Method and apparatus for generating replies to address resolution protocol requests for virtual IP addresses
First Claim
1. For use with multiple networked computing hosts using the Internet Protocol (IP) and the Address Resolution Protocol (ARP), a method of processing ARP requests, comprisingin response to the activation of an adapter X at a first host, determining what physical network N contains the adapter X, if the first host owns one or more VIPAs, where a VIPA is an IP address associated with the first host rather than with an adapter, assigning responsibility for responding to ARP requests directed to a VIPA to adapter X, in response to the inactivation of adapter X, determining if there is another adapter Y owned by the first host and in the same physical network N as adapter X, if there is another adapter Y in network N, designating adapter Y as backup for adapter X by broadcasting an ARP message into the network mapping the IP address associated with adapter X with the Media Access Control (MAC) address of adapter Y, determining if adapter X owns responsibility for responding to ARP requests directed to a VIPA and, if so, assigning responsibility for responding to ARP requests directed to a VIPA to adapter Y.
1 Assignment
0 Petitions
Accused Products
Abstract
The invention ensures that a single and consistent reply is made to an ARP request in a system of connected IP networks. When an adapter becomes active, the relative network on which it resides is determined by transmitting control packets over it and all other adapters known to the host and observing if and where responses are returned to the adapters. One adapter on a network is designated as active. If the same network contains other adapters, they are marked as standby adapters for the purpose of responding to ARP messages. Special processing is provided for offload adapters that perform there own ARP processing.
-
Citations
9 Claims
-
1. For use with multiple networked computing hosts using the Internet Protocol (IP) and the Address Resolution Protocol (ARP), a method of processing ARP requests, comprising
in response to the activation of an adapter X at a first host, determining what physical network N contains the adapter X, if the first host owns one or more VIPAs, where a VIPA is an IP address associated with the first host rather than with an adapter, assigning responsibility for responding to ARP requests directed to a VIPA to adapter X, in response to the inactivation of adapter X, determining if there is another adapter Y owned by the first host and in the same physical network N as adapter X, if there is another adapter Y in network N, designating adapter Y as backup for adapter X by broadcasting an ARP message into the network mapping the IP address associated with adapter X with the Media Access Control (MAC) address of adapter Y, determining if adapter X owns responsibility for responding to ARP requests directed to a VIPA and, if so, assigning responsibility for responding to ARP requests directed to a VIPA to adapter Y.
-
4. Apparatus for processing Address Resolution Protocol requests (ARP requests) at a networked host computer, comprising
a plurality of communications adapters on the host computer that individually communicate with one of a plurality of networks, means at the host computer for identifying a network with which each adapter communicates, means responsive to a determination that at least two adapters X and B communicate with the same network for designating a first one X of the adapters as active for processing ARP requests by broadcasting an ARP message into the network mapping the IP address associated with adapter X with the Media Access Control (MAC) address of adapter X, and means responsive to the inactivation of the first adapter X for designating the second adapter as active for processing ARP requests by transmitting an ARP message into the network mapping the IP address associated with adapter X with the Media Access Control (MAC) address of adapter B.
-
5. A method of processing Address Resolution Protocol requests (ARP requests) at a networked host having a plurality of communications adapters each communicating with one of a plurality of networks, comprising the steps of
identifying a network on which each adapter communicates, if there are at least two adapters that communicate with the same network N, designating a first one of the adapters X as active for processing ARP requests from the network by transmitting into the network N an ARP message mapping the IP address associated with adapter X with the Media Access Control (MAC) address of adapter X, and responsive to the inactivation of the first adapter X, designating the second adapter B as active for processing ARP requests by transmitting an ARP message into the network mapping the IP address associated with adapter X with the Media Access Control (MAC) address of adapter B.
-
6. A computer program product for storing computer instructions, which when loaded into a computer and executed cause the computer to process Address Resolution Protocol requests (ARP requests) in a networked host according to the steps of
identifying a network on which each adapter communicates, if there are at least two adapters that communicate with the same network N, designating a first one of the adapters X as active for processing ARP requests from the network by transmitting into the network N an ARP message mapping the IP address associated with adapter X with the Media Access Control (MAC) address of adapter X, and responsive to the inactivation of the first adapter X, designating the second adapter B as active for processing ARP requests by transmitting an ARP message into the network mapping the IP address associated with adapter X with the Media Access Control (MAC) address of adapter B.
-
7. A method of processing Address Resolution Protocol requests (ARP requests) at a networked host having a plurality of communications adapters each communicating with one of a plurality of networks, comprising the steps of
in response to the activation of an adapter X at a first host, a) transmitting an ARP message via adapter X mapping the Internet Protocol address of X to the Media Access Control Address of adapter X, b) if there are other adapters on the first host, determining which of those are on the same network as adapter X, in response to the inactivation of adapter X, c) if there is another adapter B on the first host and on the same network as adapter X as determined at step b), transmitting an ARP message via adapter B mapping the Internet Protocol address of X to the Media Access Control Address of adapter B.
Specification