Transcript CCNA 1 Module 11 TCP/IP Transport and Application Layers

CCNA 2 v3.0 Module 7
Distance Vector Routing
Protocols
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Objectives
• Distance vector routing
• RIP
• IGRP
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Distance vector routing
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Distance Vector Updates
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Problem: Routing Loops
• Routing loops can occur when
inconsistent routing tables are not
updated due to slow convergence in a
changing network.
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Problem: Counting to Infinity
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Solution: Defining a Maximum for
Infinity
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Solution: Split Horizon
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Solution: Route Poisoning
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Solution: Triggered Updates
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Solution: Holddown Timers
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RIP
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Key Characteristics of RIP
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RIP Commands
• Using router rip and network
commands to Enable RIP
• Enabling RIP on an IP-addressed network
• Monitoring IP packet flow using the show
ip protocol command
• The show ip route command
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Configuring RIP
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Using the ip classless Command
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RIP Configuration Issues
• To reduce routing loops and counting to
infinity, RIP uses the following:
Defining infinity
Split horizon
Route poisoning & poison reverse
Triggered updates
Holddown timers
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The show ip protocols Command
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The show ip route Command
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Troubleshooting RIP Update Issues
• debug ip rip
• show ip rip database
• show ip protocols {summary}
• show ip route
• debug ip rip {events}
• show ip interface brief
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Preventing Routing Updates through
an Interface
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Load Balancing with RIP
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Administrative Distance
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Integrating Static Route with RIP
• A router running RIP can receive a default
route via an update from another router
running RIP.
• Another option is for the router to
generate the default route itself.
• The administrator can override a static
route with dynamic routing information by
adjusting the administrative distance
values.
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IGRP
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IGRP Features
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IGRP Commands
• Using router igrp and network
commands to enable IGRP
• Enabling IGRP on an IP-addressed
network
• Monitoring IP packet flow using the show
ip protocol command
• The show ip interfaces command
• The show ip route command
• The debug ip rip command
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IGRP Metrics
• Bandwidth – The lowest bandwidth value
in the path
• Delay – The cumulative interface delay
along the path
• Reliability – The reliability on the link
towards the destination as determined by
the exchange of keepalives
• Load – The load on a link towards the
destination based on bits per second
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IGRP Routes:
Interior, System, & Exterior
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IGRP Stability Features
• Holddowns, Split horizons, & Poison-reverse
updates
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Configuring IGRP
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Migrating RIP to IGRP
1. Verify existing routing protocol (RIP) on
the routers to be converted.
2. Configure IGRP on RouterA and RouterB
3. Enter show ip protocols on RouterA
and RouterB
4. Enter show ip route on RouterA and
RouterB
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Verifying IGRP Configuration
• Some commands for checking IGRP
configuration are as follows:
show interface interface
show running-config
show running-config interface
interface
show running-config | begin interface
interface
show running-config | begin igrp
show ip protocols
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Troubleshooting IGRP
• The following commands are useful when
troubleshooting IGRP:
show ip protocols {summary}
show ip route
debug ip igrp events IGRP protocol
events
debug ip igrp transactions IGRP
protocol transactions
ping
traceroute
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