A method is provided for resolving a call collision in a communication network. The method comprises, at a network node of the communication network: receiving a first call request message from a first user device to set up a call from the first user device to a second user device; checking whether the second user device has in turn sent a second call request message to set up a call from the second user device to the first user device; and in the affirmative, routing the first call request message to a conference bridge.