttrig) has elapsed.
Let A1 and A2 be two customer servers configured with:
(a) a DNS virtual address of 10.1.1.1;
(b) a NTP virtual address of 10.2.2.2; and
(c) a SMTP server address of 10.3.3.3.
In this case, all DNS query datagrams sent by A1 or A2 will have 10.1.1.1 as their destination address.
Referring to
Router 14 performance logic determines the response times 28 of the candidate DNS servers and stores the response times 28 in dynamic address translation table 16, which in the illustrated instances are as follows:
response time of 20 millisecond for the server 22 at 1.1.1.1;
response time of 40 millisecond for the server 22 at 2.2.2.2;
response time of 10 millisecond for the server 22 at 3.3.3.3; and
no response for the server 22 at 4.4.4.4.
The performance logic determines a rank for each candidate DNS server based on its weight 24 and the measured response time 28. The performance logic also stores the ranks 26 of the candidate DNS servers in dynamic address translation table 16. In the present example, candidate DNS server at IP address 3.3.3.3 is ranked first because of its weight 24 times its response time 28 yields a product of 20, which is lower than either of the other two products. In the variation illustrated, servers having smaller weights are ranked higher than servers having associated larger weights in the case of ties. Thus, although the products of weights 24 and response times 28 for the server 22 at address 2.2.2.2 is ranked higher than the server 22 at address 1.1.1.1. It will be appreciated that the ranks of candidate DNS servers 22 may vary from one monitoring period to the next, depending on availability and response times 28.
On receipt of a DNS request datagram from customer server A1 or A2 (i.e. datagram with virtual destination address 10.1.1.1), router 14 NAT logic translates the virtual address (10.1.1.1) into the physical IP address (3.3.3.3) of the currently highest ranked candidate DNS server. NAT logic does this by looking up the highest rank for the servers 22 associated with a “10.1.1.1” virtual destination address 20 in table 16 and then looking up the physical address 22 associated with that rank 26. Conversely, on receipt of a DNS response datagram from the highest ranked candidate DNS server, router 14 NAT logic translates its “3.3.3.3” physical IP address 22 into the “10.1.1.1” virtual DNS address 20. NAT logic does this by looking up “3.3.3.3” in the column of physical IP addresses 22, which may be a content addressable memory, and then looking across the table 16 to the “10.1.1.1” virtual destination address 20 associated with that “3.3.3.3” physical IP address 22.
Router, Server and Computer System
It should be understood that the use of the terms “router” and “server” are not intended to limit the router or server of the present invention to a particular form. A router according to the present invention may take the form of a computer system. Likewise, a server according to the present invention may take the form of a computer system. It should be understood that the term “computer system” is intended to encompass any device having a processor that executes instructions from a memory medium, regardless of whether referred to in terms of a microcontroller, personal computer system, mainframe computer system, workstation, server, or in some other terminology.
Referring now to
Referring now to
Performance logic of router 14 is operable to rank performance of the respective servers, as described herein above. Network address translation logic 710 selects the physical IP address responsive to the performance ranks and inserts the selected physical address in the datagram for directing the datagram to the certain server.
Performance logic 715 also includes detecting logic 720 for detecting levels of service for listed servers of the router. Detecting logic 720 includes sending logic 725 for sending polling datagrams to the respective listed servers and response time measuring logic 730 for measuring response times based upon responses received for the polling datagrams. The polling datagrams poll applications running on the respective listed servers. The polling of such an application is at an application level, so as to ensure that the application is actually working.
In another aspect of detecting logic 720, for listed servers of router 14 detecting logic 720 includes availability detecting logic 735 for detecting availability of the listed servers based upon lack of responses within a certain interval for the polling datagrams.
Detecting logic 720 includes storing logic 740 for storing nonresponse indications based upon such a lack of response, as determined by availability detecting logic 735 and for storing response times measured by response time measuring logic 730.
Performance logic 715 also has computing logic 745 for computing products for the respective servers' predetermined weights and measured response times. Performance logic 715 also ranking logic for ranking the servers according to these products, wherein a lowest product is ranked first and a highest product is ranked last.
Network address translation logic 710 includes match checking logic 750 for checking whether the virtual address of the received datagram matches a virtual address among preconfigured virtual addresses listed in address translation table 16 of router 14. Network address translation logic 710 also includes selecting logic 755 for selecting a highest performance rank in the router's address translation table for the matching virtual address responsive to the performance ranks and selecting a certain physical network address in the address translation table, i.e., the physical network address that is associated with the highest rank. Selecting logic 755 communicates the selected physical address to transmitting logic 760 for inserting in the datagram. Thus, the forwarded datagram includes the selected physical address for directing the datagram to the certain server.
General Remarks and Variations
The present invention provides a mechanism for centrally changing network configurations, such as Internet Protocol configurations, without necessitating manual reconfiguring of each application server on a network. In particular, each IP service is designated with a predefined virtual address and each application server is preconfigured with these virtual addresses. A virtual address is static and the process of mapping a virtual address to a physical IP address is facilitated by the ranked list of candidate IP service servers for the requested IP service. In essence, this mechanism makes it easier to add, delete or displace an IP service server from a network since it is no longer necessary to independently reconfigure each application server on the network.
While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood that various changes in form and detail may be made therein without departing from the spirit, and scope of the invention.
Moreover, the processes of the present invention are capable of being distributed in the form of a computer readable medium of instructions. Such computer readable medium may have a variety of forms. The present invention applies equally regardless of the particular type of signal bearing media actually used to carry out the distribution. Examples of computer readable media include recordable-type media such a floppy disc, a hard disk drive, a RAM, and CD-ROMs and transmission-type media such as digital and analog communications links.
Various embodiments implement the one or more software programs in various ways, including procedure-based techniques, component-based techniques, and/or object-oriented techniques, among others. Specific examples include XML, C, C++ objects, Java and commercial class libraries. Those of ordinary skill in the art will appreciate that the hardware depicted herein may vary depending on the implementation. For example, other peripheral devices may be used in addition to or in place of the hardware depicted in
The terms “logic” or “memory” are used herein. It should be understood that these terms refer to circuitry that is part of the design for an integrated circuit chip. The chip design is created in a graphical computer programming language, and stored in a computer storage medium (such as a disk, tape, physical hard drive, or virtual hard drive such as in a storage access network). If the designer does not fabricate chips or the photolithographic masks used to fabricate chips, the designer transmits the resulting design by physical means (e.g., by providing a copy of the storage medium storing the design) or electronically (e.g., through the Internet) to such entities, directly or indirectly. The stored design is then converted into the appropriate format (e.g., GDSII) for the fabrication of photolithographic masks, which typically include multiple copies of the chip design in question that are to be formed on a wafer. The photolithographic masks are utilized to define areas of the wafer (and/or the layers thereon) to be etched or otherwise processed.
The resulting integrated circuit chips can be distributed by the fabricator in raw wafer form (that is, as a single wafer that has multiple unpackaged chips), as a bare die, or in a packaged form. In the latter case the chip is mounted in a single chip package (such as a plastic carrier, with leads that are affixed to a motherboard or other higher level carrier) or in a multichip package (such as a ceramic carrier that has either or both surface interconnections or buried interconnections). In any case the chip is then integrated with other chips, discrete circuit elements, and/or other signal processing devices as part of either (a) an intermediate product, such as a motherboard, or (b) an end product. The end product can be any product that includes integrated circuit chips, ranging from toys and other low-end applications to advanced computer products having a display, a keyboard or other input device, and a central processor.
To reiterate, one or more embodiments were chosen and described in order to best explain the principles of the invention and its practical application, and to enable others of ordinary skill in the art to understand the invention. Various other embodiments having various modifications may be suited to a particular use contemplated, but may be within the scope of the present invention.
Herein above, and in the following claims, the term “comprises” is synonymous with “includes.” The use of terminology such as “X comprises A, B and C” is not intended to imply that A, B and C are necessarily all of the components of X, unless this is clearly and explicitly stated. Likewise, the terms “including,” “carrying,” “having,” “containing,” “involving,” and the like are to be understood to be open-ended, that is, to mean including but not limited to. Only the transitional phrases “consisting of” and “consisting essentially of,” respectively, shall be closed or semi-closed transitional phrases, as set forth, with respect to claims, in the United States Patent Office Manual of Patent Examining Procedures (Eighth Edition, August 2001 as revised May 2004), Section 2111.03.
The claims that follow are not intended to imply any particular sequence of actions, unless this is clearly and explicitly stated. The inclusion of labels, such as a), b), c), etc., for portions of the claims does not, by itself, imply any particular sequence, but rather is merely to facilitate reference to the portions. Likewise, use of ordinal terms such as “first”, “second,” “third,” etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed. Such ordinal terms may be used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term). Of course, ordinal terms in the context of ranking do indicate order.
| Number | Date | Country | Kind |
|---|---|---|---|
| 05106221.4 | Jul 2005 | EP | regional |
