Wireless and Crossover co-operation

I run a wireless system, consisting a desktop (SP Home) and a notebook (SP
Pro)

I have installed a crossover cable to permit faster transfer of files but
cannot get both systems to run at once. Either must be disabled before the
other will run.

Is this normal or are there a other setting to get co-operation.

regs
dj

Juan Hanglow wrote in
dju5rv$evu$(E-Mail Removed):

> I run a wireless system, consisting a desktop (SP Home) and a
> notebook (SP Pro)
>
> I have installed a crossover cable to permit faster transfer of files
> but cannot get both systems to run at once. Either must be disabled
> before the other will run.
>
> Is this normal or are there a other setting to get co-operation.

TCP/IP gets very confused if there is more than one means of sending traffic
between the two PCs - the wireless route and the wired route. You'd think
that traffic would be sent over both routes and the once with the faster
response time would "win", maybe even teaching TCP that that is the route to
concentrate on sending traffic over in future - but it doesn't seem to work
that way.

I think that I'd expect that you would have to disable one route or the
other (eg by disabling either the LAN or wireless adaptor on one of the two
PCs).

I have experienced something similar. My main PC is connected by cable to my
router. My laptop is normally connected by wireless, but if I want extra
speed for large PC-to-PC transfers I connect it to the router by cable. If I
do this, I must remember to unplug the wireless adaptor (USB) first,
otherwise neither connection works. The main PC can ping the laptop, because
I must choose either the LAN or wireless IP, but ambiguous comms (eg using
the laptop's computer name, as in "net view \\laptop" or "net use
\\laptop\c" or the Windows Explorer equivalents) fail to find the laptop
when executed on the main PC. Similarly for "ping main" or "net view \\main"
executed on the laptop because these are ambiguous.

"Martin Underwood" <(E-Mail Removed)> wrote in message
news:4362babd$0$6523$(E-Mail Removed)...
> Juan Hanglow wrote in
> dju5rv$evu$(E-Mail Removed):
>
>> I run a wireless system, consisting a desktop (SP Home) and a
>> notebook (SP Pro)
>>
>> I have installed a crossover cable to permit faster transfer of files
>> but cannot get both systems to run at once. Either must be disabled
>> before the other will run.
>>
>> Is this normal or are there a other setting to get co-operation.
>
> TCP/IP gets very confused if there is more than one means of sending
> traffic between the two PCs - the wireless route and the wired route.
> You'd think that traffic would be sent over both routes and the once with
> the faster response time would "win", maybe even teaching TCP that that is
> the route to concentrate on sending traffic over in future - but it
> doesn't seem to work that way.
>
> I think that I'd expect that you would have to disable one route or the
> other (eg by disabling either the LAN or wireless adaptor on one of the
> two PCs).
>
> I have experienced something similar. My main PC is connected by cable to
> my router. My laptop is normally connected by wireless, but if I want
> extra speed for large PC-to-PC transfers I connect it to the router by
> cable. If I do this, I must remember to unplug the wireless adaptor (USB)
> first, otherwise neither connection works. The main PC can ping the
> laptop, because I must choose either the LAN or wireless IP, but ambiguous
> comms (eg using the laptop's computer name, as in "net view \\laptop" or
> "net use \\laptop\c" or the Windows Explorer equivalents) fail to find the
> laptop when executed on the main PC. Similarly for "ping main" or "net
> view \\main" executed on the laptop because these are ambiguous.
>

Thanks Martin, I thought as much.

In message <4362babd$0$6523$(E-Mail Removed)>, Martin
Underwood <(E-Mail Removed)> wrote:

> Juan Hanglow wrote in
> dju5rv$evu$(E-Mail Removed):
>
>> I run a wireless system, consisting a desktop (SP Home) and a
>> notebook (SP Pro)
>>
>> I have installed a crossover cable to permit faster transfer of files
>> but cannot get both systems to run at once. Either must be disabled
>> before the other will run.
>>
>> Is this normal or are there a other setting to get co-operation.
>
> TCP/IP gets very confused if there is more than one means of sending
> traffic between the two PCs.

No it doesn't. I suspect the problems is that both the wired and wireless
networks have the same (default) IP address range.

> You'd think that traffic would be sent over both routes and the once with
> the faster response time would "win", maybe even teaching TCP that that is
> the route to concentrate on sending traffic over in future - but it
> doesn't seem to work that way.

TCP doesn't choose routes. With luck the naming protocol Windows uses will
do the right thing. Otherwise, since ad-hoc wireless can't be bridged it
then get very complicated.

> I have experienced something similar. My main PC is connected by cable to
> my router. My laptop is normally connected by wireless, but if I want
> extra speed for large PC-to-PC transfers I connect it to the router by
> cable. If I do this, I must remember to unplug the wireless adaptor (USB)
> first, otherwise neither connection works. The main PC can ping the
> laptop, because I must choose either the LAN or wireless IP, but ambiguous
> comms (eg using the laptop's computer name, as in "net view \\laptop" or
> "net use \\laptop\c" or the Windows Explorer equivalents) fail to find the
> laptop when executed on the main PC. Similarly for "ping main" or "net
> view \\main" executed on the laptop because these are ambiguous.

Strange, that works here. But it's rather pot-luck which interface is used.

--
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Timothy Baldwin wrote in
djvk0s$35t$(E-Mail Removed):

> In message <4362babd$0$6523$(E-Mail Removed)>,
> Martin Underwood <(E-Mail Removed)> wrote:
>
>> TCP/IP gets very confused if there is more than one means of sending
>> traffic between the two PCs.
>
> No it doesn't. I suspect the problems is that both the wired and
> wireless networks have the same (default) IP address range.

Is that a problem? So are you saying that even though the wireless and wired
adaptors have different IP addresses, the fact that they are both in (for
example) 192.168.1.x would cause problems? Given that this is how you'd
normally set up a network - alternative means of connecting one computer to
a network - then that's TCP (and/or services that use TCP) failing to cope
with that situation. If you have two totally different subnets for the two
adaptors, then there's only one route to any given IP address, but if both
adaptors are in the same subnet then you've got ambiguity: the same remote
IP can be rwached by two different adaptors. That's what I meant by "TCP/IP
gets very confused if there is more than one means of sending traffic
between the two PCs".

In the specific case that the OP mentioned, he could have both PCs wireless
adaptors in 192.168.0.x and both his wired adaptors in 192.168.1.x because
the wired network is totally private to those two PCs, but that's a special
case.