On 4/6/06, David Daney <[EMAIL PROTECTED]> wrote: > Janos Farkas wrote: > > Shouldn't it > > be more correct to not depend on the ip address of the used network, > > but to use the "scope" parameter of the given address?
> RFC 3927 specifies the Ethernet arp broadcast behavior for only > 169.254.0.0/16. Presumably you could set the scope parameter to local > for addresses outside of that range or even for protocols other than > Ethernet. Since broadcasting ARP packets usually adversely effects > usable network bandwidth, we should probably only do it where it is > absolutely required. The overhead of testing the value required by the > RFC is quite low (3 machine instructions on i686 is the size of the > entire patch), so using some proxy like the scope parameter would not > even be a performance win. Indeed, I just have a bad feeling about hardwiring IP addresses this deep. The problems with "my" idea would be, summarily, after a day: Q: Is there are reason to use broadcast ARP semantics for other IP address ranges? A: Maybe, but no RFC defines that. Q: Is there are reason to NOT use broadcast ARP semantics for the defined IP address ranges? A: Maybe, but the RFC is against it. Q: Is there a reason to expect people (and tools) to use/define scopes? A: Probably, but it's still uncommon practice :) I mean, how many of us have 192.168.x.x addresses with "global" scope? I know I do. I'm still in a losing position :) Janos - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
