The proliferation of IT equipment associated with
remote offices is a major IT concern.
Maintaining servers and applications at remote locations is
often problematic, and remote office backups are frequent
problem areas for non-IT staff. Consolidation has emerged as a
way to ease these problems. Instead of maintaining ad hoc IT
infrastructures at each remote office, consolidation moves the
IT resources back to a main data center, allowing centralized
applications and data to be accessed remotely across a wide area
network (WAN) link. Wide area file services (WAFS) is a key
technology for this type of centralization, allowing real-time,
read-write data access. Since data demands WAN bandwidth, WAN
optimization is often equally important, using a variety of
technologies to pass more data in less time, speeding data
transfers and saving bandwidth costs.
But, WAFS and WAN optimization products should be evaluated very
carefully. Now that you've reviewed the
essential issues involved in any backup
acquisition, this guide focuses on specific considerations
for WAFS and WAN optimization products. You'll also find a
series of specifications to help make on-the-spot product
comparisons between vendors, like Certeon Inc., Cisco Systems
Inc., F5 Networks Inc., Juniper Networks Inc., Riverbed
Technology Inc, Silver Peak Systems Inc. and more.
Consider the difference between product types and terms.
WAFS products typically allow for continuous read-write access to
centralized data, low latency and effective data transfer speeds
similar to LAN speeds. By comparison, WAN optimization products use
compression and data acceleration techniques to pass more data
using less bandwidth. It's important to note that these products
serve two distinctly different purposes. Some WAFS products include
WAN optimization features, but it's not universal, and the two
products can exist separately. Also, remember that vendors may rely
upon their own unique definitions of these technologies. For
example, Cisco calls this wide area application services (WAAS).
Always perform a comprehensive review of features before making any
product choice.
Consider the bandwidth and connectivity requirements.
WAFS and WAN optimization products all rely on a WAN link, so
understand exactly what types of WAN attributes the product will
support. For example, some products may demand T1 connectivity,
while other products may work over an ordinary Internet connection.
Evaluate the level of bandwidth needed to support each remote
office or location. As bandwidth costs increase, WAN optimization
features can help to mitigate bandwidth requirements. It's also
helpful to evaluate the supported transports, such as multiprotocol
label switching (MPLS), IP VPN, satellite, frame relay, ATM or
other supported transports to ensure that the product is fully
compatible with your infrastructure.
Consider local caching and cache behavior. While
connectivity and bandwidth are vital considerations, it may be even
more important to evaluate the impact of connectivity loss.
Generally speaking, WAFS works by retrieving files from the data
center across a WAN and caching those files on local storage where
users can access the data quickly. Changed files can then be sent
back across the WAN to the data center as bandwidth allows.
However, understand what happens when the WAN link is disrupted.
Ideally, any files currently in the local cache will still be
accessible, and the WAFS product will resynchronize its data with
the data center once the WAN is restored. Also consider the impact
of multiple iterations of a file -- recognize how the WAFS product
handles multiple people working on the same file simultaneously and
how WAN disruptions will affect those activities.
Consider data reduction techniques. WAN optimization
applies compression and data reduction techniques to reduce the
volume of data that needs to pass between the data center and
remote location. For example, Availl Inc. claims a 95% reduction in
traffic through byte-level differencing and compression. Cisco
claims a 100-to-1 reduction in bandwidth utilization by eliminating
redundant data and LZ compression. Citrix Systems Inc. claims an
astonishing 3,500-to-1 reduction in data by applying a variety of
compression/data reduction schemes. Data reduction will ideally
reduce bandwidth requirements, but not all data compresses the same
way. It's important to evaluate the techniques used in any
prospective product, and gauge its effectiveness on your typical
data volumes.
Consider the supported applications. WAFS products
typically support a wide range of enterprise applications, but
verify that the applications or file types used in your
organization are properly supported by a prospective WAFS product.
For example, the WAFS software from Availl claims support for all
standard file types. By comparison, wide-area data services (WDS)
appliances from Riverbed Technology Inc. claim support for all
enterprise traffic, including file, email, document management,
enterprise resource planning (ERP), customer relationship
management (CRM), Web (HTTP) applications, backup and replication.
The S-Series Application Acceleration appliances from Certeon Inc.
break the list down even further, citing the above application
types along with applications in XML, SOAP, Javascript, J2EE and so
on. (See the WAFS/WAN product specification snapshots for more
details). Careful in-house testing can help to ensure adequate
application performance across a WAFS platform.
The WAFS and WAN optimization product specifications page in
this chapter covers the following products:
- Availl Inc.; WAFS Multi-Directional software
- Certeon Inc.; S-2000 Application Acceleration
Appliance
- Certeon Inc.; S-3000 Application Acceleration
Appliance
- Cisco Systems Inc.; WAAS software and WAE family of
appliances/modules
- Citrix Systems Inc.; WanScaler 8500 WAN accelerator
appliance
- Citrix Systems Inc.; WanScaler 8800 WAN accelerator
appliance
- Expand Networks Inc.; WAFS Plug-in software for Expand
Accelerators
- F5 Networks Inc.; WANJet 200 application optimization
appliance
- F5 Networks Inc.; WANJet 400 application optimization
appliance
- Juniper Networks Inc.: WX 100 Application Acceleration
Platform
- Juniper Networks Inc.: WXC 250 Application Acceleration
Platform
- Juniper Networks Inc.: WXC 500 Application Acceleration
Platform
- Juniper Networks Inc.: WXC 590 Application Acceleration
Platform
- Packeteer Inc.; iShared appliance
- Packeteer Inc.; SkyX accelerator appliance
- Riverbed Technology Inc.; Steelhead WDS Appliances Models 100,
200
- Riverbed Technology Inc.; Steelhead WDS Appliances Models 520,
1020, 1520, 2020
- Riverbed Technology Inc.; Steelhead WDS Appliances Models 3020,
3520, 5520, 6020
- Silver Peak Systems Inc.; NX-2500 WAN acceleration
appliance
- Silver Peak Systems Inc.; NX-3500 WAN acceleration
appliance
- Silver Peak Systems Inc.; NX-5500 WAN acceleration
appliance
- Silver Peak Systems Inc.; NX-7500 WAN acceleration
appliance
- Silver Peak Systems Inc.; NX-8500 WAN acceleration
appliance
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