/// <summary>
        /// Links channels together so that destination can hear source
        /// </summary>
        public void LinkChannel(int sourceID, int destinationID, bool oneWay = true)
        {
            var channels = server.getChannels();

            // link channels
            var srcChan = channels[sourceID];
            var dstChan = channels[destinationID];

            srcChan.links = AddToArray(srcChan.links, destinationID);
            dstChan.links = AddToArray(dstChan.links, sourceID);
            server.setChannelState(srcChan);
            server.setChannelState(dstChan);

            if (oneWay)
            {
                // set ACL (dont let source hear destination)
                server.setACL(sourceID,
                              new[]
                {
                    new ACL(true, true, false, -1, "all", 0, (int)Permission.Speak),
                    new ACL(true, true, false, -1, "in", (int)Permission.Speak, 0)
                },
                              null,
                              true);
            }
        }
        /// <summary>
        /// Update exist channel
        /// </summary>
        /// <param name="channel"></param>
        /// <param name="setAcl">add acls and groups?</param>
        public void UpdateChannel(VirtualServerEntity.Channel channel, bool setAcl = false)
        {
            // set channel info
            var state = new Channel(channel.Id, channel.Name, channel.ParentId, channel.Links, channel.Description, false, channel.Position);

            // WARNING! LINKS MUST BE VALID OR InvalidChannelException will be thrown
            _server.setChannelState(state);

            if (setAcl)
            {
                // set groups
                Group[] groups = new Group[channel.Groups.Count];
                for (int i = 0; i < channel.Groups.Count; i++)
                {
                    var g = channel.Groups[i];
                    groups[i] = new Group(g.Name, g.Inherited, g.Inherit, g.Inheritable, g.Add, g.Remove, g.Members);
                }
                // set acls
                ACL[] acls = new ACL[channel.Acls.Count];
                for (int i = 0; i < channel.Acls.Count; i++)
                {
                    var a = channel.Acls[i];
                    acls[i] = new ACL(a.ApplyHere, a.ApplySubs, a.Inherited, a.UserId, a.Group, a.Allow, a.Deny);
                }
                _server.setACL(channel.Id, acls, groups, channel.InheritAcl);
            }

            // update in cache
            if (_entity.Channels.ContainsKey(channel.Id))
            {
                _entity.Channels[channel.Id] = channel;
            }
            else
            {
                _entity.Channels.Add(channel.Id, channel);
            }
        }