Remote survivable DHCP for a DHCP relay agent
First Claim
1. A method for facilitating communication between nodes of at least one computer network, the computer network including a first client system, a first DHCP server system, and a first DHCP relay agent, the first DHCP relay agent being configured or designed to facilitate communications between the first client system and the first DHCP server system, the method comprising:
- detecting a first DHCP-related request message sent from the first client system to the first DHCP server system;
determining that the first DHCP server system is unavailable;
in response to determining that the first DHCP server system is unavailable;
retrieving information relating to a first DHCP lease associated with the first client system, the first DHCP lease including DHCP lease information specifying a first assigned network address and a first lease time value;
calculating, using at least a portion of the retrieved DHCP lease information, an updated lease time value to be associated with the first DHCP lease; and
comparing the updated lease time value against a predetermined threshold value T; and
generating and sending a first DHCP response message in response to the first DHCP-related request message based upon a result of comparing the updated lease time value against the predetermined threshold value T, wherein the first DHCP response message includes updated DHCP lease information specifying the first assigned network address and the updated lease time value, wherein sending the first DHCP response message is performed without waiting until the first DHCP server system is available.
1 Assignment
0 Petitions
Accused Products
Abstract
A remote survivable DHCP technique is described for facilitating communications between nodes of a computer network. According to a specific embodiment, the network include a remote survivable DHCP (RSD) system adapted to enable a DHCP relay agent to temporarily respond, during at least a portion of times when the DHCP server is down or unreachable, to DHCP-related requests from clients that have already received a valid DHCP lease offer from a DHCP server during at least a portion of times when the DHCP server is down or unreachable.
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Citations
51 Claims
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1. A method for facilitating communication between nodes of at least one computer network, the computer network including a first client system, a first DHCP server system, and a first DHCP relay agent, the first DHCP relay agent being configured or designed to facilitate communications between the first client system and the first DHCP server system, the method comprising:
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detecting a first DHCP-related request message sent from the first client system to the first DHCP server system; determining that the first DHCP server system is unavailable; in response to determining that the first DHCP server system is unavailable; retrieving information relating to a first DHCP lease associated with the first client system, the first DHCP lease including DHCP lease information specifying a first assigned network address and a first lease time value; calculating, using at least a portion of the retrieved DHCP lease information, an updated lease time value to be associated with the first DHCP lease; and comparing the updated lease time value against a predetermined threshold value T; and generating and sending a first DHCP response message in response to the first DHCP-related request message based upon a result of comparing the updated lease time value against the predetermined threshold value T, wherein the first DHCP response message includes updated DHCP lease information specifying the first assigned network address and the updated lease time value, wherein sending the first DHCP response message is performed without waiting until the first DHCP server system is available. - View Dependent Claims (48, 49, 50)
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2. A method for facilitating communication between nodes of at least one computer network, the computer network including a first client system, a first DHCP server system, and a first DHCP relay agent, the first DHCP relay agent being operable to facilitate communications between the first client system and the first DHCP server system, the method comprising:
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detecting a first DHCP-related request message sent from the first client system to the first DHCP server system; determining that the first DHCP server system is unavailable; and initiating a first set of operations in response to detecting that the first DHCP server system is unavailable, wherein the first set of operations includes; retrieving information relating to a first DHCP lease associated with the first client system, the first DHCP lease including DHCP lease information specifying a first assigned network address and a first lease time value; calculating, using at least a portion of the retrieved DHCP lease information, an updated lease time value to be associated with the first DHCP lease; comparing the updated lease time value against a predetermined threshold value T; and generating and sending a first DHCP response message in response to the first DHCP-related request message according to a result of comparing the updated lease time value against the predetermined threshold value T, wherein the first DHCP response message includes updated DHCP lease information specifying the first assigned network address and the updated lease time value, wherein sending the first DHCP response message is performed without waiting until the first DHCP server system is available. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 51)
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17. A method for facilitating communication between nodes of at least one computer network, the computer network including a first client system, a first DHCP server system, and a first DHCP relay agent, the first DHCP relay agent being operable to facilitate communications between the first client system and the first DHCP server system, the method comprising:
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allocating a first DHCP lease to the first client system, the first DHCP lease including first DHCP lease information relating to a first network address and a first lease time value; detecting a DHCPDISCOVER message from the first client system; determining that the first DHCP server system is unavailable; initiating a first set of operations in response to detecting that the first DHCP server system is unavailable, wherein the first set of operations includes; calculating an updated lease time value to be associated with the first DHCP lease, wherein the updated lease time value is unrelated to a time during which the first DHCP server system is unavailable; comparing the updated lease time value against a predetermined threshold value T; and generating and sending, at the DHCP relay agent, a DHCPOFFER message in response to the DHCPDISCOVER message based upon a result of comparing the updated lease time value against the predetermined threshold value T, wherein DHCPOFFER message includes parameters specifying the first network address and the updated lease time value, wherein sending the DHCPOFFER message is performed without waiting until the first DHCP server system is available. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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24. A system for facilitating communication between nodes of at least one computer network, the computer network including a first client system, a first DHCP server system, and a first DHCP relay agent, the first DHCP relay agent being operable to facilitate communications between the first client system and the first DHCP server system, the system comprising:
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at least one processor; at least one interface operable to provide a communication link to at least one other network device in the data network; and memory; the system being operable to; detect a first DHCP-related request message sent from the first client system to the first DHCP server system; retrieve, in response to detecting that the first DHCP server system is unavailable, information relating to a first DHCP lease associated with the first client system, the first DHCP lease including DHCP lease information specifying a first assigned network address and a first lease time value; calculate, using at least a portion of the retrieved DHCP lease information and in response to detecting that the first DHCP server system is unavailable, an updated lease time value to be associated with the first DHCP lease, wherein the updated lease time value is unrelated to a time during which the first DHCP server system is unavailable; compare the updated lease time value against a predetermined threshold value T; and generate and send, in response to detecting that the first DHCP server system is unavailable, a first DHCP response message in response to the first DHCP-related request message according to a result of comparing the updated lease time value against the predetermined threshold value T, wherein the first DHCP response message includes updated DHCP lease information specifying the first assigned network address and the updated lease time value, wherein the first DHCP response message is sent without waiting until the first DHCP server system is available. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38)
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39. A system for facilitating communication between nodes of at least one computer network, the computer network including a first client system, a first DHCP server system, and a first DHCP relay agent, the first DHCP relay agent being operable to facilitate communications between the first client system and the first DHCP server system, the system comprising:
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at least one processor; at least one interface operable to provide a communication link to at least one other network device in the data network; and memory; the system being operable to allocate a first DHCP lease to the first client system, the first DHCP lease including first DHCP lease information relating to a first network address and a first lease time value; the system being operable to detect a DHCPDISCOVER message from the first client system; the system being operable to determine that the first DHCP server system is unavailable; the system being operable to calculate, in response to detecting that the first DHCP server system is unavailable, an updated lease time value to be associated with the first DHCP lease, wherein the updated lease time value is unrelated to a time during which the first DHCP server system is unavailable; the system being operable to compare the updated lease time value against a predetermined threshold value T; and the system being operable to generate and send, at the first DHCP relay agent and in response to detecting that the first DHCP server system is unavailable, a DHCPOFFER message in response to the DHCPDISCOVER message according to a result of comparing the updated lease time value against a predetermined threshold value T, wherein DHCPOFFER message includes parameters specifying the first network address and the updated lease time value. - View Dependent Claims (40, 41, 42, 43, 44, 45)
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46. A system for facilitating communication between nodes of at least one computer network, the computer network including a first client system, a first DHCP server system, and a first DHCP relay agent, the first DHCP relay agent being operable to facilitate communications between the first client system and the first DHCP server system, the method comprising:
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at least one processor; memory; means for detecting a first DHCP-related request message sent from the first client system to the first DHCP server system; means for determining that the first DHCP server system is unavailable; means for retrieving, in response to detecting that the first DHCP server system is unavailable, information relating to a first DHCP lease associated with the first client system, the first DHCP lease including DHCP lease information specifying a first assigned network address and a first lease time value; means for calculating, using at least a portion of the retrieved DHCP lease information and in response to detecting that the first DHCP server system is unavailable, an updated lease time value to be associated with the first DHCP lease, wherein the updated lease time value is unrelated to a time during which the first DHCP server system is unavailable; means for comparing the updated lease time value against a predetermined threshold value T; and means for generating, in response to detecting that the first DHCP server system is unavailable, a first DHCP response message in response to the first DHCP-related request message according to a result of comp arm g the updated lease time value against the predetermined threshold value T, wherein the first DHCP response message includes updated DHCP lease information specifying the first assigned network address and the updated lease time value.
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47. A system for facilitating communication between nodes of at least one computer network, the computer network including a first client system, a first DHCP server system, and a first DHCP relay agent, the first DHCP relay agent being operable to facilitate communications between the first client system and the first DHCP server system, the method comprising:
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at least one processor; memory; means for allocating a first DHCP lease to the first client system, the first DHCP lease including first DHCP lease information relating to a first network address and a first lease time value; means for detecting a DHCPDISCOVER message from the first client system; means for determining that the first DHCP server system is unavailable; means for calculating, in response to detecting that the first DHCP server system is unavailable, an updated lease time value to be associated with the first DHCP lease, wherein the updated lease time value is unrelated to a time during which the first DHCP server system is unavailable; means for comparing the updated lease time value against a predetermined threshold value T; and means for generating and sending, at the DHCP relay agent and in response to detecting that the first DHCP server system is unavailable, a DHCPOFFER message in response to the DHCPDISCOVER message based upon comparing the updated lease time value against the predetermined threshold value T, wherein DHCPOFFER message includes parameters specifying the first network address and the updated lease time value, wherein sending the DHCPOFFER message is performed without waiting until the first DHCP server system is available.
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Specification