Passthrou IM Driver Problem

NTDEV
1

After install NDIS Passthrou Driver(Sample in DDK 3790) with WLAN
underlying
device, the data transfering speed will fall down seriously(From 300+ KB/s
to
30- KB/S). Howerver, it performs normal when underlying device is EtherNet
NIC.

I test the Passthrou driver in WIndows XP SP1. What is the problem?

Also, Windows DDK wrote:

NDIS 4.0 and 5.0 intermediate drivers “must” allocate a new NDIS_PACKET to
encapsulate data that they pass on. These intermediate drivers must also
copy any out-of-band (OOB) data to the new packet. Even if the
intermediate
driver does nothing other than simply pass on incoming packets — for
example, if it simply counts the packets it must allocate a fresh packet
descriptor and manage some or all of a new packet structure.

Couldn’t I just pass the origin packet up/down to Protocol/Miniport in IM?
I have tried it, and it seems to work fine. Any reason can explain above
words in
DDK?

Thanks

2

The reasoning behind the new wrapper is just like the idea of stack
locations in an IRP. It allows NDIS to know who to return packets to
in the case of pending, and to store some other context information.

Eventually your way will break, probably quite spectacularly.

-Jeff

-----Original Message-----
From: Klee Lee [mailto:xxxxx@csie.nctu.edu.tw]
Sent: Thursday, September 04, 2003 1:02 AM
To: Windows System Software Developers Interest List
Subject: [ntdev] Passthrou IM Driver Problem

After install NDIS Passthrou Driver(Sample in DDK 3790) with WLAN
underlying
device, the data transfering speed will fall down seriously(From 300+ KB/s
to
30- KB/S). Howerver, it performs normal when underlying device is EtherNet
NIC.

I test the Passthrou driver in WIndows XP SP1. What is the problem?

Also, Windows DDK wrote:

NDIS 4.0 and 5.0 intermediate drivers “must” allocate a new NDIS_PACKET to
encapsulate data that they pass on. These intermediate drivers must also
copy any out-of-band (OOB) data to the new packet. Even if the
intermediate
driver does nothing other than simply pass on incoming packets - for
example, if it simply counts the packets it must allocate a fresh packet
descriptor and manage some or all of a new packet structure.

Couldn’t I just pass the origin packet up/down to Protocol/Miniport in IM?
I have tried it, and it seems to work fine. Any reason can explain above
words in
DDK?

Thanks

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

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