> >Hesham wrote: > > I haven't heard anyone answering my question as to why > > reverse tunnelling by the MN thru the HA is so much > > worse than triangular routing, > > > > Francis wrote in response: > > => d(bidir tunnel) = 2 * d(MN,HA) + 2 * d(HA,CN) > > d(triangular) = d(MN,HA) + d(HA,CN) + d(MN,CN) > > d(optimization) = 2 * d(MN,CN) > > and we always have d(MN,CN) <= d(MN,HA) + d(HA,CN) > > so d(optimization) <= d(triangular) <= d(bidir tunnel) > > and even stronger 2 * d(triangular) = d(optimization) + > d(bidir tunnel) > > i.e. in my poor English the cost/performance of triangular routing > > is at the middle of bidirectional tunneling and routing > optimization. > > Yes, but does that make any significant difference for real > traffic and > applications given than the traffic from CN to MN goes > through the HA > in the triangular case? > > For instance assume that the CN and MN are next to each > other (delay 1 ms) > and the HA is 100 ms away from them (one way delay). > If you route optimize TCP will see a RTT of 2 ms. > If you do triangular the rtt will be 201 ms. > If you do bidirectional tunneling the rtt will be 400 ms. > You can look at these numbers differently depending what you want to > prove. "400/201 = 2" would make your argument. > But my argument is that "201/2 = 100". > Thus if you care about rtt when the CN/MN are close > compared to the MN/HA > delay you should route optimize.
=> Exactly. So I don't see the improvement with triangular routing over bidirectional tunnelling... for real time or TCP connections. Hesham -------------------------------------------------------------------- IETF IPng Working Group Mailing List IPng Home Page: http://playground.sun.com/ipng FTP archive: ftp://playground.sun.com/pub/ipng Direct all administrative requests to [EMAIL PROTECTED] --------------------------------------------------------------------
