SD-WAN Paths Test 

Citrix SD-WAN appliance creates a reliable WAN from diverse network links, also called paths, including MPLS, broadband, and wireless. Typically, the target appliance routes the mission critical applications over the paths with fastest transit time to avoid network latency. In addition, the target appliance enables real-time application traffic duplication to guarantee no loss and balances traffic from high bandwidth applications across multiple links to provide high performance for large file transfers. By continuously monitoring each path link for packet loss, latency, jitter and congestion, administrators can mitigate link outages and errors and move traffic off poor performing links without affecting the applications routed across the links. This in turn helps administrators to maintain consistent performance of the appliance while routing the mission critical applications. This is where the SD-WAN Paths test helps administrators! 

This test auto-discovers the path links established through the target appliance, and reports the current status of each path link. This test proactively reveals whether/not each path link is impacted by congestion. This revelation helps administrators to identify the path links that are congested and move the traffic off from those links to free them up for the business critical transactions. In addition, this test also reports the jitter, one-way time latency and packet loss over each link. By analyzing these metrics, administrators can easily determine if there is an issue on the path link or not and decide on routing the traffic to other path links if any of the path links is badly affected by congestion, latency and/or loss.

Target of the test : A Citrix SD-WAN

Agent deploying the test : A remote agent

Outputs of the test : One set of results for each path link between the datacenter and branches.

Configurable parameters for the test
Parameter Description

Test Period

How often should the test be executed. By default, this is set to 5 minutes.

Host

The IP address of the target SD-WAN appliance for which this test is to be configured.

Port

Refers to the port at which the target SD-WAN listens to. By default, this will be NULL.

Timeout

Specify the time duration (in seconds) beyond which this test should time out in the Timeout text box. The default is 10 seconds.

Detailed Diagnosis

To make diagnosis more efficient and accurate, the eG Enterprise embeds an optional detailed diagnostic capability. With this capability, the eG agents can be configured to run detailed, more elaborate tests as and when specific problems are detected. To enable the detailed diagnosis capability of this test for a particular server, choose the On option. To disable the capability, click on the Off option.

The option to selectively enable/disable the detailed diagnosis capability will be available only if the following conditions are fulfilled:

  • The eG manager license should allow the detailed diagnosis capability
  • Both the normal and abnormal frequencies configured for the detailed diagnosis measures should not be 0.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

Path state

Indicates the current status of this path link.

 

The numeric values that correspond to the measure values are as follows:

Measure Value Numeric Value

Description
Dead 0

Indicates that the path hasn't received any packets since 1.5 seconds.
Bad 1

This state is reported when 3 or 4 packets out of 10 are lost.
Good 2

Every 2-3 packets of incoming packets are processed as a sample size used to report conditions back to the local device.

Note:

By default, this measure reports one of the Measure Values listed in the table above to indicate the current status of each path link. The graph of this measure however, represents the same using the numeric equivalents alone.

The detailed diagnosis of this measure displays the reason for the state change of each link and the time duration.

Congestion

Indicates whether/not this path link is affected by congestion.

 

The numeric values that correspond to measure values are as follows:

Measure Value Numeric Value
No 0
Yes 1

Note:

By default, this measure reports one of the Measure Values listed in the table above to indicate whether each path link is affected by congestion or not. The graph of this measure however, represents the same using the numeric equivalents alone.

Virtual path service state

Indicates the current status of the virtual path service on this path link.

 

The numeric values that correspond to the measure values are as follows:

Measure Value Numeric Value
Dead 0
Bad 1
Good 2

Note:

By default, this measure reports one of the Measure Values listed in the table above to indicate the current status of the virtual path service on each path link. The graph of this measure however, represents the same using the numeric equivalents alone.

The detailed diagnosis of this measure reveals the type of the virtual path service.

Maximum transmission unit

Indicates the maximum size of the packets/frames that this path link can transmit.

Bytes

A very high value of this measure may indicate the need for retransmissions if the path link can't transfer large packets. A very low value of this measure may indicate relatively more header overhead and more acknowledgments that have to be sent and handled over the path. Therefore, it is highly recommended that the administrators should not change the default Maximum transmission unit (MTU) value set by the service providers.

BOWT

Indicates the total time taken by the packets to travel from its source to its destination over this path link.

Seconds

 

Jitter

Indicates the time variation in the delay while receiving the packets over this path link.

Seconds

A high value for this measure is indicative of a long time gap between the packets, which needs to be immediately addressed by administrators to avoid .

Packets received

Indicates the number of packets received over this path link.

Packets

 

Packets out of order

Indicates the number of packets delivered in a different order from which they were sent from the source.

Number

The value of this measure is preferred to be low. A high value indicates that too many packets are received out of order, which will drastically increase retransmissions of packets on the network. As a result, the packet transmission will be delayed which will adversely impact the performance of the appliance.

Packet loss

Indicates the percentage of packets lost while transmitting through this path link.

Percent

Ideally, a low value is desired for this measure.

Data transmission

Indicates the rate at which the data was transmitted over this path link.

Mbps