[openstack-dev] [Neutron] [RFC] Floating IP idea solicitation and collaboration

Thomas Morin thomas.morin at orange.com
Tue Dec 16 13:52:45 UTC 2014

Hi Ryan,

Mathieu Rohon :
> We have been working on similar Use cases to announce /32 with the
> Bagpipe BGPSpeaker that supports EVPN.

Btw, the code for the BGP E-VPN implementation is at 
It reuses parts of ExaBGP (to which we contributed encodings for E-VPN 
and IP VPNs) and relies on the VXLAN native Linux kernel implementation 
for the E-VPN dataplane.


> Please have a look at use case B in [1][2].
> Note also that the L2population Mechanism driver for ML2, that is
> compatible with OVS, Linuxbridge and ryu ofagent, is inspired by EVPN,
> and I'm sure it could help in your use case
> [1]http://fr.slideshare.net/ThomasMorin1/neutron-and-bgp-vpns-with-bagpipe
> [2]https://www.youtube.com/watch?v=q5z0aPrUZYc&sns
> [3]https://blueprints.launchpad.net/neutron/+spec/l2-population
> Mathieu
> On Thu, Dec 4, 2014 at 12:02 AM, Ryan Clevenger
> <ryan.clevenger at rackspace.com> wrote:
>> Hi,
>> At Rackspace, we have a need to create a higher level networking service
>> primarily for the purpose of creating a Floating IP solution in our
>> environment. The current solutions for Floating IPs, being tied to plugin
>> implementations, does not meet our needs at scale for the following reasons:
>> 1. Limited endpoint H/A mainly targeting failover only and not multi-active
>> endpoints,
>> 2. Lack of noisy neighbor and DDOS mitigation,
>> 3. IP fragmentation (with cells, public connectivity is terminated inside
>> each cell leading to fragmentation and IP stranding when cell CPU/Memory use
>> doesn't line up with allocated IP blocks. Abstracting public connectivity
>> away from nova installations allows for much more efficient use of those
>> precious IPv4 blocks).
>> 4. Diversity in transit (multiple encapsulation and transit types on a per
>> floating ip basis).
>> We realize that network infrastructures are often unique and such a solution
>> would likely diverge from provider to provider. However, we would love to
>> collaborate with the community to see if such a project could be built that
>> would meet the needs of providers at scale. We believe that, at its core,
>> this solution would boil down to terminating north<->south traffic
>> temporarily at a massively horizontally scalable centralized core and then
>> encapsulating traffic east<->west to a specific host based on the
>> association setup via the current L3 router's extension's 'floatingips'
>> resource.
>> Our current idea, involves using Open vSwitch for header rewriting and
>> tunnel encapsulation combined with a set of Ryu applications for management:
>> https://i.imgur.com/bivSdcC.png
>> The Ryu application uses Ryu's BGP support to announce up to the Public
>> Routing layer individual floating ips (/32's or /128's) which are then
>> summarized and announced to the rest of the datacenter. If a particular
>> floating ip is experiencing unusually large traffic (DDOS, slashdot effect,
>> etc.), the Ryu application could change the announcements up to the Public
>> layer to shift that traffic to dedicated hosts setup for that purpose. It
>> also announces a single /32 "Tunnel Endpoint" ip downstream to the TunnelNet
>> Routing system which provides transit to and from the cells and their
>> hypervisors. Since traffic from either direction can then end up on any of
>> the FLIP hosts, a simple flow table to modify the MAC and IP in either the
>> SRC or DST fields (depending on traffic direction) allows the system to be
>> completely stateless. We have proven this out (with static routing and
>> flows) to work reliably in a small lab setup.
>> On the hypervisor side, we currently plumb networks into separate OVS
>> bridges. Another Ryu application would control the bridge that handles
>> overlay networking to selectively divert traffic destined for the default
>> gateway up to the FLIP NAT systems, taking into account any configured
>> logical routing and local L2 traffic to pass out into the existing overlay
>> fabric undisturbed.
>> Adding in support for L2VPN EVPN
>> (https://tools.ietf.org/html/draft-ietf-l2vpn-evpn-11) and L2VPN EVPN
>> Overlay (https://tools.ietf.org/html/draft-sd-l2vpn-evpn-overlay-03) to the
>> Ryu BGP speaker will allow the hypervisor side Ryu application to advertise
>> up to the FLIP system reachability information to take into account VM
>> failover, live-migrate, and supported encapsulation types. We believe that
>> decoupling the tunnel endpoint discovery from the control plane
>> (Nova/Neutron) will provide for a more robust solution as well as allow for
>> use outside of openstack if desired.

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