Re: comments on requirements draft

[Peter Tattam <peter@jazz-1.trumpet.com.au>]

On Tue, 7 Aug 2001, Geoff Huston wrote:

> one point at a time:
> 
> 
> > >   Migration to IPv6, which will allow unprecedented scaling of the
> > >   number of potentially multihomed sites, will seriously exacerbate
> > >   this stress unless a substantially different approach to multihoming
> > >   is adopted.
> >
> >It's not the move to IPv6 that will exacerbate the stress -- it's
> >the growth of the Internet and of multihoming, regardless of which
> >version of IP will be used.
> 
> 
> I would tend to suggest that growth in multi-homing is a cost and 
> perception issue.
> If the cost of multi-homing is considered to be sufficiently low and the 
> perception
> of service reliability is also sufficiently low then you will see increased 
> activity
> in multi-homing. Increase the perception of reliability, or make 
> multi-homing more
> difficult (cost, technology required, or anything else) and you reduce the
> incidence of multi-homing. To ascribe growth to multi-homing to IPv6 is a rash
> statement without adequate foundation.
> 
> Geoff
> 
> 
> 

I was at a recent conference in Aus and the issue of Service Level Agreements
was being discussed in a forum panel.  Each of three very large
telco's/provider's (by Aus standards anyway) representatives were all highly
confident that they could promise extremely high levels of redundancy and there
was no need to have more than one provider.

However by the end of the panel discussion and after several war stories were
shared by members of the audience and even one member on the panel, it
was eventually conceded that for an effective SLA, redundancy was crucial, and
in particular to multiple providers.  The forum concluded with an independent
consultant's reflection that they always recommended complete redundancy to
their clients especially at the last mile.

I also find that the further you are away from the core of the internet in your
region, the higher is the risk of things going bang.  We are multply homed to 3
providers even though we are a small ISP, and I have had occusion to depend on
each of them for large outages over the past year.  Some outages were
configuration problems in networks, while others were meltdowns in the
providers infrastructure including major cable breaks, and even one
international fibre break.  Had it not been for our multihoming, our service
would have been out for a minimum of several hours, and in one worst case
scenario we suffered, 2-3 days.

This risk of things going wrong being higher at the edge is a curious
observation as it flies in the face of the conventional wisdom that says that
the smaller you are, and further from the core, the less need one should have
for multihoming.  I would suggest the converse may actually be true.  The
smaller or perhaps more remote a site or network is, the higher is the risk
that the quality of their service is going to be degraded in one way or
another.

I guess my point is that to maintain any kind of quality of service, a small
provider has to go that extra mile (pardon the pun) and provide a better
service to differentiate their brand from the big providers.  One method of
differentiation is redundancy by multihoming, even if the perceived cost may be
high.

Peter

--
Peter R. Tattam                            peter@trumpet.com
Managing Director,    Trumpet Software International Pty Ltd
Hobart, Australia,  Ph. +61-3-6245-0220,  Fax +61-3-62450210