Velocity Reviews - Computer Hardware Reviews

Velocity Reviews > Newsgroups > Computing > Cisco > ABCs of QoS

Reply
Thread Tools

ABCs of QoS

 
 
JohnD
Guest
Posts: n/a
 
      12-18-2007
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%.

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.

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.

Thanks


 
Reply With Quote
 
 
 
 
alexd
Guest
Posts: n/a
 
      12-18-2007
On Tue, 18 Dec 2007 10:04:14 -0600, JohnD wrote:

> 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.


If you remove the load balancing device and have a session stick to one
circuit, does that improve matters? How many users do you have? Do you
actually have 24-36k per user?

> 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.


Are you monitoring your circuits to keep a record of utilisation? This
may be useful to correlate poor performance with circuit utilisation.

> 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%.


It's not obvious from InternetFrog how they measure QoS - I've just ran a
test and it says my 15M DSL gets 922kbps through with 33% QoS. I would
take it with a pinch of salt. 33% QoS obviously doesn't mean 67% packet
loss, as that would be insane.

> 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.


Ping is the simplest. For example you could run a 100-repeat ping to the
same destination from either circuit and compare packet loss.

> 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.


If you're not maxing out the link at your end, then I can't really see
what you can do about it, although it may be worth implementing QoS for
when you inevitably do run out of bandwidth.

--
<http://ale.cx/> (AIM:troffasky) ()
19:48:47 up 37 days, 8:28, 2 users, load average: 0.26, 0.32, 0.35
2x Broadband/IT/Telecoms support positions in Newcastle city centre.
For more info call 0191 229 8870 and ask for Steve. No agencies.
 
Reply With Quote
 
 
 
 
p_teatreeoil
Guest
Posts: n/a
 
      12-26-2007
If you are mixing time sensitive applications with regular internet
usage without QoS set up on your provider's edge router, you will have
problems. You can expect to experience glitches with even
"apparently" low bandwidth usage. How granular is your monitoring
software? Typically, the bottleneck is at the egress interface of
the provider to the customer, assuming your provider is a top level
ISP...and yours are.

Those QoS metrics from the frog site are dubious. I would recommend
doing a traceroute to the site and compare the path through both
providers as well as get some info on how those numbers are derived.
 
Reply With Quote
 
stephen
Guest
Posts: n/a
 
      12-26-2007
"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


 
Reply With Quote
 
Mike Silverman
Guest
Posts: n/a
 
      12-28-2007
John,

When you say this is a 'Citrixy, terminal services kind of app' do you
mean that you are publishing it through Citrix?

If there is such a high QOS requirement, you may want to consider
changing the delivery method to distributed meaning that the web browser
runs directly from the client machine as opposed to the Citrix/Terminal
Server. Then you can look at products similar to Citrix
NETScaler/WANScaler to apply a more efficient level of control to the
data stream. You should be able to trial the setup to see if it will
suit your needs before making any kind of financial investment.

Mike.

JohnD wrote:
> 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%.
>
> 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.
>
> 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.
>
> Thanks
>
>

 
Reply With Quote
 
 
 
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
[QOS] minimal hardware and IOS requirement for QOS dominix Cisco 2 02-06-2007 10:19 AM
Interfaces without ABCs? Mark P C++ 6 09-13-2005 08:16 AM
Polymorphism, iterators and ABCs? Steven T. Hatton C++ 5 09-02-2005 12:42 AM
name conventions for pure ABCs gelbeiche C++ 1 04-28-2005 03:46 PM
QOS for VOIP using 768k of FR / Auto QOS Andrew Albert Cisco 7 02-09-2005 07:42 PM



Advertisments
 



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57