SNMP Quick Start Guide - SevOne NMS 5.7

SNMP Commands

SNMP Version 1

• snmpget operation: SNMP_MSG_GET

• snmpset operation: SNMP_MSG_SET

• snmpwalk operation: SNMP_MSG_GETNEXT

SNMP Version 2c

• snmpget operation: SNMP_MSG_GET

• snmpset operation: SNMP_MSG_SET

• snmpwalk operation: SNMP_MSG_GETBULK

  • non repeaters: 0

  • max repetitions: 20

SNMP Version 3

• snmpget operation: SNMP_MSG_GET

• snmpset operation: SNMP_MSG_SET

• snmpwalk operation: SNMP_MSG_GETBULK

  • non repeaters: 0

  • max repetitions: 20

SNMP Timeouts

• Timeout: 1 second

• Retries: 5

SNMP Atomic Indicator Types

Perform the following steps on the Object Types page to add and edit SNMP atomic indicator types.

1. In the Object Types hierarchy on the left, select the object type that you would like to create an indicator type for.

2. On the right side of the page, under Indicator Types, click Add Atomic Indicator Type to display th e Add SNMP Indicator Type pop-up . To edit an existing indicator type , select the indicator type and click under Actions .

   

3. In the Indicator Name field, enter the name of the indicator type.

   We recommend using the name of the OBJECT-TYPE definition from the MIB where this indicator is defined.

4. In the Description field, enter the name to display.

   You'll see the indicator description displayed in reports and elsewhere in the UI. Keep this in mind when creating the indicator description. For example, when you look at an object's indicators, you'll notice that they're listed based on the first word of their description. If you have the two indicators Queued Bytes and Tr ansmitted Bytes, they won't appear together. However, if you use the descriptions Bytes Queued and Bytes Transmitted, the indicators will appear in close proximity to each other.

5. In the Indexed By field, you'll see the OID that you defined for the object type. This field can't be edited.

6. For certain 64-bit OIDs, you can click the OID (high bits) to display the SNMP OID Browser, where you'll select an OID to describe the top 32 bits on the OID. Otherwise, this field will be greyed-out.

   OID High Bits - SNMP version 1 specifications allow for-32 bit, unsigned integer counters. A 32-bit counter increments up to around four billion, then wraps back to zero, and continues. SNMP version 2 introduced 64-bit unsigned integer counters, which can count much higher. 64-bit counters are far more powerful and accurate than 32-bit counters. Manufacturers had two options to incorporate 64-bit counters:

   • Create a new 64-bit OID to represent the same thing as the 32-bit version.

   • Create a second 32-bit OID that represents the high bits of the 64-bit version.

7. Next to OID, click to display the SNMP OID Browser. Perform the following actions.

   1. Navigate the OID tree hierarchy to select an OID to describe the object type expression.

   2. On the right side of the page, click Select OID.

8. Click the Indicator Type drop-down and select one of the following options:

   • GAUGE - for indicators that have specific values when polled.
     

   • COUNTER32 - for 32-bit indicators that continue to increment. If you select this option, you can select the Has Precalculated Deltas check box to total the delta/differences between polls. This provides the ability to graph things like the number of errors in a day, for example.

   • COUNTER64 - for 64-bit indicators that continue to increment. If you select this option, you can select the Has Precalculated Deltas check box.

9. Click the Measured As drop-down and select a data unit.

10. Click the Display As drop-down and select a display unit.

11. Next to Max Value Expression, click to display the SNMP OID Browser. Perform the following actions.

    When an indicator is reported as a percentage, this value is used to determine utilization percentages. If utilization values don't look right, make sure to double-check your input here.

    1. Navigate the OID tree hierarchy to select an OID to be the maximum value for the indicator type.

    2. On the right side of the page, click Select OID.

12. Click the Measured As drop-down and select a data unit.

13. Select the Default allowed for new devices check box to have the plugin poll this indicator type by default when the object type is enabled and when the plugin for a device is enabled.

14. In the Note field, enter any additional information you would like to include.

15. Click Save As New.

SNMP Synthetic Indicator Types

Using synthetic indicator types, you can create your own key performance indicators (KPIs) even when those KPIs–such as Percent Usage, Percent Loss, Percent Error, and Percent Idle–don't exist on a device. For example, let's say that you want to monitor voice gateways to find out which primary rate interface (PRI) is getting the most usage. Typical poll metrics can tell you the busy status of individual bearer channels, or B channels, but they can't tell you the sum of the statuses for all the B channels. This makes it difficult to find out the total usage of a particular PRI.

In SevOne NMS, you can create a single indicator type that tells you what percentage of a PRI is being used.

First, we need the following:

• An existing indicator type that tells us how many busy B channels there are for a given PRI. Let's call this BChannelsBusy.

• The total number of B channels for our PRI. That number is 23.

Using this information, we can create a synthetic indicator type with an expression to perform the following calculation:

(BChannelsBusy*23)/100

Now we have a new indicator type–a synthetic indicator type–that tells us what percentage of the PRI is being used. There's no need to look up the number of busy B channels and perform calculations manually.

Perform the following steps on the Object Types page to add and edit SNMP synthetic indicator types.

1. If you're not already on the Object Types page, go there.
   

2. In the Object Types hierarchy on the left, c lick on an object type to display its indicator types on the right. If the object type doesn't have any indicator types, the Add Synthetic Indicator Type button won't appear.

3. Click Add Synthetic Indicator Type to display the Add Synthetic Indicator Type pop-up. To edit an existing synthetic indicator type, select the indicator type and click under Actions.

   

4. In the Indicator Name field, enter the name of the synthetic indicator type.

5. In the Description field, enter the name to display.

6. The Synthetic Indicator Expression field is where you define the calculation. Perform the following actions to create the expression for this field.

   A red border around the Synthetic Indicator Expression field indicates that your calculation is invalid. This also means that your graph results will be incorrect.

   1. In the Available Source Indicators field on the right, select an indicator type to use in the expression. Drag and drop it into the Synthetic Indicator Expression field.

      The Available Source Indicators field contains the indicator types for the object type that you selected a few steps ago.

   2. Next, enter the applicable operators to formulate your calculation in the Synthetic Indicator Expression field. For a list of available operators, see Acceptable Operators below.

   3. Drag any additional indicator types from the Available Source Indicators field and enter additional mathematical symbols to complete the expression in the Synthetic Indicator Expression field.

7. The Maximum Value Expression field lets you define a maximum value calculation for the indicator type. Perform the following actions to create the expression for this field.

   1. In the Available Source Indicators field on the right, select an indicator type to use in the expression. Drag and drop it into the Maximum Value Expression field.

   2. Next, enter the applicable operators to formulate your calculation in the Maximum Value Expression field. For a list of available operators, see Acceptable Operators below.

   3. Drag any additional indicator types from the Available Source Indicators field and enter additional mathematical symbols to complete the expression in the Maximum Value Expression field.

8. Click the Measure As drop-down and select a data unit.

9. Click the Display As drop-down and select a display unit.

10. Select the Default allowed for new devices check box to have the plugin poll this indicator type by default when the object type is enabled and when the plugin for a device is enabled.

11. In the Note field, enter any additional information you would like to include.

12. Click Save As New.

Acceptable Operators

Your expression formula can include the following characters:

• + add

• - subtract

• * multiply

• / divide

• && logical AND

• || logical OR

• <= less than or equal to

• >= greater than or equal to

• ! not equal to

• == equal to

• > greater than

• < less than

• ^ raise x to the power of y

• % modulus

• ?: if...then...else

• isnan is Not a Number. This evaluates to 1 if the value is not a number. Otherwise, it evaluates to 0.

• isValid is valid. This evaluates to 1 if the value has been discovered and is not isnan. Otherwise, it evaluates to 0.

• useIfValid use if valid. This evaluates to the value if it has been discovered and is not isnan. It evaluates to the second argument otherwise.

If your calculation results in either of the following invalid values, there will be a gap in your graph:

• Not a Number (NAN)

• Infinity (+/-INF).

The following describes how SevOne NMS attempts to prevent invalid values. These are listed in the order that they're processed.

• Zero divided by zero results in NAN.

• Any positive value divided by zero results in +INF.

• Any negative value divided by zero results in -INF.

• Zero multiplied by +/-INF results in NAN.

• Any value added to, subtracted from, multiplied by, divided by, or divided from NAN results in NAN.

• Any value compared to NAN (<, <=, ==, >=, >) results in 0. NAN != NAN.

• Any value compared to +INF is less than +INF, except that +INF == +INF

• Any value compared to -INF is greater than -INF, except that -INF == -INF

• Any value added to or subtracted from +INF results in +INF

• Any positive value multiplied by +/-INF results in +/-INF

• Any value divided by +/-INF results in 0

SNMP OID Browser

The SNMP OID Browser enables you to select the OID you use to create SNMP object types and SNMP traps. You can access the SNMP OID Browser from an SNMP object type definition workflow or from a trap event configuration workflow. In fact, we worked with the SNMP OID Browser a bit earlier when we looked at object types. You can also access the SNMP OID Browser from the navigation bar.

Perform the following steps to explore the SNMP OID Browser.

1. From the navigation bar, click Administration and select Monitoring Configuration, then SNMP OID Browser.

   

2. Notice the OID Tree section, which displays the OID hierarchical structure. The Search field allows you to filter the list of OIDs by name or by number.

3. Navigate the OID tree hierarchy and select an OID to display more information on the right. The following is an example of the OID information section.

   

   The OID information section provides the following information.

   • [Name] - the OID name, which appears at the top of the section.

   • OID - the OID number.

   • Access - the type of access available for the OID, such as Read, Read/Write, etc.

   • Type - how the OID is encoded into various SNMP structures, for example, as String, Integer, etc.

   • Status - the OID status, for example, Current, Deprecated, or 0 (no status).

   • Description - the OID description.

MIB Manager

The Management Information Base (MIB) is a hierarchical database shared between the SNMP agent and the SNMP manager. It contains managed objects for devices, and OIDs are used to uniquely identify each object in the MIB. The MIB Manager enables you to view MIB details and to add MIBs.

Perform the following steps to view and manage MIBs.

Explore the MIB Manager

1. From the navigation bar, click Administration and select Monitoring Configuration, then MIB Manager.

   

2. The MIB list includes the following information about the MIBs.

   • MIB Name - displays the MIB name.

   • File Size - displays the size of the MIB file.

   • Revision - displays the number of times you've uploaded the MIB to SevOne NMS.

   • Date Added - displays the date the MIB was added.

   • Date Updated - displays the date the MIB was most recently edited.

3. Perform the following actions to search for specific MIBs.

   1. Click the Search drop down and select the check box for each column that you would like to include in the search. By default, all columns are selected.

   2. In the Search text field, enter all or part of the text to search for in the column(s) that you specified.

4. Click on any MIB in the MIB Name column to view information about it in the MIB Viewer pop-up.

   

Upload MIBs

1. At the top of the page, click Add MIBs to display the MIB Uploader pop-up.

   

2. Click Select MIB(s)... to display the file uploader pop-up.

3. Navigate the folder structure and select a MIB. To add multiple MIBs, zip the MIB files into a .zip file and select that .zip file.

4. After selecting a file, click Open.

5. On the MIB Uploader pop-up, click Upload.

6. A green bar will appear at the top of the page to confirm your upload. It may take up to thirty minutes for the change to take effect.

Download MIBs

1. Select the check box next to the MIB you want to download.

2. Right-click on the selected MIB to display options.

   

3. Select Download.

Delete MIBs

1. Select the check box for the MIB that you want to delete.

2. Right-click on the selected MIB to display options.

   

3. Select Delete.

Using Device Types

The device type concept lets you organize devices for polling purposes. This expedites policy definition and allows you to run manufacturer-independent reports for similar but not identical objects. By using device types, you can associate a collection of object types to multiple devices. Each device can belong to multiple device types. For end users, device types appear in all device group lists and provide an additional method to secure, sort, and filter devices.

You can define rules to automatically add devices–across multiple manufacturers/products–that implement the same MIBs to device types. When you create device types, you specify the metrics that you want to poll. During discovery, the device type rules add these devices.

The Device Type Hierarchy

Let's take a look at the Device Type hierarchy.

1. From the navigation bar, click Administration and select Monitoring Configuration, then Device Types.

   

2. The Device Type hierarchy appears on the left.

3. Next to Generic, click to expand the section.

You can drag and drop device types to move them to different locations within the device type hierarchy.

Add a Device Type

Perform the following steps to add a device type.

1. Select the device type that you'd like to add a new device type under.

2. At the top of the page, click Add Device Type to display the Add Device Type pop-up.

   

3. In the Device Type Name field, enter the device type name.

4. Click Save.

To edit a device type name or delete a device type, select the device type and click either or under Actions.

Manage Metadata Values

Perform the following steps to edit a device type's metadata values. For more information on SevOne NMS Metadata, please see our documentation on the topic.

1. Select a device type and click to display the Edit Metadata pop-up.

   

2. Select the attribute that you'd like to edit, then click under Actions to edit the the Value field.

   

3. Click Update to save the value.

4. Click Save.

Device Type Membership Rules

Perform the following steps to manage device type membership rules.

1. In the Device Type hierarchy on the left, select a device type.

2. In the upper right part of the page, view existing device type rules.

   

3. Click Add Rule to display the Add Device Type Membership Rule pop-up.

   

4. Provide input for one (or more) of the following fields.

   Each rule requires input for only one field. If you populate several fields for a single rule, the device being added will have to meet the criteria of ALL those fields. For example, let's say you've entered Remote in the Device Name field and ^192\.168 in the Management IP Address field for a rule. Because you entered both of these in the same row, the device must have both Remote in the name and an IP address that starts with 192.168 to be added to the device type.

   • Device Name - the device name (wild cards are implied).

   • Device Description - the device description.

   • Management IP Address - the IP address of the device (^192\.168 adds any device whose IP address starts with 192.168).

   • sysDescr - the text you get when you SNMP walk the sysDescr OID.

   • sysContact - the text you get when you SNMP walk the sysContact OID.

   • sysLocation - the text you get when you SNMP walk the sysLocation OID.

   • sysName - the text you get when you SNMP walk the sysName OID.

   • sysObjectID - the text you get when you SNMP walk the sysObjectID OID.

   • Walkable OID - the number of the OID to walk. Make sure that the OID can actually be walked. You may be able to get an OID and get a response. However, if you walk an OID and the result from the snmpgetnext falls outside of the OID tree, discovery won't add the device to the device type.

     Example:

     getnext .1.3.6.1.2.1.1.1.0 – get .1.3.6.1.2.1.1.2.0 - doesn't match the pattern .1.3.6.1.2.1.1.1.0.X

     getnext .1.3.6.1.2.1.1.1 – get .1.3.6.1.2.1.1.1.1 - does match the pattern .1.3.6.1.2.1.1.1.X

5. Click Save.

Object Types tab

Use the Object Types tab to associate the SNMP object types that you want the SNMP plugin to try to poll on the devices that are members of a given device type.

1. In the Device Type hierarchy on the left, select a device type.

2. In the lower right part of the page, the Object Types tab displays by default.

3. Select the check box for each object type to poll on the devices that are members of the device type.

   

4. Click Associate to associate the object types to the device type.

Device Type Membership tab

When you select a device type in the Device Type hierarchy, the Device Type Membership tab displays a list of its member devices. You can pin devices to device types. You can also create a rule to add device types, as we looked at earlier (in the Device Type Membership Rules section). When you add a device by pinning it, its membership isn't affected by rules. To remove a pinned device, you'll need to manually unpin it. On the other hand, devices that are added by a rule can automatically be removed if you change that rule later.

Next to each device, under Pin, you'll see one of the following icons. These indicate how the device became a member of the device type.

• - indicates that the device was pinned to the device type at this level.

• - indicates that the device was added by a device type membership rule at this level.

Membership Management

You can pin devices that are already members of the device type. You can also can pin devices that aren't members of the device type.

Pin member devices

1. In the Device Type hierarchy on the left, select a device type.

2. In the lower right part of the page, select the Device Type Membership tab.

3. Member devices are listed on the tab. Select the check box for each device that you want to pin to the device type.

4. Click and select Pin Selected Devices.

Pin non-member devices

1. In the Device Type hierarchy on the left, select a device type.

2. In the lower right part of the page, select the Device Type Membership tab.

3. Click Pin Devices to display the Pin Devices pop-up, which lists all devices in SevOne NMS.

   

4. Select the check box for each device that you want to pin to the device type.

5. Click Pin to Type.

Unpin devices

1. Select the check box for each device that you want to unpin.

2. Click Unpin Devices.

3. When the Remove From Membership pop-up appears, click Yes to unpin and remove the selected devices.

View Metadata

To view metadata information for a device, select the device and click under Actions.

SNMP Walk Output

The following is a sample SNMP walk of the RFC1213 MIB for a particular device to illustrate what an SNMP walk might look like.

All of these OIDs refer to three interfaces, identified by the final number of each OID. In this case, these include 1 (for Ethernet3/0), 2 (for Serial3/0), and 8 (for Loopback0). The information about each particular interface is interleaved with that of the others.

If you wanted to find out whether Ethernet3/0 is up or down, for example, you would perform the following steps.

1. Search every ifDescr entry until you find the one whose value matches Ethernet3/0.

2. Remember the index (the last number) for it.

3. Check the value for ifOperStatus using that index.

Logged Traps

When SevOne NMS receives SNMP traps that you've defined a trap event for, these traps appear in the Logged Trap page. Logged traps have a trap event. The Cluster Manager enables you to define how long to save logged traps.

Let's look at the Logged Traps page. From the navigation bar, click Events and select Archives, then Logged Traps.

Filter

Using filters lets you limit the traps that appear in the list. All filters are optional and cumulative.

Traps

The logged traps list displays logged traps from most recent to oldest. The following information is provided in the log.

• IP Address - displays the IP address that the trap was sent from.

• Time - displays the time that SevOne NMS received the trap.

• OID - displays the OID that met the conditions for the trap event.

• Variable Number - displays the number of variable conditions associated with the trap.

Variables

Click on a trap to display the following information in the Variables section, which appears to the right of the Traps log.

• Variable - displays the name of the variable.

• Type - displays the variable type.

• Value - displays the value that triggers the trap.

Unknown Traps

There are some SNMP traps that no trap events apply to. These traps appear on the Unknown Traps page and are less meaningful than traps that you define a trap event for. As we mentioned earlier, when you define a trap, you assign real meaning to it. You can define trap events for the traps on this page that are specific to your environment. The Cluster Manager enables you to define how long to save unknown traps.

Let's look at the Unknown Traps page. From the navigation bar, click Events and select Archives, then Unknown Traps.

The sections Filter, Traps, and Variables contain the same fields as the Logged Traps page, which we just looked at.

Configure Trap Event

On the lower half of the page, under Trap Manager, there's a Configure Trap Event button. When you click on a trap from the list, the button becomes available.

If you click on the Configure Trap Event button, the Edit Trap Event pop-up appears, where you can define a trap event for the trap that you selected. Once you've defined a trap event for it, the trap is handled in the way you specify, and future trap occurrences appear on the Logged Traps page, when applicable. We'll look at the Trap Event Editor next.

Trap Event Editor

Using the Trap Event Editor, you can configure how SevOne NMS handles traps. Traps that you associate to a trap event can appear on the Logged Traps page, while traps without a trap event appear on the Unknown Traps page. SevOne NMS provides a collection of common default trap events.

Let's look at the Trap Event Editor. From the navigation bar, click Events and select Configuration, then Trap Event Editor.

Filter

Using filters lets you limit the traps that appear in the list. All filters are optional and cumulative. Each trap has a primary OID, which designates the trap type. Each trap event has a target OID. When the primary OID of the trap matches the target OID of the trap event–as well as any trap event variable conditions you define–the trap triggers the trap event.

Add a trap event

There are a couple ways to add trap events. You can add a new trap event, or you can define a trap event for an unknown trap (from the Unknown Traps page, which we just looked at).

Perform the following steps to add (or edit) a trap event.

1. On the lower half of the page, under Events, click Add Trap Event to display the Add Trap Event pop-up. To edit an existing trap event, select the trap event and click under Actions.

   

2. Select the Enabled check box to enable the trap event. If you leave the box clear, the trap event won't be applied, and applicable traps will appear on the Unknown Traps page.

3. The Match section enables you to apply the trap event to a specific OID as well as specific device groups/device types and devices. Matching is a logical OR option, meaning that the trap primary OID must come from the specified device group/device type or device to trigger the trap event. To make the trap event applicable for all device groups/device types and devices, don't define any Match options. The following options are available.

   • Target OID. Click to access the SNMP OID Browser, where you can select the target OID for the trap event. When you edit a trap event or access the Trap Event Editor from the Unknown Traps page, this field displays the name of the OID you select. You can manually enter the OID name in this field if you know it.

   • Device Groups. Click the drop-down to display device groups and device types. Then select the check boxes for the device groups/device types that you want to associate with the trap event.

   • Devices. Click the drop-down to display devices. Then select the check boxes for the devices that you want to associate with the trap event.

4. The Variable Conditions field enables you to define the conditions that the trap event is applicable for. Perform the following actions to add a condition.

   1. Click Add to add a row to the table and to define a new variable condition.

      

   2. Under OID, click to display the SNMP OID Browser, where you select the trap target OID.

   3. Click the Op drop-down and select a comparison operator.

   4. In the Value field, enter the value that has to be met to associate the trap to the trap event.

   5. Click Update to save the variable condition.

   6. Repeat to add additional variable conditions. All variable conditions for a trap event are ANDed together.

5. The Unique OIDs field enables you to designate unique OIDs to associate to the trap event. Perform the following actions to add a condition.

   1. Click Add to add a row to the table and to add an OID.

      

   2. Under OID, click to display the SNMP OID Browser, where you select the OID.

   1. Click Update to save the OID with the trap event.

   2. Repeat to add additional OIDs.

6. On the right side of the pop-up, under Actions, select the Log check box to display the trap on the Logged Traps page.

   As a rule, all traps received appear on either the Unknown Traps page or the Logged Traps page. To prevent a trap from appearing on either of these pages, define an enabled trap event and leave this check box clear. While there's plenty of benefit in logging traps, you may choose not to log particular traps. For example, let's say that you've set up specific devices to send traps when traffic is denied through a firewall rule. A logged trap is useful here because it lets you trace the events to a firewall in order to determine what caused the missed traffic. There are other cases when you might not want to log traps. For instance, frequent but irrelevant traps, such as those that occur each time a new IP address is leased via DHCP, may not be useful.

7. Select the Alert check box to have the trap trigger an alert and perform the following actions.

   1. Next to Alert, click the drop-down and select the alert severity to display.

   2. Below that, in the text field, enter the message to appear for the trap when the trap event triggers. You can use the following variables in the message. This field contains a default message. Hover over the message to display a legend containing information about the available variables. You can change this message or replace it with new text to suit your specific needs.

   • $dev - to display the name of the device that the trap came from.

   • $oid - to display the trap target OID in name format.

   • $oidnum - to display the trap target OID in number format.

   • $var - to display the variable condition for the trap in name format.

   • $varnum - to display the variable condition for the trap in number format.

   • $n - where n is an integer representing a variable binding, or varbind, to display the varbind received in the trap. For example, $1 would display the first varbind. $2 would display the second varbind, and $3, the third, etc.

   • ${numericOID} - to display the value of the varbind represented by the numeric OID that you specify. Replace numericOID with the full numeric representation of the OID, including the leading dot, for example: ${.1.3.6.1.4.1.4055.1.2.1}.

   • ${alphaOID} - to display the value of the varbind represented by the alphanumeric OID that you specify. Replace alphaOID with the name of the object identifier that represents the value, for example: ${ifName} . Note that the appropriate MIB must be loaded on the SevOne appliance for a varbind to be represented by an alphanumeric name as opposed to a numeric OID.

     When specifying variable OIDs (varbinds), it is helpful to review Unknown Traps. From there you can search for and identify any previous traps that have been received and the variables (varbinds) that were received with the trap.

8. Select the Email check box to enable the Email fields and perform the following actions.

   1. Select the Mail Once check box to send one email when a trap triggers the first occurrence of the trap event. Subsequent occurrences won't be emailed.

   2. Click the Users drop-down and select the users who will receive an email when the trap event triggers.

   3. Click the Roles drop-down and select the user roles to receive an email when the trap event triggers.

   4. In the Email Addresses field, click Add to enter the email addresses where an email is to be sent when the trap event triggers.

      

   5. Click Update.

9. Click Save.

Trap Destinations

The Trap Destination page lets you specify where SevOne NMS sends traps to. Trap destinations can be third-party applications, such as your company’s event console or fault management system, for example. Each trap can be sent to multiple destinations.

Perform the following steps to add (or edit) a trap destination.

1. From the navigation bar, click Events and select Configuration, then Trap Destinations.

   

2. Click and select Add New Destination to display the Trap Destination Settings pop-up. To edit an existing destination, select the check box for it, click , and select Edit Selected.

   

3. In the Destination Name field, enter the trap destination name.

4. In the IP Address field, enter the IP address of the trap destination device.

5. In the Port Number field, enter the port number to send the trap to.

6. In the SNMP Read Community String field, enter the read community string that SevOne NMS needs to authenticate onto the device.

7. Click the SNMP Version drop-down and select an SNMP version.

8. Select the Default check box to send traps to the destination by default. You can designate multiple default trap destinations. You can also define individual thresholds and policies to not use a default destination for specific traps.

9. Select the Enable check box to enable the trap destination.

10. Click Save.

Trap Destination Associations

The Trap Destination Associations page lets you associate devices or device groups/device types with the trap destinations you define on the Trap Destinations page. SevOne NMS sends traps from devices or device groups/device types to their associated trap destinations.

Perform the following steps to configure trap destination associations.

1. From the navigation bar, click Events and select Configuration, then Trap Destination Associations.

   

2. Click the Grouping drop-down and select one of the following options.

   • Device Group - to associate all the devices in a device group or device type to trap destinations.

   • Device - to associate an individual device to trap destinations.

3. To the right of that, click the Device Group or Device drop-down and select the device group/device type or the device that you want to associate the trap destinations to.

4. In the Unassigned Trap Destinations field, select the trap destinations to associate to the device group/device type or device.

5. Click to move the trap destinations you select to the Assigned Trap Destinations field. Traps are sent from the device group/device type or device to the trap destinations listed in the Assigned Trap Destinations field.

6. In the Assigned Trap Destinations field, select a trap destination and click one of the following buttons.

   • Enable - to enable the association of a trap destination that's currently disabled.

   • Disable - to save the trap association but suspend sending traps to the destination. Disabled trap destinations appear in light text.

Human breakdown

So what does this mean? Let's consider the following example.

SevOne NMS discovers and polls a router with two network cards with two ports on each.

All objects belong to the Interfaces object type.

Each port is an object.

You rename the ports on the router. Upon rediscovery, the SNMP plugin continues to poll the objects with no change or data loss as long as you don't change the object description or the SNMP index.

You remove the first card from the router. The router automatically renames each port. Upon rediscovery, the SNMP plugin continues to poll the objects with no change or data loss as long as you don't change the description or the index.

You add the card back to the router within the number of Days Until Delete setting in the Cluster Manager. The router automatically changes the object name.

You decide to rename port four and change its description.

How OIDs Are Indexed

Device manufacturers name SNMP OIDs using a series of numbers. For example, the OID sysDescr is .1.3.6.1.2.1.1.1. Everything that comes after a named OID is the OID index. System-wide information is usually denoted as .0 information. The .0 generally means there is only one instance of the OID. For example, the sysDescr index is always .0. The OID ifDescr is indexed by a single number that is not 0. For example, the description of an Ethernet card in a server might be ifDescr.3. There's no limit to the count of numbers that follow an OID. Some manufacturers use integer indexes that have a constant amount of numbers following each OID, and some manufacturers use string indexes for readability. A string index represents a piece of text (the string) as a series of characters where each character is represented as its ASCII value. String indexes are sometimes prefixed with the length of the string.

Index Types

Integer - A single number of any size.

• For example, this could be a simple integer, such as 7, which could be used for an interface index.

String (with length) - A string of text, prefixed with the number of characters and followed by the ASCII value of each character.

• For example, the text CPU is the number of characters (3) followed by the ASCII value of each, which would be 3.67.80.85.

String (no length) - A string where the length is not prefixed.

• For example, the text CPU in ASCII values without the number of characters would be 67.80.85. Compare to the previous example.

Number (with length) - A string index where the numbers don't have an ASCII meaning.

• For example, the IP address 4.192.158.0.1 includes its length (4) before the octets.

Number (no length) - A string index with no length and where the numbers don't have an ASCII meaning.

• For example, the IP address 192.158.0.1 appears as a series of integer indexes and contains no information about its length. Compare to the previous example.

Scripts

An S3 script is a sequential evaluation of one or many statements. Each statement is executed in sequence. The only logic provided by S3 comes from flavors of the ternary operator, which acts like an IF statement. The final result of the script is the result of the final statement in the script.

S3 OID Handling

OIDs are evaluated. Anything that isn't text, a variable, an operator, a normal number, or otherwise a special symbol is considered an OID. When an OID is evaluated, it evaluates to the value of the OID on the current device. If the OID isn't present on the device, the OID, followed by the default SNMP index, is used instead. If the OID can't be evaluated, it evaluates to the empty string.

It's critical to note here that a variable without backticks around it is treated exactly as it would be if the value of the variable were to be used instead. This means that a variable that contains a string representation of an OID is evaluated as that OID when it's encountered.

The following example might not work as anticipated.

Symbols

Symbols are special tokens (characters or collections of characters) that have a special function in S3.

Precedence

The precedence of operators and symbols is as follows. When given the choice (that is, when parentheses aren't used), S3 evaluates operations in the following sequence.
The normal mathematical operator precedence (* / + -) is preserved in this list.

Variable Assignment Example

The following examples assign the proper values to variables. The name of each variable matches its value.

Full Examples

Object Context

The main purpose of S3 is to define ways to describe specific objects from a generic set of rules. As the SNMP discover script goes through the possible object types, it generates a list of individual object indexes for each object type. The rules for that object type are applied to each index that it encounters in order to generate a unique object per index.

The following SNMP Object Editor fields are evaluated, in order, for each object.

Before any evaluation happens, the [INDEX] variable is set to the SNMP index of the current object. This is a vector variable. Each index in the vector corresponds with each specific index key defined for this object type. Each of those could also be a vector. Because of the sequence that the system variables are generated in, S3 generates an error if a variable is used before it's generated.

Indicator Context

The Expression field in the SNMP Indicator Editor for a particular indicator is also an S3 expression. Indicators should not set variables. The Maximum Value Expression field is also an S3 expression.

An indicator expression and maximum value expression can use any of the variables defined above for the object, including any user-defined variables in the Variables field.

This enables an indicator definition to get around any strange indexing (including out-of-order indexing) by using S3 to assemble the OID to poll as necessary.