| 摘要 |
<p>A first site comprises a first ISP, a first server and a first router interposed between the first ISP and the first server. A second site comprises a second ISP, a second server and a second router interposed between the second ISP and the second server. While the second server is operating, both the first and second routers broadcast announcements of an IP address of the second server. The announcements of the IP address broadcast by the first router indicate the first router as a less preferred route to the IP address than the announcements of the IP address by the second router indicating the second router as a route to the IP address. Consequently, packets addressed to the IP address are routed to the second server via the second ISP and the second router. Subsequently, the second site fails, and concurrently, the second router ceases to broadcast announcements of the IP address of the second site and the first router continues to broadcast announcements of the IP address of the second site. Consequently, subsequent packets addressed to the IP address are routed to the first server via the first ISP and the first router, bypassing the second ISP. A semiautomatic technique is also disclosed.</p> |
