Quality of Service Behavioral Model

Last updated: September 2008

Common questions and answers regarding Cisco® Network-Based Application Recognition (NBAR) follow.

– Help Ensure Performance for Mission-Critical Applications: NBAR allows the network to provide differentiated services to each application. You can provide absolute priority and guaranteed bandwidth to your mission-critical applications such as Oracle or an application that runs on a particular Web page. At the same time you can limit the bandwidth consumed by the less essential applications. The end result is that users can access their mission-critical applications with minimal delay without the need to upgrade costly WAN links or cutting off access to commonly used, but not mission-critical, applications.

– Reduce WAN Expenses: In many parts of the world, and especially between countries, telecommunications links can still be prohibitively expensive. This leads to a dilemma for the network manager: on the one hand you need to provide access to new client-server and Internet-enabled applications, while on the other hand you need to control WAN service costs. NBAR provides a solution to this problem by enabling you to intelligently utilize WAN bandwidth so that you can provide acceptable service levels with the minimum possible bandwidth.

– Manage Web Response: The Web is now a critical business resource in many enterprises, for both internal and external communications. Employees, partners, and customers must have access to the Web pages they need without such problems as slow downloads or Web-based application failure. NBAR allows you to identify the Web pages and type of Web content that you deem critical.

– Improve VPN Performance: VPNs often reduce networking costs while providing increased flexibility. Unfortunately, the service quality in a VPN is often difficult to guarantee. Running NBAR and VPN concurrently in the same router solves this problem by identifying mission-critical traffic before it is encrypted, allowing the network to apply the appropriate QoS controls. By running both VPN and NBAR concurrently, we help ensure that the packets are processed in the correct order to achieve both maximum security and the appropriate QoS. NBAR can also mark the tunnel packet so that the service provider can provide differentiated service to different applications on the service provider's WAN.

– Improve Multiservice Performance: Multiservice networks allow you to combine your data, voice, and video requirements into one unified network. Unfortunately, each of these services requires different network characteristics. NBAR is able to intelligently identify the type of each packet and provide the proper network characteristics.

Details

– Cisco 800 Series Routers

– Cisco 1700 Series Modular Access Routers

– Cisco 1800 Series Integrated Services Routers

– Cisco 2600XM Series Router

– Cisco 2800 Series Integrated Services Routers

– Cisco 3700 Series Multiservice Access Routers

– Cisco 3800 Series Integrated Services Routers

– Cisco 7100 Series VPN Routers

– Cisco 7200 Series Routers

– Cisco 7300 Series Routers

– Cisco 7500 Series Routers

Please refer to the link below for Cisco IOS Software releases for NBAR support: http://www.cisco.com/en/US/products/ps6350/products_configuration_guide_chapter09186a0080455985.html

Table 1. Peer-to-Peer Protocols

Table 2. VoIP Protocols

Table 3. TCP and UDP Stateful Protocols

Table 4. Non-UDP and Non-TCP Protocols

Table 5. TCP and UDP Static Port Protocols

– Guaranteeing bandwidth with Class-Based Weighted Fair Queuing (CBWFQ)

– Policing and limiting bandwidth

– Marking for differentiated service downstream or from the service provider (ToS or Diff Serv code points [DSCP])

– Drop policy to avoid congestion (Weighted Random Early Detection [WRED])

– Packet and byte counts

– Bit rates