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Trial by Fire
On Monday, February 4, 2008, RF Cafe began using the services of a company that
provides proprietary DNS IP address lookup and Internet data packet routing via
private "Managed DNS" servers located across the globe in strategic locations (see
red dots on image below).
 The prime motivation for subscribing
to this service (it is not cheap) is to make visiting RF Cafe as efficient as possible
for you. Efficiency as defined by my criteria is thus:
1) How quickly does a page begin loading after you instruct your browser to fetch
it?
2) How long does it take the page to completely load once started?
3) Does the requested page fail to either begin or complete loading?
The best way to meaningfully gauge the user experience is to ask you, the user.
Please take a moment to vote in the poll below. You do not need to register - just
click on the button that best describes your experience. (Poll removed)
I spend a lot of time surfing the Internet looking for data and links to data
or articles to present to RF Cafe's visitors. Being provided with lots of new and
useful content is what (hopefully) keeps you coming back again and again. In my
daily quest, I visit a lot of websites; a few are excellent, the vast majority are
OK, and a few are downright atrocious. Page load time is not as big of a deal as
it was back when there were still a lot of unfortunate souls still using dial-up
service, but there are still some pages out there (including on RF Cafe) that are
so heavy on content that it can take three to five seconds to fully load. If the
slow loading time is due to a lot of large images or due to some silly animated
presentation that only the designer thinks is cool and worth wasting your time on,
then unless I really need what is being offered, I leave the website.
Even more offensive to my fragile psyche is the cursed full-page entry advertisement.
I of all people realize the need for paying advertisers to help underwrite the cost
of maintaining a website, but personally think those are going to far. Particularly
insulting are the ones that have the utterly untruthful message saying that the
page you really want to see is loading, implying that the ad is just there so you
do not have to watch the page load. ...but I digress.
Believe it or not, I spend a very large fraction of my waking hours working on
RF Cafe. Call it dedication or an obsession, but if I spend time doing anything
other than creating content for the website, I feel as if I am neglecting my duties.
Always in the background of my RF Cafe activities is a real concern about how each
change or addition is going to affect the overall quality of the user's experience.
Will a busy engineer, manager, student, or even a hobbyist deem RF Cafe truly useful,
or just a waste of time? Having to wait a long time for pages to load is definitely
a waste of his/her time, so that is why I decided to employ a professional service
to help guarantee that every requested page is received without errors, and then
all of those in an acceptable amount of time.
I have merely a layman's knowledge of the way the Internet
works. The domain name system (DNS) functions within it to take a browser's request
for a certain web page using the alias that is a domain name and converts it to
an equivalent IP address, which is then used to fetch and deliver the page to the
browser. While the workings of the Internet are a well-defined and cogent set of
rules encoded in hardware and software throughout the world, the fact that everything
works so well (or at all) borders on the miraculous.
Rather than risk constructing my own inept explanation
for how this new "Managed DNS" service works to bring RF Cafe to you in a more effective
and efficient manner, I will resort to proving a few snippets of wisdom form the
company's website. In the spirit of
Linus Van Pelt
when responding to Charlie's famous question: Isn't there Anyone who knows what
"Managed DNS" is all about?
Lights please...
"The network currently consists of a mesh of fourteen (14) globally synchronized
DNS server nodes located
on five (5) continents. By utilizing dedicated hardware, each major component of
the system is partitioned to function independently while providing a means of marshaling
access control. Hardware is transparently added to an existing node without negatively
impacting service at that node. Once a new DNS server is added, it immediately begins
announcing the appropriate Anycast addresses and is included in the pool of servers available
to answer queries within that node. Similarly, if a server fails, or is removed
for maintenance, it ceases announcing the Anycast addresses, and queries continue
to be received and answered by the remaining operational servers in that node with
no end-user impact.
Diverse network connectivity is utilized within the network. Primary
IPv4 connectivity
is provided by three International network carriers. Each node is multi-homed with
100 Mbps (Fast Ethernet) connections to each carrier. In addition, every node is
also connected natively to a global IPv6 network. Finally, each node is connected to the local public
peering fabric at that node, with a liberal peering policy. To ensure robustness
and redundancy, a carefully architected matrix of network announcements is utilized
to ensure that both minor and catastrophic failures of any elements within the network
will not result in failures of resolution for end users. This includes unique combinations
of network (IP address) announcements, network providers and collocation facility
operators so that the catastrophic failure of an entire backbone carrier, combined
with the failure of all facilities controlled by a collocation operator, would have
no material impact on the service levels provided to customers.
The unprecedented internetworking reliability and minimized resolution latency
****** offers are achieved in part by the implementation of advanced IP Anycast
techniques. The term 'Anycast' describes packets being sent between a single source
and the nearest (in terms of network topology) of several possible destinations
in a group, all having the same IP address. Anycast is different from multicast
(packets between a single source and multiple, unique destinations) and unicast
(packets between a single source and a single destination).
By injecting BGP (Border Gateway Protocol) route announcements from each node,
the system leverages the features of BGP to enable the routing of user queries to
a topologically nearby node, resulting in the following network efficiencies and
advantages:
Reduction of network latency for DNS transactions, as compared with a 'standard'
deployment of DNS services. Reduction in the number of queries routed to distant
servers, thereby reducing the likelihood of encountering congested routers. Reduction
in the number of query packets that are dropped, and which then result in DNS timeouts/retries.
Improved performance and reliability to the end user. Utilizing Anycast, the same
six IP addresses are announced in different combinations from each DNS resolver
in the network infrastructure. This implementation provides additional redundancy
in the face of network routing problems that can be caused by third parties. In
the unlikely event that one or more of the IP addresses become unreachable, queries
from users are seamlessly directed to an alternate node, which is also announcing
the same IP address.
Anycast allows the geographical distribution of requests to any available DNS
resolver for redundancy to effectively distribute traffic/requests to any given
IP address globally, and to increase responsiveness of the overall system by using
the closest (in terms of network topology) available resource to answer any query
that enters the system."
... That's what "Managed DNS" is all about,
Charlie Brown.
For the time being, I will protect the identity of the company - just in
case RF Cafe does not realize the anticipated gain.
Posted January 10, 2008
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