FECN - Forward Explicit Congestion Notification
This is a bit within the address field which notifies the receiving device
that the network is experiencing congestion.
The end device (ie., router, FRAD etc.) is informed that congestion was
experienced on route...subsequent packets could be delayed, discarded or
even damaged.
The end device *should* take remedial action to adjust to the new
transmission environment, from the source...ie., inform the source to
"throttle-back".
This is achieved by using a complimentary bit field in the address
field...BECN (Backward Explicit Congestion Notification)...in packets sent
to the source router/FRAD.
In the real world, what tends to happen, is that there is no way traffic
from upstream hosts (ie., PC's, servers etc.) can be slowed down to the
router/FRAD.
Increasing the size of the buffers (ie., memory) at the source router helps,
but this is useless in the face of severe packet loss to the destination.
Hence, the concept of "Becky and Fecky" can only be really used to detect
congestion, by setting SNMP trap conditions, not give *real*
throttle-control, as
the text books would describe!
Without a though the answers: A
Regards,
Serge :)
----- Original Message -----
From: Shaw, Winston Mr. <[EMAIL PROTECTED]>
To: 'cslx' <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
Sent: Sunday, November 19, 2000 6:25 PM
Subject: RE: what is the purpose of FECN?
> Looks like a trick question.
> I would choose answer a.
>
> Answer b corresponds to what is called the BECN.
> The reason that it is a trick question is that the immediate reaction
would
> be to discard Answer a because FECN is not the only way to tell if a
packet
> experienced congestion.
>
> Winston.
> -----Original Message-----
> From: cslx [mailto:[EMAIL PROTECTED]]
> Sent: Sunday, November 19, 2000 10:39 AM
> To: [EMAIL PROTECTED]
> Subject: what is the purpose of FECN?
>
>
> what is the purpose of FECN?
> a.To tell the router that a packet experienced congestion
> b.To tell the router that packets it is sending to a remote site are
> experiencing congestion
> c.To tell the router that there is bandwidth available
>
>
>
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