Replify Accelerator is a software-based WAN optimization solution that provides protocol optimization, de-duplication, and compression to remove redundant data and improve application performance over wide area networks. It can be deployed as individual clients, virtual appliances in branch offices and data centers, or in hybrid scenarios. Replify Accelerator analyzes application traffic patterns and caches frequently used data to optimize protocols like CIFS, HTTP, and others. This significantly reduces the number of requests and amount of data transferred over latency-heavy WAN links. Reporting tools provide insights into optimization effectiveness and traffic patterns.

1. Replify Accelerator
Technical Overview
October 2010
V1.1
© Replify 2010

2. Replify Accelerator Technical Overview
Table of Contents
Background ............................................................................................................................................. 3
Software-Based WAN Optimization ........................................................................................................ 3
Optimizations .......................................................................................................................................... 4
Protocol Optimization ......................................................................................................................... 5
CIFS Optimization ............................................................................................................................ 5
HTTP Optimization .......................................................................................................................... 5
HTTPS/SSL Optimization ................................................................................................................. 6
Other Protocols ............................................................................................................................... 6
De-Duplication through Replify XDR .................................................................................................... 6
Compression ....................................................................................................................................... 7
Optimization Effectiveness ................................................................................................................. 7
Deployment Scenarios ............................................................................................................................ 8
Branch Office to Data Center .............................................................................................................. 8
Individual Client to Data Center .......................................................................................................... 8
Location Awareness ............................................................................................................................ 9
Multi-Site Deployments ...................................................................................................................... 9
Reporting Functionality......................................................................................................................... 10
Technical Requirements........................................................................................................................ 11
Component Overview ....................................................................................................................... 11
Replify Virtual Appliance ............................................................................................................... 11
Replify Client ................................................................................................................................. 11
Replify Enterprise Manager .......................................................................................................... 12
Extending WAN Optimization ............................................................................................................... 12
Summary ............................................................................................................................................... 12
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3. Replify Accelerator Technical Overview
Background
Company networks are changing. Site and server consolidation is moving IT infrastructure from
branch offices to central locations, cloud computing is beginning to deliver IT services externally,
and users are needing more flexibility
to move between offices, work from
home and work remotely while
travelling. These changes mean that
more and more users are working Server
Cloud Services
Consolidation
remotely from the applications they
are accessing day-to-day.
The applications that users are Remote
accessing are also becoming more Workers
network dependent, providing richer
experiences through web 2.0 interfaces, providing advanced collaboration capabilities, or allowing
users to participate in complex business processes.
More remote users and more content-heavy applications are pushing the requirement for WAN
Optimization technology. Replify Accelerator provides software-based WAN optimization focusing
on the user’s experience with the applications they use.
Software-Based WAN Optimization
Traditional approaches to WAN optimization have made networks more efficient by providing a
hardware device located at each side of the network. These hardware devices control the
connection to the network and provide efficiencies. Hardware based solutions provide great
optimization but introduce deployment problems – IT management required on each side of the
network, costly purchase and upgrade processes, inability to support cloud scenarios or individual
remote workers. Hardware vendors are beginning to provide their capabilities in software –
however this has required re-engineering of their solutions leading to limited software versions
which remain as costly as their hardware predecessors.
Replify Accelerator has been designed from the beginning to provide the capabilities of hardware
based WAN optimization entirely in software – with algorithms appropriate to meet the
requirements of low-footprint clients, and virtualized commodity servers.
As a software-based WAN Optimization solution, Accelerator has the following advantages:
Full optimization capabilities within an individual client or software appliance
Easy to deploy within cloud infrastructures
Extensive optimizations efficiently in software
Straight-forward deployment, without changing the network
Targeted acceleration for problem applications or specific users
Scales up and down without friction as needs change
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4. Replify Accelerator Technical Overview
Replify Accelerator intercepts traffic destined for accelerated application servers, routing the traffic
through the Replify software on the client side of the network (either an individual PC client, or
through a shared virtual appliance). The client side software routes traffic to the Replify server-side
appliance. With traffic routed through Replify Accelerator on both sides of the network, the Replify
software can remove redundant unnecessary calls across the network, pre-fetch and bulk transfer
and remove as many bytes from the transfer. All traffic destined for the application server is routed
through Replify Accelerator, allowing the acceleration software to learn traffic patterns and provide
the maximum optimization.
Mobile
worker
Mobile
worker DATA
Mobile CENTE
worker WAN R
Branch
Office
Routing of the application server traffic is performed through a number of possible techniques:
Individual client intercepts traffic destined for application servers
The local virtual appliance acts as the default gateway for a branch or remote office
Traffic in a site is routed to the local virtual appliance using policy based routing
Traffic in a site is routed through the WCCP protocol which automatically routes traffic to be
optimized via the local Replify virtual appliance
Static routing is configured between clients and the local virtual appliance
Once the traffic is routed through Replify Software within the client network, it is then optimized
and passed through the server-side virtual appliance. The server-side virtual appliance re-creates
the original network request and sends it on to the application server being accelerated. Any
response from the application server goes through the same process in reverse back to the user.
By understanding the traffic patterns and connections being made between the client and the
application servers across the WAN, Replify Accelerator can remove redundant calls, and remove as
many bytes as possible transferring across the WAN link.
Optimizations
Replify Accelerator provides comprehensive WAN Optimizations specifically designed for the
requirements of software-based scenarios. Accelerator provides three categories of optimization:
Protocol Optimization
De-duplication through Replify XDR
Compression
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5. Replify Accelerator Technical Overview
Protocol optimization is the only optimization which is directly dependent on the actual protocol
being used across the network. De-duplication and compression provide benefits regardless of the
protocol or data being transferred.
Protocol Optimization
Protocol optimization looks at the message sequences for specific protocols, and ensures that
redundant requests are removed and not passed over the WAN connections. The Replify client or
client-side virtual appliance recognizes requests made to application servers and identifies the
protocols being used within the requests. Many protocols do not make the most efficient use of the
network, making requests across the network which are not required, or which ask for information
in small, inefficient amounts.
Replify provides a number of protocol optimizations to make protocols more efficient. These
combine with the other optimizations to ensure that traffic to and from systems such as email (via
MAPI or HTTPS), file shares, collaboration and ERP applications are fully optimized.
CIFS Optimization
A typical example of an inefficient protocol is the Common Internet File System (CIFS) protocol. CIFS
provides the file share capabilities built into Windows based solutions. The CIFS protocol was not
designed with wide area networks in mind – it transfers information across the network in small
requests, resulting in very inefficient use of the network for large files. Small requests across the
network are very sensitive to any latency on the connection which results in the end user experience
suffering.
Replify Accelerator intercepts CIFS requests made across the network and identifies when large
content is about to be transferred. Instead of making small requests for the content across the
WAN, Replify Accelerator pre-fetches blocks of content in a pre-fetch buffer. Accelerator then
serves content from the pre-fetch buffer on the client side of the network instead of making further
small requests across the network.
WAN
Pre-fetching significantly decreases the number of requests across the network, and avoids the
latency of the network affecting the end user experience. For example, the number of requests for a
2Mb file across a wide area network with 200ms latency decrease from 234 requests down to 3
requests with Accelerator pre-fetching. This decreases a user’s wait time from over a minute to 15
seconds. See the Replify CIFS whitepaper for more information on Accelerator’s CIFS optimizations.
HTTP Optimization
Replify Accelerator’s HTTP Optimization includes header identification and manipulation, NTLM
authentication pooling, and HTTP de-chunking. These protocol optimizations focus on ensuring that
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6. Replify Accelerator Technical Overview
the block caching and compression optimizations work effectively on the largest possible data within
the network request.
HTTPS/SSL Optimization
Often connections across the WAN are encrypted using HTTPS/SSL encryption. Encryption ensures
communication is private. To an observer it appears as if the requests contain random data even if
the same requested document is being returned. This encryption can prevent pattern matching and
compression optimizations built into a WAN optimization system from operating.
Replify Accelerator provides optimization for encrypted information – ensuring patterns are
recognized between requests, and allowing compression to work effectively. Optimizing encrypted
information involves providing the Replify Virtual Appliance within the data center with the
certificate of any encrypted application server. Certificates never move outside the data center. All
data transferred from client to Replify VAs on to the target application server will continue to be
made over fully encrypted connections, ensuring the privacy of the communication is maintained.
See the Replify SSL whitepaper for more information on Accelerator’s optimizations in encrypted
scenarios.
Other Protocols
Accelerator has various other optimizations that help identify and accelerate traffic for particular
protocols. Other protocols currently supported include MAPI (via RPC or over HTTP), print servers,
DoubleTake, iSCSI, RDP, SQL and VNC. If a protocol is not currently identified by Replify Accelerator,
it will still be optimized through de-duplication and compression. Replify is continuing to enhance
Accelerator with new protocols at each release.
De-Duplication through Replify XDR
XDR is a key technology of the Replify Accelerator product. XDR de-duplicates patterns of information
as the information passes across the network. It is bi-directional, replacing patterns of data with
cache references as information is sent to, or received from, the application servers.
As Accelerator is used to optimize connections to an application server, the XDR technology learns
the patterns being transferred between users and the server. If any pattern is seen more than once,
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7. Replify Accelerator Technical Overview
a reference to the pattern is sent across the network instead of the original block of data. This
removes considerable traffic from the network for similar content.
The algorithms built into the XDR technology ensure that Replify Accelerator can quickly determine if
a pattern within traffic passing across the network has previously been seen and can be replaced
with a reference. The cache size available for XDR is configurable. The XDR technology ensures that
patterns seen most frequently remain within the cache and patterns which are infrequently used are
dropped from the cache. XDR can make use of in-memory and disk-based cache to ensure the
maximum throughput possible.
In office-to-office scenarios, with a local virtual appliance in each office, XDR provides shared caching
for all users in the office, providing greater optimizations for all. Since the cache is based on content
that would be sent or received by individual users, security of the content is always maintained.
XDR works regardless of the type of traffic or application server, and detects patterns across multiple
unrelated applications. For example if similar content is seen in an email attachment and a file share
copy. XDR is extremely successful within collaboration scenarios where information is retrieved,
changed and uploaded again. Since it is bi-directional, and protocol independent, XDR will replace
data with references if, for example, a user downloads a file from a content management application
and subsequently sends it within an email.
See the Replify XDR whitepaper for more in-depth information on Accelerator’s de-duplication
functionality.
Compression
The final step in Replify Accelerator’s optimizations is to compress any remaining information which
would be sent across the wide area network. With modern data types like HTML and XML being text
based – and with the frequent transfer of text-based content, compression plays an important part
in removing bytes from the network by minimizing the data that needs to be transferred.
Compression is also very effective on print traffic.
Optimization Effectiveness
Replify Accelerator’s various optimizations combine to remove a high percentage of bytes from the
network, and improve the user experience to applications across remote connections. Accelerator
typically takes between 70 and 90% of information away from the network, depending on the data
and patterns of information passing across the network.
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8. Replify Accelerator Technical Overview
Deployment Scenarios
As a software-based solution Replify Accelerator has the widest deployment capabilities. It can be
deployed easily to cloud or highly distributed scenarios and can accelerate individual connections
through a client installation on a laptop.
All deployments can be installed and configured centrally without the need for end-user
involvement. The software can be reconfigured centrally through the administration interfaces, or
through active directory.
Branch Office to Data Center
For branch offices with a number of users and with some IT infrastructure, a Replify Accelerator
Virtual Appliance can be deployed within the branch office site. This branch office virtual appliance
is peered with the virtual appliance on the data center side – and provides the local Replify
Accelerator capabilities for all the users within the branch office site. User’s access to the
application servers must be routed through their local virtual appliance. This routing can be done
through configuration, by using the WCCP protocol, by configuring the virtual appliance as a
gateway, or by using the Replify client. Optimization can be provided without requiring a software
installation on the client machines.
Individual Client to Data Center
For branch offices without IT Infrastructure, or for users travelling or working from home, Replify
provides an individual client that provides the same optimizations as the virtual appliance within the
branch office. The low-footprint client can be installed and configured without end-user
involvement. The client runs as a local service intercepting traffic destined for the application
servers, and routing the traffic to the remote virtual appliances. The client can run invisibly to the
end-user.
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9. Replify Accelerator Technical Overview
Location Awareness
Typically, users connect from a range of different locations – moving between offices, working from
home or on the road. This means that a static deployment with users always being accelerated
through the same office-based virtual appliance would not work for many scenarios. Replify
Accelerator’s location awareness can automatically determine the location for a connecting user,
and connect to the most appropriate virtual appliance. For example, while the user is within an
office, the Accelerator routes the traffic through the local office virtual appliance, thereby taking
advantage of the shared cache provided within the local virtual appliance. When outside the office,
traffic will be optimized by the local client running on the user’s machine. Location Awareness is
achieved by understanding the network addresses that users connect from, or by tagging users
belonging to particular groups.
Multi-Site Deployments
Many real world scenarios deployments are complex – all applications and file servers are not
centralized in a data center, but are distributed throughout a number of branch offices. Replify
Accelerator works in a distributed environment by ensuring that office-based virtual appliances
behave not just as branch office client accessing data center virtual appliances, but also accelerate
access to application servers available locally within their own networks. Replify uses a combination
of location awareness, virtual appliance peering, and client tagging to accelerate traffic for remote
users accessing applications wherever they are located. A Replify Accelerator system can be
configured to include multiple virtual appliances to provide failover and resilience.
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10. Replify Accelerator Technical Overview
Reporting Functionality
The Replify Virtual Appliances and Enterprise Manager both provide comprehensive reporting
functionality on the optimizations that are being provided for particular sites, for specific application
servers, for groups of users and right down to the optimizations provided for individual users. The
reporting functionality clearly shows the data savings that are delivered by Replify Accelerator.
1 Optimization by Protocol
2 Live Traffic View showing actual (optimized) and effective (raw) traffic
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11. Replify Accelerator Technical Overview
3 Traffic by Protocol
Technical Requirements
Component Overview
Replify Virtual Appliance
Replify Virtual Appliances installed within operational sites create an acceleration mesh which
optimizes inter-site traffic between the chosen applications and end-users.
The Virtual Appliance can run on commodity hardware within almost any virtualization hosting
environment required. Replify provides images for all the common virtualization platforms.
Memory requirements for the virtual appliance are dependent on the traffic, number of users and
the amount of caching desired. The virtual appliance can run in as little as 350Mb of memory for
non-cached scenarios. For typical deployments with caching we recommend 2Gb of RAM.
The processor and disk requirements are again dependent on traffic, users and caching. We
recommend assigning dual processors to the virtual appliance, and 40Gb of disk space if caching is
required.
Replify Client
The Replify Client is a Windows service which is installed on the end-point devices. The Replify Client
can provide application acceleration in exactly the same way as a Virtual Appliance, but for an
individual device. Client intelligence called “location awareness” means that the client will use a local
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12. Replify Accelerator Technical Overview
Virtual Appliance if one is present, giving the additional benefit of shared caching across multiple
users.
Processor and memory overhead of the Replify Accelerator windows client is negligible. Disk usage
depends on the cache configured for each user.
Replify Enterprise Manager
The Replify Enterprise Manager (REM) provides centralized configuration and control of your Replify
deployment, with detailed reporting on all of your Clients and Virtual Appliances. The REM provides
Clients and VAs with their application acceleration rules and also controls the licensing across an
enterprise or managed service provider.
The REM processor and memory requirements are dependent on the number of users in the overall
system. Disk usage is negligible. For typical scenarios we recommend assigning a REM with 512Mb
of memory and a single processor.
For detailed sizing of a Replify Accelerator system which is specific to a particular scenario, please
contact Replify Support (support@replify.com).
Extending WAN Optimization
Replify Accelerator ensures that network connections between users and applications are used as
efficiently as possible. In many scenarios, however, a user cannot depend on the availability or
quality of a network. Network issues should not stop the user from accessing, updating and adding
to information within mission critical applications accessed across the network. Replify works to
improve Remote Application Usability, even in scenarios where network is not always available.
Accelerator’s companion product Replify Syncstor provides a synchronized store allowing users
frustration-free uninterrupted access to application content regardless of the status of their network
connection. For more information on Replify Syncstor, see http://www.replify.com/products/replify-
syncstor/
Summary
Replify Accelerator’s unique software-based WAN optimization functionality provides significant
acceleration of network connections, improving usability for users accessing applications remotely.
The software is designed to meet a very broad range of deployment needs including highly dispersed
offices and large numbers of remote users. Protocol optimizations, bi-directional, block level de-
duplication and compression combine to provide 70-90% offload in typical scenarios. The software-
only algorithms are designed to provide optimizations in low-footprint installations with commodity
hardware.
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