Enterprise Synthetic and sequence

Aborted transactions

The number of aborted transactions (transaction error code: -3). An aborted transaction is reported when one or more consecutive URLs detected in the traffic match the defined transaction steps, but the next URL detected does not match the transaction definition.

Application Delivery Channel Delay

In WAN optimized scenario, Application Delivery Channel Delay (ADCD) is a quality metric represented in milliseconds. The ADCD is determined by initial observation of the traffic between a client and a server. ADCD is a derivative of RTT measured on a WAN link expressed in time and as such it can be understood as latency, where the larger ADCD would indicate a higher network latency. ADCD also includes time spent in the data center WOC for traffic buffering and processing. A change of ADCD from its initial value reflects a change of quality in WAN optimization service. For example, sudden increase of ADCD would suggest that the quality of the service has worsened and conversely, a sudden decrease of ADCD value could suggest an improvement in WAN optimization.

Application performance

For transactional protocols, this is the percentage of software service transactions completed in a time shorter than the performance threshold. For transactionless TCP-based protocols, this is the percentage of monitoring intervals in which user wait time per kB of data was shorter than the threshold value.

Application processing time

Sum of transfer time for operations in which the server for the given transaction played the actual role of the server plus sum of time between operations but only if the second operation client played the role of the server for given transaction. See the basic transaction model for reference.

graphical illustration
graphical illustration

Attempts

Attempts

Availability (total)

The percentage of successful attempts, calculated using the following formula:

Availability (total) = 100% * (All Attempts – All failures) / All Attempts

where

All attempts = all failures + all successful operations + all standalone hits not classified as a failure + all aborts not classified as a failure

All failures = all failures (transport) + all failures (TCP) + all failures (application).

Client RTT

Client RTT is the time it takes for a SYN packet (sent by a server) to travel from the AMD to the client and back again, as shown in the following picture.

graphical illustration
graphical illustration

A client RTT measurement begins when the SYN ACK packet from the server to the client passes by the AMD (T5). The packet reaches the client machine (T6) and is processed, while an acknowledgment is sent back to the server (T7). Client processing time impact (T7-T6) is again very low. Client RTT measurement ends when the ACK packet reaches the AMD (T8). Therefore, the Client Round Trip Time is calculated as T8-T5. Depending on the actual setup, Client RTT measurements may vary dramatically. In corporate environments, it may be a few milliseconds for LAN-connected clients or a couple dozens milliseconds for WAN-connected clients. In this case, where the client is coming from the Internet, the end-to-end Client RTT measurement is a compound of transit time through the Internet backbone as well as through the "last mile" access network. The impact of the last mile can be easily calculated, based on the connection speed and the packet size (56B in case of TCP SYN packet). For a 28 kbps dial-up connection, this amounts to 16 milliseconds one way, or 32 milliseconds for a complete round-trip measurement. For a 1.6 Mbps DSL line, this makes 56 microseconds towards complete client RTT measurement.

Client bytes

The number of bytes sent by the clients. Note that this includes headers.

Client packets

The number of packets sent by the client.

Client response time

Client response time is calculated for operations in which the client for a given transaction played the role of the server. It is a sum of transfer time for such operations. See the basic transaction model for reference.

graphical illustration
graphical illustration

Client time

Client time is the time interval between the last data packet from transaction response message from TCP session server to the first packet of the acknowledgment from TCP session server to the client. Client time is similar to server time, but measured in context of transaction response message.

Client time (failed transactions)

The client time for all failed transactions (transactions with a -2 status code). This metric is valid only for 'Transactions (Synthetic Monitoring)' transaction source.

Client time (requests)

The client time for all transaction requests (both requests that became successful transactions and requests that ended as transactions with errors). This metric is valid only for 'Transactions (Synthetic Monitoring)' transaction source.

Failed transactions

For Synthetic Monitoring transactions, it is the number of transactions for which the give-up threshold was exceeded. For RUM transactions, failed transactions are all transactions with status other than -3 (aborted).

Failures (total)

The total number of failures, that is all Failures (transport) + all Failures (TCP) + all Failures (application)

HTTP abort error

This error is reported when one of the URLs in a transaction detected in a monitored traffic does not match the transaction definition. This refers to any URL in a sequence of URLs, except the firs one.

HTTP client errors (4xx)

The sum of all HTTP client errors (4xx). This includes 4 categories of errors (4xx), by default HTTP Unauthorized (401, 407) errors, HTTP Not Found (404) errors, custom client (4xx) errors and Other HTTP (4xx) errors. The contents of the first 3 categories can be configured by users.

HTTP client errors - category 3 (default name)

The number of HTTP custom client errors (4xx). By default, there is no specific error type assigned here.

HTTP not found errors 404 (default name)

The number of observed custom HTTP 404 Not found errors.

HTTP other client errors (4xx)

The number of HTTP other client errors (4xx).

There are four categories of HTTP client errors (4xx), of which three can be configured by users. By default, the first category includes HTTP Unauthorized (401, 407) errors, the second category - HTTP Not Found (404) errors. The 3rd category contains no default error types assigned, and can be configured by a user. Finally, a group of Other HTTP (4xx) errors contains all errors that do not fall into any other client errors category.

The number is calculated based on the formula: [HTTP errors 4xx] - [HTTP Not Found errors 404] - [HTTP Not Authorized (401+ 407)] - [HTTP errors configured by user].

HTTP other server errors (5xx)

The number of HTTP server errors (5xx) that do not fall into categories 1 or 2 of custom HTTP server errors (5xx).

HTTP server errors (5xx)

The number of all observed HTTP server errors (5xx).

HTTP server errors – category 1 (default name)

The number of custom HTTP server errors (5xx), category 1. By default, there are no specific error types assigned to this category.

HTTP server errors – category 2 (default name)

The number of custom HTTP server errors (5xx), category 2. By default, there are no specific error types assigned to this category.

HTTP timeout error

This type of error is reported if the time between the occurrence of consecutive URLs constituting a transaction exceeds the predefined timeout value.

HTTP unauthorized errors 401, 407 (default name)

The number of observed custom HTTP authentication related errors. These include "HTTP 401 Unauthorized" and "HTTP 407 Proxy authentication required" errors.

HTTP servers generate errors "401 Unauthorized" in cases, when anonymous clients are not authorized to view the requested content and must provide authentication information in the WWW-Authenticate request header. The 401 errors are similar to "403 Forbidden" errors, however used when authentication is possible but it has failed or not yet been provided. The 407 error is basically similar to 401, but it indicates that the client should first authenticate with a proxy server.

The AMD will report these errors only if the server-level authentication has been configured. Simple and basic user access policies are common in Web sites that do not store user-sensitive and/or business critical information.

Most commercial-grade applications, based on HTTP, such as home banking applications or online shopping sites, rely on the application-level authentication rather than the server-level authentication. Such applications are designed in the way that even if the user authentication fails, the HTTP server usually sends the 200 OK response code and the authentication error message in the page content. Therefore, the 401 Unauthorized and 407 Proxy authentication required error codes are quite rare in commercial environments.

Incomplete transaction error

This error tells us that transaction was reported although monitored traffic did not match the first steps in the transaction definition.

Network time

The time the network takes to deliver the request to the server and to deliver the resulting response back to the user. In other words, network time is the portion of the operation time that is spent on transferring data over the network.

Network time (failed transactions)

The network time for all failed transactions (transactions with a -2 status code). This metric is valid only for 'Transactions (Synthetic Monitoring)' transaction source.

Network time (requests)

The network time for all transaction requests (both requests that became successful transactions and requests that ended as transactions with errors). This metric is valid only for 'Transactions (Synthetic Monitoring)' transaction source.

No response error

The number of errors of the category No response . These errors are reported when a request is detected in the monitored traffic, but the actual operation following this request is not observed.

RTT measurements

The number of RTT measurements.

Server RTT

The time it takes for a SYN packet to travel from the AMD to a monitored server and back again.

graphical illustration
graphical illustration

Server bytes

The number of bytes sent by servers. The number includes headers.

Server packets

The number of packets sent by the servers.

Server time

The time it took the server to produce a response for the given request.

Server time (failed transactions)

The server time for all failed transactions (transactions with a -2 status code). This metric is valid only for 'Transactions (Synthetic Monitoring)' transaction source.

Server time (requests)

The server time for all transaction requests (both requests that became successful transactions and requests that ended as transactions with errors). This metric is valid only for 'Transactions (Synthetic Monitoring)' transaction source.

Slow transactions

The number of transactions for which the transaction time was above a predefined threshold value.

Transaction requests

The number of all transaction requests, both requests that became successful transactions and requests that ended as transactions with errors.

Transaction time

The time it took to complete a transaction.

Transactions

The number of transactions.

Unique users

The number of unique users detected in the monitored traffic.

Server re-transmissions

The number of re-transmitted TCP packets sent by a server.