Management via SNMP

This chapter provides information about using Simple Network Management Protocol (SNMP) commands for remote system monitoring and control. This system recognizes SNMP v1 and v2c commands.

Introduction

Simple network management protocol (SNMP) is an ISO standard communication protocol widely used by network and element management systems to monitor network devices for both alarms and other significant conditions.

SNMP accesses information about network devices through management information base (MIB) objects. MIBs are hierarchical tree-structured descriptions used to define database elements. SNMP is used to manage individual data elements and the values assigned to MIB objects.

SNMP addresses a single MIB object using a numeric string called an object identifier (OID). The OID defines a branching path through the hierarchy to the location of the object. In addition to the OID, a MIB object is identified by its object descriptor. Both are unique to each MIB object.

Also defined for each MIB object is the access that SNMP can afford to the object data value. For example, if a MIB object has read-write access, SNMP can be used to both get (retrieve) and set (define or change) the value of the object. If an object is read-only, SNMP can be used to get the object value, and cannot change it.

MIBs Used in the iNode

MIBs used in the iNode are listed in the following table. There are not any proprietary MIBs in the iNode; only standard MIBs are supported.

HMS MIBs and Related MIBs -- MODULE

Load and Compile Order

Prerequisites

SNMPv2-SMI,

SNMPv2-TC,

SNMPv2-CONF,

SNMPv2-MIB,

INET-ADDRESS-MIB

HMS028 - SCTE-ROOT

SCTE-ROOT

HMS072 - SCTE-HMS-ROOTS

SCTE-ROOT, SCTE-HMS-ROOTS

HMS025 - SCTE-HMS-FIBERNODE-MIB

SCTE-ROOT, SCTE-HMS-ROOTS, RFC1215-MIB, SCTE-HMS-FIBERNODE-MIB

HMS024 - SCTE-HMS-COMMON-MIB

SCTE-ROOT, SCTE-HMS-ROOTS, RFC1215-MIB, SCTE-HMS-COMMON-MIB

HMS023 - SCTE-HMS-ALARMS-MIB

SCTE-ROOT, SCTE-HMS-ROOTS, RFC1215-MIB, SCTE-HMS-COMMON-MIB, SCTE-HMS-ALARMS-MIB

HMS026 - SCTE-HMS-PROPERTY-MIB

SCTE-ROOT, SCTE-HMS-ROOTS, SCTE-HMS-PROPERTY-MIB

SNMP-TARGET-MIB

SNMP-FRAMEWORK-MIB, SNMP-TARGET-MIB

SNMP-FRAMEWORK-MIB

SNMP-FRAMEWORK-MIB

SNMP-NOTIFICATION-MIB

SNMP-FRAMEWORK-MIB, SNMP-TARGET-MIB, SNMP-NOTIFICATION-MIB

The following access codes (Code) are used in the MIB tables in this chapter.

Code

Description

RO

Read Only

Data is displayed for reading.

RW

Read-Write

Data can be read and changed.

na

Not Applicable

Data is not applicable to the equipment.

SNMP Community String

You should change the SNMP community string only using the LCS or iNode Manager. It is an alphanumeric string of not more than 32 characters.

MIB-2 System MIB

The System MIB gives an overview for the iNode. By default, sysContact, sysName, and sysLocation can be changed. All three are saved in nonvolatile memory.


Note

The iNode does not have a Real Time Clock (RTC). Therefore, sysUpTime is only a time estimate.

HMS MIB Specifications

SCTE-HMS-PROPERTY-MIB

The Property MIB consists of the following tables:

  • analog properties table

  • discrete alarms table

  • current alarms table


Note

Information contained in the current alarms table can be determined by studying the other Property MIB tables.

Analog Property Table

The analog property table allows you to adjust certain alarm thresholds, hysteresis values, and settings with respect to alarm and trap generation. The thresholds displayed by the property MIB fall into two categories.

  1. Thresholds that cannot be changed (na and RO in the following table). These parameters are informational and cannot be changed. Since the MIB itself has read-write access, you can edit the table. However, if an edited value has read-only access in the module, information coming from the module on the next polling cycle will overwrite your edits for that particular setting.

  2. Threshold values that represent alarm thresholds (Alarm). These are used to generate a trap if the monitored value crosses one of these thresholds.

Equipment

Parameter OID

Thresholds Changed

Code

LinePowerVoltage

fnLinePowerVoltage

na

RO

nodeTemperature

commonInternalTemperature

Alarm

RW

Transmitter

fnReturnLaserOpticalPower

na

RO

Receiver

fnOpticalReceiverPower

na

RO

Power Supply

fnDCPowerVoltage

Alarm

RW

The following table indicates the default values for the analog properties table.

Name

Major Hi

Minor Hi

Minor Lo

Major Lo

Dead band

Units

fnLinePowerVoltage

95

90

45

40

1

VAC

commonInternalTemperature

70

65

-35

-40

2

degC

fnReturnLaserOpticalPower

-30

-50

-120

-150

10

mW

fnOpticalReceiverPower

16

13

2

1

1

mW

fnDCPowerVoltage (-6Vb)

-46

-48

-64

-66

1

0.1 VDC

fnDCPowerVoltage (5Vb)

72

70

53

51

1

0.1 VDC

fnDCPowerVoltage (8Vb)

99

97

81

79

2

0.1 VDC

fnDCPowerVoltage (24Vb)

265

263

241

239

1

0.1 VDC

Current Alarm Table Sample

Instance

currentAlarmOID

currentAlarmAlarmState

currentAlarmVal

12.1.3.6.1.4.1.5591.1.3.1.12.0

commonTamperStatus

caasDiscreteMajor(6)

2

Discrete Property Table

The discrete property table alerts you when a specific monitored value changes state. The alarms are set up to send a trap when a value changes from a nominal state to alarm state. Some are also set up to signal other states. The following table provides an overview of discrete property parameters and the values that may cause trap generation.

Equipment

Parameter OID

discreteAlarmValue

TamperSwitch

commonTamperStatus

Compromised(2)

SCTE-HMS-ALARMS-MIB

The alarm MIB keeps a copy of the last 50 alarms generated when a monitored value crosses an alarm threshold. The alarmLogTable contains the alarmLogInformation OID with values defined in the properties of the OID. Significant is the fifth octet that describes the Alarm Type as an enumeration representing one of the following:

  1. Nominal

  2. HiHi

  3. Hi

  4. Lo

  5. LoLo

  6. Discrete Major

  7. Discrete Minor

Starting with octet seven until the value at the end, the OID of the monitored value causing the alarm state displays. Finally, the actual value shows in the last few octets. Traps are similar to the logged alarms.

Table 1. Alarm Table Sample

Ins

alarmLogIndex

alarmLogInformation

11

11

5A.7B.5A.FB.06.08.0C.2B.06.01.04.01.AB.57.01. 03.01.0C.00.02.02.00.02

In the preceding sample, the commonTamperStatus, with a numeric OID of 1.3.6.1.4.1.5591.1.3.1.12.0 or hexadecimal 2B.06.01.04.01.AB.57.01.03.01.0C.00, is in an alarm state of 6 (Discrete Major) with a value of 2 (compromised) or 00.02 in hexadecimal. The commonTamperStatus, has a positive value. However, if the value of a monitored item is negative then the hex value would display like the following example. For the decimal value of -242, the hexadecimal equivalent is FF.0E. The 12 (or hex 0C) at the start of the OID in the current alarm table instance is the number of octets in the OID that follows.

Table 2. Alarm Log Example Shown With Decimal and OID Equivalents

Alarm Type

OID

Value

Value

Octet

5

7-m

n-z

decimal

Hex

06

06.01.04.01.AB.57.01.03.01.0C.00

00.02

2

Decimal

6

1.3.6.1.4.1.5591.1.3.1.12.0

OID

SCTE-HMS-COMMON-MIB::

commonTamperStatus.0

SCTE-HMS-COMMON-MIB

The Common MIB is self-explanatory. A few significant OIDs are highlighted here. The iNode’s serial number is found in commonSerialNumber, the iNode’s software version is found at commonVendorInfo, while the MAC address is found in commonPhysAddress. Set commonReset to 1 to reboot the iNode. This triggers a software upgrade, if a newer image exists (see Software Upgrade).

SCTE-HMS-FIBERNODE-MIB

The fibernode MIB displays data related to the transmitters, receivers, redundancy, and power supplies.