A3COM0054-BRASICA2-SPECIFIC: View SNMP OID List / Download MIB

This object controls whether cut-thru is enabled on the stack. Enabling cut-thru can help to minimise the delay experienced by packets before they are forwarded to their destination. Setting cut-thru to 'fastForward' causes frame forwarding to begin as soon as 32 bytes of the frame have been received. Setting it to 'fragmentFree' causes frame forwarding to begin when 64 bytes have been received. This is slower, but eliminates the risk of forwarding an illegally short frame to the destination port, however a valid length frame might still be forwarded even though it had a CRC error. Setting this object to 'storeAndForward' disables cut-thru completely, and frames will not be forwarded until they have been received in their entirety. When the mode is set to intelligent, the effective switching mode is set initially to fast forward. The switch then monitors the total error rate of frames received on each port, and if it exceeds 20 error frames a second it changes the effective mode for the port to store and forward. If the error rate then drops to zero the effective mode is restored to fast forward. Whatever forwarding mode is selected, cut-thru cannot operate if the destination port is currently involved in 'cut-thru' from another port. In this case the device will process the frame in store and forward mode. Enumeration: 'fastForward': 1, 'intelligent': 4, 'storeAndForward': 3, 'fragmentFree': 2.

This object specifies the type of backoff algorithm used on the units in the stack. Any port can use the standard ethernet algorithm or, for PACE applications, it can be set into low latency mode. In this mode, the backoff algorithm is optimised to minimise the possibility of collisions. The value of this object defines the setting that those ports will use which have prConPortPaceMode set to useDefault(2). PACE mode can be set for the whole stack or for individual ports. When a unit is initialised to factory defaults, prconPortPaceMode for every port is set to useDefault(2), and the actual setting for the port is decided by the value of this object. The manager has the choice, therefore, of varying the mode for every port in the stack, or for individual ports only. Enumeration: 'notApplicable': 1, 'normalEthernet': 2, 'lowLatency': 3.

This object specifies the VLAN mode to be used. Setting it to portMode(2) requires the user to configure each port's VLAN membership individually, whereas autoSelect(3) causes it to acquire its membership from the VLAN Server. The value of this object defines the setting that those ports will use which have prConPortVLANConfigMode set to useDefault(2). VLAN mode can be set for the whole stack or for individual ports. When a unit is initialised to factory defaults, prconPortVLANConfigMode for every port is set to useDefault(2), and the actual setting for the port is decided by the value of this object. The manager has the choice, therefore, of varying the mode for every port in the stack, or for individual ports only. Enumeration: 'notApplicable': 1, 'portMode': 2, 'autoSelect': 3.

This determines the ifIndex of the port a user wishes to monitor on the copy port. Monitoring causes all data from the study port to be copied to the copy port. The port is specified using its ifIndex because that uniquely identifies a single port in the stack.

This is the value of ifIndex specifying the port to which data will be copied (mirrored), and must be set to a valid value, along with the study port, before monitoring can be enabled.

This object controls the Roving Analysis Port (RAP) feature in conjunction with prConStackRAPStudyPort and prConStackRAPCopyPort. The RAP feature allows all frames sent and received on the study port to be copied to the copy port, where they can be observed. Setting this object to on(2) will enable monitoring. To succeed both prConStackRAPStudyPort and prConStackRAPCopyPort must have been set to the ifIndex values of suitable ports, and if either are invalid this operation will fail. Enumeration: 'on': 2, 'off': 1.

The value of this object determines whether the switch is to operate as a single bridge or as a bridge per VLAN (the default). In multiple bridge mode the switch maintains a separate filtering database for each VLAN, whereas in single bridge mode it uses a single database for them all. Thus in multiple bridge mode the MAC address of a station can be learnt on more than one port provided they are in separate VLANs, while in single bridge mode the switch makes just one entry for each address. Multiple bridge mode is useful in that separate VLANs may be joined by a bridge external to the switch, whereas in single bridge mode VLANs may only be connected by routers. Not all switches will support both modes, and any attempt to set the mode to an unsupported value will be rejected. Enumeration: 'single': 1, 'multiple': 2.

Table providing configuration information about a port on a Switch unit.

Configuration options for a single port.

This object specifies the VLAN mode to be used. Setting it to portMode(3) requires the user to configure the port's VLAN membership explicitly, whereas autoSelect(4) causes it to acquire its membership from the VLAN Server. VLAN mode can be set for the whole stack or for individual ports. When a unit is initialised to factory defaults, prConPortVLANConfigMode for every port is set to useDefault(2), and the actual setting for the port is decided by the value of prConStackVLANConfigMode. The other values of this object allow the setting to be varied for the individual port. Enumeration: 'notApplicable': 1, 'portMode': 3, 'useDefault': 2, 'autoSelect': 4.

This object controls Intelligent Flow Management for the port, which specifies what action the port takes whenever it is unable to receive a packet because its buffers are full. When set to off(1), the packet is dropped immediately. If it is set to any of the values maxJams6(2) to maxJams13(10), a jam signal is transmitted to the segment attached to the port to force a collision so that the originator will stop and retransmit the frame. This will be repeated a maximum of 6 to 13 times depending on the setting. If the port is then still unable to receive the packet it is dropped. Intelligent Flow Management should be disabled on ports which are connected to repeater segments. Intelligent flow management only functions when a port is operating in half duplex, either as a result of auto-negotiation, or by management action. Enumeration: 'off': 2, 'maxJams9': 6, 'maxJams8': 5, 'maxJams7': 4, 'maxJams6': 3, 'maxJams11': 8, 'maxJams10': 7, 'notApplicable': 1, 'maxJams12': 9, 'maxJams13': 10.

This object controls whether the 'Discard-on-transmit' feature is enabled for frames originating at this port. If set to on(3), the unit will discard frames destined for any other port if that port's transmit buffers are full. If this attribute is set to off(2), a frame will be held until that port has space available for the frame. Enumeration: 'notApplicable': 1, 'off': 2, 'on': 3.

This object specifies the type of backoff algorithm used on the port. A port can use the standard ethernet algorithm or, for PACE applications, it can be set to low latency mode. In this mode, the backoff algorithm is optimised to minimise the possibility of collisions. PACE mode can be set for the whole stack or for individual ports. When a unit is initialised to factory defaults this object is set to useDefault(2) for every port, and the actual setting for the port is decided by the value of prConStackPaceMode. The manager has the choice, therefore, of varying the mode for every port in the stack, or for individual ports only. Enumeration: 'notApplicable': 1, 'normalEthernet': 3, 'lowLatency': 4, 'useDefault': 2.

This object specifies whether a switch port will go to the forwarding state immediately if spanning tree is turned on. When this object is set to on(2), the normal intermediate startup states of listening and learning are skipped and the port is allowed to enter the forwarding spanning tree state immediately. This is to allow switch ports that are directly connected to just one endstation to be immediately available when the link is detected or the switch powers up. Note that this object must be set of off(1) for all switch ports that are connected to ethernet segments or other switches, routers or bridges. The default state for all ports is off(1). Enumeration: 'on': 2, 'off': 1.

This object represents the operational full duplex flow control state of the port, as determined by either (1) the result of auto-negotiation, or (2) if auto-negotiation is not enabled for this port, by the value of the object prConPortFlowCntlDefaultStatus. In the latter case a set to prConPortFlowCntlDefaultStatus will force the port into the new operating mode. If the port is operating in half duplex, the value of this object is notApplicable(3). Enumeration: 'disabled': 2, 'notApplicable': 3, 'enabled': 1.

This object represents the administratively-configured full duplex flow control status of the port. If auto-negotiation is not enabled for this port, the value of this object determines the operational full duplex flow control status, and in this case a set to this object will force the port into the specified state. If auto-negotiation is enabled for this port, the operational status of the port is determined by auto-negotiation and indicated by the value of the prConPortFlowCntlStatus object. The value of this object denotes the state to which the port will automatically revert should auto-negotiation be disabled. The value of this object is ignored if the port is operating in half duplex mode. Enumeration: 'disabled': 2, 'enabled': 1.