Messages in this thread | | | From | urlichs@noris ... | Subject | Re: Patch for route.c | Date | 8 Apr 1997 18:34:45 +0200 |
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"Richard B. Johnson" <root@analogic.com> writes: > > This is _NOT_ nonsense! If you are running gated in the manner, you > are contributing to LAN congestion by duplicating packets. > Why?
Gated is smart enough to realize that it should toss a route when it knows a better one. (In that case, there are no duplicate packets.) _If_ it is configured properly.
> A machine on __any__ single __physical__ network link needs only two routes. > Note the emphasis on "any" and "physical". > > (1) A route to its local network or subnet. > (2) A route to all other places. > Wrong. An Ethernet is a single physical network. If there's more than one router on that network, and all the local machine knows is its default route, _then_ there will be duplicate packets.
If by "single link" you mean "point-to-point link", then you're right, but most people here don't assume that a priori.
> This is _NOT_ nonsense! Traceroute will see the routing that occurred > in spite of the fact that another machine will take these same packets, > duplicate them on the same wire, and send them to the same destination > address. The destination address will then get the duplicate packets > which it will throw away in the (overburdened) network code.
These are not broadcast packets. There _is_ no other machine that will also see the packets. All of these packets go from one machine to one other machine, and traceroute _will_ show every hop.
If you have inefficient routing, i.e. a -> b -> c where a and c are on the same Ethernet, then you need to install a better route on a. There are only two ways to do that, i.e. either run gated on a, b and c, or install the necessary static routes on a.
-- Q: What is the difficulty with writing a PDP-8 program to emulate George Bush? A: Figuring out what to do with the other 3K. -- Matthias Urlichs \ noris network GmbH / Xlink-POP Nürnberg Schleiermacherstraße 12 \ Linux+Internet / EMail: urlichs@noris.de 90491 Nürnberg (Germany) \ Consulting+Programming+Networking+etc'ing PGP: 1024/4F578875 1B 89 E2 1C 43 EA 80 44 15 D2 29 CF C6 C7 E0 DE Click <A HREF="http://info.noris.de/~smurf/finger">here</A>. 42
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