DMA OperationsGuide SNMP Overview
432 Polycom, Inc.
We recommend using a MIB browser to explore the PolycomDMA system
MIB, but a copy of the MIB is available in “The Polycom DMA System MIB”
on page442. The DMA system MIB is self-documenting, including
information about the purpose of specific traps and inform notifications.
Note that you should understand how your SNMP management system is
configured in order to properly configure the DMA system’s SNMP transport
protocol, version, authentication, and privacy settings.
See also:
“List of Available SNMP MIBs” on page 433
“SNMP Settings” on page 433
“SNMP Procedures” on page441
“The Polycom DMA System MIB” on page 442
SNMP Versions Supported
The Polycom DMA system supports:
•SNMPv2c—The Polycom DMA system implements a sub-version of
SNMPv2. The key advantage of SNMPv2c is the Inform command. Unlike
Traps, Informs are messages sent to the management system that must be
positively acknowledged with a response message. If the management
system doesn’t reply to an Inform, the DMA system re-sends the Inform.
SNMPv2c also has improved error handling.
One drawback of SNMPv2c is that it doesn’t encrypt communications
between the management system and SNMP agents, so it’s subject to
packet sniffing of the clear text community string from the network traffic.
•SNMPv3—The Polycom DMA system implements the newest version of
SNMP. Its primary feature is enhanced security. The
contextEngineID
in
SNMPv3 uniquely identifies each SNMP entity. The
contextEngineID
is
used to generate the key for authenticated messages.
The Polycom DMA system implements SNMPv3 communication with
authentication and privacy (the
authPriv
security level as defined in the
USM MIB).
To im pl em ent th is se cur it y l ev el, yo u m us t de fi ne SN MP u se rs to be a dd ed
to the SNMP agent user list. Agents use this list to protect SNMPv3
packets from interception. Each user has a secret key to ensure
authentication and privacy.
—Authentication ensures that only the intended recipient receives the
SNMP message. As messages are created, they’re given a special key
that’s based on the
contextEngineID
of the entity. The key is shared
with the intended recipient and used to receive the message.
—Privacy encrypts the SNMP message to ensure that unauthorized
users can’t read it.