

Elastic Network Interfaces in the Virtual Private Cloud - jeffbarr
http://aws.typepad.com/aws/2011/12/new-elastic-network-interfaces-in-the-virtual-private-cloud.html

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trout
I'm curious what the technology behind it is. There have been some standards
based things recently (VXLAN) as well as some non-standards based (OTV, F5
DCI).

It sounds like VXLAN. VXLAN in short is encapsulating a L2 packet inside a
UDP-VXLAN packet and then using multicast to route the packet to multiple
switches. The same concepts of subnets still exist, it's just hacking together
multiple L2 domains by multicasting between configured switches. The VXLAN
header allows for identification between the different networks to specify
which actual VLAN it should be mapped to. What's interesting is there are more
potential VXLANs than multicast addresses so there is not a mapping between
multicast address and VXLAN. As well, the actual VLAN the messages are sent to
don't need to match on the other side of the VXLAN.

This is all of course assuming Amazon didn't homebrew their own L2 over L3
extension protocol. VXLAN shows promise, so it would be cool, but it is
layered with multicast and broadcast complexities.

~~~
wmf
They're now allowing multiple vNICs, but they look like basically the same
implementation that VPC has been using for a while; it definitely predates
VXLAN. When it comes to networking, EC2 does nothing the industry-standard
way.

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sturadnidge
Amazon out-innovating the competition again. My money is on this being an
implementation of Microsoft Research's VL2, given James Hamilton was a co-
author of this
([http://research.microsoft.com/pubs/80693/vl2-sigcomm09-final...](http://research.microsoft.com/pubs/80693/vl2-sigcomm09-final.pdf))

~~~
csears
ENI seems like it would be simple to implement without VL2. Why do you think
it's related?

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mitchellh
Amazing. Another huge reason to go into VPC with AWS.

Their use cases they list are all good and valid (at least two apply to me
personally). Additionally, this should enable some decent HA options, along
the exact same lines as VIPs (except not as fast, most likely).

I'm looking forward to going to work tomorrow to play around with how long it
takes after hot swapping ENIs for traffic to flow to the new instance, since
for managing servers purely in AWS, this looks to be a beautiful option for
server-level HA with a hot-standby.

Unfortunately, this does add even more domain knowledge necessary to jump into
VPC (which is already a very non-trivial affair for those who aren't very
familiar with sysadmin work/networking in general).

I'd have to say this sounds like my favorite feature launched this year behind
VPC.

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briandoll
I love that Amazon continues to explode our previous model of computing. The
entire ecosystem of PaaS providers that are built on top of AWS benefit from
these advances and Amazon wins by continuing to be the platform to build a
PaaS on top of.

While I'm sure it's not their aim, the AWS console and associated web
interfaces are functional but have pretty terrible user experience. It's as if
AWS has found this perfect customer fit... build awesome tech, build an
interface just-barely-good-enough to administer it... foster the ecosystem of
providers that make your tech easier to use... rake in the cash because at the
end of the day everyone is running on AWS regardless of who charges their
card.

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notatoad
the number of TLAs in that post is a little OTT.

