I'm also curious about what exactly happens if a *faster moving
packet*, say segment 2 of a stream arrives at the client in Mumbai
before a slower, segment 1 (say via the Tajikistan link, while
segment 2 came via Quicker Iran)?
Will the Linux kernel just HOLD
segment 2 forever inside RAM or something while waiting for the rest
to turn up? (that's not a good thing, is it?) What about Windows?
Now the first router on the hop outwards from the EU server will CHECK
which way the route is less congested, right, before it picks one of
these 2 paths, without which the net would have been unworkable by now?
Now my question is, how does IT, sitting in the *EU*, know whether
the link between *TAJIKISTAN* and Mumbai is free, as opposed to the
link between *Iran* and Mumbai?
Is this info constantly shared between routers like, per MILLISECOND
or something??
Also, I heard that CISCO somehow (!!) knows how WORLD internet traffic
is moving - is this somehow because CISCO routers "send something back"
to them or "call home"?
Otherwise how could they know this?? HIGHLY disturbing!
I'm also curious about what exactly happens if a *faster moving
packet*, say segment 2 of a stream arrives at the client in Mumbai
before a slower, segment 1 (say via the Tajikistan link, while segment
2 came via Quicker Iran)? Will the Linux kernel just HOLD segment
2 forever inside RAM or something while waiting for the rest to turn
up? (that's not a good thing, is it?) What about Windows?
Thanks.
I don't know, but it could either
- discard #2 and ack #1, forcing the sender to retransmit
- ack #0, but keep #2 around in case #1 shows up
I suspect the latter happens.
"Forever" sounded like a bad thing, but I don't think it is.
If the local application is alive, if it hasn't requested any timeouts,
if it doesn't tell the socket to die, and if there's no explicit
evidence that the other side is dead, then the socket should be kept.
Even if you're without network for a week.
What if I send you packets #2, #3, #4, #5, #6, #7, #8, #9, #10, #11,
#12, #13, #14, #15, #16, #17, #18, … #3,985, … #1,234,567,890.
Do you still want to hold onto the billion packets that I've sent you? Probably not.
Sysop: | Keyop |
---|---|
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