This document provides a response from RTI and Cisco to an OMG RFI on SDN programming requirements. It recommends focusing on standardizing an information model to represent observable and controllable network state using MDA. This model would then be mapped to existing middleware technologies like DDS, XMPP, and AMQP to enable observation and control of SDN elements in a standardized way while leveraging existing protocols and APIs. Benefits include distributed consistency, scalability, and interoperability across heterogeneous devices and protocols.

1. OMG
So'ware
Defined
Networks
(SDN)
RFI
Response
from
RTI
and
Cisco
December
2013
mars/2013-­‐12-­‐14
Gerardo
Pardo-­‐Castellote,
Ph.D.
(RTI,
gerardo
AT
rO
DOT
com)
hPp://www.rO.com,
hPp://community.rO.com
Gary
Berger
(Cisco,
gaberger
AT
cisco
DOT
com
hPp://www.cisco.com

2. SDN
programming
requirements
FuncOonal:
• Query
network
(network
components)
state
• Define
forwarding
policies
• Update
forwarding
policies
Non-­‐FuncOonal:
• Simple,
High-­‐Level
interface
• Scalability
• Distributed
consistency
• Management
of
heterogeneous
devices
• Management
of
mulOple
protocols
(OpenFlow,
OF-­‐CONFIG,
PCEP,
I2RS,
OVSDB,
OnePK,
…)
12/29/13
©
2012
RTI
•
COMPANY
CONFIDENTIAL
2

3. Response
main
points
See: http://www.omg.org/cgi-bin/doc?mars/13-11-27.pdf
• Focus
on
standardizing
the
InformaOon
Model
that
represents
the
Observable
and
Controllable
state
of
SDN
Network
Elements
• Use
MDA
to
define
an
SDN
model
of
the
informaOon,
interacOons,
services,
and
APIs
• Map
MDA
model
to
exisOng
middleware
technologies
(DDS,
XMPP,
AMQP,
REST/HTTP)
to
create
specific
ways
to
observe/control/
configure
SDN
elements
12/29/13
©
2012
RTI
•
COMPANY
CONFIDENTIAL
3

4. ObservaOons/MoOvaOon
• A
single/common
middleware
plaform
is
unlikely
to
succeed
due
to
exisOng
investments,
vendor
preferences
and
need
to
interoperate
with
deployed
systems
– IntegraOon
of
all
these
approaches
around
a
common
MDA
informaOon
model
is
the
next-­‐best
approach
• Leveraging
exisOng
middleware
plaforms
automaOcally
bring
standard
APIs,
data-­‐representaOons,
protocols,
discovery
and
proven
scalability,
robustness.
– Effort
can
be
directed
towards
high-­‐level
abstracOons,
composiOon,
segmentaOon
of
controller
logic,
etc.
• A
common
SDN
InformaOon
model
can
be
the
foundaOon
for
bridging
exiOng
protocols
and
remain
open
to
support
new
ones
in
the
future
12/29/13
©
2012
RTI
•
COMPANY
CONFIDENTIAL
4

5. Steps
to
MDA
SDN
InformaOon
Model
1. Use
UML
to
define
data-­‐centric
informaOon
model
for
SDN
– Data-­‐Centric
Model
makes
not
assumpOon
about
protocols,
interacOons
or
APIs.
Models
simply
the
observable
and
controllable
state
2. Map
the
InformaOon
Model
to
exisOng
technologies:
–
–
Standards:
SNMP,
OpenFlow
Vendor
technologies:
Cisco
OnePK,
Juniper
Contrail,
VmWare
NSX
3. Maps
InformaOon
Model
to
exisOng
middleware
plaforms:
– DDS,
XMPP,
AMQP,
REST
©
2013
RTI
•
CISCO
•
ALL
RIGHTS
RESERVED
5

6. Some
benefits
of
leveraging
standard
middleware
technologies
• Many
things
come
for
free.
E.g.
in
DDS:
– Discovery
– Asynchronous
noOficaOon
(events/traps/signals)
– Content
based
Filtering
at
the
source
– Scalability
– Reliability
in
the
presence
of
failures/disconnects
–
Qos,
PrioriOzaOon
– History
and
Durability/Persistence
– Etc.
©
2013
RTI
•
CISCO
•
ALL
RIGHTS
RESERVED
6

7. RFI
QuesOons:
1.
SDN
Maintain
open,
vendor
neutral…
• Standard
InformaOon
Model
defined
using
MDS
is
available
to
all
and
maintained
by
an
standards
body
open
to
all
• Mapping
of
the
InformaOon
Model
to
standard
middleware
plaforms
also
done
and
maintained
by
standard
body
such
as
the
OMG.
– New
mappings
can
be
developed
for
new
standards
and
also
contributed
by
vendors
to
match
their
own
plaforms
©
2013
RTI
•
CISCO
•
ALL
RIGHTS
RESERVED
7

8. Many
things
come
“for
free”
2.
support
for
network
related
enOty
discovery,
connecOon,
…
3.
Support
interoperability
of
network
control
and
operaOonal
data…
4.
Support
for
mulOple
programming
languages…
5.
What
architectural
paPerns
could
miOgate
the
Controller
choke
point
problem?
8.
How
are
SDN
ecosystem
events
from
…
handled?
10.
How
does
the
SDN
ecosystem
support
federated
data
centers?
11.
How
to
handle
(DIL)
environments?
These
are
all
already
provided
by
each
middleware
plaform
so
it
comes
“for
free”
©
2013
RTI
•
CISCO
•
ALL
RIGHTS
RESERVED
8

9. 6.
Support
of
exisOng
network
standards
9.
Interoperate
with
legacy
network
architectures
• Each
standard/architecture
should
be
mapped
to
the
common
SDN
InformaOon
Model
• Standard
Bridges/Gateways
can
be
developed
between
different
standards
as
they
are
all
mapped
to
the
same
InformaOon
Model
©
2013
RTI
•
CISCO
•
ALL
RIGHTS
RESERVED
9

10. 7.
RelaOonship
to
exisOng
SDN
efforts
• OMG
should
focus
on
its
areas
of
core
experOse:
– Use
of
UML
to
define
a
MDA
Common
InformaOon
Model
for
SDN
– Mapping
to
Middleware
technologies:
DDS,
REST,
XMPP
©
2013
RTI
•
CISCO
•
ALL
RIGHTS
RESERVED
10

11. Discussion