On Mon, 6 Jun 2005, Niall O Broin wrote:
> I've used heartbeat (http://www.linux-ha.org) a few times before,
> rather successfully - it just works. However, I'm now looking at
> deploying it fro a project in a large organisation which has a very
> expensive network infrastructure and there is some concern about
> how their switches will react when packets from IP address w.x.y.z
> suddenly start arriving in on port B when they used arrive on port
> A (I presume this is an ARP issue of some sort). This has never
> been an issue whenever I've used heartbeat before, but it has been
> raised by the networking people in this organisation.
It shouldn't be a problem at all as far as common switches are
concerned. They only look at the MAC addresses and MAC<->port
relationshop, which won't change by using heartbeat.
For anymore fancy switches which feel the need to inspect IP headers,
heartbeat does gratuitous ARP on takeover, iirc - which should update
any MAC<->IP state in snoopers. That said switches which inspect IP
headers typically do so for optimising multicast, and they do it by
monitoring IGMP messages - so this would be out of scope for
heartbeat. (And not a concern unless your application uses
multicast). Finally, for switches which do so, it tends to be
configurable (IM*VL*E) via some kind of 'igmp snooping' option.
Paul Jakma paul at clubi.iepaul at jakma.org Key ID: 64A2FF6A
The nice thing about Windows is - It does not just crash, it displays a
dialog box and lets you press 'OK' first.
(Arno Schaefer's .sig)
Maintained by the ILUG website team. The aim of Linux.ie is to
support and help commercial and private users of Linux in Ireland. You can
display ILUG news in your own webpages, read backend
information to find out how. Networking services kindly provided by HEAnet, server kindly donated by
Dell. Linux is a trademark of Linus Torvalds,
used with permission. No penguins were harmed in the production or maintenance
of this highly praised website. Looking for the
Indian Linux Users' Group? Try here. If you've read all this and aren't a lawyer: you should be!