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Table Of Contents
Configuring RMON Alarms and Events
Collecting Group History Statistics on an Interface
Collecting Group Ethernet Statistics on an Interface
Understanding ML-Series Card CRC Error Threshold
Threshold and Triggered Actions
SONET/GFP Suppression of CRC-ALARM
Configuring the ML-Series Card CRC Error Threshold
Clearing the CRC-ALARM Wrap with the Clear CRC Error Command
Configuring ML-Series Card RMON for CRC Errors
Configuration Guidelines for CRC Thresholds on the ML-Series Card
Accessing CRC Errors Through SNMP
Configuring an SNMP Trap for the CRC Error Threshold Using Cisco IOS
Determining the ifIndex Number for an ML-Series Card
Manually Checking CRC Errors on the ML-Series Card
Configuring RMON
This chapter describes how to configure remote network monitoring (RMON) on the ML-Series card for the ONS 15454 SONET/SDH.
RMON is a standard monitoring specification that defines a set of statistics and functions that can be exchanged between RMON-compliant console systems and network probes. RMON provides you with comprehensive network-fault diagnosis, planning, and performance-tuning information. The ML-Series card features RMON and is designed to work with a network management system (NMS).
Note
For complete syntax and usage information for the commands used in this chapter, see the "System Management Commands" section in the Cisco IOS Configuration Fundamentals Command Reference, Release 12.2.
Note
This chapter consists of these sections:
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Understanding RMON
RMON is an Internet Engineering Task Force (IETF) standard monitoring specification that allows various network agents and console systems to exchange network monitoring data. You can use the RMON feature with the Simple Network Management Protocol (SNMP) agent to monitor all the traffic flowing among ML-Series card and other switches on all connected LAN segments.
For information on the MIBs supported by the ML-Series card, see the "Supported MIBs" section on page 22-5.
Figure 21-1 Remote Monitoring Example
Configuring RMON
These sections describe how to configure RMON on your ML-Series card:
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Default RMON Configuration
RMON is disabled by default; no alarms or events are configured.
Configuring RMON Alarms and Events
You can configure your ML-Series card for RMON by using the command-line interface (CLI) or an SNMP-compatible network management station. We recommend that you use a generic RMON console application on the NMS to take advantage of RMON's network management capabilities. You must also configure SNMP on the ML-Series card to access RMON MIB objects. For more information about configuring SNMP, see Chapter 22, "Configuring SNMP."
Beginning in privileged EXEC mode, follow these steps to enable RMON alarms and events. This procedure is required.
To disable an alarm, use the no rmon alarm number global configuration command on each alarm you configured. You cannot disable all the alarms that you configured by not specifying a specific number. You must disable each alarm separately. To disable an event, use the no rmon event number global configuration command. To learn more about alarms and events and how they interact with each other, see RFC 1757.
You can set an alarm on any MIB object. The following example configures RMON alarm number 10 by using the rmon alarm command. The alarm monitors the MIB variable ifEntry.20.1 once every 20 seconds to check the change in the variable's rise or fall until the alarm is disabled. If the ifEntry.20.1 value shows a MIB counter increase of 15 or more, such as from 100000 to 100015, the alarm is triggered. The alarm in turn triggers event number 1, which is configured with the rmon event command. Possible events can include a log entry or an SNMP trap. If the ifEntry.20.1 value changes by 0, the alarm is reset and can be triggered again.
ML_Series(config)# rmon alarm 10 ifInErrors.65539 20 delta rising 15 1 fall 0
Note
Where 65539 is the SNMP IfIndex for interface POS 0. You can get the SNMP ifIndex for a given port with an SNMP get. In the example output, you can see that the SNMP ifIndex for POS0 is 65539:
tuvoks-view:128> getmany -v2c 10.92.56.97 tcc@1 ifDescrifDescr.65536 = GigabitEthernet0ifDescr.65537 = GigabitEthernet1ifDescr.65538 = Null0ifDescr.65539 = POS0ifDescr.65540 = POS1ifDescr.65541 = SPR1tuvoks-view:129>The following example creates RMON event number 1 by using the rmon event command. The event is defined as High ifOutErrors and generates a log entry when the event is triggered by the alarm. The user jjones owns the row that is created in the event table by this command. This example also generates an SNMP trap when the event is triggered.
ML_Series(config)# rmon event 1 log trap eventtrap description "High ifOutErrors" owner jjonesCollecting Group History Statistics on an Interface
You must first configure RMON alarms and events to display collection information.
Beginning in privileged EXEC mode, follow these steps to collect group history statistics on an interface. This procedure is optional.
To disable history collection, use the no rmon collection history index interface configuration command.
This example shows how to collect and show RMON history for the owner root:
ML_Series(config)# interface gigabitethernet1ML_Series(config-if)# rmon collection history 2 owner rootML_Series(config-if)# endML_Series# show rmon historyEntry 2 is active, and owned by rootMonitors ifIndex.393217 every 1800 second(s)Requested # of time intervals, ie buckets, is 50,Collecting Group Ethernet Statistics on an Interface
Beginning in privileged EXEC mode, follow these steps to collect group Ethernet statistics on an interface. This procedure is optional.
To disable the collection of group Ethernet statistics, use the no rmon collection stats index interface configuration command.
This example shows how to collect RMON statistics for the owner root:
ML_Series(config)# interface gigabitethernet1ML_Series(config-if)# rmon collection stats 2 owner rootUnderstanding ML-Series Card CRC Error Threshold
The POS ports on the ML-Series card report alarms for SONET/SDH defects and GFP defects, including signal fail (SF) and signal degrade (SD) alarms. In most circumstances, these alarms alert the user to problems that also cause excessive CRC errors on the POS port. But there are situations where excessive CRC errors will occur on the POS port, but the link will not have any SONET defects or GFP defects to report. Examples of this situation include an ML-Series card at the other end of the link sending out packets with CRC errors or a bit error rate too low to trigger SF or SD defect, but high enough to cause a meaningful CRC packet error rate.
In these situations with a default ML-Series card Cisco proprietary RPR implementation and no reported SONET/SDH or GFP defects, the POS interface remains in the up state as a member of the shared packet ring (SPR) interface. Traffic is lost quietly and does not trigger any alarms or action.
The FCS threshold configuration and detection feature fixes this problem. The user can now configure the ML-Series card to raise an alarm if the percentage of packet loss due to CRC errors crosses a configureable threshold. The alarm raised is the CRC Threshold Crossing Alarm (CRC-ALARM), which is a service-affecting (SA) SONET/SDH alarm with a Major (MA) severity. Reported SONET/SDH alarms can be viewed under the Alarms tab of CTC.
The user can also configure the CRC-ALARM to trigger a link state down on the port and to wrap an Cisco proprietary RPR . By default, the CRC-ALARM is disabled. When the alarm is configured, the link down and wrap actions are still disabled by default. This feature is also supported on the ML-Series card Ethernet ports.
Threshold and Triggered Actions
The configureable threshold is not set with a BER, since variable frame lengths and varying percentages of bandwidth can impair the usefulness of this measure. Instead, the users configure a more relevant measure using CRC error rate as a percentage of the traffic. The available triggering thresholds are:
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The default threshold is a CRC error rate of 0.1% of the traffic. For voice and video traffic, an error rate of 1% is typically a critical issue and 0.1% is a major issue. Voice and video needs to trigger a wrap if the error rate is higher than 0.1% (1 error every 1000 packets). For normal data traffic, an error rate of 10% traffic is a critical issue, requiring an immediate fix, and 1% traffic is a minor issue.
The following actions occur after the detection of excessive CRC errors:
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SONET/GFP Suppression of CRC-ALARM
This detection of excessive CRC errors is independent of SONET/GFP defects. A problem may have the potential to trigger both the SONET/GFP defects and the CRC-ALARM. In this scenario, the SONET/GFP defect will trigger before the CRC-WRAP alarm because CRC error threshold detection is a slower process. If the SONET/GFP defect causes the link to go down, this link-down happens before the CRC-ALARM is detected, and it suppresses the CRC-ALARM. If the SONET/GFP defect that causes CRC-ALARM is not a link-down trigger and the CRC-ALARM is configured to take the link down, the CRC-ALARM will report and trigger the link down.
Clearing of CRC-ALARM
When the trigger action is disabled (default), the CRC-ALARM automatically clears when the error rate falls below the threshold for a significant time period.
When the trigger action is enabled, a CRC-ALARM requires a manual clear from the user. This is required because the wrap or link down caused by the alarm blocks both traffic and the CRC errors in the traffic from the port. So with no CRC errors, an automatic clear would occur even though the underlying problem, such as dirty fiber or a defective ML-Series card, still exists. Interface flapping can occur in this situation.
Before doing a manual clear, the user needs to determine the root cause of a CRC-ALARM and correct it. After that, the user has several alternative methods to manually clear the alarm:
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Unwrap Synchronization
The software on the ML-Series card raises the CRC-ALARM alarm on the POS interface that sees the errored frames. For unidirectional FCS errors, the user only needs to issue the unwrap command on the POS port at one end of the span, the one which raised the CRC-ALARM alarm. For bidirectional failures, both ends of the span raise the CRC-ALARM alarm and the user is required to issue the command once at each end of the span.
Since the POS ports at each end of the link are wrapped, removing the wrap (unwrapping) when the CRC-ALARM is cleared requires coordination. The software must also make sure that other errors that might cause wrapping are absent. The following examples illustrate this process for both unidirectional and bidirectional failures. For simplicity, the examples assume that excessive CRC errors is the only existing condition that might cause wrapping.
Unidirectional Errors
Figure 21-2 shows an Cisco proprietary RPR wrapped by excessive unidirectional CRC errors on POS port 0 of node E, which is also reporting the CRC-ALARM. This caused POS port 1 on node E and POS port 0 on node D to wrap. The figure captions further explain the process.
Figure 21-2 Wrapped Cisco proprietary RPR with Unidirectional Excessive CRC Errors
Figure 21-3illustrates the unwrap sequence for Figure 21-2. The traffic hit for the unwrap is dependent on the soak time required to declare PDI cleared on node D.
Figure 21-3 Unwrapped Cisco proprietary RPR with Unidirectional Excessive CRC Errors
Bidirectional Errors
Figure 21-4 shows a Cisco proprietary RPR wrapped by excessive bidirectional CRC errors, both ports are reporting CRC-ALARMs. The figure captions further explain the process.
Figure 21-4 Wrapped Cisco proprietary RPR with Bidirectional Excessive CRC Errors
Figure 21-5 illustrates the first part of the unwrap sequence for Figure 21-4. This occurs after the unwrap command is configured on node E. For unwrap in this bidirectional scenario, the user must configure the command on the POS ports at both ends of the link.
Figure 21-5 First Stage of Unwrapped Cisco proprietary RPR with Bidirectional Excessive CRC Errors
Node E has not unwrapped POS port 1 after the first CRC-ALARM clear command. Since node D continues to send PDI to node E, node E will raise the TPTFAIL alarm once the CRC-ALARM is cleared. At this point, the Cisco proprietary RPR is in a state similar to the unidirectional failure. The unwrap completes after the user issues the second unwrap command, as illustrated by Figure 21-5.
Figure 21-6 Second Stage of Unwrapped Cisco proprietary RPR with Bidirectional Excessive CRC Errors
Configuring the ML-Series Card CRC Error Threshold
Beginning in privileged EXEC mode, follow these steps to configure the ML-Series card CRC error threshold:
Clearing the CRC-ALARM Wrap with the Clear CRC Error Command
The Cisco IOS CLI clear crc alarm interface interface-type interface-number command is intended to clear the Cisco proprietary RPR wrap when it occurs due to FCS errors without corresponding SONET/SDH errors. It is not intended to unwrap wraps due to other causes, such as SONET/SDH defects or keep alive (KA) failures. If SONET/SDH or KA defects are present without FCS errors, the software rejects the command with an error message. When FCS errors are present and SONET/SDH or KA defects are present, the command is accepted by the software but the node unwraps only after all the failures have been fixed. In this case, the user does not need to reissue the command after the SONET/SDH or KA defect has cleared.
Note
Beginning in privileged EXEC mode, follow these steps to clear the ML-Series card CRC-ALARM:
Step 1
ML_Series # clear crc alarm interface interface-type interface-number
Clears the SONET/SDH CRC-ALARM and allows the Cisco proprietary RPR to unwrap when conditions are met.
Configuring ML-Series Card RMON for CRC Errors
The ML-Series card supports using an NMS for SNMP performance monitoring (PM), including monitoring cyclic redundancy check (CRC) errors. If the NMS supports periodic polling and programmed threshold values to monitor interface index errors (ifInErrors) for all the ML-Series card interfaces, you can manage and monitor CRC errors by relying on the NMS.
If the NMS does not support polling or if the desired polling frequency uses too much bandwidth, you can configure SNMP traps on the ML-Series card through the Cisco IOS CLI. This method is only for ML-Series cards on the ONS 15454 SONET/SDH. RMON capabilities for ML-Series cards on the ONS 15310-CL and ONS 15310-MA are best managed through Cisco Transport Controller (CTC), Transaction Language One (TL1), or Cisco Transport Manager (CTM) in the standard manner for the node.
Configuration Guidelines for CRC Thresholds on the ML-Series Card
These are the guidelines for determining the interface CRC errors (ifInErrors) threshold values for generating an NMS PM alert:
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Accessing CRC Errors Through SNMP
CRC errors for each interface are reported in the IF-MIB object ifInErrors (OID 1.3.6.1.2.1.2.2.1.14). Users can check the current value of ifInErrors through SNMP get requests. Each ML-Series card runs a separate instance of SNMP. SNMP requests are relayed to the individual ML-Series card based on the community string. The community string uses the following format:
com_str_configured_from_CTC@ml_slot_numberConfiguring an SNMP Trap for the CRC Error Threshold Using Cisco IOS
The ML-Series card supports RMON trap functionality in Cisco IOS. You must use the Cisco IOS CLI to configure RMON to monitor ifInErrors and generate a trap to an NMS when a threshold is crossed. The ML-Series card on the ONS 15454 SONET/SDH does not support the configuration of RMON traps through an SNMP set request, which typically initiates an action on a network device.
Beginning in privileged EXEC mode, follow these steps to configure RMON to monitor ifInErrors and generate a trap for an NMS when a threshold is crossed:
Step 1
configure terminal
Enter global configuration mode.
Step 2
rmon event number [log] [trap community] [description string] [owner string]
Add an event in the RMON event table that is associated with an RMON event number.
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Step 3
rmon alarm number ifInErrors.ifIndex-number interval {absolute | delta} rising-threshold value [event-number]
falling-threshold value [event-number]
[owner string]Set an alarm on the MIB object.
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Step 4
end
Return to privileged EXEC mode.
Step 5
show running-config
Verify your entries.
Step 6
copy running-config startup-config
(Optional) Save your entries in the configuration file.
Below is an example of configuring an SNMP trap for the CRC error threshold.
ML_Series # configure terminalML_Series(config)# rmon event 10 log trap slot15 owner configML_Series(config)# rmon alarm 9 ifInErrors.983043 300 delta rising-threshold 1000 10 falling-threshold 1000 10 owner configML_Series(config)# endML_Series # show running-configML_Series # copy running-config startup-configThe ifIndex number of an ML-Series card interface in decimal form used for the rmon alarm command in the example is ifInErrors.983043. This variable is the MIB object to monitor combined with the ifIndex number of an ML-Series card interface. For information on determining the ifIndex number for an ML-Series card, see the "Determining the ifIndex Number for an ML-Series Card" section.
Below is an example of a rising-threshold trap generated by 1002 ifInErrors crossing a threshold of 1000 in a 5-minute period.
2005-03-22 16:25:38 ptlm9-454e56-97.cisco.com [10.92.56.97]:SNMPv2-MIB:sysUpTime.0 = Wrong Type (should be Timeticks): 43026500SNMPv2-MIB:snmpTrapOID.0 = OID: RMON-MIB:risingAlarmRFC1271-MIB:alarmIndex.9 = 9RFC1271-MIB:alarmVariable.9 = OID: IF-MIB:ifInErrors.983043RFC1271-MIB:alarmSampleType.9 = deltaValue(2)RFC1271-MIB:alarmValue.9 = 1002RFC1271-MIB:alarmRisingThreshold.9 = 1000SNMPv2-SMI:snmpModules.18.1.3.0 = IpAddress: 10.92.56.97Determining the ifIndex Number for an ML-Series Card
When an NMS polls an ML-Series card for performance data, the NMS uses ifIndex numbers internally to consolidate interface data from multiple MIBs and associate this data with an interface name. The user can rely on the interface name and does not need to know the actual ifIndex number.
When you use the Cisco IOS CLI to configure the ML-Series card to generate traps directly, you do not have this associated name to use. You must use the actual ifIndex number for each interface being configured with a trap. To determine the actual ifIndex number, you can use an NMS to retrieve the ifIndex number of each ML-Series card interface and VLAN subinterface, or you can calculate the ifIndex number for the interface.
The user can also use a MIB browser (SNMP MIB definition lookup service) to examine the ifDescr for the appropriate ifIndex number. The ifIndex number from the ifDescr must be the ifIndex number for the desired port.
On an ML-Series card, the ifIndex number of Ethernet and POS interfaces is compiled from two pieces of information:
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The slot and port are combined to form the ifIndex using the following formula:
ifIndex = (slot * 10000h) + (port)
10000h is the hexadecimal equivalent number of 65536. The resulting ifIndex is a meaningful two-part number in hexadecimal, but seems confusing and arbitrary in decimal. For example, ifIndex E0002h is Slot 14, Port 2. This same number in decimal notation is 917506. The rmon alarm command requires the ifindex number in decimal form.
As an additional reference for calculating the correct ifindex value to use with the rmon alarm command, Table 21-1 lists the base ifindex number for Slots 1 to 17. The desired port number can be added to the slot base number to quickly determine the correct ifIndex number.
Manually Checking CRC Errors on the ML-Series Card
Users can also check the current count of ML-Series card CRC errors on an interface by using the show interface command. The example shows six total input errors, which are all CRC errors, in the last line of the output.
ML_Series(config)# show interface pos 0
POS0 is up, line protocol is upHardware is Packet/Ethernet over Sonet, address is 0005.9a39.713e (bia 0005.9a39.713e)MTU 1500 bytes, BW 48384 Kbit, DLY 100 usec,reliability 255/255, txload 1/255, rxload 182/255Encapsulation: Cisco-EoS-LEX, crc 32, loopback not setKeepalive set (10 sec)Scramble enabledARP type: ARPA, ARP Timeout 04:00:00Last input never, output never, output hang neverLast clearing of "show interface" counters neverInput queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0Queueing strategy: fifoOutput queue: 0/40 (size/max)5 minute input rate 34621000 bits/sec, 60083 packets/sec5 minute output rate 0 bits/sec, 0 packets/sec311190527 packets input, 931220183 bytesReceived 0 broadcasts (0 IP multicast)6 runts, 0 giants, 0 throttles0 parity6 input errors, 6 CRC, 0 frame, 0 overrun, 0 ignoredDisplaying RMON Status
Note
To display the RMON status, use one or more of the privileged EXEC commands in Table 21-3.
Example 21-1 shows examples of the commands in Table 21-3.
Example 21-1 CRC Errors Displayed with show rmon Commands
ML_Series# show rmon alarms
Alarm 9 is active, owned by config
Monitors ifInErrors.983043 every 300 second(s)
Taking delta samples, last value was 0
Rising threshold is 1000, assigned to event 10
Falling threshold is 1000, assigned to event 10
On startup enable rising or falling alarm
ML_Series# show rmon events
Event 10 is active, owned by config
Description is
Event firing causes log and trap to community slot15,
last event fired at 0y3w2d,00:32:39,
Current uptime 0y3w6d,03:03:12
Current log entries:
index uptime description
1 0y3w2d,00:32:39
Posted: Thu Nov 8 01:01:13 PST 2007
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