The default capture buffer size is, in fact, *nominally* 1MB; however,

libpcap/WinPcap and the capture mechanism atop which they run might
either silently limit the buffer size to a smaller value or raise it to
a higher value - that's the part that's platform-dependent.

svn path=/trunk/; revision=32718

2 files changed, 14 insertions, 8 deletions

diff --git a/doc/dumpcap.pod b/doc/dumpcap.pod
index f08bd66488..64cde86c15 100644
--- a/doc/dumpcap.pod
+++ b/doc/dumpcap.pod
@@ -100,10 +100,13 @@ to specify two criterion, each must be preceded by the B<-b> option.
 
 =item -B  E<lt>capture buffer sizeE<gt>
 
-Set capture buffer size (in MB; default is platform-dependent).  This is
-used by the the capture driver to buffer packet data until that data can
-be written to disk.  If you encounter packet drops while capturing, try
-to increase this size.
+Set capture buffer size (in MB, default is 1MB).  This is used by the
+the capture driver to buffer packet data until that data can be written
+to disk.  If you encounter packet drops while capturing, try to increase
+this size.  Note that, while B<Dumpcap> attempts to set the buffer size
+to 1MB by default, and can be told to set it to a larger value, the
+system or interface on which you're capturing might silently limit the
+capture buffer size to a lower value or raise it to a higher value.
 
 This is available on on UNIX systems with libpcap 1.0.0 or later and on
 Windows.  It is not available on UNIX systems with earlier versions of
diff --git a/doc/tshark.pod b/doc/tshark.pod
index 01dc1ec46f..5b57653cb5 100644
--- a/doc/tshark.pod
+++ b/doc/tshark.pod
@@ -181,10 +181,13 @@ to specify two criterion, each must be preceded by the B<-b> option.
 
 =item -B  E<lt>capture buffer sizeE<gt>
 
-Set capture buffer size (in MB; default is platform-dependent).  This is
-used by the the capture driver to buffer packet data until that data can
-be written to disk.  If you encounter packet drops while capturing, try
-to increase this size.
+Set capture buffer size (in MB, default is 1MB).  This is used by the
+the capture driver to buffer packet data until that data can be written
+to disk.  If you encounter packet drops while capturing, try to increase
+this size.  Note that, while B<Tshark> attempts to set the buffer size
+to 1MB by default, and can be told to set it to a larger value, the
+system or interface on which you're capturing might silently limit the
+capture buffer size to a lower value or raise it to a higher value.
 
 This is available on on UNIX systems with libpcap 1.0.0 or later and on
 Windows.  It is not available on UNIX systems with earlier versions of