Remote survivable DHCP for a DHCP relay agent
AssigneeCisco Technology, Inc., a corporation of California
InventorAlan Ford
Life of this patent
Estimating the term…
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.
Claims40
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 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;
- 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
- generating a first DHCP response message in response to the first DHCP-related request message, wherein the first DHCP response message includes updated DHCP lease information specifying the first assigned network address and the updated lease time value.
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 DHCP relay agent being configured or designed to facilitate communications between the first client system and the first DHCP server system, the method comprising:
- 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;
- calculating an updated lease time value to be associated with the first DHCP lease;
- and
- generating, at the DHCP relay agent, a DHCPOFFER message in response to the DHCPDISCOVER message, wherein DHCPOFFER message includes parameters specifying the first network address and the updated lease time value.
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 DHCP relay agent being configured or designed to facilitate communications between the first client system and the first DHCP server system, the system comprising:
- at least one processor;
- at least one interface configured or designed to provide a communication link to at least one other network device in the data network;
- and
- memory;
- the system being configured or designed to detect a first DHCP-related request message sent from the first client system to the first DHCP server system;
- the system being configured or designed to determine that the first DHCP server system is unavailable;
- the system being configured or designed to retrieve 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;
- the system being configured or designed to calculate, 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
- the system being configured or designed to generate a first DHCP response message in response to the first DHCP-related request message, wherein the first DHCP response message includes updated DHCP lease information specifying the first assigned network address and the updated lease time value.
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 DHCP relay agent being configured or designed to facilitate communications between the first client system and the first DHCP server system, the system comprising:
- at least one processor;
- at least one interface configured or designed to provide a communication link to at least one other network device in the data network;
- and
- memory;
- the system being configured or designed 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 configured or designed to detect a DHCPDISCOVER message from the first client system;
- the system being configured or designed to determine that the first DHCP server system is unavailable;
- the system being configured or designed to calculate an updated lease time value to be associated with the first DHCP lease;
- and
- the system being configured or designed to generate, at the DHCP relay agent, a DHCPOFFER message in response to the DHCPDISCOVER message, wherein DHCPOFFER message includes parameters specifying the first network address and the updated lease time value.
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 DHCP relay agent being configured or designed to facilitate communications between the first client system and the first DHCP server system, the method comprising:
- 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 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, an updated lease time value to be associated with the first DHCP lease;
- and
- means for generating a first DHCP response message in response to the first DHCP-related request message, wherein the first DHCP response message includes updated DHCP lease information specifying the first assigned network address and the updated lease time value.
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 DHCP relay agent being configured or designed to facilitate communications between the first client system and the first DHCP server system, the method comprising:
- 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 an updated lease time value to be associated with the first DHCP lease;
- and
- means for generating, at the DHCP relay agent, a DHCPOFFER message in response to the DHCPDISCOVER message, wherein DHCPOFFER message includes parameters specifying the first network address and the updated lease time value.
Dependencies are inferred from the claim text.