Fred Baker (fred) wrote:
On Oct 28, 2014, at 11:28 PM, David Lamparter<[email protected]> wrote:
What I'm personally wondering most in this regard is: to what extent
will larger networks deploy multiple prefixes to the hosts?
Well, define “larger”. Any network that gets a PI prefix is unlikely to deploy
multiple prefixes. The question is at what size network is makes sense to
obtain an AS number and a PI prefix, and use BGP to talk with one’s upstream.
I don't agree with this statement for the following reasons.
Availability: There are many enterprises that have very numerous
far-flung sales-office type locations which do not host any critical
data or applications, but which could benefit from higher availability
than that provided by a single ISP provider (some of which are currently
served by a specialised box offering a Very Small Office Service running
dual IPSec tunnels to a central site, which then performs the break out
to the corporate intranet/Internet)
Latency: There are many sites which could benefit from local Internet
breakout to regional cloud services, where you don't want to suffer the
latency associated with a back haul from an office in Australia to a
regional hub in Hong Kong, or even East coast US to West coast US and
back. You'd still also want some back up via the central breakout if the
local breakout failed.
Cost: There are cost savings to be made in many countries where private
network services are still many orders of magnitude more expensive than
plain old Internet. So Internet offload for non-mission-critical traffic
can be very attractive. If you could achieve this via direct host-server
connections using address selection rules or multipath TCP; rather than
via PBR, GRE tunnels + NAT, that would be a lot simpler.
Wherever that boundary is, below that networks will use PA prefixes. The
question then becomes: will they multi home?
And I think the answer today is that we don’t know the answer.
This I agree with.
--
Regards,
RayH
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