Brian,
>It still isn't clear to me what the flow label adds to the semantics
>used by existing 5-tuple QOS classifiers.
First go look at RSVP. Thats one. In our RSVP implementation apps can
set the flowid and then get reserved resources along the path for audio
or video or even more mundane things like file transfer for mission
critical apps like downloading coordinates to a military operation.
Respond to Itojun's mail it says it all. The bottom line is the
client or a server can set the flowlabel and with the address none of
those other tuples are needed and it can also be useful when IPsec is
being used to identify connections at a server that has a front end
router parsing connections for a large MP machine as another example and
get us away from monolithic TCP/IP processing.
Itojuns mail attached. Also look at Itojuns draft.
regards,
/jim
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To: Brian E Carpenter <[EMAIL PROTECTED]>
Cc: Jim Bound <[EMAIL PROTECTED]>, "Ipng (E-Mail)" <[EMAIL PROTECTED]>
In-reply-to: brian's message of Sat, 25 Nov 2000 12:55:14 CST.
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Subject: Re: Usage of IPv6 flow label
From: [EMAIL PROTECTED]
Date: Sun, 26 Nov 2000 07:00:05 +0900
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>It still isn't clear to me what the flow label adds to the semantics
>used by existing 5-tuple QOS classifiers.
just checking, here by "5-tuple" you meant:
- IP address pair (src/dst)
- layer 4 port number pair (src/dst)
- protocol type
is it correct?
except for IP address, they may be embedded into ESP, or may be buried
in IP header chain. so for efficient router operation we need to
use flow label, which will effectively give us the following 3 items
(depending on the definition of "flow"):
- layer 4 port number pair
- protocol type
see RFC2205 page 9.
i believe this (availability of flow label field) is one of important
value-adds of IPv6 against IPv4.
itojun
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