Re: Interface Details >Receive but no buffer ISUUE

[Guy Harris <guy () alum mit edu>]

On Dec 30, 2009, at 4:45 AM, Tal Bar-Or wrote:

> i noticed that on Interface Details the Receive but no Buffer  is huge and increasing my question is could it be the 
> reason for such latency and lost data, what could be the cause for such huge values.

"Receive but no Buffer" is the value reported for OID_GEN_RCV_NO_BUFFER.  Microsoft's description of it:

        http://msdn.microsoft.com/en-us/library/bb648558.aspx

says:

        As a query, the OID_GEN_RCV_NO_BUFFER OID specifies the number of frames that the NIC cannot receive due to 
lack of NIC receive buffer space. Some NICs do not provide the exact number of missed frames; they provide only the 
number of times at least one frame is missed.

That sounds as if it's possible for it to cause those problems.  However, if it only happens when you're capturing in 
promiscuous mode, that's probably *not* the problem, as network adapters are normally *not* running in promiscuous 
mode, and, if you're on a non-switched network, going into promiscuous mode could significantly increase the number of 
packets you receive, which might overflow the normal amount of buffering that the network adapter's driver allocates.  
(If you're on a switched network, you probably won't be sent many packets that aren't broadcast packets, multicast 
packets, or packets intended for you, so going into promiscuous mode probably won't increase the number of packets you 
see by very much.)
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