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Metropolitan Area Network
Evolution
Author:Jipson Paul Kolenchery
Supervisor:Prof.Raimo Kantola
Instructor:Timo-Pekka Heikkinen
Outline
•
•
•
•
•
•
•
•
•
Introduction
Drive for Ethernet in metro networks
MAN evolution
Evolution of Ethernet to Carrier Grade Ethernet
Metro Ethernet Forum
Metro Ethernet Deployment models
Analysis of Packet carrier transport technologies
Scenario analysis
Conclusion
Introduction
•
•
•
•
MAN-Metropolitan Area Network
MAN implementation options
Traffic pattern in MAN
Packet carrier transport in MAN
– Ethernet in MAN
• Options for Ethernet transport
– Native Ethernet based PBB-TE
– MPLS-TP
– SDH based Metro Ethernet
Drive for Ethernet in metro
networks
• Traditional MAN deployments
– TDM based
– Best suited for voice
• TDM interfaces
– Bandwidth grows in step function
– BW scaling requires provisioning at CPE and Central
office which increases OPEX
• Ethernet interfaces
– Fine grained granularity in bandwidth scaling
– Bandwidth scaling requires less OPEX
MAN evolution
• MAN evolution
– From TDM based implementation to carrier
grade packet transport
• Evolution depends on
– Type of service provider
– Geographical area
– Regulations
Evolution of Ethernet to Carrier
Grade Ethernet (1)
• Ethernet
– Medium Access Control standard
– Invented by Robert M. Metcalfe
– IEEE 802.3
• Evolution to carrier grade Ethernet
–
–
–
–
Ethernet VLAN (IEEE 802.1Q)
Provider Bridge (IEEE 802.1ad)
Provider Backbone Bridge (IEEE 802.1ah-2008)
Provider Back Bone Bridge with Traffic Engineering
(IEEE 802.1Qay)
Evolution of Ethernet to Carrier
Grade Ethernet(2)
• Ethernet VLAN (802.1 Q)
– 32 bit VLAN tags which contain 12 bit VLAN ID
Ethernet frame without VLAN Tag
FCS
Type/
Length
Data
Source address
Destination
address
Ethernet frame with 32 bit VLAN Tag (802.1Q)
FCS
Type/
Length
Data
Tag
Source address
Destination
address
32 bit
TCI- Tag Control
Identifier
TPID- Tag Protocol
Identifier
16 bit
16 bit
VLAN ID
CFI
12 bit
1 bit
802.1p
3 bit
TPID- Tag Protocol Identifier
16 bit
Evolution of Ethernet to Carrier
Grade Ethernet(3)
• Provider Bridge (IEEE 802.1ad)
– Two VLAN tags and hence called Q-in-Q
Ethernet frame without VLAN Tag
FCS
Type/
Length
Data
Source address
Destination
address
Ethernet frame with 32 bit VLAN Tag (802.1Q)
FCS
Data
Type/
Length
Tag
Source address
Destination
address
Ethernet frame with 32 bit VLAN Tag (802.1ad)
FCS
Data
Type/
Length
C-Tag
S-Tag
Source address
Destination
address
Evolution of Ethernet to Carrier
Grade Ethernet(4)
• Provider Bridge back bone(IEEE 802.1ah-2008)
– A new header for service provider network
– True traffic separation
Backbone Ethernet Frame
B-FCS
Customer Ethernet
Frame
I-Tag
Type/
Length
B-Tag
B-Source
address
B-Destination
address
32 bit
64-1492 Bytes
32 bit
16 bit
32 bit
48 bit
48 bit
Customer Ethernet Frame
FCS
Data
Type/
Length
VLAN
Tag
Source address
Destination
address
32 bit
64-1492 Bytes
16 bit
32 bit
48 bit
48 bit
Evolution of Ethernet to Carrier
Grade Ethernet(5)
• Provider Bridge Backbone with Traffic Engineering
(PBB-TE) IEEE 802.1ag
• PBB + TE
• Uses pre-established connection oriented path
• Uses faster protection switching
– Two redundant paths per every virtual connection
– 802.1ag Connectivity Fault Management messages for
performing OAM
• Features
–
–
–
–
No loops in the path
No Spanning Tree Protocol (STP)
No dynamic forwarding tables
No flooding
Example of Provider Bridge Backbone
with Traffic Engineering (PBB-TE) IEEE
802.1ag
Customer A
site 1
Primary active path
Customer A
site 2
Provider edge
bridge
Service
provider
network
Provider backbone
bridge
Protection path
Metro Ethernet Forum
• Formed in 2001
• A global consortium of industries
– Promote interoperability and world wide deployment
of Carrier Ethernet networks and services
• Defined 5 attributes for Carrier Ethernet
–
–
–
–
–
Standardised Services
Scalability
Reliability
QoS
Service Management
Metro Ethernet deployment
models(1)
• Virtual connections
– Point-to-point EVC
– Multipoint-to-multipoint EVC
• Deployment models
– Native Ethernet based (PBB-TE)
– SDH based
– MPLS based (MPLS-TP)
Metro Ethernet deployment
models(2)
• Point-to-point EVC
Metro Ethernet Network
UNI
UNI
Point-to-Point
EVC
UNI
Metro Ethernet deployment
models(3)
• Multipoint-to-multipoint EVC
UNI
UNI
UNI
UNI
Metro Ethernet Network
Multipoint-tomultipoint EVC
Metro Ethernet deployment
models(4)
Native Ethernet based-PBB-TE
Customer
LAN site 1
Customer
LAN site 2
Service provider PBB-TE network
Customer
LAN site 4
Customer
LAN site 3
Client Ethernet
frame
PBB Ethernet
frame
Client Ethernet
frame
Metro Ethernet deployment
models(5)
SDH based
ADM
SDH Core MAN Network
ADM
ADM
ADM
Carrier Class
Ethernet Switch
Metro Ethernet deployment
models(6)
MPLS based
• IP/MPLS is not carrier grade
• Layer-2 MPLS to provide VPN and VPLS
service
• MPLS-TP – A carrier grade layer-2 MPLS
standard
– Jointly developed by ITU-T and IETF
– Separate OAM and MPLS forwarding
VPLS using layer-2 MPLS
Customer A,
Customer A,
VFI for VPN1
VFI for VPN3
Site3
Site 2
PE3
PE2
Customer B,
Customer B,
Site 2
Site 3
Customer A,
Site 4
PE4
PE1
MPLS backbone
Customer B,
Customer A,
Site 1
Site 1
VPN1
Layer-2 LSP
Layer-2 Virtual Circuits
VPN2
VPN3
Analysis of Packet carrier transport
technologies (1)
•
Four metrics to compare PBB-TE and
MPLS-TP
1. Performance
– MPLS-TP for voluminous traffic
– PBB-TE for medium and low traffic
2. Scalability
– MPLS-TP is more scalable for voluminous
traffic
– PBB-TE for low and medium loads
Analysis of Packet carrier transport
technologies(2)
3. Reliability
–
MPLS-TP
•
•
•
–
PBB-TE
•
•
•
•
•
Offers linear protection mechanism
Unidirectional and bidirectional switching
Non revertive operation and revertive operation
TE capability of protocol
Protection switching triggered using CFM
Non revertive operation and revertive operation
Load sharing possible
Both PBB-TE and MPLS-TP offer carrier grade
transport with less than 50 ms protection
switching interval
Analysis of Packet carrier transport
technologies(3)
4. Complexity and manageability
–
–
–
–
–
–
PBB-TE interoperable with installed Ethernet
bridges; provisioning needed only at PE
MPLS-TP is compatible with IP/MPLS; provisioning
needed only at PE
Both PBB-TE and MPLS TP offer strict operator
control and efficient OAM
Low CAPEX for PBB-TE as it is based on native
Ethernet standard
Less skilled labour needed for PBB-TE
Network peering possible in PBB-TE using NNI
while peering is rarely seen in MPLS-TP
Scenario Analysis
Choice of transport network
technology
Scenario Analysis
• To propose an appropriate transport
technology for meeting the present and
future needs of a service provider
• Based on Paul J.H Schoemaker’s method
• Three scenarios
– Incumbent MAN service provider
– A green field MAN service provider
– A MAN service provider selling transport
service to a mobile network
Procedure for Scenario Analysis
• Scenario Planning
• Identify scope and time frame of the
scenario
• Identify major stakeholders
• Identify basic trends
• Identify uncertainties
• Develop scenario themes
• Propose implementation scenarios
Scenario Planning
• Helps to imagine how future would unfold
minimising under prediction and over prediction
• Divide our knowledge into two areas: things we
know something about (trends ) and elements
we are not certain about (uncertainties)
• Simplify the possible outcomes of uncertainties
• Identify themes from outcomes of uncertainties
and trends
– Literature, survey, simulation results, brainstorming,
and interviews of major stakeholders to propose
decision scenarios
Scope and time frame of the
scenario
• Time frame of this scenario planning is 5 years
• Change of traffic pattern
– more voice – less data to more data and less voice
• Internet users increasing by 16%
• The power consumption of the network elements
worldwide increasing by 12%
• Arrival of mobile broadband, increase in data
traffic and QoS requirements
• Service providers are searching for a better
technology to meet the needs with less Capex
and Opex
The major stakeholders of this
scenario
1. Subscribers or customers of various
operators
2. Access network operators (Fixed and
mobile)
3. Transport network service providers
4. Vendors
Basic trends that effect MAN
evolution
• Customer traffic is increasing
• The global mobile traffic is expected to increase 26-fold between
2010 and 2015
• Most voice services will be replaced by VOIP
• VOIP applications needs greater QoS
• Fine grained and more dynamic BW scaling needed
• Delay in backhaul is a serious concern
• Improved OAM mechanism in their network that can isolate and
rectify faults quickly
• Electric power and cooling needed for capacity expansion
• Service providers are looking for a packet based transport
• PBB-TE and MPLS-TP standards are available
• 40 Gigabit Ethernet (40GbE) and 100 Gigabit Ethernet(100GbE) are
coming to market soon
• Energy Efficient Ethernet (EEE)
Uncertainties in MAN evolution
1.
2.
3.
4.
5.
6.
7.
Will carrier packet transport networks
based on PBB-TE and MPLS-TP
standards be soon adopted for transport
in MAN?
Will there be lower power consumption
for PBB-TE and MPLS-TP products?
Is there a need for heavier cooling
arrangements for the products based on
PBB-TE and MPLS-TP products?
Will the chip design technology reach the
level to process data at 10Gigabit and
100 Gigabit speeds sooner?
Will the regulations for using packet
based transport becomes more flexible in
the near future, especially in America?
Is it easy to develop or find laborers with
the skill set needed to run these
technologies?
What is the significance of economies of
scale in packet transport technologies?
1 2 3 4 5 6 7
1 X + -
+ + + +
2 X X -
? ? ? ?
3 X X X ? ? ? ?
4 X X X X ? ? ?
5 X X X X X ? +
6 X X X X X X ?
7 X X X X X X X
Correlation matrix of uncertainties in MAN
Scenario Themes
• Packet carrier transport is the ultimate solution
• Two competing technologies are PBB-TE and
MPLS-TP and both of them have its significance
• Choice depends on type of service provider and
type of operators supported by service providers
• Three main themes are
– Incumbent service provider
– Green field service provider
– Service provider providing mobile backhaul
Scenario analysis and decision scenario for
an incumbent MAN service provider
•
OAM network
•
Edge
network
2G/3G/
BTS
Network
Controller
Metro
network
MPLS-TP
PE
Core
network
LSR
LSR
LSR
LSR
MPLS-TP
PE
IP/MPLS
IP/MPLS
network
network
Corporate
Corporate
network
network
IP
MPLS-TP
PE
MPLS-TP
•
•
DSL
MPLS-TP
PE
•
IP/MPLS
Incumbent
service provider
uses IP/MPLS in
its network
MPLS-TP is
compatible
IP/MPLS
Less CAPEX as
provisioning is
needs only at PE
Easy to train
existing IP/MPLS
work force to
MPLS-TP
Choice is MPLSTP
Scenario analysis and decision scenario for
a green field MAN service provider
•
OAM network
Customer
LAN site 4
Edge
network
Metro network
PBB core
bridges
Core network
•
Customer
LAN site 1
•
2G/3G/
BTS
Customer
LAN site 3
MPLS
MPLS
network
network
Network
Controller
•
•
Service provider PBB-TE network
•
Customer
LAN site 2
Client Ethernet
PBB edge
bridges
PBB Ethernet
MPLS
Green field service
provider prefers a
revolutionary
technology at low
cost
PBB-TE needs less
CAPEX as it is
native Ethernet
based
Less OPEX as
provisioning is
needed only at PE
Less skilled work
force needed
E-LAN and E-Line
offers fine grained
granularity
Choice is PBB-TE
Scenario analysis and decision scenario for
a service provider providing mobile backhaul
RAN
•
RNC
BS
VLAN-Trunk
UNI
VLAN-Trunk
UNI
UNI
•
UNI
PBB-TE
CEN-A
RNC
•
VLAN-Trunk
VLAN-Trunk
E-NNI
E-NNI
PBB-TE
CEN-C
eNB
PBB-TE
CEN-B
MSS
CS-CN
P-GW
MGW
SGSN
PS-CN
GGSN
MME/
S-GW
LTE CN
•
Large amount
of data with
HSPA and LTE
Dynamic nature
of traffic in
mobile network
Dynamic and
fine grained
BW allocation
needed
PBB-TE is the
best solution
due to fast
scaling EVCs,
network
peering
capability of
NNI,dynamic
provisioning etc
Timing solution in packet carrier
transport
•
Timing-over-packet
–
–
•
Implemented with
Precision Timing Protocol
(PTP) IEEE 1588v2
protocol
Independent of layer-2 and
layer-3 networks
BTS
RNC
Synchronous Ethernet
–
–
–
–
Operates in the physical
layer
Defined in ITU G.8261
needs to be supported in
all nodes along the chain
between the switching
office and the cell site
link frequency is
synchronised to a
traceable primary
reference clock and
physical layer of Ethernet
is used to synchronise all
participating nodes to the
same reference clock
Packet
network
PTP
master
BTS
Network
reference
External
reference
Unicast timing
packets
Timing over packet
Reference models proposed by
MEF for Ethernet based mobile
backhaul
BTS
RNC
UNI
BTS
RNC
UNI
UNI
GIWF
UNI
CEN-A
CEN-A
GIWF
E-NNI
Carrier Ethernet
backhaul network
RNC
RNC
E-NNI
CEN-A
UNI
UNI
UNI
GIWF
UNI
CEN-A
E-NNI
GIWF
BTS
BTS
Single Domain Reference
Model
Multi Domain Reference
Model
Use case models for single and
dual Iub proposed by MEF (1)
Legacy Network
RNC
BS
UNI
UNI
GIWF
CEN
GIWF
Legacy Split access
RNC
GIWF
BS
UNI
UNI
CEN
Legacy Backhaul
GIWF
Use case models for single and
dual Iub proposed by MEF (2)
Legacy Network
RNC
BS
UNI
UNI
CEN
Split access
RNC
UNI
BS
UNI
CEN
Full Ethernet
Conclusion
• PBB-TE and MPLS-TP give carrier grade features to
Ethernet in MAN
• Usability depends on scenarios
– Greenfield service provider>PBB-TE
– Incumbent service provider>MPLS-TP
– For mobile backhauling>PBB-TE
• PBB-TE is suitable for highly varying low and dynamic
loads
– Suitable for MAN
• MPLS-TP is suited for very high and less dynamic traffic
– Suitable for core
Thank You
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