Method and apparatus for generating replies to address resolution protocol requests
US6775278B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 14, 2000 |
| Grant date | Aug 10, 2004 |
| Priority date | — |
| Expiry date | Apr 14, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L69/40
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
The invention ensures that a single and consistent reply is made to ARP request in a system of connected IP networks. When an adapter (A) becomes active, the owning host sends an ARP advertisement into the network over the adapter. If the advertisement is also received at the sending host over a different adapter B, then the host knows that adapter B is on in the same physical network as adapter A and B can be designated as a backup adapter for A and A can be designated as backup adapter for B. If adapter A fails or becomes inactive, the host resets the backup adapter field for any adapter it owns for which A is marked as the backup adapter. If a backup adapter B has been designated for A, the host also sends an ARP advertisement associating MAC-B with IP-A. This allows network connections originally served via adapter A to continue non-disruptively over adapter B and it also provides access to the host for subsequent new connections. When adapter A becomes active again, the host sends a gratuitous ARP advertisement that maps IP-A to MAC-A. This allows adapter A to re-assume responsibility for responding to ARP requests for IP-A.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.