BGP Route Selection Using NLRI Priority for Link Failure Bypass
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Solution Overview
Problem
The Border Gateway Protocol (BGP) faces defects in calculating packet forwarding paths, particularly when network devices become unreachable, leading to failures in path calculation.
Innovation Solution
A method where network devices exchange route information to select paths that avoid specific links by adjusting priority attributes and storing NLRI in local databases, ensuring alternative routes are calculated even when direct connections fail.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If BGP SPF algorithm is used for path calculation, then packet forwarding path can be calculated in normal network conditions, but path calculation fails when network devices become unreachable
Solution Approach 1:
The patent applies preliminary action by having network devices store NLRI (Network Layer Reachability Information) in their local link databases before link failures occur. When a link failure is detected, the stored NLRI allows the device to immediately calculate alternative paths without waiting for path re-convergence, thus resolving the contradiction between reliable path calculation and adaptability to network failures.
Solution Approach 2:
The patent introduces an intermediary mechanism where the link database stores route information as an intermediate buffer. This intermediary storage allows the system to maintain path calculation capability during network failures by using pre-stored information, thereby improving both path calculation reliability and failure adaptability simultaneously.
2Reliability
If route information is stored in local link database, then alternative paths can be calculated during failures, but network device complexity increases
Solution Approach 1:
The patent applies universality by making the link database serve multiple functions: it stores NLRI for normal path calculation, acts as a failure detection mechanism, and provides alternative path information during outages. This multi-functionality improves path calculation reliability without proportionally increasing device complexity, as the same database structure handles multiple purposes.
Data Source
AI summary
Embodiments of this application disclose a route information processing method and an apparatus, which may be used for a network device that supports a BGP protocol, to resolve a defect in an existing BGP SPF protocol. The network device may be a forwarding device, for example, a router or a switch. For example, in embodiments of this application, a priority attribute is introduced to route information that carries NLRI through an extended BGP protocol, to indicate a priority of the route information. This influences a BGP NLRI selection process performed by the network device. For example, embodiments of this application provide a network fault processing method, to help resolve a problem that a network device cannot calculate a packet forwarding path in some scenarios in an existing protocol.