The router uses its IP
routing table to
determine which path to
use to forward a packet
Two Functions of Router
Determine the best path
for the packet to take
Routing
The longest match is the route in the
routing table that has the greatest
number of far-left matching bits with
the destination IP address of the packet
Packet Forwarding
Decision Process
Packet Forwarding
Mechanisms
Process switching
Fast switching
Cisco Express Forwarding (CEF)
Basic Router
Configuration Review
Configuration
Commands
ipv6 unicast-routing
ipv6 address X.X.X.X
ipv6 address X.X.X.X
link-local
Verification
Commands
show ip
interface brief
show running-config
interface interface-type
number
show interfaces
show ip interface
show ip route
ping
Filter Command Output
section
include
exclude
begin
IP Routing Table
Route Source
Directly connected
networks
Static routes
Dynamic routing
protocols
Routing Table Principle
Decision based on
the information
The information not
necessarily match
the routing table
Does not provide return
routing information
Routing Table Entries
Route source
Destination network
Administrative distance
Metric
Next-hop
Route timestamp
Exit interface
Static Routes
Dynamic Routing
Protocols
Default Route
Static and
Dynamic Routing
Dynamic Routing
Protocol Concepts
Data structures
Routing protocol
messages
Algorithm
Best Path
RIP
OSPF
EIGRP
Load Balancing
The routing table contains the
single destination network, but
has multiple exit interfaces, one
for each equal cost path.