SIMPLE MSRP Chat draft-niemi-simple-chat-06.txt

1
SIMPLE MSRP Chatdraft-niemi-simple-chat-06.txt

• 68th IETF
• Prague, Check Republic
• SIMPLE WG
• 21/22-March-2007
• Miguel Garcia ltmiguel.an.garcia_at_nokia.comgt
• Aki Niemi ltaki.niemi_at_nokia.comgt

2
History and scope

• Version -00 of this draft appeared in January
  2004.
• Since then, the draft has been bouncing back and
  forth between SIMPLE and XCON
• XCON was even fed with requirements in (expired)
  draft-garcia-xcon-private-messaging-reqs
• Goals of the draft-niemi-simple-chat-06
• Leverage the SIP conference framework (RFC 4353)
  and the conference event package (RFC 4575) with
  MSRP chats
• Provide MSRP-specific mechanisms to enable
  private messaging and rudimentary pseudonyms
  through nicknames with MSRP chats
• Provide solutions that are forward-compatible
  with the conference management protocol
  eventually coming out of XCON
• Aim at the same level of functionality as with
  other standard chat protocols (e.g., IRC,
  XMPP/Jabber)

3
Architecture
Chat room server
SIP
SIP
Conference focus
Participant
Participant
MSRP
SIP
MSRP
SIP
MSRP mixer
MSRP
MSRP
Participant
Participant
4
Main functions

• SDP negotiation
• Ability to learn of support and ability to use
  the chat extensions at the conference focus
  MSRP mixer
• Nickname handling
• Ability to set a unique nickname for the duration
  of the session
• The MSRP mixer can decline and in case of
  collisions, even suggest other (similar)
  nicknames
• Regular messaging
• Ability to exchange messages with all
  participants in the chat room
• Private messaging
• Ability to send and receive private messages with
  selected participants through the MSRP mixer
• Outside the scope
• Sidebars
• Control
• Roles and policies

5
Joining a conference

• Participants sent INVITE requests to join
• The draft advocates the usage of message/cpim
• So the SDP in the INVITE should contain
• aaccept-typesmessage/cpim
• The draft defines a new media-level chatroom
  attribute in SDP, which is included in the SDP
• Used to learn support between the participant and
  the chat room server
• And to discover policies for usage of nicknames
  and private messages
• achatroomnickname private-messages

6
Nicknames

• A nickname is defined as the combination of a
  Display-Name and a SIP URI formatted according to
  a special naming convention
• The Display-Name need not be unique in the chat
  room
• The SIP URI part is scoped to the chatroom URI.
• The SIP URI must contain the chatroom URI.
• Examples
• "Alice" ltsipalice40wonderland_at_chats.example.comgt
  
• "Beer Lover" ltsipbeerlover40chat34_at_example.comgt
  
• Properties
• The nickname URI is not publicly connected to the
  real SIP identity of the user
• The nickname URI resolves to the chat room server
  -gt It provides pseudonimity
• The URI is globally unique (but the Display-Name
  is necessarily not)

7
Setting a nickname
Chat room server
Participant

• New MSRP method NICKNAME
• Two new MSRP headers Set-Nickname and
  Proposed-Nickname
• Reuse of the existing 423 response code
• By default, nicknames are valid for the duration
  of the session
• Nicknames are advertised through the conference
  event package
• Extension not yet defined, but could be a new
  ltnicknamegt element child of ltusergt
• ltconference-infogt
• ltusersgt
• ltuser entity"sipuser_at_example.com"gt
• ltdisplay-namegtAlice Brownlt/display-namegt
• ltnickname entity"sipalice_at_chat22.ex.com"gt
• ltdisplay-namegtAlice in Wonderlandlt/display-
  namegt
• lt/nicknamegt
• ltendpointgt ... lt/endpointgt
• lt/usergt
• lt/usersgt
• lt/conference-infogt

MSRP d93kswow NICKNAME Set-Nickname "Alice"
ltsipalice40chatroom22_at_chat.example.comgt
MSRP d93kswow 423 Nickname already in
use Proposed-Nickname "Alice 2"
ltsipalice240chatroom22_at_chat.example.comgt
MSRP d93kswow NICKNAME Set-Nickname "Alice
Two" ltsipalice240chatroom22_at_chat.example.comgt
MSRP d93kswow 200 Set-Nickname "Alice Two"
ltsipalice240chatroom22_at_chat.example.comgt
8
Sending instant messages
Chat room server
Participant

• Sender MUST wrap message in CPIM
• CPIM To header set to chatroom URI
• CPIM From header set to any senders URI
• SIP URI
• TEL URL
• IM URI
• Nickname URI
• ... and send it in a SEND request
• MSRP mixer does not alter bodies when forwarding
  to other participants
• No reports of errors on the other side of the
  mixer

MSRP d93kswow SEND Content-Type
message/cpim To ltsipchat34.example.comgt From
Bob" ltsipbob_at_chat34.example.comgt Content-Type
text/plain Hello -------d93kswow
MSRP d93kswow 200
9
Sending private instant messages
Chat room server
Participant

• Sender MUST wrap message in CPIM
• CPIM To header set to any recipient(s) URI
• SIP URI
• TEL URL
• IM URI
• Nickname URI
• CPIM From header set to any senders URI
• SIP URI
• TEL URL
• IM URI
• Nickname URI
• ... and send it in a SEND request
• MSRP mixer does not alter bodies when forwarding
  to other participants
• No reports of errors on the other side of the
  mixer

MSRP d93kswow SEND Content-Type
message/cpim To Alice ltsipalice_at_chat34.exampl
e.comgt From Bob" ltsipbob_at_chat34.example.comgt
Content-Type text/plain Hello -------d93kswow
MSRP d93kswow 200
10
Dropping the Big One

• Will you marryHHHHH work on this?