About Cisco WAAS
The Cisco WAAS system consists of a set of devices called Cisco WAEs that work together to optimize TCP traffic over your network. When client and server applications attempt to communicate with each other, the network intercepts and redirects this traffic to the WAEs so that they can act on behalf of the client application and the destination server. The WAEs examine the traffic and use built-in optimization policies to determine whether to optimize the traffic or allow it to pass through your network unoptimized.
Cisco WAAS Version 5.0 introduced a new AppNav deployment model that greatly reduces dependency on the intercepting switch or router by taking on the responsibility of distributing traffic among Cisco WAAS devices for optimization. Cisco WAAS appliances with AppNav Controller Interface Modules operate in a special AppNav Controller mode, with AppNav policies controlling traffic flow to Cisco WAAS devices performing optimization. The AppNav model is well suited for data center deployments and addresses many of the WAN optimization challenges in this environment.
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You can deploy Cisco WAAS in either the AppNav model, or in the traditional model without using AppNav Controllers. |
Use the Cisco WAAS Central Manager GUI to centrally configure and monitor the Cisco WAEs and optimization policies in your network. You can also use the Cisco WAAS Central Manager GUI to create new optimization policy rules so that the Cisco WAAS system can optimize both custom applications and less common applications.
Cisco WAAS helps enterprises meet the following objectives:
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Provide branch office employees with LAN-like access to information and applications across a geographically distributed network.
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Migrate application and file servers from branch offices into centrally managed data centers.
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Minimize unnecessary WAN bandwidth consumption through the use of advanced compression algorithms.
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Improve application performance over the WAN by addressing the following common issues:
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Low data rates (constrained bandwidth)
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Slow delivery of frames (high network latency)
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Higher rates of packet loss (low reliability)
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Note |
A Cisco WAAS Express device, which is a Cisco router with Cisco WAAS Express functionality enabled, can interoperate with other Cisco WAAS devices. A Cisco WAAS Express device provides basic WAN optimization and some application optimization, but no virtualization. For more information on Cisco WAAS Express, see Configuring WAAS Express. A device having the AppNav-XE component, typically, a Cisco router or virtual Cisco Cloud Services Router with virtual AppNav functionality, can interoperate with other Cisco WAAS devices that are acting as WAAS nodes. Such a device acts as an AppNav Controller that distributes traffic to other Cisco WAAS devices acting as WAAS nodes that optimize the traffic. However, a device with the AppNav-XE component cannot interoperate with other AppNav Controller hardware appliances. For more information on AppNav-XE, see the AppNav-XE documentation. For more information on AppNav, see the chapter Configuring Cisco AppNav. A Cisco vWAAS instance is a virtual Cisco WAAS appliance running on a VMware virtual machine and providing all of the same features as a Cisco WAAS appliance. A Cisco WAAS Central Manager can manage Cisco WAEs, Cisco WAAS Express devices, and Cisco vWAAS instances all in the same Cisco WAAS network. For more information on Cisco vWAAS, see the Cisco Virtual Wide Area Application Services Configuration Guide . Cisco ISR-WAAS is a virtualized Cisco WAAS instance running on a Cisco ISR router. It provides added optimization without the need for additional hardware or external appliances. A Cisco WAAS Central Manager can monitor and configure Cisco ISR-WAAS. |
The following table shows how Cisco WAAS uses a combination of TCP optimization techniques and application acceleration features to overcome the most common challenges associated with transporting traffic over a WAN.
WAN Issue |
Cisco WAAS Solution |
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High network latency |
Intelligent protocol adapters reduce the number of round-trip responses common with chatty application protocols. |
Constrained bandwidth |
Data caching provided with the file services feature and data compression reduce the amount of data sent over the WAN, which in turn, increases data transfer rates. These solutions improve application response time on congested links by reducing the amount of data sent across the WAN. |
Poor link utilization |
TCP optimization features improve network throughput by reducing the number of TCP errors sent over the WAN and maximizing the TCP window size that determines the amount of data that a client can receive at one time. |
Packet loss |
Optimized TCP stack in Cisco WAAS overcomes the issues associated with high packet loss and protects communicating end points from the state of the WAN. |