After suing Microsoft this past January, Marble VOIP Partners LLC has filed a second Western District of Texas complaint, this one accusing Mitel Networks and RingCentral (6:22-cv-00259) of infringing the same patent, which is generally related to using the Session Initiation Protocol (SIP) to enable VoIP in applications. Infringement allegations target the parties’ MVP Platform, RingCentral’s video platform, and Mitel’s SIP-DECT system. Connected to a seemingly “David versus Goliath” themed set of plaintiffs, the plaintiff pleads that joinder of these defendants in a single case is proper “because Mitel and RingCentral agreed to integrate RingCentral’s MVP Platform with Mitel’s CloudLink Technology platform in order to transition users from on-premises PBX systems to RingCentral’s MVP platform”.