EP0865180A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Load distribution among servers in a TCP/IP network
Assignee: Nokia of America Corp
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Filing: 1998-03-03
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Granted: —
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Expires: 2018-03-03
Abstract
Abstract Methods and apparatus for hosting a network service on a cluster of servers, each including a primary and a secondary Internet Protocol (IP) address. A common cluster address is assigned as the secondary address to each of the servers in the cluster. The cluster address may be assigned in UNIX-based servers using an ifconfig alias option, and may be a ghost IP address that is not used as a primary address by any server in the cluster. Client requests directed to the cluster address are dispatched such that only one of the servers of the cluster responds to a given client request. The dispatching may use a routing-based technique, in which all client requests directed to the cluster address are routed to a dispatcher connected to the local network of the server cluster. The dispatcher then applies a hash function to the client IP address in order to select one of the servers to process the request. The dispatching may alternatively use a broadcast-based technique, in which a router broadcasts client requests having the cluster address to all of the servers of the cluster over a local network. The servers then each provide a filtering routine, which may involve comparing a server identifier with a hash value generated from a client address, in order to ensure that only one server responds to each request broadcast by the router.
Inventors
- 👤 Pi-Yu Chung
- 👤 Om P. Damani
- 👤 Yennun Huang
- 👤 Chandra M. Kintala
- 👤 Yi-Min Wang
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 06:27
CPC Classifications
H; H04; H04L; H04L61/00; H04L61/35; H04L61/50; H04L61/5069; H04L67/00; H04L67/01; H04L67/10; H04L67/1001; H04L67/1004; H04L67/1023; H04L9/00; H04L9/40; G; G06; G06F; G06F2209/00; G06F2209/46; G06F2209/462; H04L61/45; H04L67/1034; H04L69/00; H04L69/16
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
76 words
A method of routing client requests to a plurality of servers configured
to support a network service over a communication network, each of the servers having
a primary address, the method comprising the steps of: assigning a common address as a secondary address for each of the
plurality of servers; and processing client requests directed to the common address such that each
of the requests is processed by a particular one of the plurality of servers.
Claim 2
Dependent Claim
25 words
The method of claim 1 wherein the network utilizes a TCP/IP protocol
and the primary and secondary addresses are primary and secondary IP addresses,
respectively.
Claim 3
Dependent Claim
29 words
The method of claim 2 wherein the common address is an IP address
which does not correspond to a primary IP address of any of the plurality of servers.
Claim 4
Independent Claim
45 words
The method of any of the preceding claims wherein at least one of the
plurality of servers is a UNIX-based server including multiple network interface cards,
and the assigning step includes assigning the common address for the at least one server
using an ifconfig command..
Claim 5
Independent Claim
41 words
The method of any of claims 1 to 3 wherein the plurality of servers are
UNIX-based servers, and the assigning step includes assigning the common address
utilizing an ifconfig alias option for at least a subset of the plurality of servers.
Claim 6
Independent Claim
45 words
The method of any of the preceding claims wherein the processing
step includes the step of dispatching a request of a given client to one of the plurality of
servers based on application of a hash function to an IP address of the given client.
Claim 7
Dependent Claim
34 words
The method of claim 6 wherein the hash function is determined based
on an analysis of a distribution of client IP addresses in an access log associated with
one or more of the servers.
Claim 8
Dependent Claim
40 words
The method of claim 6 wherein the dispatching step includes
reapplying the hash function to the client IP address to identify another servers if a
server identified as a results of a previous application of the hash function has failed.
Claim 9
Independent Claim
68 words
The method of any of claims 1 to 5 wherein the processing step
includes the steps of: routing client requests directed to the common address to a dispatcher
connected to a local network associated with the plurality of servers; and selecting a particular one of the servers to process a given client request
based on application of a hash function to a corresponding client address in the
dispatcher.
Claim 10
Independent Claim
68 words
The method of any of claims 1 to 5 wherein the processing step
includes the steps of: broadcasting a given client request directed to the common address to
each of the plurality of servers over a local network associated with the servers; and implementing a filtering routine in each of the plurality of servers so that
the given client request is processed by only one of the servers.
Claim 11
Dependent Claim
54 words
The method of claim 10 wherein the implementing step includes the
steps of: applying a hash function to a client IP address associated with the given
client request; and comparing the result of the applying step to an identifier of a particular
server to determine whether that server should process the given client request.
Claim 12
Independent Claim
77 words
An apparatus for routing client requests to a plurality of servers
configured to support a network service over a communication network, each of the
servers having a primary address, the apparatus comprising: means for assigning a common address as a secondary address for each
of the plurality of servers; and means for processing client requests directed to the common address
such that each of the requests is processed by a particular one of the plurality of servers.
Claim 13
Dependent Claim
41 words
The apparatus of claim 12 wherein the processing means is operative
to dispatch a request of a given client to one of the plurality of servers based on
application of a hash function to an IP address of the given client.
Claim 14
Dependent Claim
34 words
The apparatus of claim 13 wherein the hash function is determined
based on an analysis of a distribution of client IP addresses in an access log associated
with one or more of the servers.
Claim 15
Dependent Claim
43 words
The apparatus of claim 13 wherein the processing means is further
operative to reapply the hash function to the client IP address to identify another server
if a server identified as a result of a previous application of the hash function has failed.
Claim 16
Independent Claim
69 words
The apparatus of any of claims 12 to 15 wherein the processing
means further includes a dispatcher connected to a local network associated with the
plurality of servers, wherein the dispatcher is operative to receive client requests
directed to the common address, and to select a particular one of the servers to process a
given client request based on application of a hash function to a corresponding client
address.
Claim 17
Independent Claim
71 words
The apparatus of any of claims 12 to 15 wherein the processing
means further includes: means for broadcasting a given client request directed to the common
address to each of the plurality of servers over a local network associated with the
servers; and means for filtering the given client request in each of the plurality of
servers so that the given client request is processed by only one of the servers.
Claim 18
Dependent Claim
54 words
The apparatus of claim 17 wherein the filtering means is operative to
apply a hash function to a client IP address associated with the given client request, and
to compare the result of the applying step to an identifier of a particular server to
determine whether that server should process the given client request.
Claim 19
Independent Claim
91 words
An apparatus for routing client requests for a network service over a
communication network, the apparatus comprising: a plurality of servers configured to support the network service, each of
the servers having a primary address and a secondary address, wherein a common
address is assigned as the secondary address for each of the plurality of servers; and a router coupled to the servers and operative to route client requests
directed to the common address such that each of the requests is processed by a
particular one of the plurality of servers.
Claim 20
Dependent Claim
47 words
The apparatus of claim 19 wherein the router is further operative to
route client requests such that a request of a given client is routed to one of the plurality
of servers based on application of a hash function to an IP address of the given client.
Claim 21
Dependent Claim
34 words
The apparatus of claim 20 wherein the hash function is determined
based on an analysis of a distribution of client IP addresses in an access log associated
with one or more of the servers.
Claim 22
Dependent Claim
37 words
The apparatus of claim 20 wherein the hash function is reapplied to
the client IP address to identify another server if a server identified as a result of a
previous application of the hash function has failed.
Claim 23
Independent Claim
70 words
The apparatus of any of claims 19 to 22 further including a
dispatcher coupled to the router and to a local network associated with the plurality of
servers, such that the router directs client requests having the common address to the
dispatcher, and the dispatcher selects a particular one of the servers to process a given
client request based on application of a hash function to a corresponding client address.
Claim 24
Independent Claim
66 words
The apparatus of any of claims 19 to 22 wherein the router is further
operative to broadcast a given client request directed to the common address to each of
the plurality of servers over a local network associated with the servers, and further
wherein each of the servers implements a filtering routine so that the given client
request is processed by only one of the servers.
Claim 25
Dependent Claim
47 words
The apparatus of claim 24 wherein the filtering routine involves
applying a hash function to a client IP address associated with the given client request.
and comparing the result to an identifier of a particular server to determine whether that
server should process the given client request.
Claim 26
Independent Claim
29 words
The apparatus of any of claims 12 to 25 wherein the network utilizes
a TCP/IP protocol and the primary and secondary addresses are primary and secondary
IP addresses, respectively.
Claim 27
Dependent Claim
29 words
The apparatus of claim 26 wherein the common address is an IP
address which does not correspond to a primary IP address of any of the plurality of
servers.
Claim 28
Independent Claim
43 words
The apparatus of any of claims 12 to 27 wherein at least one of the
plurality of servers is a UNIX-based server including multiple network interface cards,
and the common address is assigned for the at least one server using an ifconfig command.
Claim 29
Independent Claim
48 words
The apparatus of any of claims 12 to 27 wherein the plurality of
servers are UNIX-based servers, and the common address is assigned as the secondary
address of the plurality of servers by utilizing an ifconfig alias option for at least a
subset of the plurality of servers.
References Cited (Backward Citations)
No citation records indexed.
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