A typical Meru deployment requires 30% fewer access points than a
similar deployment from any competitor. This is because all Meru radios
can transmit at their full power, whereas other systems require that
each access point's power level be adjusted to avoid interference.
Reducing power results in a complex microcell architecture in which cells
continually shrink as new access points are added. In contrast, access
points that are part of a Meru Virtual Cell augment rather than
interfere with each other. All can transmit simultaneously at full power.
I Need To Compare Meru WLAN Virtualization
& Legacy WLAN Solutions
There are many wireless LAN infrastructure vendors in business today. They all seem to make the same claims: They will make your life easier, enable mobility, keep end-users happy and save you money. However, since most of them use the same basic microcell architecture and offer the same features, they all run into the same problems – unreliable wireless connectivity, poor roaming, limited scalability and complex management.
Meru really is different. To see how, ask other wireless vendors each of these ten questions that cover the most critical aspects of wireless networking – from installation to upgrades to cost. Meru beats competitors in every one of them.
1. How many access points do I
need?
2. How much channel planning is required?
The same interference that forces access points to turn down their
power also forces adjacent access points to use
non-overlapping channels. Calculating the power level and channel
setting of each access point is a complex process, requiring
specialized software that often makes inaccurate predictions about
coverage. Upgrading to 802.11n makes the whole process even worse, as
multipath effects make the coverage of 802.11n access points inherently
unpredictable. With Meru, no channel planning is needed. All radios in
a Virtual Cell can use the same channel without interference.
3. What do moves and changes entail?
Microcell channel planning isn't a one-time activity. It needs to be
repeated every time an access point is added to a network or moved,
because
a new access point causes more interference that neighbors must retune
to avoid. Even moving a cabinet around can change the RF coverage
available to wireless clients and potentially create a coverage hole.
With Meru, adding new access points to fill coverage holes or extend
coverage to new areas is as simple as changing a lightbulb. Each new
access point uses the same channel and transmits at the same maximum
power as every other access point within the Virtual Cell.
4. How long is the roaming latency?
Microcell systems force clients to decide for themselves which access
point they should connect to. The client must constantly scan each
channel, then try to guess when it should disconnect from one access
point and connect to another. This often causes noticeable delays,
especially in voice networks, and can even sever a connection
completely. Meru avoids the problem by virtualizing the link. Clients
remain connected to the same Virtual Port wherever they move in the
network, with zero handoff latency.
5. How great a bandwidth density can the network scale
to?
With Meru, bandwidth scales linearly as new radios are added. Each
new radio can service a different Virtual Cell on a different radio
channel, boosting the network to support higher user densities or new
applications. Microcell networks don't scale so well, as much of the
available spectrum is already consumed with mitigating interference. At
2.4
GHz., this makes Meru the only vendor able to support the full 40 MHz.
channels without co-channel interference. At 5 GHz., a Meru network can
scale almost without limit, with multiple network segments layered in
the same physical space.
6. How good do VoIP calls sound?
Every vendor claims to offer the highest quality-of-service for VoIP
traffic, but most fall short of toll-quality when their sound quality
is measured objectively. In independent tests by Novarum, the Mean
Opinion Score (MOS) of VoIP devices on a Meru network was 4.38 –
greater than the 4.0 usually considered toll quality. For
comparison, cell phones tend to score between 3.0 and 4.0, while Meru's
two largest competitors scored below 3.0 on the same tests.
7. How predictable is the network's performance?
Vendors love to promote their maximum data rates, minimum roaming
times or best MOS scores. But the worst cases are often more important,
as they represent the problems that users will notice. Meru's Virtual
Port makes performance consistent and controllable, eliminating
contention for access to the medium. Each packet at a given
quality-of-service level is given equal treatment, making the standard
deviation in most performance metrics less than 10%. The result is low
jitter as well as low latency.
8. Do slower clients drag down 802.11n performance?
Most wireless access points are like Ethernet hubs. Clients contend
for access randomly, with no guarantees that any will be able to
transmit a packet. Once they do, each is allowed to send roughly the
same amount of data – a serious problem when 802.11n needs to
coexist with legacy clients, as slower devices take longer to transmit
the same number of bytes. The slowest client ends up dominating the
network, wasting much of the investment in 802.11n infrastructure. Meru
prevents this with airtime fairness, giving each client an equal share
of the network's time. Each client can transmit at it's own maximum
speed during
that time. Data rates are negotiated individually as in an Ethernet
switch.
9. Where is the network secured?
Like most other enterprise vendors, Meru includes WPA and WPA2
Enterprise security that encrypts all traffic over the air and requires
strong authentication. A widely supported standard, this makes wireless
networks stronger at the network layer than most wired networks. But
Meru does not rely on this alone. It also offers true physical layer
security as an additional layer of defense. By preventing radio signals
from particular networks from crossing a physical perimeter, physical
layer security can do for
802.11 what walls, gates and security guards do for wired Ethernet.
10. Can access points monitor the network while serving
voice traffic?
Most enterprise wireless LAN vendors include some kind of security
and management scanning, with access points able to double as sensors
that detect rogues or intruders. However, neither of Meru's two largest
competitors can do both at the same time: Their products must act as
either access points or sensors. This is a severe problem with
VoIP and other real-time traffic, because voice packets must be sent so
frequently that an access point does not have time to switch to and from
sensor mode between transmissions. Meru is different, with access
points able to scan for threats while serving voice clients.

