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Manual Chapter: Introducing BIG-IP WAN Optimization
Manual Chapter
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The BIG-IP® WAN Optimization Module increases distributed application performance by optimizing, thus reducing, the amount of data that is transferred over a wide area network (WAN). Deployed as BIG-IP systems on either side of a WAN, WAN Optimization Modules accelerate all TCP traffic including CIFS, MAPI, FTP, and other common protocols. You can use the WAN Optimization Module to optimize applications such as file transfer, email, client-server applications, and data replication, resulting in increased performance for users. Paired WAN Optimization Modules, called local and remote endpoints, can optimize up to 20,000 connections.
WAN optimization and acceleration capabilities are tightly integrated into Traffic Management Operating System (TMOSTM) and BIG-IP Local Traffic Manager. The WAN Optimization Module operates on various BIG-IP hardware platforms that scale from branch office to data center appliances. You can add optimization capabilities to existing BIG-IP Local Traffic Manager deployments, or deploy additional BIG-IP systems for WAN optimization. Local and remote WAN Optimization Modules work transparently across all wide-area network links, including dedicated, frame relay, and satellite connections.
The WAN Optimization Module gathers application knowledge, analyzes data streams, and determines how to optimize the data most efficiently. The WAN Optimization Module incorporates technologies including symmetric adaptive compression, data deduplication, adaptive TCP optimization, QoS and rate shaping, and site-to-site encryption.
Data deduplication decreases the amount of bandwidth that repeated data transfers consume across a WAN link, and symmetric adaptive compression reduces the amount of data that the system needs to transfer. Adaptive TCP optimization enables the WAN Optimization Module to adapt to the characteristics of WAN links, and then to accelerate application traffic. Layer 7 QoS and rate shaping policies let you assign more bandwidth to critical network traffic. The WAN Optimization Module uses SSL encryption to protect the traffic moving from site to site.
The BIG-IP WAN Optimization Module is one of several products that constitute the BIG-IP product family. All BIG-IP products run on the Traffic Management Operating System, commonly referred to as TMOS. For an overview of the complete BIG-IP product offering, see the introductory chapter of the TMOSTM Management Guide for BIG-IP® Systems.
The WAN Optimization Module employs adaptive TCP optimization to speed up traffic by fully using available bandwidth over the WAN. TCP optimization includes techniques such as session-level application awareness, persistent tunnels, selective acknowledgements, error correction, and optimized TCP windows. These techniques enable the WAN Optimization Module to adapt, in real time, to the latency, packet loss, and congestion characteristics of WAN links, and accelerate virtually all application traffic.
F5 Networks' symmetric data deduplication technology reduces the amount of bandwidth consumed across a WAN link for repeated data transfers. For example, without data deduplication, a 1 MB file transferred across a WAN link by 100 different users would consume 100 MB of bandwidth. With data deduplication, the same transfer consumes less than 10 MB of bandwidth. This is a reduction of more than 90% in WAN traffic volume.
With data deduplication, the system performs pattern matching on the data rather than caching. As a result, a user can change the name or edit the contents of a file and still experience the same dramatic performance improvement with data deduplication.
The WAN Optimization Module implements data deduplication to maximize bandwidth savings while minimizing processing latency. Data deduplication technology examines the transmitted data to determine whether any part of it has been previously sent. If so, the WAN Optimization Module replaces the previously transmitted data with references.
Symmetric data deduplication routines identify and remove all repetitive data patterns on the WAN. As data flows through the two WAN Optimization Modules, each one records the byte patterns and builds a synchronized dictionary. If an identical pattern of bytes traverses the WAN more than once, the WAN Optimization Module nearest the sender replaces the byte pattern with a reference to it, compressing the data. When the reference reaches the remote WAN Optimization Module, it replaces the reference with the data, restoring the data to its original format.
Client A requests a file from the corporate server. The server on which the file is stored returns the file to Client A. The WAN Optimization Modules on two BIG-IP systems copy the data to RAM or onto disk.
The WAN Optimization Module on the local endpoint requests the data from the corporate server. The remote endpoint gets the data and looks for patterns it has seen before and sends references for any matching patterns, instead of resending all the data over the WAN. The local endpoint then replaces the references with the data and sends the entire file to Client B.
After symmetric data deduplication removes all previously transferred byte patterns, the WAN Optimization Module applies a second level of data reduction routines called symmetric adaptive compression. While data deduplication focuses on repeat transfer performance, symmetric adaptive compression improves first transfer performance by examining smaller repetitive patterns.
Symmetric adaptive compression handles the data that remains after data deduplication processing by using intelligent network and application-aware routines that encode the remaining data in as few bytes as possible, improving performance for WAN users.
Common Internet File System (CIFS) is a remote file access protocol that forms the basis of Microsoft® Windows file sharing. CIFS is the Microsoft protocol most commonly used to transfer files over the network. The WAN Optimization Module can optimize CIFS traffic, resulting in faster performance during file transfer, when downloading or saving files, when opening Microsoft applications, and when browsing directories on networked drives.
MAPI (Messaging Application Program Interface) is the email protocol that Microsoft® Exchange Server and Outlook® clients use to exchange messages. It enables applications to send and receive email (with document attachments) and calendar appointments. The WAN Optimization Module can optimize MAPI traffic to reduce the amount of bandwidth required to transfer the traffic across the WAN for any application that uses MAPI.
Using dynamic discovery, you can configure the WAN Optimization Module to automatically locate remote endpoints and the networks that they serve. Instead of having to reconfigure the system when other offices install new endpoints, the WAN Optimization Module continuously examines requests to new hosts to see whether a remote endpoint exists on the other side of the WAN. If the WAN Optimization Module locates a remote endpoint and can authenticate it, the WAN Optimization Module adds the remote endpoint to its list. The WAN Optimization Module optimizes subsequent requests to a host if the local and remote endpoints are configured to optimize that type of traffic.
You can use the WAN Optimization Module as a symmetric SSL proxy to optimize application traffic that is encrypted with the Secure Sockets Layer (SSL) protocol. The WAN Optimization Module can decrypt, optimize, and then re-encrypt SSL traffic on both sides of the network to provide accelerated delivery of applications that run over SSL. This configuration does not require distribution of certificates or private keys to each remote device.
An iRule is a customized script that controls the behavior of connections on the BIG-IP system. You can use iRules to perform advanced operations on traffic that the WAN Optimization Module is optimizing. iRules let you fine-tune the performance of TCP, symmetric adaptive compression, symmetric data deduplication, CIFS, and MAPI traffic. Documentation and sample iRules are located on F5 Networks DevCentral web site (
Two BIG-IP systems with WAN Optimization Modules use SSL to encrypt and decrypt all optimized connections between them.
You can use Web Cache Communication Protocol (WCCP) to specify which kinds of traffic the router should redirect to the WAN Optimization Module. Cisco Systems® developed WCCP to specify interactions between one or more routers (or Layer 3 switches) and one or more devices. The purpose of the interaction is to establish and maintain the transparent redirection of selected types of traffic flowing through a group of routers.
When using WCCP, you must deploy the BIG-IP system on which the WAN Optimization Module resides as a transparent proxy in a one-arm deployment. In this deployment, the BIG-IP system has a single (hence the term one-arm) connection to the WAN router (or LAN switch). The WAN router (or switch) redirects all relevant traffic to the WAN Optimization Module.
WCCPv2 support is available on all BIG-IP systems that have provisioned the WAN Optimization Module. For more information about WCCP settings, refer to Chapter 6, Configuring WCCPv2 Redirection.
Layer 7 QoS (Quality of Service) rate shaping is a form of traffic shaping that provides better service for specific data flows by raising the priority of a particular type of traffic and limiting the priority of other traffic. Accordingly, QoS rate shaping provides complex networks with a guaranteed level of performance for different applications and traffic types. Your networks data transmission is optimized, providing more control over network resources, and ensuring the delivery of mission-critical data.
Using QoS rate shaping, you can reduce the WAN bandwidth of less important network activities and, at the same time, prioritize important and critical data transfer. This way, your system uses bandwidth to optimally transfer the data that is most important to you.
QoS rate shaping is available on all BIG-IP systems. For more information about configuring L7 QoS rate shaping settings, see the Configuration Guide for BIG-IP® Local Traffic Management.
The BIG-IP system includes options that support setting, enforcing, or passthrough of ToS (Type of Service) and DSCP (Differentiated Services Code Point) bits. If you want to preserve ToS or DSCP bits for traffic that you are optimizing, you have to change the IP ToS setting for appropriate TCP profiles to pass. The default IP ToS value is 0, which clears the ToS bits for all traffic using that profile.
The WAN Optimization Module supports deployments where one or both of the BIG-IP systems are behind a Network Address Translation (NAT) router. In this deployment, the IP addresses by which the WAN Optimization Modules are reachable from the remote endpoints are different from the actual local endpoint IP addresses. You can specify whether you want the system to accept connections for traffic that is coming from behind a NAT router where the IP address was changed. Supporting NAT traversal simplifies the configuration of WAN optimization and allows you to optimize traffic within your existing networking topology.
The BIG-IP system includes a graphical monitoring and reporting tool called the dashboard. You can use the dashboard for viewing general BIG-IP system statistics and performance overview, or more specific statistics on the WAN Optimization Module (if provisioned on the system).
The Performance Overview dashboard displays system information including real-time CPU usage, memory allocations and usage, the number of open TCP connections, and traffic throughput.
The WAN Optimization Module dashboard shows real-time and historical data concerning CIFS and MAPI application optimizations, bandwidth gain, the percentage of traffic handled by each application, deduplication and compression effectiveness, and a list of remote endpoints accessible from the local device. You can use the dashboard to easily see what types of optimizations are taking place.
This guide describes how to configure and use the WAN Optimization Module. Its intended audience consists of network administrators, information system engineers, and network managers responsible for the configuration and ongoing management of the WAN Optimization Module.
Before you use this guide, we recommend that you run the Setup utility on the BIG-IP system to perform basic networking configuration such as self IP addresses, interfaces, and VLANs. After running the Setup utility, you can configure the WAN Optimization Module to optimize traffic. For instructions on initial setup of the BIG-IP system, refer to the BIG-IP® Systems: Getting Started Guide.
All examples in this documentation use only private class IP addresses. When you set up the solutions we describe, you must use valid IP addresses suitable to your own network in place of our sample IP addresses.
For example, after you have completed the hardware configuration, using either the LCD panel or a console connected to the F5 appliances serial port, you can configure the WAN Optimization Module using the browser-based utility, called the Configuration utility.
We apply bold formatting to a variety of items to help you easily pick them out of a block of text. These items include web addresses, IP addresses, utility names, most controls in the Web UI, and portions of commands, such as variables and keywords.
For example, if the IP address of the appliance is, type in the web browser to log in to the WAN Optimization Module.
We use italic text to denote a reference to another document or section of a document. We use bold, italic text to denote a reference to a book title. For example, see Configuring Virtual Servers, in the Configuration Guide for BIG-IP® Local Traffic Management for details about creating virtual servers on BIG-IP systems.
We show actual, complete commands in bold Courier text. Note that we do not include the corresponding screen prompt, unless the command is shown in a figure that depicts an entire command line screen.
Table 1.1 explains additional special conventions used in command line syntax.
In addition to this guide, there are other sources of documentation that you can use to work with the WAN Optimization Module. The information is available in the guides and documents described here.
The Configuration utility has online help for each screen. The online help contains descriptions of each control and setting on the screen. Click the Help tab in the navigation pane to view the online help for a screen.
The AskF5SM Knowledge Base web site
The F5 Networks Support web site,, provides the latest documentation for the product, including:
AskF5SM Knowledge Base
Note: To access this site, you need to register at
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