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QOS

Frame-relay Discard Eligibility Bit (DE)

What is the DE bit ? The DE bit is used to indicate that the frame has a lower importance than other frames and should be dropped first if the network experienced congestion. How to set the DE bit? We can use a simple network to test our configuration. R1 is connected via frame-relay to R2 Method1: Frame-relay de-list command R1 Configuration R1(config)#access-list 1 permit 1.1.1.1 !-- packets sourced from 1.1.1.1 with size > 500 will have DE bit set R1(config)#frame-relay de-list 1 protocol ip list 1 R1(config)#frame-relay de-list 1 protocol ip gt 500 !-- assign the DE list to …

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Frame-relay traffic shaping using MQC

To apply frame-relay traffic shaping using a normal map-class, the command frame-relay traffic-shaping must be applied to the main interface. This method has a pitfall; the problem is that when you apply the frame-relay traffic-shaping command to the main interface any DLCI that has no explicit map-class will be shaped to 56K by default. This means that if you need to apply traffic shaping to only one PVC all other PVCs will be shaped to 56K by default. MQC shaping can be used to solve this problem by configuring shaping on specific PVC without the need to use the command …

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CAR – Rate limit examples

CAR is a policing mechanism used to limit the transmission rate of some traffic flow. Cisco actually recommends using MQC policing for its modularity and features, but CAR is still used widely in most operational networks for its simplicity. CAR can be used whenever you need to place a limit o­n upload/download traffic of any interface or any specific traffic flow passing through this interface. Rate-limit can be used to enforce your organization policy, bandwidth reservation method or even as a security mitigation technique. CAR uses the token bucket algorithm to limit the transmission rate of data flows in or …

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Limiting non-business related applications during work hours

In this post we will explore how to limit or even stop your employees from using applications that are not related to the business during work hours. In the following example I am going to use HTTP as an example for unwanted applications, you can specify any type of application you would like to limit or stop (file sharing, chatting, downloading ..) Configuration Steps: 1- create your time range in which these applications will be deined as show below !– This timerange matches everyday from 9am to 5pm expcet weekends time-range WEEKDAYS periodic weekdays 9:00 to 17:00 2- Identify non-business …

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PBR as a QOS tool

In order to apply QOS policies in your network, traffic should be classified first. There are many techniques available for packet classification. PBR is one of these techniques as discussed below. PBR can be used to match a specific flow and then apply QOS policies on it, like marking this traffic or routing the traffic to special optimized or dedicated connections to handle this traffic type. For example you may have two internet connections, one for normal internet traffic [FTP, HTTP, downloads] and another one for critical applications or to be dedicated only for use by the managers or critical …

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