Frontend Connection

What Is the Frontend Connection Condition?

Frontend Connection is a condition type used to make traffic routing and manipulation decisions by evaluating the number of active client connections currently connected to the vService (frontend).

vService · web-frontend :443

… N clientsNActive Connections

With this condition, dynamic decisions can be made according to the load status on the vService.

Comparison of Similar Conditions:

Metric	Checked Information	Usage
Frontend Connection	Total active connections	Instantaneous load
Frontend Number of HTTP Requests /s	HTTP requests per second	HTTP traffic density
Frontend Number of New Sessions /s	New sessions per second	Traffic flow rate

The Importance of the Frontend Connection Condition

The instantaneous connection count is an important metric that shows the load status of the system.

With the Frontend Connection condition:

• A warning page can be shown under high load,
• Traffic can be routed to different Backend Services according to the connection count,
• DDoS attacks can be detected,
• Queue or reject can be applied when capacity is exceeded,
• Load balancing strategies can be changed dynamically.

Common Usage Scenarios:

Scenario	Operator	Value	Action
Low density	<	1000	Canary/test traffic
High load	-	5000-10000	Show warning
Critical load	>	10000	Bandwidth limitation

Supported vService Types

HTTP

L7 TCP

Network

The condition can be used at both the request (At Request) and response (At Response) stages; the instantaneous connection count is read at the time of evaluation. The counter is specific to the related vService: it expresses not the total connections across the device but the number of concurrent connections on the vService in which the condition is used.

How to Add?

A new Frontend Connection Condition can be added through the TR7 web management interface by following the steps below:

1. The Configuration Menu is opened by clicking the TR7 logo at the bottom left.
2. The Load Balancer → Conditions → Add steps are followed.
3. Frontend connection is selected as Criteria.
4. The related configurations of the condition are made.
5. The condition is added by clicking the Add button.

Frontend Connection Condition Add Form

Frontend Connection Condition Add Form

INFO

Condition Name

An optional name can be entered for the condition to be created.

This field is especially important in the following scenarios:

• When many conditions are defined under the same vService,
• When conditions with similar criteria need to be distinguished,
• When it is necessary to quickly understand which business rule the condition represents.

When this field is left empty, TR7 analyzes the content of the related condition and creates an automatic, descriptive name in the Condition Description field. This generated description is used as the name in condition lists.

INFO

Criteria Required

The field that determines the type of the condition; Frontend connection is selected from the searchable dropdown list. This selection determines the fields displayed in the form. The criterion cannot be changed after the condition is saved: if a different criterion is needed, a new condition is defined. For all criteria in the list and their scopes, the criteria catalog on the Conditions page can be referred to.

INFO

Operator

The numeric comparison operator and value are entered. The form opens with the operator Equals to (=) selected and the value empty; the entered value must be an integer.

Operator	Symbol	Description
Less than	<	The value must be less
Equals to	=	The value must match exactly
Greater than	>	The value must be greater
Range	-	The value must be between two values; when selected, a second value field opens; both boundaries are included in the range

TIP

The values should be determined according to the server capacity and normal traffic patterns. Appropriate threshold values should be identified by monitoring the normal connection count in the system.

INFO

Condition Description

It is created automatically by TR7 in line with the entered criteria and values.

This description:

• which value the condition applies to,
• which criterion it works on,
• the quick understanding of the condition on listing screens

is produced dynamically by the system so as to provide these.

INFO

Form Buttons

Add

The condition adding process is completed by clicking the Add button.

Add & Repeat

With the Add & Repeat button, the condition adding process is completed, and another new condition can be added with different configurations without leaving the related window.

Condition Added

Operational Usage Recommendations

• Graduated Thresholds Should Be Defined. Different actions should be defined for different connection count thresholds (warning, rate limit, block).
• Normal Values Should Be Monitored. Correct thresholds should be determined by monitoring the normal connection count in the system.
• It Should Be Used for DDoS Protection. An abnormally high connection count can be an indicator of a DDoS attack.
• Capacity Planning. This metric should be used for capacity planning and scaling decisions.

Common Usage Scenarios in Live Environments

The examples below show how the related condition is applied in the most frequently encountered use cases in real systems. These scenarios are based on practices that are widely preferred in live environments and rest on experience gained in the field.

Scenario 1: High Load Warning Page

Purpose: To show users an information page about system congestion when the connection count on the vService enters the high load band, and to manage the waiting time.

Configuration: Operator → Range (-) 5000-10000

Action Recommendations:

• ✅ Show Content → The warning page "The system is experiencing high load, please wait" is shown.
• ✅ Add HTTP Header → The X-Load-Status: high and X-Active-Connections: 5000+ headers are added, and the Backend Service accesses the load information.

Scenario 2: Critical Load Bandwidth Limitation

Purpose: To prevent a system crash by applying bandwidth limitation for each client when the vService reaches the critical load level, and to keep serving the existing users.

Configuration: Operator → Greater than (>) 10000

Action Recommendations:

• ✅ Bandwidth Limitation → A maximum bandwidth limit of 100 Mbps is applied for each client, and excessive resource consumption is prevented.
• ✅ Add HTTP Header → The X-Rate-Limited: critical-load header is added, and the critical load state is marked.
• ✅ Advanced Traffic Inspection → Critical load events, bandwidth limitation applications and their durations are reported.

Scenario 3: Gradual Release (Canary) Traffic at Low Density

Purpose: To open the new release to limited traffic while system density is low; when the connection count increases, to stop the canary traffic automatically and leave all requests to the stable release.

Configuration: Operator → Less than (<) 1000

Action Recommendations:

• ✅ Add HTTP Header → The X-Canary: eligible header is added; the Backend Service side routes the request to the new release with this marker.
• ✅ Advanced Traffic Inspection → The rate of traffic going to the canary and the error distribution are reported.