Measures reported by CbrLscStatsTest
Service classes are user-defined groups of IP addresses and port numbers that allow the Branch Repeater to accelerate or not accelerate a particular group of connections or a single connection.
Once a service class is created, acceleration (also known as flow control) and compression can be enabled or disabled for that particular service class.
Post service class configuration, it is good practice to observe the accelerated traffic to and from each service class, so that you can check the effectiveness of the acceleration/compression rules that you have set per service class. This is where the CbrLscStatsTest test helps.
This test auto-discovers the service classes configured in the branch repeater, monitors the volume of traffic sent and received by each service class, captures packet drops that occur when QoS thresholds are violated by a service class, and enables administrators to determine the following:
- How well the branch repeater accelerates/compresses traffic to/from service classes;
- Service classes for which acceleration/compression rules may have to be fine-tuned
The measures made by this test are as follows:
| Measurement |
Description |
Measurement Unit |
Interpretation |
| Sent_Volume |
Indicates the rate at which data was sent by this service class. |
KB/Sec |
WAN links have low bandwidth when compared to LAN links. Moreover, any attempt made to send or receive traffic faster than the link throughput can result in congestion. Therefore, the branch repeater should make sure that just about enough data is sent and received by the IP addresses and ports grouped under a service class to prevent congestion and optimize throughput.
If the values of these measures exceed or are dangerously close to the bandwidth limit of the WAN links used by a service class, it signals a potential congestion or slowdown of traffic over one/more of those WAN links. It also indicates that you may have to reconfigure the branch repeater with more robust traffic shaping policies to prevent such unpleasant eventualities. |
| Received_Volume |
Indicates the rate at which data was received by this service class. |
KB/Sec |
| Sent_Packets |
Indicates the number of packets transmitted by this service class. |
Number |
WAN links have low bandwidth when compared to LAN links. Moreover, any attempt made to send or receive traffic faster than the link throughput can result in congestion. Therefore, the branch repeater should make sure that just about enough data packets are sent and received by the IP addresses and ports grouped under a service class to prevent congestion and optimize throughput.
If the values of these measures exceed or are dangerously close to the bandwidth limit of the WAN links used by a service class, it signals a potential congestion or slowdown of traffic over one/more of those WAN links. It also indicates that you may have to reconfigure the branch repeater with more robust traffic shaping policies, acceleration rules, and compression algorithms to prevent such unpleasant eventualities. |
| Received_Packets |
Indicates the number of packets received by this service class. |
Number |
| Dropped_Sent_Volume |
Indicates the rate of traffic not sent by this service class over all its WAN links due to QoS threshold settings. |
KB/Sec |
QoS (quality-of-service) is a set of policies and priorities assigned to the application traffic prioritized under traffic shaping policies in BR devices. A QoS threshold allows a sender to deliver only as much data as the branch repeater allows it to send, and this data is placed on the link at exactly the right rate to keep the link full but not overflowing. By eliminating excess data, the branch repeater is not forced to discard it. Without the branch repeater, the dropped data would have to be sent again, causing delay.
You can compare the value of these measures across service classes to identify that service class, the WAN links of which have dropped the maximum data. This could be owing to any of the following reasons:
- The bandwidth of the WAN links used by the service class is low. Hence, very rightly, a high QoS threshold has been set that allows only limited data to be sent/received over those WAN links; as a result, a large amount of data gets automatically excluded from transmissions/receptions over those WAN links, thus maximizing the speed of the links;
- The branch repeater has been misconfigured with a high QoS threshold that forces the WAN links used by this service class 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 QoS policy.
|
| Dropped_Received_Volume |
Indicates the rate of traffic not received by this service class due to QoS threshold settings. |
KB/Sec |
| Dropped_Sent_Packets |
Indicates the number of packets not sent over all the WAN links used by this service class due to QoS threshold settings. |
Number |
QoS (quality-of-service) is a set of policies and priorities assigned to the application traffic prioritized under traffic shaping policies in BR devices. A QoS threshold allows a sender to deliver only as much data as the branch repeater allows it to send, and this data is placed on the link at exactly the right rate to keep the link full but not overflowing. By eliminating excess data, the branch repeater is not forced to discard it. Without the branch repeater, the dropped data would have to be sent again, causing delay.
You can compare the value of these measures across service classes to identify that service class, the WAN links of which have dropped the maximum packets. This could be owing to any of the following reasons:
- The bandwidth of the WAN links used by the service class is low. Hence, very rightly, a high QoS threshold has been set that allows only limited number of packets to be sent/received over those WAN links; as a result, many data packets gets automatically excluded from transmissions/receptions over those WAN links, thus maximizing the speed of the links;
- The branch repeater has been misconfigured with a high QoS threshold that forces the WAN links used by this service class to send/receive fewer data packets than what it can handle; this causes a many data 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 QoS policy.
|
| Dropped_Received_Packets |
Indicates the number of packets not received by this service class due to QoS threshold settings. |
Number |
|