nanog mailing list archives
Re: IPv6 /64 links (was Re: ipv6 book recommendations?)
From: Dave Hart <davehart () gmail com>
Date: Fri, 8 Jun 2012 03:08:33 +0000
On Fri, Jun 8, 2012 at 12:48 AM, Karl Auer <kauer () biplane com au> wrote:
Yes - whether with ARP or ND, any node has to filter out the packets that do not apply to it (whether it's done by the NIC or the host CPU is another question, not relevant here).
It is relevant to the question of the scalability of large L2 networks. With IPv4, ARP presents not only a network capacity issue, but also a host capacity issue as every node expends software resources processing every broadcast ARP. With ND, only a tiny fraction of hosts expend any software capacity processing a given multicast packet, thanks to ethernet NIC's hardware filtering of received multicasts -- with or without multicast-snooping switches.
The original post posited that ND could cause as much traffic as ARP. My point is that it probably doesn't, because the ND packets will only be seen on the specific switch ports belonging to those nodes that are listening to the relevant multicast groups, and only those nodes will actually receive the ND packets. In contrast to ARP, which is broadcast, always, to all nodes, and thus goes out every switch port in the broadcast domain. This is pretty much the *point* of using multicast instead of broadcast.
I agree.
Current thread:
- Re: IPv6 /64 links (was Re: ipv6 book recommendations?), (continued)
- Re: IPv6 /64 links (was Re: ipv6 book recommendations?) Alexandru Petrescu (Jun 19)
- Re: IPv6 /64 links (was Re: ipv6 book recommendations?) Owen DeLong (Jun 19)
- Re: IPv6 /64 links (was Re: ipv6 book recommendations?) Karl Auer (Jun 06)
- Re: IPv6 /64 links (was Re: ipv6 book recommendations?) Ricky Beam (Jun 07)
- Re: IPv6 /64 links (was Re: ipv6 book recommendations?) Dave Hart (Jun 07)
- Re: IPv6 /64 links (was Re: ipv6 book recommendations?) Karl Auer (Jun 07)
- Re: IPv6 /64 links (was Re: ipv6 book recommendations?) Dave Hart (Jun 07)
- Re: IPv6 /64 links (was Re: ipv6 book recommendations?) Karl Auer (Jun 07)
- Re: IPv6 /64 links (was Re: ipv6 book recommendations?) Mark Andrews (Jun 07)
- Re: IPv6 /64 links (was Re: ipv6 book recommendations?) Karl Auer (Jun 07)
- Re: IPv6 /64 links (was Re: ipv6 book recommendations?) Dave Hart (Jun 07)
- Re: IPv6 /64 links (was Re: ipv6 book recommendations?) Karl Auer (Jun 07)
- Re: IPv6 /64 links (was Re: ipv6 book recommendations?) Karl Auer (Jun 07)
- Re: IPv6 /64 links (was Re: ipv6 book recommendations?) Jean-Francois . TremblayING (Jun 08)
- Re: IPv6 /64 links (was Re: ipv6 book recommendations?) Masataka Ohta (Jun 12)
- Re: IPv6 /64 links (was Re: ipv6 book recommendations?) Karl Auer (Jun 12)
- Re: IPv6 /64 links (was Re: ipv6 book recommendations?) Masataka Ohta (Jun 12)
- RE: IPv6 /64 links (was Re: ipv6 book recommendations?) Tony Hain (Jun 12)
- Re: IPv6 /64 links (was Re: ipv6 book recommendations?) Masataka Ohta (Jun 12)
- RE: IPv6 /64 links (was Re: ipv6 book recommendations?) Tony Hain (Jun 12)
- Re: IPv6 /64 links (was Re: ipv6 book recommendations?) Masataka Ohta (Jun 12)