At 02:05 PM 7/16/2003 -0700, Karl Auerbach wrote:
The last time I saw a comparision of checksum algorithm strengths was back
in the OSI days when the IP checksum was compared to the OSI Fletcher
checksum (my memory is that the IP checksum came in second.)
um, well, it was certainly behind the
Why, oh WHY would I want to receive a known corrupted packet ?
why oh why would you ever want to talk with someone over a phone that
occasionally clicked or popped?
and why would i mind cheese with holes in it? i don't care about
cheese or voice phones. i care about internet data packets.
The biggest questions I have are:
- where to put this bit?
Right now, the *only* way an L2 with varied service levels can derive
what service levels to use for best-effort traffic is to perform a
layer violation. Continuing this tradition, the bit would be:
How would an app know to set this bit? The problem is that different
L2s will have different likelihoods of corruption; you may decide that
it's safe to set the bit on Ethernet, but not on 802.11*.
Aah, there's the confusion. The apps we have in mind would think that
it is pointless (but
On 17/7/03 8:30, bill wrote:
I would have a hard time taking an IP header bit and making it the Do
not drop this packet in the presense of a bit error somewhere in the
frame from layer 2 - layer 3. Don't think it is a good idea.
What if that bit got corrupted?
Jonathan
On woensdag, jul 16, 2003, at 21:59 Europe/Amsterdam, Keith Moore wrote:
I'm not sure what the problem is here:
- UDP checksums are optional
Not in IPv6. If this is the only thing we need at the transport layer
then we might want to change this back to the IPv4 behavior.
- IPv6 could define an
In message [EMAIL PROTECTED], Iljitsch van Beijn
um writes:
Interesting aspect: it should be possible to make this work with IPsec
encryption but not authentication, but not so well with ciphers in CBC
mode. A stream cipher would be better here.
Here is the Security Considerations text that
] What bit is needed ?
]
] Again, this is a layer 2 property. If you want to receive layer 2
] frames with errors in them just get a Layer 2 device and tell it to not
] do the checksum calculation (much like you put an ethernet nic into
] Promiscous mode so it doesn't drop all of the frames not
Gruesse, Carsten;
How would an app know to set this bit? The problem is that different
L2s will have different likelihoods of corruption; you may decide that
it's safe to set the bit on Ethernet, but not on 802.11*.
Aah, there's the confusion. The apps we have in mind would think that
On donderdag, jul 17, 2003, at 14:24 Europe/Amsterdam, Keith Moore
wrote:
] I would have a hard time taking an IP header bit and making it the
Do
] not drop this packet in the presense of a bit error somewhere in the
] frame from layer 2 - layer 3. Don't think it is a good idea.
I don't know
Jonathan Hogg wrote:
On 17/7/03 8:30, bill wrote:
I would have a hard time taking an IP header bit and making it the Do
not drop this packet in the presense of a bit error somewhere in the
frame from layer 2 - layer 3. Don't think it is a good idea.
What if that bit got corrupted?
I'm not sure what the problem is here:
- UDP checksums are optional
- optional checksums probably aren't applicable to TCP
- IPv4 has IP header checksums
- IPv6 could define an option for IP header checksum
(could be applicable to IPv4 also, if you want a stronger checksum
for the header)
-
Keith Moore wrote:
so it seems like what we need is a bit in the IP header to indicate that
L2 integrity checks are optional, and to specify for various kinds of
IP-over-FOO how to implement that bit in FOO.
How would an app know to set this bit? The problem is that different L2s
will have
Ok, I have to ask a silly question (not like that would be a first on this list)
Why, oh WHY would I want to receive a known corrupted packet ?
Are we talking about someone thinks they can eeke out 1% more performance
because their phy/mac can cut over immediately rather than wait for the packet
On Wed, 16 Jul 2003, Keith Moore wrote:
so it seems like what we need is a bit in the IP header to indicate that
L2 integrity checks are optional
A lot of folks seem to forget that from the point of view of IP L2
includes the busses between memory and the L2 network interface. There
have been
so it seems like what we need is a bit in the IP header to indicate
that L2 integrity checks are optional
A lot of folks seem to forget that from the point of view of IP L2
includes the busses between memory and the L2 network interface.
There have been more than a few recorded cases
so it seems like what we need is a bit in the IP header to indicate
that L2 integrity checks are optional, and to specify for various
kinds of IP-over-FOO how to implement that bit in FOO.
How would an app know to set this bit? The problem is that different
L2s will have different
Why, oh WHY would I want to receive a known corrupted packet ?
why oh why would you ever want to talk with someone over a phone that
occasionally clicked or popped?
why or why would you ever want to watch a video with snow, or an
occasional missing pixel, or even an occasional missing frame?
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