Monitoring Cisco Switches
You can adviser and administer your Catalyst switches in a cardinal of altered ways. One way
is primarily through a animate anchorage appliance either the command-line interface (CLI) or other
methods for assuming arrangement administration functions, such as Cisco Discovery Protocol
(CDP), Embedded Alien Ecology (RMON), or Switched Anchorage Analyzer (SPAN). The
console anchorage is an EIA/TIA-232 DCE interface to which you can affix a animate terminal or
modem. The blazon of connector, however, acclimated depends on the hardware. On a Catalyst 5000
with Supervisor I or II, a rollover cable is acclimated with the aloft hardware. On a Supervisor III or
a Catalyst 6000, a beeline through cable is acclimated in affiliation with a modular plug. Other
kinds of switches may be different.
Through the animate port, you can anon admission the CLI or configure a Consecutive Band Internet
Protocol (SLIP) interface to admission such arrangement administration functions as Telnet, ping, and
SNMP. An IP abode can be assigned to the Cisco about-face for administration purposes. Once the
address is in place, you can complete Telnet to admission the IP abode of the about-face to ability the CLI.
You can additionally use the IP abode of the about-face to admission an SNMP agent, such as CiscoWorks
2000.
NOTE This affiliate contains references and commands that are based on Cisco Switch-Based IOS.
Out-of-Band Management
Out-of-band administration admission for Cisco switches in accepted is performed via the following
methods:
• Animate Anchorage Connection
• SLIP
Console Anchorage Connection
The animate anchorage is the bounded (out-of-band) animate terminal affiliation to the switch—a DB-
25 changeable adapter apparent in Figure 13-2. Added switches may crave altered animate cables
in affiliation with modular plugs instead of the DB-25.
Monitoring Cisco Switches 431
Figure 13-2 The Catalyst 5000 Animate Port
To use the animate port, affix via a straight-through cable, an EIA/TIA-232 terminal
(configured for 9600 baud, no parity, eight abstracts bits, and one stop bit), modem, or network
management workstation, as apparent in Figure 13-3. As acclaimed above, however, this may vary
depending on the blazon of about-face used.
Figure 13-3 Attaching to the Animate Port
The animate anchorage enables you to accomplish the afterward functions:
• Configure the about-face with a command-line interface.
• Adviser arrangement statistics and errors.
• Configure SNMP abettor parameters.
• Download software updates to the about-face or administer software images residing in Flash
memory to absorbed devices.
CONSOLE
Desktop system
terminal settings:
Straight through EIA/TIA-232 cable with
a 25-pin D blazon connector
. 9600 baud
. 8 bits
. 1 stop bit
. No parity
Console port
Supervisor Engine module
100 BaseTX RJ-45 and M3 connectors
432 Affiliate 13: Ecology and Troubleshooting
Serial Band Internet Agreement (SLIP)
You can admission the Cisco about-face command band appliance Consecutive Band Internet Agreement (SLIP). This
protocol is a adaptation of Internet Agreement (IP) that runs over consecutive links acceptance IP
communications through the animate port.
Configuring SLIP on the Animate Port
Catalyst alternation switches abutment out-of-band administration through the use of a modem attached
to the animate port. This out-of-band affiliation works in affiliation with SLIP. The out-ofband
connection can be acclimated to:
• Authorize a Telnet affair that provides admission to the Cisco about-face CLI.
• Use the Telnet Server feature.
• Authorize an SNMP administration affair that provides the adequacy to use an SNMPbased
management belvedere such as the CiscoWorks 2000 solution.
To authorize an out-of-band affiliation on a Cisco switch, affix a 100 percent Hayescompatible
modem by agency of a straight-through cable with a 25 pin D blazon adapter as
shown in Figure 13-4. The modem should be configured for auto acknowledgment mode.
Figure 13-4 Out-of-band Administration Appliance SLIP
Use the SLIP (sl0) interface for point-to-point SLIP admission amid the about-face and an IP
host.
CAUTION You charge use the animate anchorage for the SLIP connection. Back the SLIP affiliation is enabled
and SLIP is absorbed on the animate port, an EIA/TIA-232 terminal cannot affix via the
console port. If you are affiliated to the about-face CLI through the animate anchorage and you admission the
slip attach command, you will lose the animate anchorage connection. Use Telnet to admission the
switch, admission advantaged mode, and admission the blooper abstract command to restore the animate port
connection.
Telnet or SNMP
Console port
Supervisor Engine module
100BaseTX RJ-45 and M3 connectors
Modem Modem
SLIP
Monitoring Cisco Switches 433
To accredit and attach SLIP on the animate port, accomplish the afterward arrangement of tasks:
Step 1 Admission the about-face from a alien host with Telnet via the telnet
{host_name | ip_addr} command.
Step 2 Admission advantaged approach on the about-face via the accredit command.
Step 3 Set the animate anchorage SLIP abode and the destination abode of
the absorbed host via the set interface sl0 slip_addr dest_addr
command.
Step 4 Accredit SLIP for the animate anchorage via the blooper attach command.
Step 5 Verify the SLIP interface agreement via the appearance interface
command.
Example 13-1 shows how to configure SLIP on the animate anchorage and verify the configuration:
In-Band Management
The afterward protocols are acclimated to accomplish in-band administration of a Cisco switch:
• Simple Arrangement Administration Agreement (SNMP)
• Telnet
• Cisco Discovery Agreement (CDP)
Example 13-1 Configuring SLIP on the Animate Anchorage and Verifying the Configuration
sparc20% telnet 172.20.52.71
Trying 172.20.52.71 ...
Connected to 172.20.52.71.
Escape appearance is '^]'.
Cisco Systems Console
Enter password:
Console> enable
Enter password:
Console> (enable) set interface sl0 10.1.1.1 10.1.1.2
Interface sl0 blooper and destination abode set.
Console> (enable) blooper attach
Console Anchorage now active SLIP.
Console> (enable) appearance interface
sl0: flags=51
slip 10.1.1.1 dest 10.1.1.2
sc0: flags=63
vlan 523 inet 172.20.52.71 netmask 255.255.255.224 advertisement 172.20.52.95
Console> (enable)
434 Affiliate 13: Ecology and Troubleshooting
SNMP
Simple Arrangement Administration Agreement (SNMP) is an appliance band agreement advised to
facilitate the barter of administration advice amid arrangement devices. The SNMP
system consists of three parts—SNMP manager, SNMP agent, and Administration Information
Base (MIB).
Instead of defining a ample set of commands, SNMP places all operations in a get-request, getnext-
request, and set-request format. For example, an SNMP ambassador can get a amount from
an SNMP abettor or abundance a amount into that SNMP agent. The SNMP ambassador can be allotment of a
network administration arrangement (NMS), and the SNMP abettor can abide on a networking device
such as a switch. The SNMP abettor can acknowledge to MIB-related queries actuality beatific by the NMS.
The afterward account capacity the basal functions accurate by SNMP agents:
• Accessing a MIB capricious appliance the get-request or get-next-request format—This
function is accomplished by the SNMP abettor as a aftereffect of a appeal for the amount of a MIB
variable from a arrangement administration station. The SNMP abettor gets the amount of a MIB
variable by accessing advice stored in the MIB and again responds.
• Setting a MIB variable—This action is additionally accomplished by the SNMP abettor as a aftereffect of
a bulletin from a arrangement administration station. The SNMP abettor requests that the value
of a MIB capricious be changed.
• SNMP trap—This action is acclimated to acquaint a arrangement administration base that an
extraordinary accident has occurred at an agent. Back a allurement action occurs, the SNMP
agent sends an SNMP abettor allurement bulletin to anniversary of the arrangement administration stations as
specified in the allurement receiver table.
To configure SNMP on your switch, accomplish the afterward steps:
Step 1 Configure the SNMP association strings via the set snmp
community {read-only | read-write | read-write-all}
community_string command.
Step 2 Accredit a allurement receiver abode and association via the set snmp
trap rcvr_address rcvr_community command. If you enter
incorrect information, admission the bright snmp allurement command to
delete the entry. Again re-enter the set snmp allurement command.
Step 3 If desired, configure the about-face so that it issues an authentication
trap via the set snmp allurement accredit command.
The set snmp Command Options
The syntax for the set snmp association command, acclimated to configure SNMP community
strings, is as follows:
set snmp association {read-only | read-write | read-write-all} [community_string]
Monitoring Cisco Switches 435
The keywords for the set snmp association command are as follows:
• read-only—Keyword to accredit read-only admission to the defined SNMP community.
• read-write—Keyword to accredit read-write admission to the defined SNMP community.
• read-write-all—Keyword to accredit read-write admission to the defined SNMP community.
The read-write-all offers admission to the association strings themselves.
• community_string—An alternative parameter. This is the name of the SNMP community.
The absence SNMP association strings are as follows:
— read-only (public)
— read-write (private)
— read-write-all (secret)
Example 13-2 demonstrates some sample achievement afterwards entering the set snmp community
command appliance all three community_string options.
As approved in Archetype 13-3, to appearance the options of the set snmp command admission the
command at the CLI in accredit mode.
An IP admittance allurement is beatific back crooked admission based on the IP admittance account is attempted. The
set snmp allurement command is a advantaged approach about-face command acclimated to accredit or attenuate the
different SNMP accessories on the arrangement or to add an admission into the SNMP affidavit trap
receiver table. The absence agreement has SNMP accessories disabled. Use the appearance snmp
Example 13-2 set snmp association Command Output
Console> (enable) set snmp association read-only public
SNMP read-only association cord set.
Console> (enable) set snmp association read-write private
SNMP read-write association cord set.
Console> (enable) set snmp association read-write-all secret
SNMP read-write-all association cord set.
Example 13-3 Viewing set snmp Command Options
Console> (enable) set snmp
Set snmp commands:
----------------------------------------------------------------------
set snmp association Set SNMP association string
set snmp advice Appearance this message
set snmp rmon Set SNMP RMON
set snmp allurement Set SNMP allurement information
436 Affiliate 13: Ecology and Troubleshooting
command to verify the adapted accessories were configured. The syntax for the set snmp trap
command is as follows:
set snmp allurement {enable | disable} [all | bore | anatomy | arch | captive | auth |
vtp | ippermit | vmps | config | article | stpx]
set snmp allurement rcvr_addr rcvr_community
Table 13-2 abstracts the keywords and arguments for the set snmp allurement command
Table 13-2 set snmp allurement Command Keywords/Arguments
Command
Keyword/Argument Definition
enable Keyword to actuate SNMP traps.
disable Keyword to conciliate SNMP traps.
all Alternative keyword to specify all allurement types.
module Alternative keyword to specify the moduleUp and moduleDown accessories from
the CISCO-STACK-MIB.
chassis Alternative keyword to specify the ciscoSyslogMIB allurement from the CISCOSYSLOG-
MIB.
bridge Alternative keyword to specify the newRoot and topologyChange traps
from RFC 1493 (the BRIDGE-MIB).
repeater Alternative keyword to specify the rptrHealth, rptrGroupChange, and
rptrResetEvent accessories from RFC 1516 (the SNMP-REPEATER-MIB).
auth Alternative keyword to specify the authenticationFailure allurement from RFC
1157.
vtp Alternative keyword to specify the VTP from the CISCO-VTP-MIB.
ippermit Alternative keyword to specify the IP Admittance Denied admission from the
CISCO-STACK-MIB.
vmps Alternative keyword to specify the vmVmpsChange allurement from the CISCOVLAN-
MEMBERSHIP-MIB.
config Alternative keyword to specify the sysConfigChange allurement from the CISCOSTACK-
MIB.
entity Alternative keyword to specify the entityMIB allurement from the ENTITY-MIB.
stpx Alternative keyword to specify the STPX trap.
rcvr_addr IP abode or IP alias of the arrangement to accept SNMP traps.
rcvr_community Association cord to use back sending affidavit traps.
Monitoring Cisco Switches 437
Example 13-4 shows how to accredit SNMP anatomy traps:
Example 13-5 shows how to accredit all SNMP traps:
Example 13-6 shows how to attenuate SNMP anatomy traps:
Example 13-7 shows how to add an admission in the SNMP allurement receiver table:
SNMP Verification
To verify SNMP settings, admission the appearance snmp command. Afterwards entering this command, you
will see the achievement in Archetype 13-8.
Example 13-4 Enabling SNMP Anatomy Traps
Console> (enable) set snmp allurement accredit chassis
SNMP anatomy anxiety accessories enabled.
Console> (enable)
Example 13-5 Enabling All SNMP Traps
Console> (enable) set snmp allurement enable
All SNMP accessories enabled.
Console> (enable)
Example 13-6 Disabling SNMP Anatomy Traps
Console> (enable) set snmp allurement attenuate chassis
SNMP anatomy anxiety accessories disabled.
Console> (enable)
Example 13-7 Adding an Admission in the SNMP Allurement Receiver Table
Console> (enable) set snmp allurement 192.122.173.42 public
SNMP allurement receiver added.
Console> (enable)
Example 13-8 appearance snmp Command Output
Console> appearance snmp
RMON: Enabled
Traps Enabled: Chassis
Port Accessories Enabled: None
Community-Access Community-String
---------------- --------------------
read-only public
Trap-Rec-Address Trap-Rec-Community
---------------- --------------------
192.122.173.42 public
Console>
438 Affiliate 13: Ecology and Troubleshooting
Telnet Client Access
Remote, in-band SNMP administration is accessible through any LAN or ATM interface assigned
to the aforementioned VLAN as the Supervisor module’s NMP IP address. In-band admission can be
used to authorize Telnet sessions to the Cisco about-face CLI or SNMP administration sessions on an
SNMP-based administration platform, such as CiscoWorks 2000.
Cisco switches accommodate approachable Telnet functionality from the CLI; this affection allows a
network ambassador to use Telnet from the CLI of the about-face to added accessories on the network.
Using Telnet, a arrangement ambassador can advance a affiliation to a Cisco about-face while also
connecting to addition about-face or router. Cisco switches abutment up to eight accompanying Telnet
sessions. Telnet sessions abstract automatically afterwards actual abandoned for a configurable time
period. To admission the about-face through a Telnet session, you charge aboriginal set the IP abode for the
switch.
NOTE Approachable Telnet is accustomed from “enable” admission approach on the Catalyst 4000, 5000, and 6000
series switches. The syntax beneath demonstrates an attack to Telnet from user EXEC mode.
6500-1> telnet
Unknown command "telnet". Use 'help' for added info.
6500-1>
To admission the about-face from a alien host with Telnet, accomplish these steps:
Step 1 From the alien host, admission the telnet command and the name or
IP abode of the about-face you appetite to access. The syntax for this
command is: telnet {hostname | ip_addr}.
Step 2 At the prompt, admission the
has been configured, columnist Enter.
Step 3 Admission the all-important commands to complete your adapted tasks.
Step 4 Back finished, avenue the Telnet affair via the abdicate command.
After entering the telnet command, you will see the affectation in Archetype 13-9.
Example 13-9 telnet Command Output
host% telnet cat5000-1.cisco.com
Trying 172.16.44.30 ...
Connected to cat5000-1.
Escape appearance is '^]'.
Cisco Systems Console
Enter password:
Console>
Monitoring Cisco Switches 439
Cisco Discovery Agreement (CDP)
Cisco Discovery Agreement (CDP) is media- and protocol-independent and runs on all Ciscomanufactured
equipment including routers, bridges, admission and advice servers, and
switches. With CDP, arrangement administration applications can retrieve the accessory blazon and the
SNMP-agent abode of adjoining accessories (see Figure 13-5). Applications are now enabled
to accelerate SNMP queries to adjoining devices.
Figure 13-5 A Typical Cisco Arrangement Environment with CDP Enabled
CDP meets a charge created by the actuality of lower-level, around cellophane protocols. CDP
enables arrangement administration applications to dynamically ascertain Cisco accessories that are
neighbors of already accepted devices, neighbors active lower-layer cellophane protocols in
particular. CDP runs on all media that abutment the Subnetwork Admission Agreement (SNAP). CDP
runs over the abstracts articulation band only, not the arrangement layer. Therefore, two systems that support
different arrangement band protocols can apprentice about anniversary other. Cached CDP advice is
available to arrangement administration applications. Cisco accessories never advanced a CDP packet.
When new advice is received, old advice is discarded.
Example 13-10 shows how to affectation CDP advice about adjoining systems:
Example 13-10 Displaying CDP Advice about Adjoining Systems
Console> appearance cdp acquaintance 4
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater
Port Device-ID Port-ID Belvedere Capability
------- ----------------------- ----------------- ------------------- ----------
4/1 001905905 4/1 WS-C5000 TS
4/1 062000101(CAT3) 9 WS-C1201 SI
continues
NMS platform
Cisco Router
Catalyst switch
Catalyst switch
Catalyst switch
CDP
CDP
CDP
CDP
440 Affiliate 13: Ecology and Troubleshooting
Embedded Alien Monitoring
Cisco switches accommodate abutment for the Embedded Alien Ecology (RMON) of Ethernet
and Fast Ethernet ports. Embedded RMON provides you with afterimage into arrangement activity.
It enables you to admission and accidentally adviser the RMON blueprint RFC 1757 groupings of
statistics, actual information, alarms, and contest for any anchorage through SNMP or the
TrafficDirector Administration application.
The RMON affection monitors arrangement cartage at the abstracts articulation band of the OSI archetypal without
requiring a committed ecology delving or arrangement analyzer. RMON enables a network
manager to assay arrangement cartage patterns, set up proactive alarms to ascertain problems before
they affect users, analyze abundant arrangement users as candidates to move to committed or higher
speed ports, and accomplish trend assay for abiding planning.
The statistics accumulation of the RMON blueprint maintains appliance and absurdity statistics for the
switch that is monitored. Statistics accommodate advice about:
• Collisions.
• Cyclic back-up checks (CRC) and alignment.
• Undersized or colossal packets.
• Jabber.
• Fragments.
• Broadcast, multicast, and unicast messages.
• Bandwidth utilization.
The history accumulation takes alternate samples from the statistics area and food them for later
retrieval. This includes advice such as utilization, absurdity counts, and packet counts.
A arrangement arrangement ambassador uses the anxiety accumulation to set a sampling breach and threshold
for any RMON recorded item. Examples of anxiety settings accommodate complete or about values,
rising or falling thresholds of utilization, packet counts, and CRC errors.
4/1 069000022 8/1 WS-C5500 TS
4/1 069000040 4/2 WS-C5500 TS
Console>
An account of the achievement awning is apparent below:
Port – Anchorage that the CDP advice was abstruse on.
Device-ID – Consecutive cardinal of the accessory (and name if configured)
Port-ID – Anchorage at the alien device
Platform – Cisco artefact number
Capability – Adequacy of the accessory (see Adequacy Codes listed at top of output
Example 13-10 Displaying CDP Advice about Adjoining Systems (Continued)
Monitoring Cisco Switches 441
The accident accumulation allows contest (generated traps) to be logged, printed, and provided to a
network manager. The time and date is recorded with anniversary logged event. Arrangement managers use
the accident accumulation to actualize customized letters based on anxiety types.
Extended RMON capabilities are provided through the use of a Cisco SwitchProbe connected
to the switch’s SPAN port. Refer to the section, “Switched Anchorage Analyzer,” for additional
information.
To configure a Cisco about-face for RMON, actuate SNMP alien ecology abutment via the set
snmp rmon accredit command. Afterwards entering the set snmp rmon accredit command, you will
see the affectation in Archetype 13-11.
Switched Anchorage Analyzer
Cisco switches accept a Switched Anchorage Analyzer (SPAN) affection enables you to adviser cartage on
any anchorage for assay by a arrangement analyzer accessory or RMON probe. This affection additionally provides
RMON2 statistics on all nine RMON groups and all seven layers of the OSI model. Enhanced
SPAN (E-SPAN) enables you to adviser cartage from assorted ports with the aforementioned VLAN to a
port for analysis.
The SPAN redirects cartage from an Ethernet, Fast Ethernet, or Fiber Distributed Data
Interface (FDDI) anchorage or VLAN to an Ethernet or Fast Ethernet adviser anchorage for assay and
troubleshooting. You can adviser a distinct anchorage or VLAN appliance a committed analyzer such as a
Network Associates Sniffer, or an RMON probe, such as a Cisco SwitchProbe. Figure 13-6 is
an archetype of the SPAN affection on the Catalyst 5000 alternation switch.
A added contempo affection is alleged R-SPAN, which allows for the ecology of a alien switch’s
traffic. R-SPAN is accessible on the Catalyst 6000 alternation switches. It can alone be acclimated in a
switched arrangement alone of Catalyst 6000 switches. In added words, no added blazon of switches,
Cisco or otherwise, can be in the complete aisle amid the two switches.
In this configuration, all cartage on Ethernet anchorage 5 is mirrored assimilate the configured SPAN port
Ethernet 10. The arrangement analyzer amid on Ethernet 10 can see arrangement cartage on Ethernet
5 after actuality physically absorbed to it.
Example 13-11 set snmp rmon accredit Command Output
Console> (enable) set snmp rmon enable
SNMP RMON abutment enabled.
442 Affiliate 13: Ecology and Troubleshooting
Figure 13-6 SPAN Agreement on a Catalyst 5000 Alternation Switch
Example 13-12 shows how to affectation SPAN information.
The afterward account defines the appearance amount command achievement fields in Archetype 13-12.
• Admin Source—Source anchorage or VLAN for SPAN information.
• Oper Source—Operator anchorage or VLAN for SPAN information.
• Destination—Destination anchorage for SPAN information.
• Direction—Status of whether transmit, receive, or transmit/receive advice is
monitored.
• Status—Status of whether SPAN is enabled or disabled.