Transcript Routing Protocols & Troubleshooting the Network Semester 2

Routing Protocols &
Troubleshooting the Network
Semester 2, Chapter 12-13
Static Routing
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Static Routes – configure with ip route
command, example:
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(config)#ip route network address SNMask interface address
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Administrative distance is the rating of
trustworthiness of routing info source
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Can go from 0 to 255
Static routes are 1
Default for RIP is 120
Default Routes
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Use default route when you only have partial
information about destination network
Send data to default network when you don’t
have info in routing table
Keeps routing table shorter
IP Default-network command addes to all
routers in network, example:
IP default-network 152.43.0.0
Autonomous Systems
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A group of routers that show a consistent
view of routing to the outside world.
Assigned a unique number by InterNIC
IGRP routing protocol requires an
assigned number Ex: Router IGRP 100
Exterior routing protocols are used
between autonomous systems -BGP
RIP
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Distance Vector Protocol
Uses hop count – over 15 is discarded
Sends updates every 30 seconds
(Config)#router rip
(config-router)#network <attached network(s)>
Show ip protocol command shows protocol,
networks, gateways, distance, update times,
administrative distance
Show ip route – contents of routing table
Troubleshooting The Network:
Examples of problems in each layer might include:
Layer 1 - incorrect cable used
Layer 2 - interface not configured for Ethernet
Layer 3 - subnet mask is incorrect
Layer 1 errors include:
broken cables
disconnected cables
cables connected to the wrong ports
intermittent cable connection
wrong cables used for the task at hand (must use
rollovers, cross-connects, and straight-through
cables correctly)
transceiver problems
DCE cable problems
DTE cable problems
devices turned off
Layer 2 errors include:
improperly configured serial interfaces
improperly configured Ethernet interfaces
improper encapsulation set (HDLC is default
for serial interfaces)
improper clockrate settings on serial interfaces
Layer 3 errors include:
routing protocol not enabled
wrong routing protocol enabled
incorrect IP addresses
incorrect Subnet Masks
incorrect DNS to IP bindings