It’s the New Phone

I finally lost my patience with my old mobile provider last week & decided it was time for a change.  While I was changing, I decided that maybe it was time for a Smartphone… Wow.  It definitely isn’t perfect yet, but this is by far the best mobile device that I’ve ever used.  Having instant…


SMB Perf articles

I’ve been working a lot with file sharing performance, and I’m trying to write a few essays on those experiences.  The first, on SMB Performance, is up now.  When I have some more time, I’m going to write a bit on the impact of packet loss on SMB connections on a WAN link…


SMB/CIFS Performance Over WAN Links

I often have customers who ask me to wrestle with the performance of SMB (otherwise known as CIFS) across a WAN link.  Their experience is usually that file transfers from Windows Explorer or from the command prompt don’t meet their expectations of their inter-site link, even when FTP (ewwww!) performs much better. Background There are…


Quick Figuring Optimal TCP Window Size

There generally isn’t a single correct way to figure out the optimal TCP window for an interface since you’re probably connecting to different hosts across different links at different latencies; however, you can roughly guess what the optimal window would be if you’re only primarily worried about your communication with one other host (or, perhaps,…



My favorite cartoonist wrote something that started me thinking… “All products are conversations.” I suppose that, in terms of product support, this is self-evident.  Every product we ship results in a conversation with support. The exciting thing is that, for me, these conversations have changed drastically over the years.  When I started, most of the…


Finding Retransmits in Ethereal

With the full version of Netmon, it’s relatively easy to find retransmitted packets with the expert; however, in Ethereal, it’s not quite as clear… Ethereal supports analysis of TCP sequence numbers to find retransmits & do other neat things; however, the default is to turn this off (because, I would guess, it will increase load…



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Network Sniffing Tools

Posted on my favorite network sniffing tools.


Network Sniffing Tools

Intro Network sniffing is a major part of my life — I’ve probably pored over, on average, a trace a day every day for the past seven years.  This is an area where having the right tool is of the upmost importance as a good tool can cut hours (or even days) off of your…


Categorizing Packet Loss

I’ve quite frequently run into situations where I’ve been asked to diagnose packet loss based only on a network trace.  While it is almost impossible to find an exact answer, a network trace can provide some valuable clues about the cause of the packet loss. The first step, if possible, is to get network traces…