Cisco Technology, Inc.

Jayadev Kumarasamy

Richard A Johnson

Kenneth Kinnear, Jr

Mark Stapp

Shujin Zhang

Xiao Gong

This invention provides a method and apparatus for issuing or renewing a host address. The apparatus has an input device to receive a data packet having a host identifier, a memory to store a list of host identifiers, and a processor to match the host identifier with the list of host identifiers. If a match is found, an output device transmits the data packet to an address allocation device to issue or renew the host address. The method provides for retrieving the host identifier in the header of the data packet, matching the host identifier with a list of host identifiers, and maintaining a state of authentication for the host if a match is found, otherwise maintaining a state of unauthentication for the host. The method further provides for inserting a proxy address in a relay agent address field, setting a flag, and transmitting the data packet to an address allocation device to issue or renew the host address. The proxy address is also set in a server identifier address field and the flag is unflaged before any data packets are forwarded to the host.

Proxy for network address allocation

Techniques for managing leased network addresses for multiple networks using overlapping address spaces include storing banks of addresses corresponding to the multiple networks. A request for a network address for a host on a first network is received from a relay agent on an intermediate device. The request includes a qualifier associated with the first network by the relay agent. A first bank of addresses is selected based on the qualifier. A first network address from the first bank is identified based at least in part on the request. A response for the host is sent to the relay agent. The response indicates the first network address and the qualifier. Thus a dynamic host configuration protocol (DHCP) server can provide the same network address for several hosts spread over different networks, such as different virtual private networks (VPNs).

Techniques for dynamic host configuration using overlapping network addresses

Techniques for providing sets of network addresses for dynamically configuring hosts on a network include sending to a first server a first request for a first count of network addresses in a first set of network addresses. A first message indicating the first set of network addresses is received. A second message is received from a second server that requests a second count of network addresses for a second set of network addresses. The second set of network addresses is determined based at least in part on the first set of network addresses and the second count. In response to the second message, a first response indicating the second set is sent to the second server. The techniques allow an administrator to enter available subnets at any DHCP server. The DHCP servers using these techniques then automatically apportion subnets among each other based on the relative usage of the subnets.

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Morgan Hill, CA, United States of America

Jayadev Kumarasamy