Overview of traffic steering filters

To define a traffic steering policy for your domains on IBM® NS1 Connect®, you can configure a Filter Chain for each DNS record that determines the routing logic the platform will use to determine the optimal answer to return to each incoming request.

Each Filter Chain contains one or more traffic steering filters where each applies a unique processing method to sort (rearrange) or sift (eliminate) answers based on some condition or rule.

Sorting filters rearrange the list of answers based on relevant metadata. For example, the Geotarget Regional filter references the geographic-related metadata and rearranges answers (representing endpoints) based on their proximity to the requester’s location.
Sifting filters eliminate answers from the answer pool based on relevant metadata. For example, the Up filter references the “up” metadata. If an answer’s “up” metadata is set to false, it is eliminated from the answer pool.

Note: Some filters, such as the Priority filter, can be configured to function in sorting or sifting mode.

Fencing filters

These filters are used for more granular traffic steering, allowing you to map requesting clients to specific endpoints based on the requester’s location, IP address, or ASN. It’s important to note, however, that fencing filters should not be used to enforce strict security policies or to block access to specific endpoints since the NS1 Connect platform will always try to return at least one answer, even if all answers are eliminated—as in, no answers meet the criteria specified in the Filter Chain.

Netfence ASN filter: Maps requesting clients to a specific endpoint based on their ASN.
Netfence Prefix filter: Maps requesting clients to a specific endpoint based on their IP address.
Geofence Country filter: Maps requesting clients to specific endpoints based on their country, subdivision, state, or province.
Geofence Regional filter: Maps requesting clients to specific endpoints based on their region.

Geographic filters

A set of geographic filters reference the location of the requester and each available endpoint (answer), either arranging the answers based on their proximity to the requester or eliminating answers that do not meet some geographic criteria. Geographic-based DNS routing is a common technique to connect users to the closest proximate endpoint, which can help ensure better performance.

Geotarget Country filter: Steers traffic toward the most proximate endpoints based on country, subdivision, state, or province.
Geotarget Regional filter: Steers traffic toward the most proximate endpoints based on region.
Geotarget Latlong filter: Steers traffic toward the most proximate endpoints based on longitude and latitude.
Geofence Country filter: Maps requesting clients to specific endpoints based on their country, subdivision, state, or province.
Geofence Regional filter: Maps requesting clients to specific endpoints based on their region.

Health check filters

These filters reference specific answer metadata fields to determine the current status of each available endpoint in terms of either availability or load.

Up filter: Eliminates down or unavailable answers based on their "up" status in the answer metadata.
Shed Load filter: Steers traffic away from overloaded endpoints by comparing load-related metrics against the user-defined low and high thresholds.

Priority filters

These filters allow you to prioritize specific answers based on cost or a user-defined priority value.

Cost filter: Steers traffic toward lower-costing endpoint(s) based on user-defined values.
Priority filter: Steers traffic toward higher-priority endpoints based on user-defined values.

RUM-based traffic steering filters

Organizations using NS1 Connect’s RUM-based traffic steering solution Pulsar can access a set of filters that leverage real-time performance and availability data collected from active application users to inform routing decisions.

Pulsar Performance Stabilize filter: Eliminates endpoints whose latency measurements fall outside of the user-defined threshold.
Pulsar Availability Threshold filter: Eliminates endpoints whose percentage of successful connections over the last five minutes falls outside of the user-defined threshold.
Pulsar Performance Sort filter: Steers users toward higher-performing endpoints based on real-time latency measurements.
Pulsar Availability Sort filter: Steers users toward endpoints with higher percentages of successful connections over the last five minutes.
Pulsar Route Map filter: Maps users to specific endpoints based on their source IP and a custom map file containing user-defined targets.

Shuffle filters

These filters rearrange the list of answers randomly—in some cases, prioritizing answers with a user-defined “weight” applied. These filters are helpful for more general load-balancing purposes in cases where you want to distribute requests evenly across all your endpoints or to skew traffic distribution toward specific endpoints more often.

Shuffle filter: Randomizes the order of answers in the list.
Weighted Shuffle filter: Randomizes the order of answers, prioritizing specific answers more often.
Sticky shuffle filter: Randomizes the order of answers in the list, retaining the answer order for subsequent requests from the same client.
Weighted Sticky Shuffle filter: Randomizes the order of answers while prioritizing specific answers more often and retaining the answer order for subsequent requests from the same client.
Group Sticky Shuffle filter: Randomizes the list of answer groups while repeating the same answer group order for subsequent requests from the same client.

Select First filters

These filters eliminate all but the first N number of answers or answer groups from the list.

Select First N filter: Eliminates all but the first answer in the list.
Select First Group filter: Eliminates all answers except those in the first answer group.

Non-steering filters

Certain filters don’t contribute to the traffic steering decision but are used to modify the response to incoming queries.

Additional Metadata filter: Allows you to add information as TXT records in the response, which can be helpful for system troubleshooting, organization, and more.