How to know the device's type from SNMP

[Mote]

I use SNMP to collect SNMP Agent's information.
If I want to know the type of node from SNMP Agent
What is the object identifier that I can find this information?

[wsmith]

I'm no expert, but it seems that most 'device discovery' routines look for this Mandatory OID:

Name: sysDescr
Type: OBJECT-TYPE
OID: 1.3.6.1.2.1.1.1
Full path: iso(1).org(3).dod(6).internet(1).mgmt(2).mib-2(1).system(1).sysDescr(1)
Module: RFC1213-MIB

Parent: system
Next sibling: sysObjectID

Numerical syntax: Octets
Base syntax: OCTET STRING
Composed syntax: DisplayString
Status: mandatory
Max access: read-only
Size list: 1: 0..255

Description: A textual description of the entity. This value
should include the full name and version
identification of the system's hardware type,
software operating-system, and networking
software. It is mandatory that this only contain
printable ASCII characters.