On Jan 25, 2016, at 12:33 PM, Johnny Billquist <bqt
at softjar.se> wrote:
On 2016-01-25 18:17, Robert Armstrong wrote:
I will
participate.
Oh, and sure - I'll go along provided I can get the routing results that I want.
Sorry to be selfish, but I'm not going to put up with some nonsensical routing path
just so that we can have standardized costs.
I already put forth my requirements for the routing a while ago - there are only two.
a) If two nodes have a direct point to point link, then that link should be the
preferred route.
b) I really want symmetrical routing.
I already know that there are those who believe that symmetrical routing is impossible to
achieve, so maybe I'll give up on (b). I still want (a) though.
Symmetrical routing will be impossible. DECnet is not designed in a way that makes it
possible.
Correct.
More precisely, symmetric routing is not a design goal of DECnet. (Nor is it in other
networks I can think of.)
If you set link costs the same at both endpoints, then routes will be symmetric if there
are no equal cost paths between the given source and destination. If equal cost paths
exist, the outcome will depend on the node addresses, and in general you won't get
symmetric routes.
Nor does it matter. There is no end user benefit to symmetric routes, and the debugging
benefits, if any, are small at best.
paul