Routing table and FIB table

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The functions and meanings of the routing table and FIB table are as follows:
Routers forward packets based on routing tables and forwarding information base (FIB) tables. Each router maintains at least one routing table and one FIB table.
A routing table stores routes discovered by various routing protocols. Routes are classified into the following types based on the origin:
-Direct route: is discovered by link layer protocols.
-Static route: is manually configured by network administrators.
-Dynamic route: is discovered by dynamic routing protocols.
Each entry in the FIB table contains the physical or logical interface through which a packet is sent to a network segment or host to reach the next router. An entry also indicates whether the packet can be sent to a destination host in a directly connected network.

Other related questions:
Differences between the three multicast-related routing tables on an S series switch
On an S series switch, the following tables are generally searched for MFIB entries: PIM routing table, multicast routing table, and multicast. - A PIM routing table contains entries generated by PIM at the protocol layer. You can view source and group information learned by PIM at the protocol layer in a PIM routing table. - A multicast routing table associates the protocol layer with the MFIB module. Entries at the protocol layer are stored in a multicast routing table before being delivered. Entries stored in the MFIB module must be the same as those stored in the multicast routing table. - A multicast forwarding table contains entries stored in the MFIB module. The MFIB module stores forwarding entries delivered from the protocol layer in the multicast forwarding table. The forwarding entries are then delivered to the multicast module of a switch. Normally, entries stored in the multicast forwarding table must be the same as those stored in the multicast routing table.

Why is the number of routes in the routing table inconsistent with the number of FIB entries after a required route iteration on an S series switches
Q: Why is the number of routes in the routing table inconsistent with the number of FIB entries after a required route iteration? A: After routes are iterated as required, routes of multiple outbound interfaces are not generated and there is only one route with multiple outbound interfaces. This route is iterated to multiple routes when delivered to the FIB. As a result, the number of routes in the routing table is inconsistent with the number of FIB entries. Among the route flags, R indicates that the route is iterated, and D indicates that the route is successfully delivered to the FIB.

Why are routes in the OSPF routing table on an S series switch in the inactive state
A policy that filters all OSPF routes may be configured in an OSPF process. As a result, all routes in the OSPF routing table are in the inactive state.

Route types in the routing table on the USG6000 series
Route types in the routing table on the USG6000 series include: protocol and destination address/mask.

How to clear routing table on S series switch
1. For static routes in a routing table, run the undo ip route-static command to delete them one by one. 2. For dynamic routes, run the reset command to restart the corresponding process and update the routing table. For example, to delete OSPF routing entries, run the reset ospf process command. Caution: Restarting the routing protocol will cause a loss of routing entries, and the switch will relearn routing entries.

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