Direct Federation

The final form of federation is really the legacy version that was introduced back in Live Communications Server 2005. Direct federation requires each partner to specify the SIP domain name and the Access Edge service FQDN providing that federation service. Direct federation operates the same way as enhanced federation in that it doesn’t allow any more messages per second, and it requires greater administrator overhead. Not only do users need to request federation with a specific partner’s SIP domain, but the Lync administrators from both parties must now meet to exchange information about what server names are used.

The main use case for direct federation is when the Edge Server’s FQDN does not match the partner’s SIP domain. For example, partners trying to reach [email protected] must locate an Edge Server also in the companyabc.com DNS namespace, or they will drop the connection because the namespace does not match. Direct federation provides an override for that drop, and tells the Edge Server to ignore the name mismatch by connecting to the specified Access Edge service FQDN. The disadvantages to direct federation are in the administration overhead and the fact that this can easily break if one organization changes an Access Edge service FQDN.

A good analogy here when considering whether to enable federation, and allow dynamic discovery, is to think of federation in terms of email. Imagine if email operated like direct federation such that users in different domains could not send mail to each other without an administrator on both sides first manually configuring a connection to the partner domain. If that were the case, email probably would not have become the universal communication modality that it is today. Instead, any user can generally send mail to any domain without administrators making server configuration changes. Dynamic and enhanced federation are the Lync Server equivalent of that capability; users have full access to presence, instant messaging, web conferencing, and A/V conferencing with any other user across the world without any additional configuration. Federation has a leg up on email because it allows for much richer communication methods between partners.

When discussing federation, organizations should follow these guidelines:

• Identify whether federation to partners or Office 365 for mobile push notifications is a business requirement.

• Discuss whether dynamic federation and partner discovery will be enabled.

• Prepare a list of federated partners by involving end users or monitoring existing Lync Edge Server logs, and add those domains for enhanced federation.

• Identify which partners will require direct federation and collect the Access Edge service FQDNs.