1. OpenStack Neutron &
Software Defined Networks (SDN)
OpenStack BCN MeetUp - March 2014
Iñaki Pascual – Software Engineer

2. Neutron & SDN OpenStack BCN MeetUp - March 2014
Acknowledgments
I want to thank all the developers and members in OpenStack Community, OpenStack
Foundation and Open Networking Foundation. Also to my colleges in PLUMgrid Inc.
Information presented here is sourced from my own experience as PLUMgrid employee and from:
● OpenStack Foundation Documents & Community
● Open Networking Foundation
● Stanford Seminar 2013 - “Software-Defined Networking at the Crossroads” by Scott Shenker,
University of California, Berkeley http://www.youtube.com/watch?v=WabdXYzCAOU
● OpenStack Summit Presentations
“OpenStack Neutron Modular Layer 2 Plugin Deep Dive"
By: Kyle Mestery,Robert Kukura in OpenStack
https://www.openstack.org/summit/openstack-summit-hong-kong-2013/session-videos/presentat
ion/openstack-neutron-modular-layer-2-plugin-deep-dive
● PLUMgrid Inc, http://plumgrid.com/resources/
Views and technical points expressed here are solely presenter’s and doesn’t reflect the
views/positions of PLUMgrid Inc in any way.

3. Neutron & SDN OpenStack BCN MeetUp - March 2014
Agenda
● Demo. Intro to Neutron (Havana release).
● Dashboard and CLI overview.
● Create networks, spawn VMs, test connectivity.
● Floating IPs, create, assign. Test external connectivity.
● Load Balancer create and test.
● Test isolation of overlapping networks.
● Slides. Neutron Overview
● Network as a Service *(NaaS)
● Components
● Architecture
● New plugin ML2.
● Demo. Neutron.
● REST API example with curl.
● View components, network namespaces, soft switches.
● Slides. SDN.
● Definition, architecture.
● Virtual Networks.
● Software Edges.
● Example: PLUMgrid.
● Conclusions. Neutron and SDN.

4. Neutron & SDN OpenStack BCN MeetUp - March 2014
Demo
Dashboard and CLI overview.
Create Networks, spawn VMs, test connectivity.
Create and assign floating IPs, test external access.
Load balancer create and test.
Overlapping IPs, test tenant isolation.

5. Neutron & SDN OpenStack BCN MeetUp - March 2014
Neutron in Openstack

6. Neutron & SDN OpenStack BCN MeetUp - March 2014
Neutron in Openstack

7. Neutron & SDN OpenStack BCN MeetUp - March 2014
Network as a Service (NaaS)
● Provides REST APIs to manage network connections for the
resources managed by other OpenStack Services (e.g. Nova)
● Technology Agnostic (framework based on “plug-ins”)
● Multi-tenancy: Isolation, Abstraction, full control over virtual
networks
● Modular Design: API specifies service, vendor provides its
implementation. Extensions for vendor-specific features.
● Standalone Service : It is not exclusive to OpenStack. Neutron
is an autonomous service
● Exposes vendor-specific network virtualization and SDN
technologies

8. Neutron & SDN OpenStack BCN MeetUp - March 2014
Neutron Components

9. Neutron & SDN OpenStack BCN MeetUp - March 2014
Neutron Components
Neutron Server
● Runs on Controller node.
● Exposes API. Enforces network model.
● Passes requests to Neutron plugin.
Neutron Plugin
● Runs on Controller node.
● Implements the API.
● Interacts with neutron server, database and agents.
Queue
● Enhance communication between each components of neutron
Database
● Persistent network model
Plugin agent (*)
● Run on each compute node
● Connect instances to network port
DHCP Agent (*)
● Start/stop dhcp server
● Maintain dhcp configuration
L3 Agent (*)
● To implement floating IPs and other L3 features, such as NAT
(*) These components may be overridden by the plug-in

10. Neutron & SDN OpenStack BCN MeetUp - March 2014
Modular Layer 2 Plug-in (ML2)
● New in Havana, deprecates the OpenVSwitch and LinuxBridge plug-ins
(but not the agents).
● Modularity through drivers:
● TypeDrivers: flat, VLAN, GRE...
● Mechanism Drivers: OVS, LinuxBridge...
● One mechanism Driver may support several Type Drivers.
● Vendors may implement a new plug-in or a mechanism driver.

11. Neutron & SDN OpenStack BCN MeetUp - March 2014
Network Devices – Compute Node

12. Neutron & SDN OpenStack BCN MeetUp - March 2014
Network Devices - Network Node.

13. Neutron & SDN OpenStack BCN MeetUp - March 2014
Demo (II)
Neutron REST API, example with curl.
Neutron Internals:
Network namespaces – DHCP, Router, LoadBalancer
OVS Bridges - VLANs

14. Neutron & SDN OpenStack BCN MeetUp - March 2014
Demo (II)
Neutron API example with cURL.
How to update a network:
1.- get the token from keystone
2.- list existing networks to get id of network to update
3.- update network name
After these, check in Dashboard that name has actually changed
$ export IP=<host_ip>
$ export PASS=<admin_password>
$ curl -d "{"auth":{"tenantName": "admin", "passwordCredentials":
{"username": "admin", "password": "$PASS"}}}" -H "Content-type: application/json"
http://$IP:35357/v2.0/tokens
$ export TOKEN=<token_id>
$ curl -H "X-Auth-Token: $TOKEN" http://$IP:9696/v2.0/networks
$ export NET=<network_id>
$ curl -H "X-Auth-Token: $TOKEN" -X PUT -d '{"network": {"name": "network_updated"}}'
http://10.0.2.15:9696/v2.0/networks/$NET.json
APIs:
http://docs.openstack.org/api/openstack-identity-service/2.0/content/POST_authenticate_v2.0_
tokens_.html
https://wiki.openstack.org/wiki/Neutron/APIv2-specification#API_Operations

15. Neutron & SDN OpenStack BCN MeetUp - March 2014
Demo (II)
Show soft bridges. We can see the vlan tags in integration bridge.
$ sudo ovs-vsctl show
e80f467f-bd33-452a-a495-e7c89736c552
Bridge br-int
Port "tap0b53fd22-35"
tag: 2
Interface "tap0b53fd22-35"
Port "tapd7e7242f-64"
tag: 3
Interface "tapd7e7242f-64"
Port br-int
Interface br-int
type: internal
Port "qr-63a50193-d2"
tag: 2
Interface "qr-63a50193-d2"
type: internal
Port "qr-2ad51820-c7"
tag: 1
Interface "qr-2ad51820-c7"
type: internal
Port "tap2f696f92-6c"
tag: 2
Interface "tap2f696f92-6c"
type: internal
...

16. Neutron & SDN OpenStack BCN MeetUp - March 2014
Demo (II)
Show network namespaces
$ ip netns show
qlbaas-9035ea38-1916-4cf9-855f-06f1a41b1899
qdhcp-a389d59d-5275-4470-9edf-44bf7de6cb0f
qdhcp-f030bfa9-5209-477b-a260-e0bc552ebffd
qrouter-9de1459b-c453-485c-b89e-99cb09e82371
qrouter-91a3612b-835c-400b-b8db-6d11dade6b11

17. Neutron & SDN OpenStack BCN MeetUp - March 2014
Demo (II)
Execute commands in network namespaces
$ sudo ip netns exec qdhcp-a389d59d-5275-4470-9edf-44bf7de6cb0f ifconfig
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
tapae991773-bd Link encap:Ethernet HWaddr fa:16:3e:80:a8:0f
inet addr:30.0.0.4 Bcast:30.0.0.255 Mask:255.255.255.0
inet6 addr: fe80::f816:3eff:fe80:a80f/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:40 errors:0 dropped:0 overruns:0 frame:0
TX packets:25 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:5048 (5.0 KB) TX bytes:3074 (3.0 KB)
inaki@precise:~/devstack$ sudo ip netns exec qdhcp-a389d59d-5275-4470-9edf-44bf7de6cb0f
tcpdump -i tapae991773-bd
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on tapae991773-bd, link-type EN10MB (Ethernet), capture size 65535 bytes

18. Neutron & SDN OpenStack BCN MeetUp - March 2014
SDN Introduction
● Why SDN?:
● Networks have a high operational cost.
● Networks are difficult to evolve.
● There is a need for NaaS
● 2008: The Open Networking Foundation (ONF) releases
OpenFlow (Standford University) and NOX (Nicira).
● There was previous efforts like Software Defined Radio, MPLS
and other works in Universities and Companies' labs.

19. Neutron & SDN OpenStack BCN MeetUp - March 2014
SDN Definition (by Open Networking Foundation)

20. Neutron & SDN OpenStack BCN MeetUp - March 2014
SDN Architecture

21. Neutron & SDN OpenStack BCN MeetUp - March 2014
Network Virtualization
● In the original SDN 3-layer architecture,
the control programs are aware of the
underlying physical network.
● New intermediate layer allows operator
to express his needs in a higher level
language, so decoupling from the
physical infrastructure.
● Network hypervisor will convert them
into Network OS language.
● Allows the creation of tenant isolated
virtual networks.

22. Neutron & SDN OpenStack BCN MeetUp - March 2014
Core/Edge Nodes Differentiation
● Concept borrowed from MPLS. Two
different kind of nodes: core/edge.
● Core: Transport packets among edge
nodes.
● Edges: nodes connected to hosts.
● All functionalities can be moved to
edges while core can focus on
transport.
● Edge nodes became Software Edges.
● SDN Controller need to talk only to
edge nodes.
● Actually part of the SDN work can be
done by the software edges.

23. Neutron & SDN OpenStack BCN MeetUp - March 2014
SDN Example: PLUMgrid.
http://plumgrid.com/resources/

24. Neutron & SDN OpenStack BCN MeetUp - March 2014
Neutron & SDN
● Centralized control plane allows creating isolated
tenant virtual networks.
● Compute nodes are the software edges.
● Neutron enforces SDN but actually delegates its
implementation and functionalities to the plugin.

25. Neutron & SDN OpenStack BCN MeetUp - March 2014
Thank you!

26. Neutron & SDN OpenStack BCN MeetUp - March 2014
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