Transcript Chapter 13/Module 4: Learning about Neighboring and Remote

Learning about Neighboring
and Remote Devices
PJC CCNA Semester 2 Ver. 3.0
by
William Kelly
Cisco Discovery Protocol (CDP)
Basics
 CDP’s primary purpose is to discover all directly
connected Cisco devices
 CDP is a layer 2 protocol linking physical layer
and upper layer protocols
 CDP provides info. about connected devices,
the model number of those devices, and the
connected interfaces
 CDP is a Cisco proprietary protocol
 CDP is media and protocol independent (can
learn info. even if other devices use different
protocols)
 CDP v2 is the most recent release and runs on
IOS 12.0(3) and later
Common CDP Commands
Info. from show cdp neighbors
Command
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Device ID
Address
Port ID
Capabilities
Version
Platform
IP Network Prefix
VTP Management Domain Name (CDPv2 only)
Native VLAN (CDP v2 only)
Full/Half-Duplex (CDPv2 only)
Overview of Testing
7
Application
6
Presentation
5
Session
4
Transport
3
Network
2
Data Link
1
Physical
Telnet
ping
trace
show ip route
show interface
Telnet and Advanced Telnet
 Telnet is used to verify the application layer
between the source and the destination
 A router can have 5 simultaneous telnet sessions
(vty 0 – 4)
 Telnet depends on the TCP to accurately deliver the
data
 Ctrl + Shift + 6 followed by hitting the letter x will
escape the current telnet session
 The show sessions command will display all the
current telnet sessions
 The resume session# will resume a particular telnet
session
Alternate Connectivity Tests
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ping
traceroute
show ip route
show interfaces serial
show interfaces/clear counter
debug
The ping Command
 Ping is an echo protocol that helps evaluate
path reliability
 Ping is used to troubleshoot lower level OSI
connectivity
 The basic ping can be used in both the user
and privileged mode
Ping Return Codes
The traceroute Command
 Traceroute follows the route data travels
through a network and can be used to find
broken network connections (broken end to
end connectivity)
 Traceroute can be used at the user and
privileged level
 Traceroute operates by sending pings with ever
increasing Time to Live (TTL) values
 Ctrl-Shift-6 can be used to cancel a traceroute
Traceroute Return Codes
The show ip route Command
 The show ip route command lists the map the
router has constructed to switch packets
 The output of this command is referred to as
the routing table
The show interfaces serial
Command
 The show interfaces serial command displays
information about the serial connection
between two routers
 The hardware including cables and interfaces
 The software including protocols
The states of a serial interface
1. Serial0 is up, line protocol is up –
OPERATIONAL
2. Serial0 is up, line protocol is down –
CONNECTION PROBLEM
3. Serial0 is down, line protocol is down –
INTERFACE PROBLEM
4. Serial0 is administratively down, line protocol
is down - DISABLED
Debug Commands
 Debug all should not be used on a
production router as it will slow down or
crash your network
 Use debug ? to find the appropriate
debug command
 Use undebug all to turn off all debugging