906
Configuring IP Unicast Routing
Configuring Protocol-Independent Features
Configuring Protocol-Independent Features
This section describes how to configure IP routing protocol-independent features. For a complete description of the IP
routing protocol-independent commands in this chapter, see the
Cisco IOS IP Routing: Protocol-Independent Command
.
This section includes the following topics:
Configuring Cisco Express Forwarding, page 906
Configuring the Number of Equal-Cost Routing Paths, page 908
Configuring Static Unicast Routes, page 908
Specifying Default Routes and Networks, page 910
Using Route Maps to Redistribute Routing Information, page 911
Configuring Policy-Based Routing, page 915
Filtering Routing Information, page 919
Managing Authentication Keys, page 922
Configuring Cisco Express Forwarding
Cisco Express Forwarding (CEF) is a Layer 3 IP switching technology used to optimize network performance. CEF
implements an advanced IP look-up and forwarding algorithm to deliver maximum Layer 3 switching performance. CEF
is less CPU-intensive than fast switching route caching, allowing more CPU processing power to be dedicated to packet
forwarding. In dynamic networks, fast switching cache entries are frequently invalidated because of routing changes,
which can cause traffic to be process switched using the routing table, instead of fast switched using the route cache.
CEF uses the Forwarding Information Base (FIB) lookup table to perform destination-based switching of IP packets.
The two main components in CEF are the distributed FIB and the distributed adjacency tables.
The FIB is similar to a routing table or information base and maintains a mirror image of the forwarding information
in the IP routing table. When routing or topology changes occur in the network, the IP routing table is updated, and
those changes are reflected in the FIB. The FIB maintains next-hop address information based on the information in
the IP routing table. Because the FIB contains all known routes that exist in the routing table, CEF eliminates route
cache maintenance, is more efficient for switching traffic, and is not affected by traffic patterns.
Nodes in the network are said to be adjacent if they can reach each other with a single hop across a link layer. CEF
uses adjacency tables to prepend Layer 2 addressing information. The adjacency table maintains Layer 2 next-hop
addresses for all FIB entries.
Because the switch uses Application Specific Integrated Circuits (ASICs) to achieve Gigabit-speed line rate IP traffic,
CEF forwarding applies only to the software-forwarding path, that is, traffic that is forwarded by the CPU.
Command
Purpose
show ip protocols vrf
vrf-name
Display routing protocol information associated
with a VRF.
show ip route vrf
vrf-name
[
connected
] [
protocol
[
as-number
]]
[
list
] [
mobile
] [
odr
] [
profile
] [
static
] [
summary
] [
supernets-only
]
Display IP routing table information associated
with a VRF.
show ip vrf
[
brief
|
detail
|
interfaces
] [
vrf-name
]
Display information about the defined VRF
instances.
Summary of Contents for IE 4000
Page 12: ...8 Configuration Overview Default Settings After Initial Switch Configuration ...
Page 52: ...48 Configuring Interfaces Monitoring and Maintaining the Interfaces ...
Page 108: ...104 Configuring Switch Clusters Additional References ...
Page 128: ...124 Performing Switch Administration Additional References ...
Page 130: ...126 Configuring PTP ...
Page 140: ...136 Configuring CIP Additional References ...
Page 146: ...142 Configuring SDM Templates Configuration Examples for Configuring SDM Templates ...
Page 192: ...188 Configuring Switch Based Authentication Additional References ...
Page 244: ...240 Configuring IEEE 802 1x Port Based Authentication Additional References ...
Page 298: ...294 Configuring VLANs Additional References ...
Page 336: ...332 Configuring STP Additional References ...
Page 408: ...404 Configuring DHCP Additional References ...
Page 450: ...446 Configuring IGMP Snooping and MVR Additional References ...
Page 490: ...486 Configuring SPAN and RSPAN Additional References ...
Page 502: ...498 Configuring Layer 2 NAT ...
Page 770: ...766 Configuring IPv6 MLD Snooping Related Documents ...
Page 930: ...926 Configuring IP Unicast Routing Related Documents ...
Page 976: ...972 Configuring Cisco IOS IP SLAs Operations Additional References ...
Page 978: ...974 Dying Gasp ...
Page 990: ...986 Configuring Enhanced Object Tracking Monitoring Enhanced Object Tracking ...
Page 994: ...990 Configuring MODBUS TCP Displaying MODBUS TCP Information ...
Page 996: ...992 Ethernet CFM ...
Page 1066: ...1062 Using an SD Card SD Card Alarms ...