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Archived Manual Chapter: WANJet User Guide version 4.0: Overview - 2
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2

Overview


About the WANJet appliance

The WANJet appliance is designed to improve the performance of your networks, reducing the bandwidth consumed when transmitting data. In order for the WANJet appliance to reduce the bandwidth consumed in data transmission, it processes data at one side and reverses this process at the other. The WANJet appliance works by identifying redundancy patterns in input data and replacing those redundant patterns with symbols (encoding). When data arrives at its destination, symbols are replaced with the original patterns (decoding). The WANJet appliance stores a list of all identified redundancy patterns and their equivalent symbols, enabling it to handle both sent and received data at the same time. This process requires that at least two WANJet appliances are installed, one to process data at one side and another to reverse data processing at the other side.

Adaptive Control and Management at Layer 5

Adaptive Control and Management at Layer 5 (ACM5) operates at the session layer of the OSI model. This technology enables the WANJet appliance to recognize the redundancies in data traffic. In order to understand why deploying ACM5 technology is more efficient in data compression than other compression techniques, you have to understand the differences between the WANJet appliance utilizing ACM5 and other compression techniques.

Some applications operate at Layer 3 of the OSI model. They wait until individual application data streams merge before searching for redundancies. Merged data streams yield fewer redundancies than data streams that are not merged, so the Layer 3 approach is less than optimal.

Some other bandwidth expansion products operate at Layer 7 of the OSI model, the application layer. These products do a great job for specific applications, but other traffic crosses the WAN uncompressed, so overall bandwidth savings are limited.

Operating at Layer 5 is more efficient than operating at any other layer in the OSI model, because unlike data compression based on Layer 3, the WANJet compresses data streams before data merge, so it finds and removes more redundancies than Layer 3 methods.

Unlike Layer 7 techniques, the WANJet appliance's ACM5 technology examines all applications and compresses all traffic types.

Transparent Data Reduction

F5 Networks' Transparent Data Reduction (TDR) technology provides a dramatic reduction in the amount of bandwidth consumed across a WAN link for repeated data transfers. For example, without TDR, a 1MB file transferred across a WAN link by 100 different users would consume 100MB of bandwidth. With TDR, the same transfer would consume less than 10MB 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.

Following is an illustrated example of how TDR works.

Client A requests a file named antivirus.dat.

 

Figure 2.1 Client requests file

The Server, on which the file is stored, returns the antivirus.dat file. WJ-A and WJ-B copy the data to RAM.

 

Figure 2.2 Server returns file

Client B requests the same antivirus.dat file.

 

 

Figure 2.3 A second client request the same file

WJ-B compares the antivirus.dat file with the data it has in RAM to see if the data has changed, confirming that the data in its RAM is still current.

 

 

Figure 2.4 The WANJet appliance compares the file to the file in its RAM

WJ-B sends a message to WJ-A to use the local data, because the data has not changed. WJ-A sends Client B the data corresponding to antivirus.dat file from its local RAM, saving bandwidth.

Application QoS

The WANJet Application QoS provides better service for specific data flows by raising the priority of a specific traffic and limiting the priority for other traffic. Accordingly, the Application QoS provides complex networks with a guaranteed level of performance for different applications and traffic types. Your network's 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.

In addition, the WANJet appliance provides high quality of service with applications that are sensitive to delays by supporting the Voice over Internet Protocol (VoIP).

Note

See Application QoS Policy for more information.

Type of Service

The Type of Service feature helps to provide the highest quality of data delivery by prioritizing the delivery of one data stream over another. The WANJet appliance deploys the Type of Service methodologies, giving you control over your data streams. You decide which data stream will get to the receiver first by using the Type of Service feature to assign a priority to data traffic using a specific port. You can assign priorities from 0 to 7, where 0 is the lowest priority, and 7 is the highest. This means that the data using a specific port is transferred according to its priority. For example, you can decide to give the HTTP traffic the lowest priority while giving the FTP traffic the highest priority. You can also assign the same priority, such as priority 7, to multiple protocols.

Simple Network Management Protocol Support

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).

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 WANJet appliance error messages and codes for error codes and descriptions.

The WANJet also stores more detailed SNMP reports that you can access using SNMP-compliant software. For the SNMP-compliant software to access the WANJet, it should authenticate itself using the community string you specify. The machine on which the SNMP-compliant software resides should have access to the SNMP data in the WANJet Web UI. See Granting Web UI access .

 

 

Figure 2.5 The WANJet appliance and SNMP data

The Management Information Base 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 such as total bandwidth saved for sent data and for received data.

For more information about configuring SNMP settings, see Configuring Syslog and SNMP settings .

Remote Monitoring support

Remote Monitoring (RMON) is an extension to SNMP that provides more comprehensive network monitoring capabilities. It is a network management protocol that monitors different types of data traffic passing through the network. Unlike SNMP, RMON gathers network data from a multiple types of MIB. This 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 MIB standards effort started in 1990 to enable network Administrators to collect information from remote network segments for the purposes of troubleshooting and performance monitoring. RMON1 focused on Layer 1 and Layer 2 of the OSI model. Due to the high market demand and increasing customer interest, RMON1-compliant software was rapidly developed and brought to market.

RMON2 is an enhanced version of the earlier RMON1 protocol. It differs from RMON1 because it includes more open, comprehensive network fault diagnosis, planning, and performance-tuning features. In addition, RMON2 focuses on the higher layers of the OSI model, Layer 3 to Layer 6.

 

 

Figure 2.6 The WANJet appliance and ROMON2

The WANJet appliance supports RMON2 to help the user gather and analyze detailed information about the network traffic, either before or after the WANJet processes it, such as:

  • Data sent and received between two nodes
  • IP addresses of these nodes
  • Port used to send and receive data
  • Data size before and after the WANJet processes the traffic
  • Time stamp
  • Number of connections

The WANJet appliance supports the following RMON2 groups.

 

Table 2.1 Supported RMON2 groups
RMON2 group
Description
Protocol Directory
Contains the protocols for which the agent monitors and maintains statistics.
Network Layer Matrix
Contains the traffic statistics for pairs of network layer addresses.
Application Layer Matrix
Contains the traffic statistics by application layer protocol for pairs of network layer addresses.
Configuration Group
Contains agent capabilities and configurations.
Protocol Directory
Contains the protocols for which the agent monitors and maintains statistics.

 

For more information about RMON2 groups, see Appendix A, RMON2 Tree. For more information about configuring RMON2, see Configuring Syslog and SNMP settings .

System Log protocol support

The System Log (Syslog) protocol is a mechanism for sending event messages to a Syslog-compliant server. Events can be sent at the start or end of a process or to transmit the current status of a process. The WANJet appliance sends system event messages to the Syslog server you specify. The data log sent by the WANJet appliance includes the sent data, and the received data. In addition, the WANJet appliance sends warning logs to the Syslog server when necessary.

For more information on how to configure the Syslog settings, see Configuring Syslog and SNMP settings .

Connection Interception

Connection Interception (CI) enables the WANJet appliance to intercept and reset an existing network connection, to ensure that it is optimized.

When to use CI

With CI, you can reset connections on a range of different ports, without having to reboot the relevant servers or restart a whole range of services. You can use the CI option when you are performing any of the following processes:

  • Installing the WANJet appliance on your network
  • Upgrading the WANJet appliance
  • Changing the WANJet appliance's mode from inactive to active
  • Restarting the WANJet appliance

Before you perform any of the proceeding procedures, verify that the ports for all connections that you are going to reset been assigned the following:

  • The ACM5 processing mode
  • The Connection Intercept option

Example CI implementation

In this example, you have a backup operation running on the FTP server, and the connection on the FTP port is not optimized for one of the following reasons:

  • The WANJet appliance was introduced to the network after the FTP connection was opened. Therefore, even if the port for this connection has an optimization policy assigned to it, the traffic for this port will be handled as passthrough.
  • The WANJet appliance is inactive.
  • You are currently upgrading the WANJet appliance.
Note

You can use the following process to optimize any port. The best usage for CI is when you want to reset connections on a range of ports, without having to either reboot the relevant servers or restart a whole range of services. The WANJet appliance allows you to reset connections automatically, without having to restart the server or manually reset the connections.

For this example, you need to optimize FTP data by performing the following steps. The WANJet appliance allows you to use this procedure to automatically reset FTP connections, without having to restart the FTP server or restart the connections manually.

To automatically reset FTP connections

  1. In the navigation pane, expand Optimization and click Optimization Policy.
    The WANJet Optimization Policy screen displays.
  2. From the Service Name column, click the service you want to modify. In this example they are the FTP ports (typically ports 20 and 21, or ports 989 and 990 for a secure connection).
    The Edit Port/Service Name screen displays in a separate window.
  3. From the Processing Mode list, select ACM5.
  4. Check the Connection Interception box.
  5. Click the OK button.
    The Edit Port/Service Name screen closes and the WANJet Optimization Policy screen displays.
  6. Verify that the WANJet appliance operational mode is set to active.
  7. Restart the WANJet appliance.
    This forces Connection Interception on all configured ports (the FTP ports, in this example). The data using these ports is then optimized once the WANJet appliance restarted.
Note

For additional details about how to configure the CI option, refer to Configuring specific ports .



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