"JohnD" <> wrote in message
news:...
> If there is a more appropriate forum for this post, please point me in the
> right direction. But you guys are generally such a font of knowledge, I
> thought I'd start here.
>
> Some of our users use a web-based application, and they are constantly
> complaining of sluggish performance and lock-ups. It is a Citrixy,
terminal
> services kind of app, and the vendor recommends something like 24k - 36k
of
> bandwidth available per user. We have an aggregate of over 6MB internet
> bandwidth, 3MB from one provider (say Sprint), and 3MB from another
provider
> (say AT&T), going through a load balancing device that does round-robin
> distribution.
>
> We have used various measurement tools and have determined that the
problem
> does not seem to be bandwidth. We never "peg-out," and there always seems
> to be bandwidth available according to our measurement tools.
>
> We told our application vendor this, and they replied that besides
> bandwidth, they require a minimum QoS of 90%. They pointed us to a site
> called InternetFrog.com where we can run bandwidth tests. Sure enough,
the
> QoS readings from this site are consistently less than 90%. We have also
> isolated the circuits, and interestingly we found that AT&T consistently
> gives poorer results than Sprint. With 100 samples for each circuit, AT&T
> averages roughly 40% QoS, while Sprint Averages 80%.
i think you need you app supplier to define what they mean by QoS in terms
of things you can measure
- common ones would be end to end latency, packet loss, and jitter.
that way you should be able to instrument the client and get some stats that
you can correlate against "good" and "bad" user experiences, or maybe come
up with a simple test script that throws packets around.
Note that the killer is often latency since you dont have much control over
how far a packet has to go to be useful in most cases - each packet has to
travel between the 2 end points which are usually fixed, and all you can do
is play around with things like choice of ISP that affect it indirectly.
you may just have an app that doesnt work properly in your environment -
maybe it needs the stability of a private network where you can use QoS
directly, or maybe it just does not work effectively over the required
distances.
>
> Questions:
>
> 1. Are there other ways to measure QoS for Internet access? I don't know
> how reliable "InternetFrog" is. If I could at least compare it with a few
> other sites, I'd feel more confident before taking this to our ISPs.
>
looking at the site it is intended for "voip" testing.
however - they give round trip time, upload / download speeds and max pause
time - which are much easier quantities to check elsewhere than the "QoS
%age they do not define.
> 2. Is there anything we can do on our end to improve QoS? Our path
through
> the Internet goes through a Cisco switch, a Cisco router, a CheckPoint
> firewall, and a load balancer. I'm not real sure which one might be
tunable
> to provide better QoS.
qos is all about controlled unfairness of forwarding for some packets. The
only bit you can control directly is outbound forwarding.
But you can make sure that the return traffic doesnt hit any unnecessary
bottlenecks as it enters your central site..
a lot depends on what they are measuring - but you might want to put your
"citrixy app" thru the best internet connection, and push everything else on
>
> Thanks
--
Regards
- replace xyz with ntl