On Tue, 24 Jul 2007, Sridhar Samudrala wrote:
> On Tue, 2007-07-24 at 10:13 -0700, Rick Jones wrote:
> > > Rick,
> > >
> > > I don't see any way around this. For example, on one of my test
> > > systems, I have the following link local routes:
> > >
> > > chance% netstat -A inet6 -rn | grep fe80::/64
> > > fe80::/64 ::
> > > U 256 0 0 eth0
> > > fe80::/64 ::
> > > U 256 0 0 eth2
> > > fe80::/64 ::
> > > U 256 0 0 eth3
> > > fe80::/64 ::
> > > U 256 0 0 eth4
> > > fe80::/64 ::
> > > U 256 0 0 eth5
> > > fe80::/64 ::
> > > U 256 0 0 eth6
> > >
> > > So if I want to run a link local test to fe80::202:b3ff:fed4:cd1,
> > > the system has no way to choose which is the correct interface to
> > > use for the test, and will give an error if the interface isn't
> > > specified.
> >
> > Yeah, I was wondering about that. I'm not sure if the attempts on "those
> > other
> > OSes" happened to involve multiple interfaces or not. Even so, it "feels"
> > unpleasant for an application to deal with and I wonder if there is a way
> > for a
> > stack to deal with it on the application's behalf. I guess that might
> > involve
> > some sort of layer violation between neightbor discovery and routing
> > (typing
> > while I think about things I know little about...)
> >
> > Is there RFC chapter and verse I might read about routing with multiple
> > link-local's on a system?
> >
> > > You must explicitly specify the desired interface. For example,
> > > on my test system, the correct interface is eth6 which is interface 8
> > > (lo eth0 eth1 eth2 ... eth5 eth6). Here is an example nuttcp test
> > > specifying interface 8:
> > >
> > > chance% nuttcp -P5100 fe80::202:b3ff:fed4:cd1%8
> > > 1178.5809 MB / 10.02 sec = 986.2728 Mbps 12 %TX 15 %RX
> > >
> > > nuttcp uses getaddrinfo() which parses the "%<ifindex>" field,
> > > and then copies the sin6_scope_id from the res structure to the
> > > server's sockaddr_in6 structure before initiating the connect().
> >
> > OK, I'll give that a quick try with netperf:
> >
> > [EMAIL PROTECTED] ~]# netperf -H 192.168.2.107 -c -C -i 30,3 -- -s 1M -S 1M
> > -m 64K
> > -H fe80::207:43ff:fe05:9d%2
>
> We can even specify the interface name instead of the interface index
> <link-local>%ethX
>
> getaddrinfo() uses if_nametoindex() internally to get the index.
>
> Thanks
> Sridhar
Cool! That's much easier and works great. :-)
chance% nuttcp -P5100 fe80::202:b3ff:fed4:cd1%eth6
1178.5468 MB / 10.02 sec = 986.3239 Mbps 13 %TX 15 %RX
Still learn something new every day. Now if I just could remember
it all when I needed it later. :-)
-Thanks
-Bill
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