[Olsr-dev] mtu problem with multicast ipv6 packets
Kaplan L. Aaron
Sun Oct 19 21:41:08 CEST 2008
I believe there was also once an issue with MTU sizes on different
(jumbo?) wifi links.
thanks for the patch!
On Oct 19, 2008, at 9:30 PM, John Hay wrote:
> While debugging some other stuff, I noticed that a lot of the olsr
> on our network was fragmented. Looking into it a bit, it turns out
> while the interface mtu might be 1500 bytes, on FreeBSD (and I
> would guess
> most other BSDs) by default multicast IPv6 packets will be
> transmitted with
> a mtu of 1280 bytes. RFC 3542 Section 11.1 gives the reasoning
> behind it.
> So here is my patch to clip the mtu in the IPv6 case. I have hardcoded
> OLSR_IPV6_MTU, but at least on the BSDs it is defined in netinet/
> ip6.h as
> IPV6_MMTU. It did not look as if ip6.h is pulled in at the moment,
> so I did
> not know if we should start now. :-)
> John Hay -- (spam-protected) / (spam-protected)
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