[RRG] TRRP Waypoint Routers

[Robin Whittle <rw@firstpr.com.au>]

Hi Bill,

In your page:

  http://bill.herrin.us/network/trrp-aapip.html

which I understand is not at all finalised, you describe a system
for getting initial packets to their destinations while the ITR is
waiting to get the mapping information.

  This (initial packet delay) can be mitigated by optionally
  transmitting the initial packets through a long path consisting
  of a highly-aggregated set of waypoint routers until the direct
  map lookup completes.

This seems to conceptually resemble ALT's approach of sending the
initial packets through its network of routers - which are also
highly aggregated - to the ETR.

In both your system and this use of ALT, ITRs are not involved and
no mapping information is required.

Can you give a more concrete example of how these Waypoint Routers
would be structured?

Most of the above page concentrates on how the ITR finds the
Waypoint Router (WR) most suitable to send the packet to.

Is this WR system like ALT in that the WRs form a separate network,
with their own links, with packets ascending the hierarchy until
they get to an aggregation point where the source address and
destination address have something in common, and then the packet
descends the hierarchy on the other side, arriving at the WR close
to the ETR?

I tried to explain my understanding of ALT in:

  http://psg.com/lists/rrg/2008/msg00229.html

and no-one indicated I was mistaken.  There is a diagram from K.
Sriram too:

  http://www.antd.nist.gov/~ksriram/strong_aggregation.png

To what extent does your system resemble ALT, and to what extent
does my critique of ALT apply to your system?  Strong aggregation
enforces links to be made without regard to geographic distance, so
the path taken by a packet could be bouncing back and forth over
continents and oceans traversing up and down the hierarchy.


By your own description, the Waypoint Router path is "long" -
compared to going direct in a tunnel to the ETR (the address of
which is not known at this time).  Presumably this "long" path will
be faster than waiting for the mapping information to arrive.

Do you have estimates for the delay times?


  - Robin


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