CDN Pricing and Availability

[envygeeks]

The problem I find is if Highwinds does this is double latency. Not only are you tapping the CNAME for an extended latency (because CNAMEs are never cached) but the CNAME is forcing out to an external URL which again, causes another reach, doubling latency on top of what's already being caused, by the time it's done, for most people the CDN just isn't viable because they are getting the same amount of latency as before, especially based on the locations of Highwinds. In some locations, specifically US to US or UK to UK or even US to UK and UK to US this could create more latency than what was originally created by just hosting it on the server.

[nullmind]

Originally Posted by envygeeks

The problem I find is if Highwinds does this is double latency. Not only are you tapping the CNAME for an extended latency (because CNAMEs are never cached) but the CNAME is forcing out to an external URL which again, causes another reach, doubling latency on top of what's already being caused, by the time it's done, for most people the CDN just isn't viable because they are getting the same amount of latency as before, especially based on the locations of Highwinds. In some locations, specifically US to US or UK to UK or even US to UK and UK to US this could create more latency than what was originally created by just hosting it on the server.

Your completely ignoring the entire purpose of a CDN, wish is to deliver content, FAST, a CNAME check plus the anycast location of the URL takes at most a ms on the first hit of the first file, you then ignoring the geographical distribution of the content and how much quicker that content is delivered to the end client.

If you live in Chicago and are hosting from a Chicago location, and delivering 1byte files, the CDN wont do squat for you, but then gain, it's not possible to speed up local and very near local traffic for extremely small files, but to the person in Florida, it will make a huge different, now to the person in Paris, a massive one indeed.

[ryan14]

hey does vps.net CDN support files? Like .exe, .zip etc? Akamai is a CDN and they do.

[nullmind]

Originally Posted by ryan14

hey does vps.net CDN support files? Like .exe, .zip etc? Akamai is a CDN and they do.

you can put anything on the CDN, it simply does not "execute" files, such as .php

[Jake]

Originally Posted by ryan14

hey does vps.net CDN support files? Like .exe, .zip etc? Akamai is a CDN and they do.

That's basicly a vps then..

[sam]

Originally Posted by Jake

That's basicly a vps then..

What do you mean by that? They're entirely different. The purpose of CDN - surprisingly - is to deliver content, the content itself is irrelevant. A VPS processes and delivers, CDN only delivers, why would using .exe etc. on CDN make it a vps?

[ospadano]

According to my experience so far, VPS.Net / Highwinds CDN cannot be used for typical web pages.

It uses HTTP permanent (301) redirect and this is the main issue.

This means that a web page with 30 images, for instance, delivered via CDN, will require 30 HTTP redirects, which is a major overhead!

According to pingdom (Pingdom Tools) using a 100KB image this means:
* ~100 ms for the HTTP redirect (from http://cdn.domain.com/... to their URL)
* ~400 ms to download the 100KB image

For a logo image of 10KB that means:
* ~70 ms for the HTTP redirect
* ~180 ms to download the 10KB image

Having the HTTP redirect for all of the images of a web page makes the page slower, as simple as that.

According to Pingdom Tools the home page of my site, which usually takes less to 4 secs to download without CDN, takes between 7 to 8 seconds or more to download using the CDN.
I did not need Pingdom to tell me that either, I could see that it was significantly slower by simply browsing the site.

These are the facts I managed to gather so far and my conclusion is that using VPS.Net / Highwinds CDN for typical web pages does not make any sense at all.
The overhead introduced by the HTTP redirect can only be accepted if you have few and large media files.

According to the technical support the HTTP redirect cannot be avoided for QoS reasons... ???!!!
It is such a pity that a bad design of the way Highwind's CDN works is ruining what could have been a very compelling offering.
I tried their URLs generated after the HTTP redirect, which are valid only for few minutes, and the results are very good.

What a pity!

Osvaldo

[markb1439]

Hmm, there are lots of people using CDN and getting stellar performance. How are you setting up your redirects? If you set your links or your URL replacement structure to point right to the files on the CDN, it should be lightning-fast. Or, for example, if you set up a virtual host and CNAME it right to the CDN, you avoid the redirect overhead.

[ospadano]

Thanks Mark.

This is exactly what I am trying to find out through VPS.Net and Highwinds. May be the way VPS.Net set-up my HTTP Pull is incorrect. I did not set-up the redirects myself.

Apparently, and I really hope I am wrong on this, Highwinds can only use HTTP redirect to point the browser to the best/nearest available CDN server. HTTP redirect is an "expensive" way of achieving that. In fact most of the other CDN providers use DNS redirect instead.

Here is an example using Pingdom tool.

This link is the logo of my website served by my servers:
Pingdom Tools

Here is the the same logo served via VPS.Net. Notice cdn.kinderwagen.com (CNAME record) and the double request (the first being an HTTP redirect)
Pingdom Tools

This does not happen when using EdgeCast's CDN, which I am now testing on my website for instance, because they use DNS redirect to get the client to the best available server rather than HTTP redirect.

It would be interesting to see if you and other people go throuh the same HTTP redirect by checking it with the Pingdom tool: http://tools.pingdom.com

If you do then your pages could be significantly faster.

[nullmind]

Apparently, and I really hope I am wrong on this, Highwinds can only use HTTP redirect to point the browser to the best/nearest available CDN server. HTTP redirect is an "expensive" way of achieving that. In fact most of the other CDN providers use DNS redirect instead.

The redirect is used not just to point you to the nearest POP possible, but also to the nearest pop that contains your data already, in a fast changing site, this is crucial.

the DNS redirect add overhead too, but it's invisible, so highwinds recognised this, in december a new system is coming out that will take the 301 away.