MID Server configuration for Service Mapping in upgraded deployments

  • Release version: Yokohama
  • Updated January 30, 2025
  • 2 minutes to read
    • Summarize
    Summarized using AI
    This content was generated using new OpenAI-powered functionality. Results are provided on an as is basis and are not guaranteed to be accurate or complete.

    Summary of MID Server configuration for Service Mapping in upgraded deployments

    When upgrading ServiceNow deployments from earlier versions to Istanbul, Service Mapping continues to use a legacy algorithm to select a MID Server for discovery requests. This process involves specific criteria focused on application assignment and IP ranges to determine which MID Server should handle a given discovery task.

    Show full answer Show less

    Key Features

    • Application Parameter: Defines the MID Server’s assigned application. Setting it to ServiceMapping reserves the MID Server exclusively for Service Mapping discovery requests. Setting it to ALL allows any ServiceNow application to use the MID Server. During upgrades, MID Servers previously configured with the Capability parameter for Service Mapping are automatically updated to have the application set to ServiceMapping.
    • IP Range: Restricts the operational scope of a MID Server to a specific IP address range. Service Mapping will not choose a MID Server for discovery requests outside its configured IP range.
    • Default MID Server: One MID Server can be configured as the default to handle discovery requests when no IP range matches. This ensures continuity of discovery in scenarios where specific IP matches are not found.
    • Legacy Selection Algorithm: By default, upgraded deployments use a legacy method where Service Mapping selects MID Servers based on application assignment and IP range matching. If no suitable MID Server is found by IP or application, it falls back to the default MID Server or randomly selects one if no default is set. Discovery cannot start if no appropriate MID Server is found.
    • New Selection Algorithm: Introduces an additional criterion, capability, which considers network protocols for more precise MID Server selection. This algorithm can be enabled in upgraded deployments to complement or replace the legacy method.

    Key Outcomes

    • Ensures continuity of Service Mapping discovery processes post-upgrade by maintaining compatible MID Server selection behavior.
    • Allows exclusive or shared MID Server usage through application parameter settings, improving resource allocation.
    • Improves discovery accuracy and control using IP range restrictions and an optional default MID Server configuration.
    • Provides flexibility to adopt the new MID Server selection algorithm when network protocol considerations become necessary.

    For ServiceNow deployments upgraded from earlier versions to Istanbul, Service Mapping uses the legacy algorithm to choose a MID Server for a discovery request.

    MID Servers have the following selection criteria that Service Mapping in upgraded deployments uses to choose a MID Server for a discovery request:
    • Application — defines what application a MID Server works with. Set it to Service Mapping to reserve this MID Server exclusively to Service Mapping discovery requests. Alternatively, set it to ALL to allow any ServiceNow application to use this MID Server.

      In earlier releases, you could configure MID Servers to work only with Service Mapping by using the Capability parameter. If you had MID Servers with this configuration, during the upgrade to Istanbul the application parameter is automatically set to ServiceMapping for them.

    • IP range — limits operation of this MID Server to this IP range. Service Mapping does not choose this MID Server for a discovery request whose endpoint is outside this IP range.

    In addition to the IP range, you can configure one of the MID Servers as the default server that Service Mapping uses. For operational information, see Configure a default MID Server for Service Mapping for upgraded deployments.

    In upgraded deployments, Service Mapping selects a MID Server using a legacy algorithm:
    • Service Mapping chooses the MID Server whose application criteria is set to ServiceMapping or to ALL.
    • By default, Service Mapping selects the MID Server whose IP range matches the IP in the discovery request.
    • If Service Mapping cannot find a MID Server with the matching IP range and matching application, it assigns the discovery request to the default MID Server.
    • If there is no default MID Server and none of the MID Servers have IP ranges configured for them, Service Mapping uses a random MID Server.
    • If there is no default MID Server and no IP range matches the IP in the discovery request, Service Mapping cannot start the discovery process.

    The new algorithm for selecting MID Servers uses an extra selection criteria: capability. It allows Service Mapping to take a network protocol into consideration. For information about updated selection criteria and the new MID Server selection algorithm, see Choose MID Server selection algorithm.

    While by default Service Mapping uses the legacy algorithm in upgraded deployments, it can support both new and legacy algorithms for selecting a MID Server. If necessary, you can enable the new MID Server selection algorithm for your upgraded deployment. For more information, see Choose MID Server selection algorithm.