Hello all,

I am one of the authors of https://datatracker.ietf.org/doc/draft-saldana-tsvwg-tcmtf/, which is being discussed in the Transport Area Working Group. Adrian Farrel has suggested me to ask for your feedback in order to take a new step with the draft.

The main idea of the draft is to combine standard protocols that provide compression, multiplexing, and tunneling over a network path for the purpose of reducing the bandwidth used when multiple streams are carried over a path.

It was first thought for real-time flows, but it can also be applied to other ones. Some examples of use:

- Online "First Person Shooter" (FPS) games use UDP datagrams, and they are one of the most "real-time" applications nowadays. Some examples: Counter Strike, Halo, Quake.

- Online "Massively Multiplayer Online Role Playing Games" (MMORPG): They use TCP, but can be considered "real-time", since the actions of the players have to be transmitted very quickly to the server. It should be taken into account that player vs player fights are one of the possible activities of the game. Some examples: World of Warcraft (more than 10 million subscribers).

- TCP is also getting used for media delivery. For many reasons, such as avoiding firewalls, the standard IP/ UDP/ RTP protocol stack is substituted in many cases by IP/ TCP/ HTTP/ FLV [3].

- Another interesting scenario is satellite communication links. Multiplexing small packets into one packet for transmission would improve the efficiency. Satellite links would also find it useful to multiplex small TCP packets into one packet - this could be especially interesting for compressing TCP ACKs.

Now we are thinking about the inclusion of MPLS as another option for the tunneling part, in addition to L2TP/IP. We have thought to add this subsection to the draft:

----------------

2.4.2 MPLS tunneling

In some scenarios, mainly in operator´s core networks, the use of MPLS is widely deployed as data transport method. The adoption of MPLS as tunneling layer in that proposal intends to natively adapt TCMTF to those transport networks.

In the same way that layer 3 tunnels, MPLS paths, identified by MPLS labels, established between Label Edge Routers (LSRs) could be used to transport the compressed payloads within an MPLS network. This way, multiplexing layer must be placed over MPLS layer. Note that, in this case, layer 3 tunnel headers should not be used, with the consequent data efficiency improvement.

---------------

So the new scheme could be this one:

       TCP    UDP  RTP/UDP

        |      |      |

         \     |     /                    ------------------------------

           \   |   /

Nothing or ROHC or ECRTP or IPHC             header compressing layer

               |

               |                          ------------------------------

               |

   PPPMUX or other mux protocols                multiplexing layer

               |

              / \                         ------------------------------

             /   \

            /     \

   GRE or L2TP     \                              tunneling layer

          |        MPLS

          |                               ------------------------------

          IP

We don’t think any modification in MPLS would be necessary, but your feedback will always be interesting.

Thank you very much,

Jose Saldana