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Archived Manual Chapter: Introducing the WANJet Appliance
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F5® Networks WANJet® appliance increases distributed application performance by optimizing, thus reducing, the amount of data that is transferred over the WAN. As a result, the WANJet appliance accelerates applications, such as file transfer, email, client-server applications, and data replication, resulting in increased performance for all WAN users.
Various WANJet hardware platforms are available for corporations, data centers, and branch offices. WANJet platforms scale from branch office to data center appliances, and optimize from 2,000 up to 20,000 connections. WANJet appliances feature fault tolerance, and work transparently across all wide-area networks, including dedicated links, frame relays, and satellite connections.
Operating at Layer 5 of the OSI reference model, the WANJet appliance can gather application knowledge, analyze data streams, and determine how to optimize the data most efficiently. The WANJet appliance incorporates technologies including Transparent Data Reduction (TDR), adaptive TCP optimization, Application QoS (traffic shaping), and site-to-site encryption.
TDR technology reduces the amount of bandwidth that repeated data transfers consume across a WAN link, and compresses the data. Adaptive TCP optimization enables the WANJet appliance to adapt to the characteristics of WAN links, and then to accelerate application traffic. Application QoS policies let you assign more bandwidth to critical network traffic. The WANJet appliance uses SSL encryption to protect the traffic moving from site to site.
The WANJet appliance 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 WANJet appliance to adapt, in real time, to the latency, packet loss, and congestion characteristics of WAN links, and accelerate virtually all application traffic.
F5 Networks Transparent Data Reduction (TDR) technology dramatically reduces the amount of bandwidth consumed across a WAN link for repeated data transfers. For example, without TDR, a 1 MB file transferred across a WAN link by 100 different users would consume 100 MB of bandwidth. With TDR, the same transfer would consume less than 10 MB of bandwidth. This is a reduction of more than 90% in WAN traffic volume.
With TDR, files are not stored or cached, so data is never out of date and it does not need to be refreshed. Every request for a piece of data is sent to the server that actually has that data (even across the WAN link).
In other words, unlike traditional caching algorithms, requests are never served from a local WANJet appliance without the file actually being sent by the server that has the data. As a result, a user can change the name of a file and still experience the same dramatic reduction with TDR.
The WANJet appliance implements TDR technology as a two-stage compression process to maximize bandwidth savings while minimizing processing latency. The first step of the process, called TDR-2, examines the transmitted data to determine if any part of it has been previously sent. If so, the WANJet appliance replaces the previously transmitted data with references. The second step, called TDR-1, further compresses the data through the use of dictionary-based compression and advanced encoding schemes.
TDR-2 data reduction routines identify and remove all repetitive data patterns on the WAN. As data flows through the two WANJet appliances, each one records the byte patterns and builds a synchronized dictionary. If an identical pattern of bytes traverses the WAN more than once, the WANJet appliance nearest the sender replaces the byte pattern with a reference to it, compressing the data. When the reference reaches the remote WANJet appliance, it replaces the reference with the data, restoring the data to its original format.
In Figure 1.1, Client A requests a file named antivirus.dat.
In Figure 1.2, the server on which the file is stored returns the antivirus.dat file. WANJetA and WANJetB copy the data to RAM or onto disk, for systems that include hard disk drives.
In Figure 1.3, Client B requests the same antivirus.dat file.
In Figure 1.4, WANJetB compares the data in the antivirus.dat file with the data stored on RAM or disk to see if it has changed, confirming that the content is still current.
Finally, in Figure 1.5, WANJetB sends a message to WANJetA to use the local data instead of resending the file, because the content has not changed. WANJetA sends Client B the contents of the antivirus.dat file from its local RAM or disk drive, saving bandwidth over the WAN.
After TDR-2 has removed all previously transferred byte patterns, the WANJet appliance applies a second level of data reduction routines called TDR-1. While TDR-2 compression focuses on repeat transfer performance, TDR-1 improves first transfer performance by examining smaller repetitive patterns and, at the same time, by adapting to changing networking conditions and application requirements.
During periods of high congestion, TDR-1 increases compression levels to reduce congestion and networking queuing delay. During periods of low congestion, TDR-1 reduces compression levels to minimize compression-induced latency. The adaptive nature of TDR-1 ensures that the appropriate compression strategy is applied without degrading application performance.
TDR-1 compresses the remaining network data through intelligent network and application-aware routines that encode the remaining data in as few bytes as possible, improving performance for WAN users.
Application QoS (Quality of Service) 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, Application QoS 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.
Utilizing Application QoS policies enables you to downsize the bandwidth consumed over less important network activities and, at the same time, prioritize important and critical data transfer. This way, your bandwidth is used optimally for the transfer of the data that is most important to you.
You can also create a named group of ports, systems, and subnets, called a traffic class. You can then apply an Application QoS policy to that traffic class, treating this type of traffic as one entity.
See Creating Application QoS policies, for information on how to add, edit, or remove Application QoS policies.
Simple Network Management Protocol (SNMP) governs the management and monitoring of network devices. SNMP sends messages to SNMP-compliant servers, where users can retrieve these messages using SNMP-compliant software. SNMP data is stored in a data structure called a Management Information Base (MIB). An SNMP trap provides notification of a significant event (such as a power outage, an error, a fault, or a security violation) that occurred on the network.
The WANJet appliance sends SNMP traps to the SNMP server you specify. The traps you view on the SNMP server are errors for troubleshooting purposes. See WAN optimization messages and codes, for error codes and descriptions.
The WANJet appliance also stores more detailed SNMP reports that you can access using SNMP-compliant software. For the SNMP-compliant software to access the WANJet appliance, it should authenticate itself using a community string you specify. The machine on which the SNMP-compliant software resides should have access to the SNMP data on the WANJet appliance.
Figure 1.6 illustrates the interaction between the WANJet appliance and the SNMP traps.
The Management Information Base (MIB) that stores the SNMP data contains details about the network cards like the network card type, physical address, the card speed, the packets sent and received through each card, the bytes sent and received through each card, and the errors of each card.
In addition, the SNMP reports include detailed information about the WANJet appliance such as total bandwidth saved for sent data and for received data.
Remote Monitoring (RMON) is an extension to SNMP that provides comprehensive network monitoring capabilities. It is a network management protocol that monitors different types of data traffic passing through the network. Unlike SNMP, RMON can gather network data from multiple types of MIBs. Thus, RMON provides much richer data about network usage. For RMON to work, network devices, such as hubs and switches, must be designed to support it.
RMON1 is the Remote Network Monitoring MIB that was developed so that network administrators could see the traffic and collect information about remote network segments for troubleshooting and performance monitoring. RMON1 focuses on Layer 1 and Layer 2 of the OSI model.
RMON2 is an extension of RMON1 that includes open, comprehensive network fault diagnosis, planning, and performance-tuning features. In addition, RMON2 includes monitoring of packets on the higher layers of the OSI model, from Layer 3 to Layer 6. Therefore, RMON2 provides data about traffic on network layers for network and application monitoring. Figure 1.7 shows how the WANJet appliance works with RMON2 technology.
The WANJet appliance supports RMON2. RMON2 helps administrators gather and analyze detailed information about network traffic, before or after the WANJet appliance processes it. This information includes:
Provides a way for an RMON2 application to determine a list of protocols for which the WANJet appliance monitors and maintains statistics.
Stores and retrieves network layer (IP layer) statistics for conversations between pairs of network addresses.
Stores and retrieves application layer statistics for conversations between pairs of network layer addresses.
When you start the WANJet appliance, some connections may have already been established. Connection Intercept (CI) intercepts and resets connections that were initiated before the WANJet appliance became active on the network. If set, the WANJet appliance resets then optimizes existing connections. As usual, the WANJet appliance optimizes new connections starting after the appliance is up and running.
Connection Intercept causes the WANJet appliance to reset connections that were initiated before it started up. You can use Connection Intercept to reset connections for specific ports or services, without having to reboot the relevant servers or restart those services.
You can enable Connection Intercept for specific services or ports when creating optimization policies. The ports on which you implement Connection Intercept require the following settings:
Optimized as the processing mode
Connection Intercept option enabled
When deployed in an inline configuration (LAN and WAN ports connected), the WANJet appliance acts as a Layer 2 bridge for network traffic that is not configured for WAN optimization. Ethernet frames with unoptimized traffic are bridged between the LAN and WAN interfaces.
The ability to act as a bridge for traffic that is not optimized allows the WANJet appliance to be incorporated into redundant network topologies and to support the high-availability features of other network devices. Protocols such as the Address Resolution Protocol (ARP), the Spanning Tree Protocol (STP), the Virtual Router Redundancy Protocol (VRRP) and the Hot Standby Redundancy Protocol (HSRP) function normally in the presence of a WANJet appliance.
Redundancy protocols typically create a shared Virtual IP address (VIP). The VIP is the default gateway for the hosts on the LAN. One router uses the VIP to actively pass traffic, while the other router acts as a standby. The redundancy protocol sends multicast packets between the active and standby routers to indicate that the active router is healthy and continues to pass traffic. These packets are bridged through the active router's WANJet appliance and LAN switches, and bridged back through the peer WANJet appliance to the standby router.
If a failure in a network component (other than the WANJet appliance) prevents the multicast packets from reaching the standby router, the standby router becomes the active router by sending out an ARP packet indicating that it now owns the VIP (this process is often called gratuitous ARP). The gratuitous ARP packet is a Layer 2 broadcast packet, which is bridged by the WANJet appliance to the LAN hosts. LAN hosts then begin using the new router (but with the same IP address, namely the VIP) as their default gateway to send traffic to other networks.
WANJet appliances themselves can use the VIP as their default gateway IP address. If WANJet appliances connect directly from their WAN ports to their routers, both WANJet appliances must use the non-virtual IP address of their connected router's interface.
To use the VIP as the WANJet appliances' default gateway (to achieve redundant default gateways for the WANJet appliances), both of the WANJet appliance WAN ports must connect to switches or other Layer 2 devices that then connect to both routers. Depending on the details of the topology and configuration of your Layer 2 devices and routers, this may introduce Layer 2 loops that require resolution through the Spanning Tree Protocol or other means.
A core feature of the WANJet appliance is its fail-to-wire feature (set by default). Fail-to-wire functionality guarantees that a failure of a WANJet appliance does not block data traveling between the LAN and WAN ports when the WANJet appliance is deployed in an inline topology (as opposed to one-armed topology). When a failure in WANJet appliance occurs, the WANJet appliance network interface hardware opens a path that connects the LAN and WAN ports directly.
A WANJet appliance in fail-to-wire state acts effectively as a patch panel connecting two Ethernet cables. In the event of a WANJet appliance failure, data continues to flow between the two connected devices (such as switches, routers, or another WANJet appliance) on either side of the WANJet appliance. By allowing data to pass between connected devices in this manner, WANJet appliance failure does not result in the loss of network connectivity for clients, servers, and other networking devices.
Fail-to-wire occurs regardless of the type of failure in the WANJet appliance, including software bugs, hardware bugs, or hardware failures in components, such as memory chips or hard disks (except physical damage to the WANJet appliance's fail-to-wire hardware components), and loss of power to the WANJet appliance.
The fail-to-wire feature requires that the Ethernet parameters (that is, duplex and speed) of the connected devices' network interfaces are the same, as they would be if cabled directly together.
You must set the duplex and speed appropriately for the ports on the connected devices. F5 Networks recommends configuring the WANJet appliance interfaces and the interfaces of connected devices to auto-negotiate duplex and speed (auto is the default value for interfaces on the WANJet appliance). If you need to change the interface to a value other than auto, refer to Configuring interfaces.
After you configure the interfaces to auto-negotiate duplex and speed, F5 Network recommends checking the Diagnostics report (see Viewing Diagnostic reports) to determine whether both the LAN and WAN interfaces have auto-negotiated the same settings. If so, fail-to-wire will work correctly in case of failure. If duplex, speed, or both settings have different values, you need to manually set the parameters on all devices to the same values.
Cabling two network devices together may require use of an Ethernet cable with standard wiring (often called a straight-through cable), or may require an Ethernet cable with pinouts 1, 2, 3, and 6 of one connector wired to pinouts 3, 6, 1, and 2 (respectively) of the connector on the other end (often called a crossover cable). The WANJet appliance Gigabit Ethernet network interfaces can automatically sense which cable type is present (auto-sensing MDI/MDI-X), so during normal operation cable type should not be an issue.
However, in fail-to-wire mode, the effective cable type (that is, the combination of the two cable types) may or may not be appropriate for the two connected devices. As per the Gigabit Ethernet specification, Gigabit Ethernet network interfaces perform auto-sensing of the crossover cable, and configure themselves appropriately. If one or both devices possess Gigabit Ethernet interfaces, you can use any combination of the two cable types for the two cables connected to the WANJet appliance. If neither connected device possesses a Gigabit Ethernet network interface, you must choose the cable type based on the type of devices that effectively connect during fail-to-wire mode.
An alternative configuration to fail-to-wire exists on the WANJet 400. You can configure the WANJet 400 to fail close, which breaks the connectivity between connected devices. You can implement this option, for example, if you want to create a redundant network architecture in which all traffic is routed to the peer WANJet appliance when a WANJet appliance failure occurs.
When used with the redundancy features of the other network components, fail close can prevent the creation of an unoptimized path through the network. Fail close requires a hardware modification. Refer to To enable Fail Close on WANJet 400 hardware, for instructions.
An alternate setup exists if you cannot use fail close, but requirements do not permit a path in the network that does not have optimization, You can use the router connected to the WAN port to perform policy-based routing of unoptimized traffic, directing it to the active peer WANJet appliance for optimization. Consult the documentation for your routing device, and contact F5 Networks Support for additional information on high-availability configuration of WANJet appliances with policy routing.
The WANJet appliance supports remote redundancy and load balancing. In a remote redundant configuration, you configure two remote WANJet appliances so that if one of the WANJet appliances or a router is not operational, the other one handles all the traffic. When both appliances are operational, the local WANJet appliance automatically load balances traffic between the two remote WANJet appliances. See Configuring remote redundancy and load balancing, for more information.
The WANJet appliance supports redundant peers, where two WANJet appliances in the same subnet communicate with each other. Every WANJet appliance model has an Ethernet port labeled Peer. You connect the peer ports of two WANJet appliances to set up redundant peers. If connected directly to each other, use a crossover cable; if connected through a switch, use an Ethernet cable.
The peer network provides an alternate path for network traffic that is being optimized by a given WANJet appliance, but due to a failure in the network the normal path to the WANJet appliance is not available. When a failure on the network prevents traffic from reaching a WANJet appliance, redundant paths in a network should permit this traffic to take a path to the peer WANJet appliance.
Instead of passing state information, the WANJet appliance updates the redundant peer when it accepts a connection for optimization. Each WANJet appliance keeps a list of the connections being optimized by its peer. When a WANJet appliance accepts a new connection for optimization, it sends a message to the peer. The peer then adds the connection to its list. After an optimized connection has ended, the WANJet appliance also sends a message to the peer to remove the connection entry from its list.
You can deploy and manage multiple WANJet appliances from the Enterprise Manager, a centralized management solution. You need to have purchased and set up Enterprise Manager, which is a separate product from the WANJet appliance. For on setting up and using Enterprise Manager, refer to the Enterprise Manager documentation available on the AskF5SM Knowledge Base web site,
This guide describes how to configure and use the WANJet appliance. Its intended audience consists of network administrators, information system engineers, and network managers responsible for the configuration and ongoing management of the WANJet appliance.
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 WANJet appliance 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 WANJet appliance.
We use italic text to denote a reference to a specific section, or another document. In references where we provide the name of a book as well as a specific chapter or section in the book, we show the book name in bold, italic text, and the chapter/section name in italic text to help quickly differentiate the two.
For example, see Chapter 6, Reviewing Hardware Specifications, in the Platform Guide: WANJet® 500 for details about the WANJet 500 appliance.
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.
For example, the following command traces the route from the WANJet appliance you are working on to the device at IP address
Table 1.2 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 WANJet appliance. The information is available in the guides and documents described below.
WANJet® Appliance Quick Start Card
The WANJet platform includes a printed Quick Start Card written for the specific platform that you purchased. It provides basic instructions for a quick setup and initial configuration of the hardware you purchased.
Platform Guide: WANJet® 300
This guide describes the WANJet 300 platform, and includes detailed instructions on how to install the WANJet 300.
Platform Guide: WANJet® 500
This guide describes the WANJet 500 platform, and includes detailed instructions on how to install the WANJet 500.
Online help
Context-sensitive online help provides basic information for each screen in the Configuration utility.
In addition to the documentation included with the platform, you can find additional technical documentation by using the following resources.
AskF5 Networks Technical Support 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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