OSPF performance/SPF calculations

Ondrej Zajicek santiago at crfreenet.org
Fri Apr 23 16:09:00 CEST 2010


On Fri, Apr 23, 2010 at 10:54:33AM +0200, Joakim Tjernlund wrote:
> > Removing of endianity swap is correct only if the Fletcher checksum
> > would return the same value regardless of endianity swap. Is this
> > a property of the Fletcher checksum? I don't see that.
> 
> Assuming the LSA's are in the same endian(Big Endian) the sum should
> be the same. You might have to swap the sum before returning it to the caller.

As i looked on the Fletcher checksum, it seems that you cannot just swap
the result instead of swapping the checked data.

> Quagga does NOT do what BIRD does and it works as it should.

Berhaps Quagga stores the LSAs in the network endianity (big endian) and
BIRD stores the LSAs in the host endianity?

-- 
Elen sila lumenn' omentielvo

Ondrej 'SanTiago' Zajicek (email: santiago at crfreenet.org)
OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net)
"To err is human -- to blame it on a computer is even more so."
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