CLI Reference Guide-R07

Chapter 28 | IP Routing Commands
Global Routing Configuration
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show ip route This command displays information in the Forwarding Information Base (FIB).
Syntax
show ip route [connected | database | rip | static | summary]
connected – Displays all currently connected entries.
database – All known routes, including inactive routes.
rip – Displays all entries learned through the Routing Information Protocol
(RIP).
static – Displays all static entries.
summary – Displays a brief list of summary information about entries in
the routing table, including the maximum number of entries supported,
the number of connected routes, the total number of routes currently
stored in the routing table, and the number of entries in the FIB.
Command Mode
Privileged Exec
Command Usage
◆ The FIB contains information required to forward IP traffic. It contains the
interface identifier and next hop information for each reachable destination
network prefix based on the IP routing table. When routing or topology
changes occur in the network, the routing table is updated, and those changes
are immediately reflected in the FIB.
The FIB is distinct from the routing table (or, Routing Information Base), which
holds all routing information received from routing peers. The forwarding
information base contains unique paths only. It does not contain any secondary
paths. A FIB entry consists of the minimum amount of information necessary to
make a forwarding decision on a particular packet. The typical components
within a forwarding information base entry are a network prefix, a router port
identifier, and next hop information.
◆ This command only displays routes which are currently accessible for
forwarding. The router must be able to directly reach the next hop, so the VLAN
interface associated with any static route entry must be up.
Example
Console#show ip route
Codes: C - connected, S - static, R - RIP, B - BGP
O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default
C 192.168.1.0/24 is directly connected, VLAN1
Console#