Late in 1997, Cisco wrote: >>With reference to the recently published Internet draft: Title : Virtual Router Redundancy Protocol Author(s) : S. Knight, D. Weaver, D. Whipple Filename : draft-whipple-vrrp-00.txt Pages : 14 Date : 11/26/1996 >>This message is to inform you that Cisco believes that this >>proposed protocol may infringe Cisco's patent #5,473,599, >>Standby Router Protocol. The original document has gone through a number of revisions and name changes. When submitted by the vrrp WG for publication, a query was sent to Cisco. The following message was received on March 11: We have done the evaluation and our response is the following: Cisco believes that implementation of draft-ietf-vrrp-spec-05.txt will require a license to Cisco's patent #5,473,599. If this protocol is approved as an IETF standard, licenses will be available to any party on reasonable, nondiscriminatory terms for implentation of the protocol. On March 20, 1998, the definitive statement from Cisco Systems was received: From: Martin McNealis The following statement is in response to recent requests for a clarification on Cisco Systems' position regarding both its Hot Standby Router Protocol (HSRP) and the Virtual Router Redundancy Protocol (VRRP) proposal:- In Cisco's assessment, the VRRP proposal does not represent any significantly different functionality from that available with HSRP and also implementation of 'draft-ietf-vrrp-spec-06.txt' would likely infringe on Cisco's patent #5,473,599. When Cisco originally learned of the VRRP proposal, the Hot Standby Router Protocol was then promptly offered for standardization with the understanding that, if approved, licenses for HSRP would be made available on reasonable, nondiscriminatory terms for implementation of the protocol. This offer stands for the adoption and implementation of HSRP. However, now that the 'draft-li-hsrp-01.txt' submission is approaching expiration and the Working Group is continuing with the VRRP proposal, Cisco Systems reserves the right to protect its intellectual property. Furthermore, Cisco takes the position that standardizing on another proposal that so closely mirrors an existing, well established, extensively deployed protocol is out of step with the principles and practices embodied in the IETF and would thus represent cause for concern within the industry. Martin McNealis IP Product Line Manager