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Hosting reliability and uptime |
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Hosting uptime refers to the percentage of time the host is accessible via the internet. Many providers state that they aim for a 99.9% uptime, but there may be server restarts and planned (or unplanned) maintenance in any hosting environment. A common claim from the popular hosting providers is '99% or 99.9% server uptime' but this often refers only to a server being powered on and doesn't account for network downtime. Real downtime can potentially be larger than the percentage guaranteed by the provider. Many providers tie uptime, and accessibility, into their own Service Level Agreement, or SLA. SLAs may or may not include refunds, or reduced costs if performance goals are not met.
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Types of hosting |
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Hosting services limited to the Web:
- Free web hosting service: is free, (sometimes) advertisement-supported web hosting, and is often limited when compared to paid hosting.
- Shared web hosting service: one's Web site is placed on the same server as many other sites, ranging from a few to hundreds or thousands. Typically, all domains may share a common pool of server resources, such as RAM and the CPU. A shared website may be hosted with a reseller.
- Reseller web hosting: allows clients to become web hosts themselves. Resellers could function, for individual domains, under any combination of these listed types of hosting, depending on who they are affiliated with as a provider. Resellers' accounts may vary tremendously in size: they may have their own virtual dedicated server to a colocated server.
- Virtual Dedicated Server: dividing a server into virtual servers, where each user feels like they're on their own dedicated server, but they're actually sharing a server with many other users. The users may have root access to their own virtual space. This is also known as a virtual private server or VPS.
- Dedicated hosting service: the user gets his or her own Web server and gains full control over it (root access for Linux/administrator access for Windows); however, the user typically does not own the server. Another type of Dedicated hosting is Self-Managed or Unmanaged. This is usually the least expensive for Dedicated plans. The user has full administrative access to the box, which means the client is responsible for the security and maintenance of his own dedicated box.
- Managed hosting service: the user gets his or her own Web server but is not allowed full control over it (root access for Linux/administrator access for Windows); however, they are allowed to manage their data via FTP or other remote management tools. The user is disallowed full control so that the provider can guarantee quality of service by not allowing the user to modify the server or potentially create configuration problems. The user typically does not own the server. The server is leased to the client.
- Colocation web hosting service: similar to the dedicated web hosting service, but the user owns the colo server; the hosting company provides physical space that the server takes up and takes care of the server. This is the most powerful and expensive type of the web hosting service. In most cases, the colocation provider may provide little to no support directly for their client's machine, providing only the electrical, Internet access, and storage facilities for the server. In most cases for colo, the client would have his own administrator visit the data center on site to do any hardware upgrades or changes.
- Clustered hosting: having multiple servers hosting the same content for better resource utilization.
- Grid hosting : this form of distributed hosting is when a server cluster acts like a grid and is composed of multiple nodes.
- Home server: usually a single machine placed in a private residence can be used to host one or more websites from a usually consumer-grade broadband connection. These can be purpose-built machines or more commonly old PC's.
Some ISP's actively attempt to block these servers by disallowing incoming requests to TCP port 80 of the user's connection and by refusing to provide static IP addresses.
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Some specific types of hosting provided by web host service providers:
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Bandwidth & Connectivity |
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Bandwidth
refers to
the data
transfer
rate or the
amount of
data that
can be
carried from
one point to
another in a
given time
period
(usually a
second) and
is often
represented
in bits (of
data) per
second
(bps). For
example,
visitors to
your server,
web site, or
applications
utilize
bandwidth as
the traffic
moves from
your server
to the
Internet and
vice versa.
Connectivity
refers to
the “access
providers”
that supply
bandwidth,
or data
transfer
rate,
through
various
connection
points
across a
network or
footprint to
one or
multiple
data centers
where
dedicated
servers are
housed.
Bandwidth
measurements
are defined
(per telecom
standards)
as the
following:
First – 95th
(measured
using
average bits
and speed of
transfer)
Second –
Unmetered
(measured in
speed or
bits)
Third –
Total
Transfer
(measured in
bytes
transferred)
95th Method:
Line Speed,
billed on
the 95th
percentile,
average or
peak usage,
refers to
the speed in
which data
flows from
the server
or device.
The
measurement
can be
compared to
mph (Miles
Per Hour),
or how fast
something
travels.
Line Speed
is measured
using bits
per second,
kilobits per
second,
megabits per
second, and
gigabits per
second.
Unmetered
Method: The
second
bandwidth
measurement
is Unmetered
service
where
providers
cap or
control the
“top line”
speed for a
server. Top
line speed
in Unmetered
bandwidth is
the total
Mbit/s
allocated to
the server
and
configured
on the
switch
level. For
example, if
you purchase
10 Mbit/s
Unmetered
bandwidth,
the top line
speed would
be 10 Mbit/s.
10 Mbit/s
would result
in the
provider
controlling
the speed
transfers
take place
while
providing
the ability
for the
dedicated
server owner
to not be
charged with
bandwidth
overages.
Unmetered
bandwidth
services
usually
incur an
additional
charge.
Total
Transfer
Method: Some
providers
will
calculate
the Total
Transfer,
the
measurement
of actual
data leaving
and coming
from the
server,
measured in
bytes.
Measurement
between
providers
varies and
includes one
of the
following
equations:
Method 1:
IN
TRAFFIC +
OUT TRAFFIC
= TOTAL
TRANSFER
Method 2:
IN TRAFFIC =
TOTAL
TRANSFER
Method 3:
OUT
TRAFFIC =
TOTAL
TRANSFER
One of the
reasons
people
choose to
outsource
dedicated
servers is
the
availability
of high
powered
networks
from
multiple
providers.
As dedicated
server
providers
utilize
massive
amounts of
bandwidth,
they are
able to
secure lower
volume based
pricing to
include a
multi-provider
blend of
bandwidth.
To achieve
the same
type of
network
without a
multi-provider
blend of
bandwidth, a
large
investment
in core
routers,
long term
contracts,
and
expensive
monthly
bills would
need to be
in place.
The expenses
needed to
develop a
network
without a
multi-provider
blend of
bandwidth
does not
make sense
economically
for hosting
providers.
Many
dedicated
server
providers
include an
SLA (Service
Level
Agreement)
based on
network
uptime. Some
dedicated
server
hosting
providers
offer a 100%
uptime
guarantee on
their
network. By
securing
multiple
vendors for
connectivity
and using
redundant
hardware,
providers
are able to
guarantee
higher
uptimes;
usually
between
99-100%
uptime if
they are a
higher
quality
provider.
One aspect
of higher
quality
providers is
they are
mostly
likely
multi-homed
across
multiple
quality
uplink
providers,
which in
turn,
provides
significant
redundancy
in the event
one goes
down in
addition to
potentially
improved
routes to
destinations.
Bandwidth
consumption
over the
last several
years has
shifted from
a per
megabit
usage model
to a per
gigabyte
usage model.
Bandwidth
was
traditionally
measured in
line speed
access that
included the
ability to
purchase
needed
megabits at
a given
monthly
cost. As the
shared
hosting
model
developed,
the trend
towards
gigabyte or
total bytes
transferred,
replaced the
megabit line
speed model
so dedicated
server
providers
started
offering per
gigabyte.
Prominent
players in
the
dedicated
server
market offer
large
amounts of
bandwidth
ranging from
500
gigabytes to
3000
gigabytes
using the
“overselling”
model. It is
not uncommon
for major
players to
provide
dedicated
servers with
1Terabyte
(TB) of
bandwidth or
higher.
Usage models
based on the
byte level
measurement
usually
include a
given amount
of bandwidth
with each
server and a
price per
gigabyte
after a
certain
threshold
has been
reached.
Expect to
pay
additional
fees for
bandwidth
overage
usage. For
example, if
a dedicated
server has
been given
3000
gigabytes of
bandwidth
per month
and the
customer
uses 5000
gigabytes of
bandwidth
within the
billing
period, the
additional
2000
gigabytes of
bandwidth
will be
invoiced as
bandwidth
overage.
Each
provider has
a different
model for
billing. As
of yet, no
industry
standards
have been
set. |
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Generic
domain names
— problems
arising out
of
unregulated
name
selection |
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Within a particular top-level domain, parties are generally free to select an unallocated domain name as their own on a first come, first served basis, resulting in Harris's lament, all the good ones are taken. For generic or commonly used names, this may sometimes lead to the use of a domain name which is inaccurate or misleading. This problem can be seen with regard to the ownership or control of domain names for a generic product or service. By way of illustration, there has been tremendous growth in the number and size of literary festivals around the world in recent years. In this context, currently a generic domain name such as literary.org is available to the first literary festival organisation which is able to obtain registration, even if the festival in question is very young or obscure. Some critics would argue that there is greater amenity in reserving such domain names for the use of, for example, a regional or umbrella grouping of festivals. Related issues may also arise in relation to non-commercial domain names.
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Top-level domains |
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A generic top-level domain is a top-level domain used (at least in theory) by a particular class of organization. These are three or more letters long, and are named for the type of organization that they represent (for example, .com for commercial organizations). The following gTLDs currently exist [1] (as does .arpa, which is sometimes considered a gTLD):
- .aero - for the air transport industry
- .asia - for companies. organisations and individuals in the Asia-Pacific region
- .biz - for business use
- .cat - for Catalan language/culture
- .com - for commercial organizations, but unrestricted
- .coop - for cooperatives
- .edu - for post-secondary educational establishments
- .gov - for government entities within the United States at the federal, state, and local levels
- .info - for informational sites, but unrestricted
- .int - for international organizations established by treaty
- .jobs - for employment-related sites
- .mil - for the U.S. military
- .mobi - for sites catering to mobile devices
- .museum - for museums
- .name - for families and individuals
- .net - originally for network infrastructures, now unrestricted
- .org - originally for organizations not clearly falling within the other gTLDs, now unrestricted
- .pro - for certain professions
- .tel - for services involving connections between the telephone network and the Internet (added March 2, 2007)
- .travel - for travel agents, airlines, hoteliers, tourism bureaus, etc.
The following gTLDs are in the process of being approved, and may be added to
the root nameservers in the near future:
- .post - for postal services
- .geo - for geographically related sites
- .cym - for Welsh language/culture
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