Hi there,
In Skype or Teams environments, companies often rely on LDAP routing, primarily based on the ‚PhoneNumber‘ attribute in LDAP. When this attribute is properly indexed on the LDAP side, it ensures that SBC requests are processed swiftly, and the routing of calls works seamlessly.
However, in my particular case, the ‚telephoneNumber‘ attribute was not indexed in the customer’s LDAP, rendering it unsuitable for routing purposes. The customer’s team was hesitant to change this, citing past issues when attempting to index this attribute.
Additionally, the customer had the requirement to simultaneously run Skype, Teams, and an Alcatel PBX with minimal routing efforts on the SBC (Session Border Controller).
Here’s the solution I devised:
Attribute Migration: The customer copied the content of ‚telephoneNumber‘ for all their users, regardless of the phone system they were using, into an unused LDAP attribute – ‚extensionAttribute11‘.
System Identification: Another unused attribute, ‚extensionAttribute6‘, was filled with information indicating whether a user was based on Teams or Skype.
Call Routing Rules: We created Call Setup Rules on the SBC to tag calls based on LDAP queries.
Rule Assignment: These Call Setup Rules were assigned to the Carrier-facing IP Groups, ensuring that every inbound call from the PSTN would undergo LDAP queries for routing.
Here is the solution as far as I can share due to GDPR and stuff:
I implemented three LDAP Routing rules:
Check ‚extensionAttribute11‘ for the user part of the incoming TO-header.
If it matches, check ‚extensionAttribute6‘ for the content „MSTeams“ (a value set by the customer in LDAP). If the condition is met, the SBC adds a destination tag „TEAMS“ to the call session, which is referenced in the routing later.
Similar to the Teams rule we have a Skype rule, but ‚extensionAttribute6‘ is checked for „Skype,“ and the SBC adds the destination tag „Skype“ to these calls.
Lets check the third LDAP-routing rule and why it is different:
For calls directed towards the legacy PBX Alcatel, we still check ‚extensionAttribute11‘ for the dialed target number. However, the condition here checks ‚extensionAttribute6‘ for „is NOT Skype and is NOT Teams.“ If this condition is met, and the source IP group is not the Alcatel itself, the call is tagged with destination „Alcatel.“
I used a condition that checks ‚extensionAttribute6‘ for numbers that are neither Skype nor Teams. Additionally, I added a condition to check that the source is not the Alcatel itself, as we encountered some routing issues when the customer changed ‚extensionAttribute6‘ in LDAP, but it wasn’t properly replicated.
As for IP2IP routing, we use a straightforward approach based on destination tags.
That was it, hope someone could use it as small help here or there.
Cheers,
Enrico
