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ISP failures and site multihoming [Re: Enforcing unreachability ofsite local addresses]
I'll take one particular issue, and Cc: to multi6 as I believe it is a
very important thing to consider.
On Fri, 14 Feb 2003, Alan E. Beard wrote:
> > > Most of the end-user-network managers among my clients now multihome,
> > > and
> > > will continue to require multihomed service in future. In every case
> > > where the user's network is multihomed, the multiple independent
> > > connections are seen as crucial for maintenance of high availability of
> > [Kurtis:]
> > I find this funny. A number of studies have shown that if this is what
> > you are after, multihoming and BGP is the wrong way to go - but never
> > mind.
> Your comment may be true, but my clients are nonetheless unwilling to risk
> the possibility of an extended network outage on a single ISP (while not
> frequent, these events are far from unprecedented) rendering their online
> customer-support environment unavailable for several hours, much less for
> a day. Shorter outages (on the order of minutes in the single digits) are
> tolerated, provided that such outages are infrequent.
This is a very problematic approach IMO.
Need more resiliency? Network outages unacceptable?
The right place to fix this is the network service provider, period.
Nothing else seems like a scalable approach.
Consider a case when many companies _phone_ services would have been
changed to VoIP. IP would be a critical service. Do the enterprises
protect against failures by getting more ISP's? Unscalable. No, the
ISP's _must_ get better. Pick one well when choosing them.
When ISP's have SLA's, a lot of customers for which continued service is
of utmost importance, the networks *will* work. There is just no other
choice. If the mobile phone of CTO, CEO or whatever rings after (1)5
minutes of network outage, things _will_ happen.
It just seems the mentality in some networks is that network outages are
ok, networks don't have to be designed with multiple connections, etc.etc.
That must change if we want to build a mission-critical IP infrastructure.
Instead of making every site try to deal with the problems themselves.
This is my view as ISP and an end-user.
Pekka Savola "You each name yourselves king, yet the
Netcore Oy kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings