SNMP ver. 1  Message Formats (Only GetRequest, GetNextRequest, SetRequest and GetResponse PDUs)

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|    Message Header   |                         Protocol Data Unit (PDU)                       |
------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------
| Version | Community | PDU type | Request ID | Error status | Error index | Variable bindings |
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                                                                     Variable bindings
                                                           -------------------------------------
                                                           | OID 1 | Value 1 | OID X | Value X |
                                                           -------------------------------------



Example:

GET .1.3.6.1.2.1.1.4.0 (sysContact.0)
 Version=0
 Community=public
 PDU type=get
 Request ID=3AB2
 Error status=0
 Error index=0
 OID=.1.3.6.1.2.1.1.4.0
 Value=null

Packet dump:
----------------------------------------------------------------------------
0000: 30 27 02 01  00 04 06 70  75 62 6C 69  63 A0 1A 02    0'.....public..
0016: 02 3A B2 02  01 00 02 01  00 30 0E 30  0C 06 08 2B    .:.......0.0...+
0032: 06 01 02 01  01 04 00 05  00                          .........
----------------------------------------------------------------------------






RESPONSE .1.3.6.1.2.1.1.4.0 (sysContact.0)
 Version=0
 Community=public
 PDU type=get
 Request ID=3AB2
 Error status=0
 Error index=0
 OID=.1.3.6.1.2.1.1.4.0
 Value=router

Packet dump:
----------------------------------------------------------------------------
0000: 30 3F 02 01  00 04 06 70  75 62 6C 69  63 A2 32 02    0?.....public.2.
0016: 02 3A B2 02  01 00 02 01  00 30 26 30  24 06 08 2B    .:.......0&0$..+
0032: 06 01 02 01  01 04 00 04  18 53 63 69  65 6E 74 69    .........Scienti
0048: 66 69 63 2D  41 74 6C 61  6E 74 61 2C  20 49 6E 63    fic-Atlanta, Inc
0064: 2E                                                    .
----------------------------------------------------------------------------







Links:

http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/snmp.htm
http://www.cisco.com/warp/public/535/3.html
http://www.dpstele.com/layers/l2/snmp_l2_tut_part1.html
http://www2.rad.com/networks/1995/snmp/snmp.htm
http://en.wikipedia.org/wiki/Simple_network_management_protocol
http://www.et.put.poznan.pl/snmp/main/mainmenu.html
http://asn1.elibel.tm.fr/oid/