Subject: [tcmtf] TCMTF: The importance of the layers

From: "Jose Saldana" <[email-masked]>
Date: Fri, 28 Sep 2012 11:39:21 +0200

(this message has to be seen in Courier letters)

We have three different layers:

Header compression

     |

Multiplexing

     |

Tunneling

This allows us to do things like these:

- Adding a new flow to a currently existing tunnel: you can merge two
tunnels coming from different aggregators: You only have to rebuild the
multiplexing and tunneling, but it would not affect header compression. The
problem here could be the added delays in each aggregator. Perhaps a
synchronization could be deployed in order to receive packets from different
tunnels just at the same time.

                     +------------+

5 flows tunnel ----->|            |

                     | aggregator | ----------> 12 flows tunnel

7 flows tunnel ----->|            |

                     +------------+

          The aggregator does not implement or use header compression

          If the two arriving tunnels were synchronized, then the aggregator
would only add processing delay

- Changing the tunneling protocol without modifying multiplexing or header
compression: in a device you could modify the tunneling header, substituting
it by other tunneling protocol.

One question: could this be done, when arriving to a MPLS network? Should
the L2TP/IP headers be maintained?:

                    +------+-------+

                    | L2TP |       +

5 flows tunnel -->  +------+ MPLS  + ----------> 5 flows tunnel

                    | IP   |       +

                    +------+-------+

What do you think? Are these things implicit in the method, or should we
also include them in the draft(s)?

Thanks,

Jose

---

From: Joe Touch <[email-masked]>
Date: Fri, 28 Sep 2012 11:15:15 -0700

> (this message has to be seen in Courier letters)
...
> also include them in the draft(s)?

I think IETF WGs are bad places to *design* protocols.

A comparison of the different approaches you give would be useful, 
especially if based on an implementation, but that suggests further 
research is needed before proceeding.

Joe