rib vs fib-How it all works

RIBs vs FIBs vs CEF and Data Plane vs Control Plane (How it all works)

Explore the intricate workings of RIBs vs FIBs vs CEF and the Data Plane vs Control Plane in networking. Understand the differences, mechanisms, and importance of each element in modern networking architectures.



Routing Information Bases (RIBs) serve as the cornerstone of routing decisions. These databases contain the routing tables that outline the paths data packets should take to reach their destinations. RIBs store comprehensive routing information, including network prefixes, next-hop addresses, and metrics. The Control Plane populates the RIB with this information through dynamic routing protocols like OSPF (Open Shortest Path First) and BGP (Border Gateway Protocol).

FIBs: Speeding Up Forwarding

Forwarding Information Bases (FIBs) are closely linked to RIBs. While RIBs store comprehensive routing data, FIBs contain a subset of that information optimized for fast packet forwarding. FIBs are used by the Data Plane to determine the immediate next-hop for packet forwarding, improving the speed of routing decisions.

CEF: Enhancing Forwarding Efficiency

Understanding Cisco Express Forwarding

Cisco Express Forwarding (CEF) is a proprietary technology developed by Cisco to accelerate packet forwarding. CEF optimizes the process of forwarding packets by using specialized data structures to create FIB and adjacency tables. This optimization allows routers to make forwarding decisions more efficiently, resulting in reduced latency and improved network performance.

FIB vs CEF: The Symbiotic Relationship

CEF works in tandem with FIBs to streamline packet forwarding. As packets arrive at a router, CEF uses the FIB to quickly determine the next-hop adjacency for forwarding. The adjacency table, created and maintained by CEF, contains Layer 2 information, such as MAC addresses, necessary for forwarding packets to their destination.

Data Plane vs Control Plane: Striking the Balance

Data Plane: Handling Packet Forwarding

The Data Plane, often referred to as the Forwarding Plane, is responsible for the actual movement of data packets across the network. It operates independently of the Control Plane and relies on information from the FIB and adjacency tables to forward packets accurately and swiftly.

Control Plane: Managing Network Intelligence

The Control Plane is the brain behind network management and routing decisions. It houses the RIB and runs routing protocols to update routing tables. While the Data Plane focuses on packet forwarding, the Control Plane ensures that the routing information is up to date and accurate.

Pros and Cons

FunctionRoute selection and calculationFast and efficient data packet forwarding
StorageStore multiple routes with attributesStore optimized routes for forwarding
ProcessingInvolves complex calculationsQuick decisions based on stored information
Memory UsageHigher memory usage due to stored routesLower memory usage due to optimized routes
FlexibilityAllows for route redundancy and choicesStreamlined, optimized forwarding decisions

The Interplay: Making It Work

Seamless Integration of Elements

The relationship between RIBs, FIBs, CEF, Data Plane, and Control Plane is symbiotic. RIBs provide routing information, FIBs optimize forwarding, CEF accelerates packet movement, the Data Plane handles forwarding, and the Control Plane manages routing intelligence. This intricate interplay ensures efficient data transmission across complex networks.

Achieving Optimal Network Performance

By harmoniously working together, rib vs fib.CEF, Data Plane, and Control Plane contribute to optimal network performance. The dynamic exchange of routing information and expedited packet forwarding facilitated by these elements result in minimal latency, improved throughput, and reliable connectivity.


How does CEF differ from traditional packet forwarding?

CEF employs optimized data structures and adjacency tables to accelerate packet forwarding, reducing latency and improving network performance. rib vs fib
Traditional packet forwarding relies on slower lookup methods, making it less efficient.

Can RIBs operate without FIBs?

While RIBs can function independently, the integration of FIBs significantly enhances routing efficiency. FIBs optimize forwarding decisions, improving packet transmission speed.

What role do routing protocols play in RIBs?

RIBs vs FIBs

Routing protocols, such as OSPF and BGP, populate the RIB with routing information. This information is then used by the Control Plane to make informed routing decisions.

How does the Data Plane handle packets with no FIB entry?

rib vs fib
If a packet arrives at the Data Plane with no matching FIB entry, it is forwarded to the Control Plane for further analysis. The Control Plane determines the appropriate action for such packets.

Can CEF be used in non-Cisco networks?

CEF is a Cisco-specific technology. However, other networking vendors have developed similar forwarding acceleration techniques to achieve comparable performance enhancements.

What happens if the Control Plane fails?

If the Control Plane becomes unresponsive, routing information will not be updated, potentially leading to incorrect routing decisions. The Data Plane may still operate based on the existing FIB and adjacency information.

RIB vs FIB: Different Roles in Networking

AspectRouting Information Base (RIB)Forwarding Information Base (FIB)
FunctionStores possible routes and attributes for decision-makingContains optimized routes for efficient packet forwarding
UsageRoute selection and calculationRapid packet forwarding decisions based on stored best routes
MemoryHolds multiple routesHolds only the best routes for faster lookup and decision-making
InteractionInteracts with routing protocols like OSPF, BGP, EIGRPPopulated by RIB, used for forwarding decisions

Cisco Express Forwarding (CEF): Speeding Up Packet Forwarding

AspectCisco Express Forwarding (CEF)
BenefitAccelerates packet forwarding decisions
EfficiencyReduces load on router’s CPU
SpeedEnables rapid forwarding in large-scale networks
DependencyRelies on Forwarding Information Base (FIB)
Vendor-SpecificProprietary technology specific to Cisco systems

Control Plane vs Data Plane: How They Collaborate

AspectControl PlaneData Plane
RoleMakes routing decisions, manages network protocolsExecutes forwarding decisions, actual data packet movement
RoutingUtilizes protocols (OSPF, BGP, etc.) and builds RIBUtilizes FIB to forward packets based on control plane’s choices
EfficiencyInvolves complex calculations and negotiationsMinimizes latency by directly forwarding packets
RelationshipControl Plane instructs Data PlaneData Plane follows Control Plane’s routing instructions

Commands to View Tables

To view the tables:

  • RIB: show ip route
  • FIB: show ip cef, show adjacency

To view specific protocol RIBs:

  • OSPF: show ip ospf rib
  • EIGRP: sh ip eigrp topology
  • BGP: show ip bgp

RIBs vs FIBs vs CEF and Data Plane vs Control Plane (How it all works)

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