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Table Of Contents
SNMP Trap Support for the Virtual Switch Interface Master MIB
Overview of the SNMP Trap Support for the VSI Master MIB
VSI Components You Can Monitor with the VSI Master MIB
Supported Standards, MIBs, and RFCs
Verifying That the SNMP Agent Has Been Enabled
Using Commands to Enable the VSI Master MIB traps
Using SNMP MIB Objects to Enable the VSI Master MIB Traps
Setting Thresholds for Cross-Connects
SNMP Trap Support for the Virtual Switch Interface Master MIB
This feature module explains how to use the virtual switch interface (VSI) Master MIB to monitor and manage ATM switches that are connected to routers through the virtual switch interface.
This document includes the following major sections:
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Supported Standards, MIBs, and RFCs
Feature Overview
The VSI master is a software module that resides on a router. The VSI master enables an application to control an ATM switch that is connected to the router. The VSI protocol runs between the VSI master and a VSI slave. The VSI master can communicate with more than one slave across a control interface that connects the router to the switch. Each master/slave connection is called a VSI session. Figure 1 illustrates VSI sessions between a VSI master and slaves.
Figure 1 VSI Master and VSI Slaves
Overview of the SNMP Trap Support for the VSI Master MIB
The VSI Master MIB allows you to manage and monitor the activities of the VSI components, including controllers, sessions, logical interfaces, and cross-connects. The MIB provides notifications in the form of traps when any of the VSI components change operational state, violate configured thresholds, or are added or removed.
The MIB allows you to specify which VSI components can send traps. To enable the traps for certain VSI components, you can use the MIB objects or Cisco IOS commands. See the section "Enabling Traps" for more information.
VSI Components You Can Monitor with the VSI Master MIB
The VSI Master MIB allows you to monitor the operation of the switch. It also displays the results of the operations. Specifically, the VSI Master MIB allows you to monitor:
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MIB Traps
The VSI Master MIB allows you to enable traps on the following components:
Controllers—When VSI controllers are added or deleted
VSI sessions—When VSI sessions are established or disconnected
Logical interfaces—When logical interfaces become active or fail.
Cross-connects—When a cross-connect cannot be established.
Virtual circuits—When cross-connect resource thresholds are below configured thresholds.
MIB Objects
The following is a partial list of the supported MIB objects.
Controllers
You can obtain the following information about the controller:
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Sessions
You can obtain the following information about the VSI sessions:
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Logical Interfaces
Logical interfaces represent external interfaces that are available for connections. When you pair two external interfaces (represented by two logical interfaces), they provide a physical path through the switch. These physical paths support cross-connects. You can gather the following information about each logical interface:
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Cross-Connects
Cross-connects are virtual links across two interfaces. The participating interfaces that support these links are listed in the MIB's vsiLogicalIfTable entries. You can gather the following information about the cross-connects:
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Restrictions
The VSI Master MIB is for ATM-LSRs running Multiprotocol Label Switching (MPLS).
Related Documents
See the following documents for more information:
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http://www.cisco.com/public/mibs/v2/CISCO-VSIMASTER-MIB.my
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http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fswtch_c/swprt3/xcftagov.htm
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http://www.cisco.com/univercd/cc/td/doc/product/wanbu/9_3/bpx/bpxi23.htm#xtocid120351
Supported Platforms
This feature is supported on the following routing platforms:
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You can use the following ATM switches to configure an ATM-LSR:
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Supported Standards, MIBs, and RFCs
Standards
No new or modified standards are supported by this feature.
MIBs
Virtual Switch Interface Master MIB
http://www.cisco.com/public/mibs/v2/CISCO-VSIMASTER-MIB.my
For descriptions of supported MIBs and how to use MIBs, see the Cisco MIB web site on Cisco Connection Online (CCO) at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.
RFCs
No new or modified RFCs are supported by this feature.
Prerequisites
Memory Requirements
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Performance
The VSI cross-connect error messages can be invoked hundreds of times every second. To prevent a performance impact on the label switch controller (LSC), enable rate-limiting to control the amount of traffic that passes into or out of an interface.
Configuration Tasks
See the following sections for configuration tasks for the VSI Master MIB feature. Each task in the list indicates whether the task is optional or required.
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Enabling the SNMP Agent
The SNMP agent for the VSI Master MIB is disabled by default. To enable the SNMP agent, perform the following steps:
Verifying That the SNMP Agent Has Been Enabled
To verify that the SNMP agent has been enabled, perform the following steps:
Step 1
prompt# telnet 10.10.10.1Step 2
router# enableStep 3
router# show running-configuration......snmp-server community public ROIf you see any "snmp-server" statements, SNMP has been enabled on the router.
Enabling Traps
SNMP notifications can be sent as traps or inform requests. A trap is an unsolicited message sent by an SNMP agent to an SNMP manager, indicating that some event has occurred. You can enable SNMP traps for the VSI Master MIB through the command line interface (CLI) or through an SNMP MIB object. The following sections explain these options.
Using Commands to Enable the VSI Master MIB traps
To enable SNMP traps, use the snmp-server enable traps command. An SNMP agent can be configured to send traps when one of the VSI Master MIB objects changes. To enable VSI Master MIB traps to be sent from the agent to the manager, perform the following tasks in global configuration mode:
Table 1 lists the CLI commands for enabling traps of specific VSI components.
Table 1 CLI Commands that Control the Type of Traps You Receive
Using SNMP MIB Objects to Enable the VSI Master MIB Traps
You can also use MIB objects to specify which VSI components should send traps. To enable all VSI Master traps, use the vsiVSITrapEnable MIB object.
Controller Traps
To enable traps about the status of the controller, use the vsiControllerTrapEnable MIB object. Table 2 lists the MIB objects that are specific to the controller.
Table 2 Controller Traps
A controller is added
vsiControllerAdded
A controller is deleted
vsiControllerDeleted
VSI Session Traps
To enable traps about the status of the VSI sessions, use the vsiSessionTrapEnable MIB object. Table 3 lists the MIB objects that are specific to the VSI sessions.
Table 3 VSI Session Traps
A VSI session is established
vsiSessionUp
A VSI session is disconnected
vsiSessionDown
Logical Interaces
To enable traps about the status of the logical interfaces, use the vsiLogicalIfTrapEnable MIB object. Table 4 lists the MIB objects that are specific to the logical interfaces.
Table 4 Logical Interface Traps
A logical interface is active
vsiLogicalIfUp
A logical interface fails
vsiLogicalIfDown
Cross-connects
To enable traps about the status of the cross-connects, use the vsiXCTrapEnable MIB object. Table 5 lists the MIB objects that are specific to the cross-connects.
Table 5 Cross-connect Traps
A cross-connect cannot be established
vsiXCFailed
The LCN resources drop, possibly causing resource exhaustion.
vsiLcnExhaustionNotice
Setting Thresholds for Cross-Connects
When cross-connects on XtagATM interfaces are created or deleted, a counter keeps a tally of the available logical channel number (LCN) resources. If the LCN resources become too low, the MIB sends messages to alert you of the possibility of resource exhaustion.
You must first set the warning and alarm thresholds for the number of LCNs. To set the warning threshold, use the vsiAvailableChnlWarnThreshold MIB object. To set the alarm threshold, use the vsiAvailableChnlAlarmThreshold MIB object. The following list explains the usage guidelines of these MIB objects:
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The following list explains the conditions under which warnings, alarms, and other messages are sent. Figure 2 illustrates the thresholds.
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To prevent an overwhelming number of warnings or alarms from being generated durng a sampling period, only one warning or alarm is generated when the number of LCNs falls below the threshold. The number of LCNs must return to normal before another warning or alarm is generated.
Figure 2 Warning and Alarm Thresholds
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Configuration Examples
In the following example, the SNMP agent is enabled.
snmp-server communityIn the following example, SNMPv1 and SNMPv2C are enabled. The configuration permits any SNMP manager to access all objects with read-only permissions using the community string public.
snmp-server community publicIn the following example, read-only access is granted for all objects to members of access list 4 that specify the comaccess community string. No other SNMP managers have access to any objects.
snmp-server community comaccess ro 4In the following example VSI Master MIB traps are sent to the host cisco.com. The community string is restricted. The first line enables the router to send VSI Master MIB traps in addition to any traps previously enabled. The second line specifies the destination of these traps and overwrites any previous snmp-server host commands for the host cisco.com.
snmp-server enable traps vsi mastersnmp-server host cisco.com restricted vsimasterCommand Reference
This section documents new or modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.2 command reference publications.
snmp-server community
Use the snmp-server community global configuration command to configure read-only or read-write Simple Network Management Protocol (SNMP) community strings. Use the no snmp-server community command to change the community string to its default value.
snmp-server community string [view view-name] [ro | rw] [number]
no snmp-server community string
Syntax Description
Defaults
Read-only (ro)
The default value of the read-only community string is public, and the default value of the read-write community string is private.
Command Modes
Global configuration
Command History
Usage Guidelines
The no snmp-server command disables both versions of SNMP (SNMPv1 and SNMPv2).
The first snmp-server command that you enter enables both versions of SNMP.
Examples
In this example, the read-write community string is set to newstring:
hostname (config)# snmp-server community newstring rwIn the following example, the string comaccess to is assigned to SNMPv,1 allowing read-only access. IP access list 4 can use the community string:
snmp-server community comaccess ro 4In the following example, the string mgr is assigned to SNMPv1, allowing read-write access to the objects in the restricted view:
snmp-server community mgr view restricted rwThe following command removes the community comaccess:
no snmp-server community comaccessThe following command disables both versions of SNMP:
no snmp-serverRelated Commands
snmp-server host
Specifies the recipient of an SNMP trap operation.
snmp-server enable-traps
Enables the router to send SNMP traps.
snmp-server enable traps
To enable the router to send SNMP traps and informs, issue the snmp-server enable traps global configuration command. Issue the no form of this command to disable the sending of SNMP traps.
snmp-server enable traps [notification-type] [notification-option]
no snmp-server enable traps [notification-type] [notification-option]
Syntax Description
Defaults
This command is disabled by default. Most notification types are disabled. However, some notification types cannot be controlled with this command. For example, some notification types are always enabled. Other notification types are enabled by a different command.
For example, the linkUpDown notifications are controlled by the snmp trap link-status command.
If you enter this command with no notification-type keywords, the default is to enable all notification types controlled by this command.
Command History
Cisco IOS Release 11.1
This command first appeared.
Cisco IOS Release 12.2(2)T
The vsimaster keyword was added.
Usage Guidelines
Issue the snmp-server enable traps command to specify which SNMP traps the router sends, and issue the snmp-server host command to specify which host or hosts receive SNMP traps.
You must issue a separate snmp-server enable traps command for each trap type.
This command is useful for disabling notifications that generate a large amount of useless noise.
SNMP notifications can be sent as traps or inform requests. This command enables both traps and inform requests for the specified notification types.
If you do not enter an snmp-server enable traps command, no notifications controlled by this command are sent. To configure the router to send these SNMP notifications, you must enter at least one snmp-server enable traps command. If you enter the command with no keywords, all notification types are enabled. If you enter the command with a keyword, only the notification type related to that keyword is enabled. To enable multiple types of notifications, you must issue a separate snmp-server enable traps command for each notification type and notification option.
The snmp-server enable traps command is used with the snmp-server host command. Issue the snmp-server host command to specify which host or hosts receive SNMP notifications. To send notifications, you must configure at least one snmp-server host command.
For a host to receive a notification controlled by this command, both the snmp-server enable traps command and the snmp-server host command for that host must be enabled. If the notification type is not controlled by this command, just the appropriate snmp-server host command must be enabled.
The notification types used in this command all have associated MIB objects that allows them to be globally enabled or disabled. Not all of the notification types available in the snmp-server host command have notificationEnable MIB objects, so some of these notifications cannot be controlled wiyh the snmp-server enable command.
Examples
The following commands enable the router to send Frame Relay and environmental monitor traps:
snmp-server enable traps frame-relaysnmp-server enable traps envmon temperatureThe following commands enable the router to send all traps to the host myhost.cisco.com using the community string public:
snmp-server enable trapssnmp-server host myhost.cisco.com publicThe following commands enable the router to send Frame Relay and environmental monitor traps to the host myhost.cisco.com using the community string public:
snmp-server enable traps frame-relaysnmp-server enable traps envmon temperaturesnmp-server host myhost.cisco.com publicRelated Commands
snmp-server host
To specify the recipient of an SNMP notification operation, issue the snmp-server host global configuration command. The no form of this command prevents the specified host from receiving SNMP notifications. You must configure at least one host to receive notifications.
snmp-server host host [traps | informs] version {1 | 2c | 3 [{auth | priv}]}] community-string [udp-port port] [notification-type]
no snmp-server host host community-string [traps | informs]
Syntax Description
Defaults
This command is disabled by default. No notifications are sent.
If you enter this command with no keywords, the default is to send all trap types.
If you do not specify the version, the default is version 1.
If you do not specify traps or informs, traps are enabled.
The no snmp-server host command with no keywords disables traps, but not informs, to the host. To disable informs, issue the no snmp-server host informs command.
Command Modes
Global configuration
Command History
Cisco IOS Release 10.0.
This command was introduced.
Cisco IOS Release 12.2(2)T
The vsimaster keyword was added.
Usage Guidelines
When multiple snmp-server host commands specify the same host, the community string in the last command is used, and the notification types set in the last command filter the SNMP messages sent to that host.
To control which traps are sent by the router, issue the snmp-server enable traps command.
Whether a notification-type option is available or not depends on the router type and the Cisco IOS software features supported on the router. For example, the envmon keyword is available only if the environmental monitor is part of the system.
SNMP notifications can be sent as traps or inform requests. Traps are unreliable because the receiver does not send acknowledgments when it receives traps. The sender cannot determine if the traps were received. However, an SNMP entity that receives an inform request acknowledges the message with an SNMP response protocol data unit (PDU). If the sender never receives the response, the inform request can be sent again. Thus, informs are more likely to reach their intended destination.
However, informs consume more resources in the agent and in the network. Unlike a trap, which is discarded as soon as it is sent, an inform request must be held in memory until a response is received or the request times out. Also, traps are sent only once, but an inform can be retried several times. The retries increase traffic and contribute to a higher overhead on the network.
If you do not enter an snmp-server host command, no notifications controlled by this command are sent. To configure the router to send those SNMP notifications, you must enter at least one snmp-server host command. If you enter the command with no keywords, all trap types are enabled for the host. To enable multiple hosts, you must issue a separate snmp-server host command for each host.
You can specify multiple notification types in the command for each host.
When multiple snmp-server host commands are given for the same host and kind of notification (trap or inform), each succeeding command overwrites the previous command. Only the last snmp-server host command remains in effect. For example, if you enter an snmp-server host inform command for a host and then enter another snmp-server host inform command for the same host, the second command replaces the first.
The snmp-server host command is used with the snmp-server enable command. Issue the snmp-server enable command to specify which SNMP notifications are sent globally. For a host to receive most notifications, at least one snmp-server enable command and the snmp-server host command for that host must be enabled.
However, some notification types cannot be controlled with the snmp-server enable command. For example, some notification types are always enabled. Other notification types are enabled by a different command. For example, the linkUpDown notifications are controlled by the snmp trap link-status command. These notification types do not require an snmp-server enable command.
Examples
The following command sends the SNMP traps defined in RFC 1157 to the host cisco.com. The community string is comaccess.
snmp-server host cisco.com comaccess snmpThe following command sends the SNMP and Cisco environmental monitor enterprise-specific traps to address 172.30.2.160:
snmp-server host 172.30.2.160 snmp envmonRelated Commands
Glossary
agent—A process in the device that handles SNMP requests.
alarm—A message that is triggered when defined values cross a given threshold. For instance, you can specify the number of Ethernet collisions, plus a time interval, such as 1 second, and a threshold, such as 60 collisions. Given this scenario, an alarm is generated when the number of Ethernet collisions exceeds 60 in 1 second.
event—The action that is triggered as result of an alarm. Alarms and events are logically connected. For example, when the number of collisions on an Ethernet segment exceeds 60 per second, the corresponding event can cause a trap message to be sent to one or more management stations.
An event is generated by the RMON agent, which could be triggered by a threshold crossing. An event can be signaled as a trap, a new entry in the MIB log table, both, or neither.
inform request—A message sent by an SNMP agent to a network management station, console, or terminal to indicate that a significant event occurred. SNMP inform requests are more reliable than traps because an inform request acknowledges the message with an SNMP response protocol data unit (PDU). If the manager does not receive an inform request, it does not send a response. If the sender never receives a response, the inform request can be sent again. Thus, informs are more likely to reach their intended destination.
Management Information Base—See MIB.
MIB-Management Information Base. Database of network management information that is used and maintained by a network management protocol such as SNMP. The value of a MIB object can be changed or retrieved by SNMP commands, usually through a network management system. MIB objects are organized in a tree structure that includes public (standard) and private (proprietary) branches.
MPLS—Multiprotocol label switching. MPLS is a method for forwarding packets (frames) through a network. It enables routers at the edge of a network to apply labels to packets (frames). ATM switches or existing routers in the network core can switch packets according to the labels.
Multiprotocol Label switching—See MPLS.
Simple Network Management Protocol—See SNMP.
SNMP—Simple Network Management Protocol. Management protocol used almost exclusively in TCP/IP networks. SNMP provides a means to monitor and control network devices, and to manage configurations, statistics collection, performance, and security.
threshold—The range in which you expect your network to perform. If a performance exceeds or goes below the expected bounds, you can examine these areas for potential problems. You can create thresholds for a specific device.
trap—Message sent by an SNMP agent to a network management station, console, or terminal to indicate that a significant event occurred. Traps are less reliable than inform requests, because the receiver does not send an acknowledgment when it receives a trap. The sender cannot determine if the trap was received.
VSI—Virtual Switch Interface. A proposed common control interface to Cisco switches. The VSI can manage connections and discover configuration information about the switch.
VSI controller—A controller, such as a PNNI SVC controller, Portable AutoRoute or MPLS controller, that controls a switch using the VSI.
VSI master—A V process implementing the master side of the VSI protocol in a VSI controller. Sometimes the whole VSI controller might be referred to as a "VSI Master," but this is not strictly correct. Also, the VSI master is a device that controls a VSI switch, for example, a VSI Label Switch Controller.
VSI slave—A VSI slave is either of the following:
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