Measures reported by CbrQosStatsTest

The Citrix Branch Repeater includes integral quality-of-service (QoS) functionality that classifies traffic by flow and application. This works with various other optimization and compression technologies to control the bandwidth used and improve the user experience.

In Citrix Repeater, a traffic-shaping engine is included to manage all the TCP or User Datagram Protocol (UDP) traffic on WAN links in the incoming as well as outgoing directions. The traffic shaper is based on bandwidth-limited fair queuing, where every connection is assigned a weighted priority based on the assigned policies. Weighted priorities are applied to the actual WAN data transferred, after compression is applied. The weighted priority is based on the Application Classifiers defined in the Service Class, and you can also apply the weighted priorities on a per-link basis.

You can use the following mechanisms to apply Quality of Service:

• Link Definition: Informs the traffic shaper which WAN link the packet is using. In a site with multiple links, each link has its own bandwidth limits and is managed independently.
• Application Classifiers: Identifies and determines the protocol or application class to which traffic belongs.
• Service Classes: Maps applications to acceleration decisions, traffic filters, and traffic-shaping policies.
• Traffic Shaping Policies: Informs the traffic shaper about weighted priority and bandwidth limits to assign to which traffic type, the application classifier.

If branch users complain of link slowdowns, then administrators should be able to identify which traffic-shaping policy governs traffic acceleration on that link and should figure out how to fine-tune that policy to increase link throughput. The CbrQosStatsTest test helps with this! This test auto-discovers the default and user-configured traffic-shaping policies and closely observes the traffic accelerated by each policy to identify those policies that may have to be tweaked in order to improve the rate of traffic acceleration, optimize bandwidth usage, and reduce packet loss.

The measures made by this test are as follows:

Measurement	Description	Measurement Unit	Interpretation
Sent_Volume	Indicates the rate at which data was transmitted for this traffic-shaping policy.	Number	At any given point in time, the value of these measures should be well-within the incoming and outgoing bandwidth usage limits set for the corresponding traffic-changing policy. If these values consistently grow towards the bandwidth usage limit, it is an indication that the traffic-shaping policy is not very effective. You may then have to fine-tune that policy to optimize bandwidth consumption.
Received_Volume	Indicates the rate at which data was received for this traffic-shaping policy.	KB/Sec
Sent_Packets	Indicates the total amount of data that was accelerated for this service class during the last measurement period.	KB	At any given point in time, the value of these measures should be well-within the incoming and outgoing bandwidth usage limits set for the corresponding traffic-changing policy. If these values consistently grow towards the bandwidth usage limit, it is an indication that the traffic-shaping policy is not very effective. You may then have to fine-tune that policy to optimize bandwidth consumption.
Received_Packets	Indicates the number of packets received for this traffic-shaping policy during the last measurement period.	Number
Dropped_Sent_Volume	Indicates the rate of traffic dropped because of this traffic-shaping policy.	KB/Sec	A high value for these measures could indicate one of the following: The traffic-shaping policy is such that it allows only very limited data to be sent/received over a link; this excludes a lot of data from transmissions/receptions and maximizes the responsiveness of the link; The traffic-shaping policy has been misconfigured, causing a link to send/receive much less data than what it can handle; this causes a lot of data to be unnecessarily dropped from transmissions/receptions, affecting the quality-of-experience in the process. In this case, you may have to fine-tune the policy.
Dropped_Received_Volume	Indicates the rate of traffic not received due to this traffic-shaping policy.	KB/Sec
Dropped_Sent_Packets	Indicates the number of packets dropped during transmissions due to this traffic-shaping policy.	Number	A high value for these measures could indicate one of the following: The traffic-shaping policy is such that it allows only a few data packets to be sent/received over a link; this excludes a lot of packets from transmissions/receptions and maximizes the responsiveness of the link; The traffic-shaping policy has been misconfigured, causing a link to send/receive fewer data packets than what it can handle; this causes many packets to be unnecessarily dropped from transmissions/receptions, affecting the quality-of-experience in the process. In this case, you may have to fine-tune the policy.
Dropped_Received_Packets	Indicates the number of packets not received due to this traffic-shaping policy.	Number