VIA now provide dedicated facilities for large meetings up to 1000 attending users. This, coupled with greater participant controls in Skype for Business allows you to perform scheduled webcasts/webinars for conferences up to 1000 attendees.
L3 users can create Meet Now & Scheduled conferences up to 250 attendees without notifying us. To schedule a conference with between 250 & 1000 attendees, please give us at least 2 weeks notice so we can dedicate hardware for you (costs apply).