SNMP Informant Knowledge-base

Article: 2005-006
Product: SNMP Informant - All versions
Subject: Decoding SNMP Informant instance numbers (converting Decimal OID instance numbers into ASCII representations)
Keywords: OID instances, Logical, Physical, Disk

This article is written to help you better understand the SNMP Informant instance numbers seen when walking disk, processor, network interface and other tables.

The modified ASCII chart (below) is provided to make it easier to read SNMP Informant instance OID values, and convert them to their ASCII equivalent.  Specifically, we removed the Hex and Octal values, leaving only the Decimal values.

As mentioned, this Decimal to ASCII conversion applies to several SNMP Informant tables, where the information is pulled directly from the Performance Data Helper (we don't make them up).

Here are four examples of this chart being used to convert an SNMP Informant Instance to an ASCII (character) equivalent.  For ease of reading, we will always assume that SNMP Informant agent is the Advanced version, and the prefix will be .iso.org.dod.internet.private.enterprises.wtcs.informant.advanced. (or .1.3.6.1.4.1.9600.1.2), and the walk will occur below that point.  The first number after the fully qualified OID (in the first couple of examples a 2) tells us how many characters follow.  The dots between the characters can be removed from the Character (ASCII) Equivalents.

 

Example 1: LogicalDisk: Logical Disk Average Read Queue Length
(we've included a Getif Screenshot in this example to provide further detail)

Fully qualified SNMP Informant OID (walk from here) SNMP Informant Instance (Decimal) OID response Character (ASCII) Equivalent
.logicalDiskTable.logicalDiskEntry.lDiskAvgDiskReadQueueLength .2.67.58 C:
.logicalDiskTable.logicalDiskEntry.lDiskAvgDiskReadQueueLength .2.68.58 D:
.logicalDiskTable.logicalDiskEntry.lDiskAvgDiskReadQueueLength .6.95.84.111.116.97.108 _Total

.2 indicates that 2 characters follow
.6 indicates that 6 character follows

 

Example 2: Processor: % Processor Time

Fully qualified SNMP Informant OID (walk from here) SNMP Informant Instance (Decimal) OID response Character (ASCII) Equivalent
.processorTable.processorEntry.cpuPercentProcessorTime .1.48 0
.processorTable.processorEntry.cpuPercentProcessorTime .1.49 1
.processorTable.processorEntry.cpuPercentProcessorTime .6.95.84.111.116.97.108 _Total

.1 indicates that 1 character follows
.6 indicates that 6 characters follows

 

Example 3: Network Interface: % Processor Time

Fully qualified SNMP Informant OID (walk from here) SNMP Informant Instance (Decimal) OID response
.networkInterfaceTable.networkInterfaceEntry.netBytesTotalPerSec .25.77.83.32.84.67.80.32.76.111.111.112.98.97.99.107.32.105.110.116.101.114.102.97.99.101
Character (ASCII) Equivalent MS TCP Loopback interface

.25 indicates that 25 characters follow

Fully qualified SNMP Informant OID (walk from here) SNMP Informant Instance (Decimal) OID response
.networkInterfaceTable.networkInterfaceEntry.netBytesTotalPerSec .27.72.80.32.78.67.51.49.54.51.32.70.97.115.116.32.69.116.104.101.114.110.101.116.32.78.73.67
Character (ASCII) Equivalent HP NC3163 Fast Ethernet NIC

.27 indicates that 27 characters follow

 

Example 4: PhysicalDisk: Physical Disk Average Disk Queue Length

Fully qualified SNMP Informant OID (walk from here) SNMP Informant Instance (Decimal) OID response Character (ASCII) Equivalent
.physicalDiskTable.physicalDiskEntry.pDiskAvgDiskQueueLength .4.48.32.67.58 0 C:
.physicalDiskTable.physicalDiskEntry.pDiskAvgDiskQueueLength .4.49.32.68.58 1 D:
.physicalDiskTable.physicalDiskEntry.pDiskAvgDiskQueueLength .6.95.84.111.116.97.108 _Total

.4 indicates that 4 characters follow
.6 indicates that 6 characters follows

SNMP Informant Decimal OID instance to ASCII Character Conversion Table

Decimal Value Character Value   Decimal Value Character Value   Decimal Value Character Value   Decimal Value Character Value
0 33 ! 64 @ 97 a
1 34 " 65 A 98 b
2 35 # 66 B 99 c
3 36 $ 67 C 100 d
4 37 % 68 D 101 e
5 38 & 69 E 102 f
6 39 ' 70 F 103 g
7 40 ( 71 G 104 h
8 41 ) 72 H 105 i
9 42 * 73 I 106 j
10 43 + 74 J 107 k
11 44 , 75 K 108 l
12 45 - 76 L 109 m
13 46 . 77 M 110 n
14 47 / 78 N 111 o
15 48 0 79 O 112 p
16 49 1 80 P 113 q
17 50 2 81 Q 114 r
18 51 3 82 R 115 s
19 52 4 83 S 116 t
20 53 5 84 T 117 u
21 54 6 85 U 118 v
22 55 7 86 V 119 w
23 56 8 87 W 120 x
24 57 9 88 X 121 y
25 58 : 89 Y 122 z
26 59 ; 90 Z 123 {
27 60 < 91 [ 124 |
28 61 = 92 \ 125 }
29 62 > 93 ] 126 ~
30 63 ? 94 ^ 127 DEL
31 95 _
32  SPACE 96 `
   = commonly  seen values