| >> The DECrepeater 900TM (DETMM) does not support automatic
>> port shutdown in the event of a jabbering node (ref: note
>> 528).
>> i.e. the ability to (optionally) auto-partition a port
>> if a jabbering node is detected, and also auto-reconnect
>> the port when the jabbering stops.
>>
>> Will it be possible for the customer to upgrade the
>> DECrepeater 900TM firmware to implement this feature at
>> a later stage ? or is this feature not supported on the
>> DETMM due to hardware constrictions ?
>>
The short answer to this question is that the DECrepeater 900TM hardware does
not support auto-partitioning a port if a jabbering node is detected, but we
are planning to implement a feature which will disable a port which detects a
jabbering node. Note that auto-partitioning a port and disabling a port are not
quite the same thing.
In general, DECrepeater auto-partition/reconnection functions are implemented
in hardware. When a fault (e.g. excessive collisions, jabber, etc) is detected,
a port is automatically placed in the partitioned state. While in this state,
the auto-partitioned port will continue to transmit data received from other
ports but data received on that port will be ignored (i.e. not repeated). If
the hardware detects that the fault is removed (usually by successfully
transmitting or receiving a packet without a collision) the port is
reconnected. All of this action ostensibly takes place in real time.
The DECrepeater 900TM will only auto-partition a port if it detects an
excessivly long collision event or an excessive number of consecutive
collisions on the port. In the feature we are planning to implement, firmware
will poll each port at some interval (on the order of once per second). If a
jabber event has been detected on the port, the port will be disabled. When
disabled, the port will neither transmit or receive data. Note that once a port
is disabled the hardware cannot tell if the node is still jabbering. At some
fixed period of time after being disabled, the port will be re-enabled. If the
node is still jabbering, the port will be disabled in the next polling cycle.
This feature is a best-effort work-around to provide jabber protection for
hardware which does not support auto-partitioning due to jabber.
Please let me know if this will/will not solve your problem. Unfortunately I
cannot give you a firm date as to when this upgrade will be available. It will
be some time after the next round of repeaters (DECrepeater 900FP, DECrepeater
90FS) are released.
Regards,
Rich Pagliaro
DECrepeater 900 firmware
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Rich,
Thanks for the quick reply.
Our customer has specified that they require the 10BaseT
repeater to provide protection against `jabbering'
devices. However the method in which this is achieved
was not specified.
Therefore we would be interested in this work-around to
provide jabber protection for the DETMM hardware, it's
not ideal but it would provide a measure of protection.
The project will begin implementation early May, is a
May - June time frame realistic for the fix ?
Regards
John
Ps : Will auto-partitioning of a jabbering port be available on the new repeaters
i.e. the per port assignable 10BaseT repeaters ?
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