Explains how RIB stores best routes from multiple protocols, selects the overall preferred routes by administrative distance, and supports forwarding and monitoring across the system.
Routing Information Base (RIB) is a distributed collection of routing connectivity information that
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maintains routing information for each router in the network
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stores the best routes learned from all routing protocols that run on the system, and
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selects the best overall routes and downloads them to the line cards for packet forwarding.
How RIB selects routes
Each routing protocol selects its own best routes and installs those routes, along with their attributes, in RIB.
Within a routing protocol, route selection depends on the metric that the protocol uses. The protocol then downloads its best routes, including equal-cost routes, to RIB.
RIB stores routes from all routing protocols and selects the best overall route by comparing the administrative distance of each protocol.
How RIB supports forwarding
After RIB selects the best overall routes, it downloads those routes to the line cards for packet forwarding.
The term RIB refers both to the RIB processes and to the collection of route data that RIB contains.
During network convergence, forwarding resources could be created and deleted before the network reached a fully converged state. In large-scale deployments, the router might not have sufficient time to update all dependent entries before the resource was deleted, which could result in packet loss.
Starting with Cisco IOS XR Release 26.3.1, the router now waits until all dependencies are cleared before completing the deletion process. This change helps prevent premature resource removal and improves traffic stability during convergence.
Programmatic configuration support
You can programmatically configure RIB for Border Gateway Protocol (BGP) and retrieve operational data by using the openconfig-rib-bgp.yang OpenConfig data model.
Prerequisites for implementing RIB
Lists the user access and base software requirements needed before implementing RIB on the router.
RIB key concepts
Explains key RIB concepts, including route selection, protocol data structures, administrative distance, IPv4 support, statistics, quarantining, and route consistency checking.
Route consistency checker
Describes how RCC compares control-plane and data-plane routes to detect inconsistencies and support on-demand or background troubleshooting.
BGP-RIB feedback mechanism for update generation
Explains how BGP waits for RIB and FIB installation feedback before advertising routes, helping prevent premature updates and traffic loss.
Deploy and monitor RIB
Explains how to use RIB show commands to verify route state, inspect route views, troubleshoot connectivity between RIB and its clients, and monitor routing behavior across the network.
RCC-based encapsulation ID checks
Explains the RCC-based encapsulation ID checks feature, which validates the encapsulation ID data and also the existing route data between RIB and FIB databases.