1. Quantum -
Services' Chaining & Insertion
Havana Design Summit, Portland, April 2013
Big Switch Networks (Sumit Naiksatam,
Kanzhe Jiang, KC Wang, Mandeep
Dhami, Mike Cohen)
Mirantis (Ilya Shakhat,
Eugene Nikanorov)
Red Hat (Gary Kotton)
Many conversations
Design doc: https://docs.google.com/document/d/1iLzieNKxM7xip_lRidmalAhF_6-Yf1b_cePF4yeAnkQ/edit
Session Etherpad: https://etherpad.openstack.org/Quantum_Services'_Chaining_and_Insertion

2. Motivation:
● A user needs to leverage more than one network
service in it's virtual topology.
● The order of services is important (a Loadbalancer
is front ended by a Firewall; traffic may need to be
steered to FW before hitting the LB).
● How does the user request this composite service?
● How does the provider support this?
Network Service 1
(Bump-in-the-wire)
Network Service 3
(Bump-in-the-wire)
Network Service 2
(Tap)
Network Service 1
(Bump-in-the-wire)
Network Service 2
(L3)

3. Proposal
● A tenant-facing "Services' Chain" abstraction that
lets the user request a composition of services.
● Enhancements to existing services' model to
support chaining at the backend.
Network
Service 1
Network
Service 2
Network
Service 3
Source
Network
Destination
Network
Services' Chain

4. Services' Chain
External
Network
Firewall (Bump-in-
the-wire)
Loadbalancer (L3)
Web Tier
App Tier
Firewall
DB Tier
Firewall
Service Chain:
[FW (BITW), LB (L3)]
source: external_nw
destination: any
● ordered list of service
instances
● source_network,
destination_network
○ Quantum networks (or
default "any")
○ Caveats exist, e.g. a
service chain with L3
service at the end of
the chain implicitly
routes to the
destination network

5. Services' Chain Templates
Issue:
Not all services combinations will be valid
Not all service combinations may be supported
Proposal:
Provider publishes service chain templates for
supported combination of services
A service chain template is an ordered list of
service-types

6. Workflow
0. Provider populates service chain templates (may also
need to bootstrap service backend, e.g. physical devices)
1. User looks up supported service chain templates
2. User instantiates service chain:
2a. For each service in the service chain user provides
configuration parameters
2b. User commits service chain configuration
3. Provider (Quantum plugin) realizes chain by stitching the
traffic flow in the order of the services in the chain

7. Resource Model

8. Services' Model Enhancements
Service Types
Category: Firewall, Loadbalancer, etc.
Insertion type: L3, L2, Bump-in-the-wire,
Tap
Vendor, version, other meta-info
Service Implementation Contract
Each service returns attachment points (e.g.
list of ingress, egress Quantum ports)

9. Prototype Experience
Quantum core plugin is the easiest place to
implement chaining
Prototype branch:
https://github.com/bigswitch/quantum/tree/sumit/chaining