Network architecture tools to support network operator requirements

1
Network architecturetools to support network
operatorrequirements

• Luc Le Beller FTRD/DAC

2
Outline

• Introduction and scope
• Generic transport layer structure
• Two examples of IP over optical network
  configurations
• Additional architectural components
• Service description
• Conclusion

3
Technical background
Transport network architecture is driven by the
following items
An important diversity of transport network
techniques in the core and the access SDH,
ATM, IP, MPLS, OTN, GbE
The development of control(s) plane(s) in
addition to management(s) plane(s) from B-ISDN
to ASON
A lot of different architectural models coming
from the standardisation ITU-T, IETF, OIF
4
Operator background
Transport network architecture is driven by the
following items

• Dynamicity
• Transport costs decreased
• Monopoly era with reliable voice and LL services
  demand forecasts is over
• Emergence of multiple new services with uncertain
  needs
• Impact of competitors market share and network
  architecture options

• Diversification from raw transport service
• Provisioning/reconfiguration time enables
  differentiation from competition
• Transport carriers must differentiate their
  services and climb on the value chain
• Bandwidth on demand (wavelengths, SDH VCs) OSP
  (optical service provider) i.e. Storm
• Modulation of quality of service (protection
  levels)
• VPN

5
Scope
Full description of the transport network
components
G.805 and derived standards, G.8080 and derived
standards very low granularity
Consistent top-down (from the service to the
network) and bottom-up (from the network to the
service) description
SG 15 bottom-up approach SG 13 top-down
approach
General interaction between transport network
components
Depending on organisation structure (actors,
business units)
Interaction between transport network components
and other networks and services components
Also depending on organisation structure with
more actors and business units
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Outline

• Introduction and scope
• Generic transport layer structure
• Two examples of IP over optical network
  configurations
• Additional architectural components
• Service description
• Conclusion

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Generic Layer Structure

• A generic layer structure for transport network,
  independent of the techniques, is obtained
• by combination of the following criteria
• Does the layer provide flexible connectivity
  (G.805 sub-network capability) or not ?
• What type of resources in the layer needs to be
  reserved in response to a client request for
  the transport of his (characteristic) information
  ?

Layer(s) offering flexible connectivity and not
requiring specific resources allocation for every
sub-network is named FW
FW
Layer(s) offering flexible connectivity and
requiring specific resources allocation
for Every sub-network is named SW/XC
SW/XC
Layer(s) offering point-to-point connectivity is
named PHY layer
PHY
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Transport Network Techniques
IP
FW
MPLS, ATM VP/VC, SDH VC-X, ETH MAC, OTN ODUk/OCh
SW/XC
SDH RS/MS, OTN OTS/OMS ETH PHY, Optical Fiber
PHY
Not only physical !!
It is assumed that a G.805 client/server
relationship is existing between all these layers
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One example
IP
IP
FW
a
b
a
a
ATM VP
ATM VP/VC
c
SW/XC
e
d
e
e
VC-4-4c
SDH VC-4/VC-4-4c
e
e
k
VC-4-4c
c
c
k
k
k
k
STM
-
N/WDM
PHY
STM-4
STM-4
Equivalent G.805 representation of a, e, k and c
client/server relationships
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Outline

• Introduction and scope
• Generic transport layer structure
• Two examples of IP over optical network
  configurations
• Additional architectural components
• Service description
• Conclusion

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IP over optical configurations
Optical Network
O3
IP Network
O2
IP Network
I6
R6
R4
I4
O1
I5
IP Network
R5
Can both IP adjacencies R4-R6 and R4-R5 coexist
on the same I4 interface ?
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Concatenated versus channelised
CHANNELISED more than one adjacency per
interface
CONCATENATED only one adjacency per interface
IP
IP
FW
IP
IP
FW
STM-16/OF
PHY
OTN
SW/XC
OTN
OTN
OTN
SW/XC
OF
PHY
OF
PHY
The SW/CX layer is supporting the PHY layer !
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Outline

• Introduction and scope
• Generic transport layer structure
• Two examples of IP over optical network
  configurations
• Additional architectural components
• Service description
• Conclusion

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General processes

• For the description of the services
  telecommunication, it is useful to structure
• all the actions required to offer a service in
  the following (and chronologically) way
• pre-sales (PSA)
• subscription (SCR)
• invocation (INV)
• assurance (ASU)
• billing (BIL)

This structure can also be applied to the
transport network and as example to the IP over
optical configurations where the service is
creation of an IP adjacency between routeur R4
and R5
IP Network
O2
O3
IP Network
I6
R6
I4
R4
O1
IP Network
R5
Optical Network
I5
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Operations for conc. and chan. (1)
Operations 1 to 4 are required to create an
adjacency between routers R4 and R5
CHANNELISED
CONCATENATED
PSA
SCR
INV
PSA
SCR
INV

• Routers
• localisation

• Create
• optical
• channel(s)

1
3
4

• Interfaces
• I4 and I5
• installation

• Routers
• localisation

• Interfaces
• I4 and I5
• installation

• Create
• optical
• channel

1
3
4

• Routers
• deployment

2

• Routers
• deployment

2
Step 4 requires a step 3 the same dynamics
applies
Step 4 can be independent of step 3 different
dynamics can apply
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Operations for conc. and chan. (2)
Optimized procedure for the CONCATENATED
configuration
Optimized procedure for the CHANNELISED
configuration
PSA
SCR
INV
PSA
SCR
INV

• Routers
• localisation

• Routers
• localisation

1

• Create
• opticals
• channels

1
3
4

• Create
• opticals
• channels

4

• Interfaces
• I4 and I5
• installation
• at maximum
• bit-rate

• Routers
• deployment

2

• Routers
• deployment

2
3

• Interfaces Ix
• installation

This requires the provisioning of routers with
the maximum capacity of interfaces
This requires installation of interfaces at the
highest capacity
! optimisation is considered from the IP
network side
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Transport service definition at G.805 level
1) Trail service
A and B access groups or sub-networks
2) Sub-network connection service
Note trail service requires at least one
sub-network connection service (except if X is a
PHY layer)
Telecommunication service modelling requires
other considerations additional transport
layers, division in actors (partitioning), control
plane components,
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Conclusion
It has been shown on a basic IP over optical
configuration that a technical choice has great
impact on the global architecture.
This was made possible by a network modelisation
at a low-level of granularity, which assembles
well defined elementary architectural components.
Elementary architectural components must continue
to be standardised independently of the technology
There is no need to standardize more global
architectural tools