3Com V6100, Руководство пользователя, Страница: 373 / 496

V6100 and V7122 User Guide
373
SNMP NAT Traversal
A NAT placed between the gateway and the element manager calls for traversal solutions:
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Trap source port – all traps are sent out from the SNMP port (default 161). A manager
receiving these traps can use the binding information (in the UDP layer) to traverse the
NAT back to the device.
The trap destination address (port and IP) are as configured in the snmpTargetMIB.
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acKeepAliveTrap – this trap is designed to be a constant life signal from the device to the
manager allowing the manager NAT traversal at all times. The
acBoardTrapGlobalsAdditionalInfo1 varbind has the device’s serial number.
The destination port (i.e., the manager port for this trap) can be set to be different than
the port to which all other traps are sent. To do this, use the
acSysSNMPKeepAliveTrapPort object in the acSystem MIB or the
ini file parameter
KeepAliveTrapPort.
The Trap is instigated in three ways:
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Via an ini file parameter (‘SendKeepAliveTrap = 1’). This ensures that the trap is
continuously sent. The frequency is set via the 9/10 of the
acSysSTUNBindingLifeTime object.
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After the STUN client has discovered a NAT (any NAT).
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If the STUN client cannot contact a STUN server.
The two latter options require the STUN client be enabled (EnableSTUN). Also,
once the acKeepAlive trap is instigated it does not stop.
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The manager can see the NAT type in the MIB:
3Com(5003).acProducts(9).acBoardMibs(10).acSystem(10).acSystemStatus(2).
acSysNetwork(6).acSysNAT(2).acSysNATType(1)
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The manger also has access to the STUN client configuration:
3Com(5003).acProducts(9).acBoardMibs(10).acSystem(10).acSystemConfiguration(1).a
cSysNetworkConfig(3).acSysNATTraversal(6).acSysSTUN(21)
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acNATTraversalAlarm - When the NAT is placed in front a device that is identified as a
symmetric NAT, this alarm is raised. It is cleared when a non-symmetric NAT or no NAT
replace the symmetric one.
3Com’ Element Management System
Using 3Com’ Element Management System (EMS) is recommended to Customers requiring
large deployments (multiple media gateways in globally distributed enterprise offices, for
example), that need to be managed by central personnel.
The EMS is not included in the device’s supplied package. Contact 3Com for detailed
information on 3Com’ EMS and on 3Com’ EVN - Enterprise VoIP Network – solution for large
VoIP deployments.
The EMS doesn’t apply to the TP-260.