Different IM protocols use a variety of ways to name chat rooms. The simplest example is perhaps IRC, where chat rooms have short, persistent, human-readable string names, and are generally global across the network. Skype chat rooms have persistent string names, so you can leave and re-join a room, but these names are opaque unique identifiers. MSN chat rooms are unnamed, and you can only join one by being invited. And XMPP wins the coveted “most complicated chat rooms” prize: chat rooms may be hosted by different servers with different DNS names; normally they have human-readable names, except that all MUCs on Google Talk's conference server have UUIDs as names, and XEP-0045 §10.1.4 Requesting a Unique Room Name defines a protocol for requesting a unique, opaque room name on the server.

This interface intends to support and differentiate these mechanisms more clearly than the TargetHandleType and TargetID properties can alone. It initially contains a pair of properties used to represent the human-readable parts of a Room_Handle's identifier, if any. The above examples for different protocols are represented as follows:

• The IRC channel #telepathy on Freenode is represented by a channel with properties TargetHandleType = Room, TargetID = "#telepathy", RoomID = "#telepathy", Server = "", indicating that the room has a human-readable identifier, and is not confined to a particular server on the network.

  Rationale:

  Actually, IRC supports creating “local” channels specific to the server they are created on. These channels have identifiers starting with & rather than #. These could be represented by setting Server appropriately.
• A Skype group chat with opaque identifier 0xdeadbeef has TargetHandleType = Room, TargetID = "0xdeadbeef", RoomID = "", Server = "", indicating that the room has an identifier but no human-readable name.
• An MSN group chat has TargetHandleType = None, RoomID = "", Server = "", indicating that the room has neither an identifier (so it cannot be re-joined later) nor a human-readable name.
• A standard Jabber multi-user chat jdev@conference.jabber.org has TargetHandleType = Room, TargetID = "jdev@conference.jabber.org", RoomID = "jdev", Server = "conference.jabber.org".
• A Google Talk private MUC private-chat-11111x1x-11xx-111x-1111-111x1xx11x11@groupchat.google.com has TargetHandleType = Room, TargetID = "private-chat-11111x1x-11xx-111x-1111-111x1xx11x11@groupchat.google.com", RoomID = "", Server = "groupchat.google.com", indicating that the room has a persistent identifier, no human-readable name, and is hosted by a particular server.
• Similarly, a XEP-0045 §10.1.4 uniquely-named room lrcgsnthzvwm@conference.jabber.org has TargetHandleType = Room, TargetID = "lrcgsnthzvwm@conference.jabber.org", RoomID = "", Server = "conference.jabber.org", indicating that the room has a persistent identifier, no human-readable name, and is hosted by a particular server.

Requestable channel classes

If the connection supports joining text chat rooms by unique identifier, like Skype, it should advertise a Requestable_Channel_Class matching:

( Fixed = { ...ChannelType: ...Text,
            ...TargetHandleType: Room,
          },
  Allowed = [ ...TargetID,
              ...TargetHandle,
            ]
)

Channel requests must specify either TargetID or TargetHandle.

If, like IRC, the room identifiers are also human-readable, the RCCs should also include RoomID in Allowed_Properties:

( Fixed = { ...ChannelType: ...Text,
            ...TargetHandleType: Room,
          },
  Allowed = [ ...TargetID,
              ...TargetHandle,
              ...RoomID
            ]
),

( Fixed = { ...ChannelType: ...Text
          },
  Allowed = [ ...RoomID,
            ]
)

Requests may specify the RoomID in place of TargetID or TargetHandle . Note how RoomID appears in Allowed_Properties of a different RCC because when TargetHandleType is omitted (or is None), both TargetHandle and TargetID must also be omitted. RoomID is allowed in conjuction with TargetID or TargetHandle in some situations, as explained below in the Requesting room channels section.

If rooms may be on different servers, Server should also be included in the allowed properties, but CMs MUST use a reasonable default Server if not explicitly specified in a channel request. The CM's default server MAY be configurable by a connection parameter specified on a RequestConnection call, similarly to how the fallback conference server is specified on jabber connections in gabble.

If the protocol supports unnamed rooms, RoomID should be fixed to the empty string, and TargetHandleType should be None:

( Fixed = { ...ChannelType: ...Text,
            ...TargetHandleType: None,
            ...RoomID: "",
          },
  Allowed = [ ]
)

Requesting room channels

When explicitly joining a room, the CM cannot know whether the room ID is unique or not. As a result, if this is the case, adding an empty string RoomID into the channel request will ensure the CM knows. For example:

{ ...ChannelType: ...Text,
  ...TargetHandleType: Room,
  ...TargetID: "qwerasdfzxcv@conference.jabber.org",
  ...RoomID: ""
}

If RoomID features in Allowed_Properties then the only value allowed in conjunction with TargetID or TargetHandle is the empty string. Requests with conflicting TargetID and RoomID properties will fail with InvalidArgument.

To create a XEP-0045 §10.1.4 uniquely-named room channel on the conference.jabber.org server, then the following channel request should be made:

{ ...ChannelType: ...Text,
  ...RoomID: ""
  ...Server: "conference.jabber.org"
}

If everything is successful, then when the channel request is satisfied, a new channel will appear with the following properties:

{ ...ChannelType: ...Text,
  ...TargetHandleType: Room,
  ...TargetID: "kajsdhkajshdfjkshdfjkhs@conference.jabber.org",
  ...RoomID: ""
  ...Server: "conference.jabber.org"
}

The CM will have received the unique room name (kajsdhkajshdfjkshdfjkhs) and then created a room with such a name on the said server. The empty RoomID property shows that the room name is not human-readable.