nanog mailing list archives

Re: The stupidity of trying to "fix" DHCPv6


From: Ray Soucy <rps () maine edu>
Date: Thu, 16 Jun 2011 15:08:37 -0400

Are you not using managed switches?

It takes me about 1 second to find exactly which device and which port
a device is connected to.  Once you know that; you have a pretty nice
collection of statistics and log messages that usually tell you
exactly what is wrong.

Or am I missing something?

On Thu, Jun 16, 2011 at 2:37 PM,  <sthaug () nethelp no> wrote:
"Ethernet doesn't scale because of large amounts of broadcast traffic."

We started to introduce multicast, and multicast-aware switches in
IPv4; in IPv6 there is no broadcast traffic.  We won't be able to
scale networks up until we can turn off IPv4,

In other words, probably not for another decade at least?

but once we can IPv6
will be able to grow much larger in terms of per-LAN.   The best
practice of no more than 512 per broadcast domain will seem very
outdated at that point; especially when you add in multicast flood
protection, the available bandwidth goes up, and performance of
network interfaces improves.

Yes and no. If you remove the broadcast traffic you can *in theory*
scale higher. However, this does nothing for the difficulty of L2
troubleshooting, which is a real problem in large flat L2 networks.

The link you pointed to is talking about flat networks of tens of
thousands of hosts; that might be excessive right now...  But I can
certainly see an IPv6-only LAN (with some filtering to make sure ARP
and IPv4 traffic is dropped at the port) scaling easily to thousands
of hosts with today's hardware.

I'm afraid I remain sceptical, unless we come up with significantly
improved methods for L2 troubleshooting.

Steinar Haug, Nethelp consulting, sthaug () nethelp no




-- 
Ray Soucy

Epic Communications Specialist

Phone: +1 (207) 561-3526

Networkmaine, a Unit of the University of Maine System
http://www.networkmaine.net/


Current thread: