BGP Route Announcement for ISP-Agnostic Packet Rerouting
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Solution Overview
Problem
Current methods for rerouting network packets to a backup site after a failure at the original site are inefficient, as they rely on DNS updates which can take up to 72 hours to propagate and do not support maintaining the original IP addresses, and require additional costly configurations or the presence of the same ISP at both sites.
Innovation Solution
A system and method where edge routers at both the original and backup sites broadcast announcements of the IP address of the second server, with the first router indicating a less preferred route, allowing packets to be routed to the second server via the second ISP, and upon failure, the first router continues to broadcast, bypassing the second ISP, ensuring seamless rerouting without the need for DNS updates or identical ISPs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If DNS updates are used to reroute packets to backup site, then packet routing is achieved, but propagation time is excessive (up to 72 hours)
Solution Approach 1:
The patent replaces the DNS-based routing mechanism with a BGP-based routing mechanism. Instead of relying on DNS updates that modify hostnames and IP address translations, the system uses BGP route announcements and withdrawals to dynamically control packet routing. This substitution enables routing changes to propagate through the network in minutes rather than hours, directly resolving the speed-time contradiction.
Solution Approach 2:
The patent implements preliminary configuration where the backup site is pre-configured with the original site's IP address space and BGP routing information before failure occurs. The backup router is prepared to immediately announce routes for the original site's IP addresses, allowing seamless failover without requiring DNS updates or IP address reconfiguration. This preliminary preparation eliminates downtime by having the routing infrastructure ready in advance.
2Reliability
If DNS updates are used for rerouting, then packet routing is achieved, but original IP addresses cannot be maintained
Solution Approach 1:
The patent replaces DNS-based name resolution with direct BGP routing based on IP addresses. The backup site announces routes for the original site's IP address space through BGP, allowing packets to be routed to the backup site while preserving the original destination IP addresses. This eliminates the need for DNS updates that would require changing IP address-hostname mappings, maintaining IP address consistency while enabling seamless failover.
3Reliability
If same ISP is installed at both sites for rerouting, then routing reliability is improved, but cost increases
Solution Approach 1:
The patent enables any ISP to serve as a backup routing provider through BGP configuration, eliminating the requirement for identical ISPs at both sites. The backup site can use a different ISP than the original site, and BGP route announcements ensure proper packet routing regardless of which ISPs are involved. This universal approach allows organizations to use the most cost-effective ISPs for each site while maintaining routing reliability through BGP's path selection capabilities.
Solution Approach 2:
The patent changes the routing parameter from ISP identity matching to BGP route announcement configuration. Instead of requiring the same ISP at both sites, the system uses BGP to dynamically determine the best path based on route announcements. The backup site announces routes for the original site's IP space, and BGP automatically selects the appropriate path, allowing different ISPs to be used at each site while maintaining routing reliability.
4Extent of automation
If BGP filters and AS_PATH prepends are used, then routing preference control is achieved, but device complexity increases
Solution Approach 1:
The patent implements self-service routing preference control through BGP's inherent path selection mechanisms. Instead of requiring complex manual configuration of routing preferences, the system uses BGP's automatic path selection based on AS_PATH length and other standard BGP metrics. The backup router naturally announces routes with longer AS_PATHs, and BGP automatically prefers shorter paths, providing automated routing preference control without excessive configuration complexity.
Data Source
Figure 1
Figure 2(A)
Figure 2(B)
AI summary
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.