Electrical computers and digital processing systems: multicomput – Remote data accessing – Accessing a remote server
Reexamination Certificate
1998-12-09
2001-12-18
Vu, Viet D. (Department: 2758)
Electrical computers and digital processing systems: multicomput
Remote data accessing
Accessing a remote server
C709S225000, C709S241000, C709S241000
Reexamination Certificate
active
06332158
ABSTRACT:
COPYRIGHT NOTICE
A portion of the disclosure recited in this application contains material which is subject to copyright protection. Specifically, a “computer program listing appendix” in accordance with 37 CFR Section 1.96 is included that lists source code instructions for a process by which the present invention is practiced in a computer system. The copyright owner has no objection to the facsimile reproduction of the specification as filed in the Patent and Trademark Office. Otherwise all copyright rights are reserved. The source code is provided on a compact disk-read only memory (CD-ROM) in accordance with recent Patent and Trademark Office guidelines.
INCORPORATION BY REFERENCE
The present application includes a Compact Disc Read Only Memory (CD-ROM) containing the following files and byte sizes: Figs, 120 KB; risley patent, 79.5 KB; and risley source code, 67.0 KB which is hereby incorporated by reference as if set forth in full in the present invention.
BACKGROUND OF THE INVENTION
The Domain Name System (DNS) is an integral part of the Internet and other networks that use Internet-type protocols (such as TCP/IP) and architecture similar to the Internet. DNS allows human users to access information on different computers connected to the Internet by typing, entering, selecting or otherwise specifying, text names as opposed to sequences of numbers. This makes it much easier to remember, access and convey the location of information in the vast Internet. For example, “coolsite.com” is generally more appealing to the average user of the Internet than “199.227.249.232.” An analogy is in the use of names of people and places as opposed to being forced to use purely numeric telephone numbers.
However, computers on the Internet execute software that uses machine addresses to access information instead of the mnemonic text domain names. Because of this, the domain names must be mapped to their machine addresses (e.g., “coolsite.com” must be mapped to 192.86.1.90 in the example above) before information at a site or location can be accessed. The mechanism that DNS uses to perform this mapping is a client-server arrangement between a name server and a client resolver. Both the name server and resolver are software processes executing on one or more computers. Essentially, the resolver submits a query to a name server about a domain name. The name server “resolves” the mapping of the domain name to a machine address and sends the machine address back to the resolver as the “answer” to the query. For a detailed discussion of the operation of name servers, routers and DNS in general, see, for example,
DNS and BIND,
by Paul Albitz and Cricket Liu, published by O'Reilly & Associates, Inc.
FIG. 1A
illustrates a DNS lookup, also called a “mapping” or “resolving” of a domain name to a machine address, as performed in the prior art.
In
FIG. 1A
, computer
10
makes a request of computer
12
. Computer
12
forms part of the Internet and, in particular, is a name server within the DNS. For example the request from computer
10
may come from a Web browser application executing on computer
10
. In response to computer
10
's user typing in a domain name such as “www.bessemer_ventures.com,” resolver code used by the browser transmits the domain name query to computer
12
. This assumes that computer
12
has been predesignated as the primary domain name server for computer
10
.
Computer
12
includes DNS name server software that receives the request. One method of DNS lookup allows computer
12
to check a local list of domain names already matched to machine addresses. If the queried domain name is in the local list then computer
12
can respond with an answer, in the form of the associated machine address, immediately. Such a local list is referred to as a “name cache” that is stored in system random access memory (RAM), disk storage or other storage associated with computer
12
. The name cache is updated periodically from other, authoritative, name servers in the Internet.
Assuming computer
12
does not have a match for the queried domain name in computer
12
's name cache, computer
12
begins a process of querying other name servers in the Internet, such as computers
14
,
16
and
18
, for knowledge of the associated machine address. This querying is organized but takes time because of the limitations of the Internet and the ever-increasing number of domain name queries that need to be handled by a limited number of name servers. For a detailed discussion of DNS lookup, see the above reference. After computer
12
has obtained the machine address associated with the domain name www.bessemer_ventures.com, the machine address,
180
.
201
.
15
.
250
, in this case, is passed back to computer
10
as the answer to computer
10
's domain name query. Note that this can take on the order of a few seconds, especially where the queried domain name does not exist in primary domain name server computer
12
's name cache. Also, the necessity of computer
12
then having to query, sometimes several or many, other name servers adds to the overall Internet traffic and consumption of limited domain name server processing resources. This results in a slower DNS response time for all users of the Internet. Since DNS lookup is a requirement in the large majority of web page accesses, this translates into a slower Internet for users throughout the world.
After computer
10
receives the machine address associated with www.bessemer_ventures.com, it may then use the machine address to communicate with the target computer having the machine address. Note that the target computer can be any computer connected to the Internet. This does not have to be (and typically isn't) the primary domain name server, such as computer
12
. Rather, the target computer is one operated by the provider of information that the user desires and might be located halfway around the world from the user's primary name server. For example, in the present example of a web browser executing on the user's computer
10
, after the user types in the domain name and the browser (via the resolver process) receives the machine address, the next action is to transfer a request to the target machine's address for a specific web page to be displayed on the user's computer
10
.
The process of obtaining a web page is shown in
FIG. 1A
as taking four steps. However, this is merely a symbolic depiction for ease of discussion. All of the communication steps typically occur over a single physical transmission line from a user's computer to an Internet server, switch, backbone, router or other network device. In accomplishing the process of mapping a domain name to a machine address there are many transactions occurring at different communication layers.
The DNS approach to resolving a domain name with an associated machine address is flexible in that it allows independent growth and relatively automatic propagation of new domain names and their associated machine addresses throughout the Internet. However, the resolution time can become unacceptably long, as where multiple, overloaded name servers must be queried in order to obtain the associated machine address. This problem is exacerbated when the domain name that is the subject of a query does not exist within DNS. This can occur, for example, when a user misspells a domain name, when a user has remembered an incorrect domain name, when an outdated domain name is used, where an error occurs in a software program or database, etc.
In the prior art DNS, when a non-existent domain name is queried for the first time it will not be present in the name cache of the primary domain name server. This starts a chain of potentially many queries to additional name servers—each of which will result in no associated machine address for the domain name. The number of queries depends on the type of DNS searching that is performed and on how many sub-domains in the full domain name are valid before an invalid sub-domain is determined. Even wher
Guzovsky Eduard
Lamb Richard
Risley Chris
Kulas Charles L.
Nwamu Fidel D.
Townsend and Townsend / and Crew LLP
Vu Viet D.
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