[155501] in North American Network Operators' Group
Re: Does anyone use anycast DHCP service?
daemon@ATHENA.MIT.EDU (Victor Kuarsingh)
Mon Aug 13 13:18:04 2012
In-Reply-To: <20120813.181802.74662906.sthaug@nethelp.no>
From: Victor Kuarsingh <victor.kuarsingh@gmail.com>
Date: Mon, 13 Aug 2012 13:18:27 -0400
To: "sthaug@nethelp.no" <sthaug@nethelp.no>
Cc: "nanog@nanog.org" <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
Sent from my iPad
On 2012-08-13, at 12:18 PM, sthaug@nethelp.no wrote:
>> I think it would be far more reliable to simply have two independent
>> DHCP servers with mutually exclusive address ranges, and have one
>> system be secondary and "delay" its responses by 2s so it always
>> "loses" when the primary is up and running well.
>>=20
>> Yes, you lose the ability for clients to get the same IP during a
>> lease refresh if the primary is down, but that is a small price to pay
>> for simplicity and robustness.
>=20
> That depends on your scenario. In some situations it is important to
> get the same IP. In other situations, using potentially double the
> address space is unacceptable.
As some have noted, your environment may dictate which is better (HA with so=
ftware considerations, or retention of IP lease information).
Example:
In an ISP environment, I would suggest that you consider prefix delegation f=
or IPv6 (--assuming you plan on IPv6 at some point ).
For traditional IPv4 networks (ISP), changing the WAN side IP address occurs=
often enough that it's annoying, but tolerable. When we consider IPv6, cha=
nging the WAN side IP is also reasonable (IA_NA). But if you plan on supply=
ing the home network a prefix delegation (IA_PD), you get into some problems=
if you wind up renumbering the home network.
Not sure if this example fits your profile, but at this point, I would not c=
onsider a deployment of any major system without considerations of IPv6.
Regards,
Victor Kuarsingh
>=20
