Transcript Verizon’s IP TV Access Architecture

Wireless Ethernet Backhaul :
A Carrier’s Perspective
Rajesh Yadav
[email protected]
Access Network Architecture and Design
Verizon Communications
Presentation Outline

Trends in Wireless Backhaul Bandwidth

Ethernet Backhaul Service Requirements

Present Wireless Backhaul Technologies

Drivers for Ethernet Backhaul over PON

Implementation of Ethernet Backhaul over GPON

Concluding Remarks
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Wireless Backhaul Bandwidth Demand

Significant increase in broadband
mobile users

Data and multimedia mobile
applications driving bandwidth
utilization exponentially

Higher growth possible with faster
adoption of LTE technology

150+ Mbps bandwidth
requirements per cell site shared by
up to 3 operators

Number of 3G/4G cell site expected
to grow from 72,000 to 225,000 by
2012*
* Source: Heavy Reading, March 2009
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Growth in High Bandwidth Base Stations
20 fold increase in number of base stations with 24M + of
backhaul capacity
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Wireless Backhaul Service Requirements
50 ms restoration; 5 ms
OW, 1 ms FRDV
10, 150-300 Mbps;
4 9s 5; fiber
100/1000; LAG
protection; dual
EVCs
10 x 1 GigE; 2 x 10 Gig; 5 9
s; LAG protection; dual
NNI
Ethernet/
C/DWDM/
??
MSC
TDM
ATM/FR/TD
M - PW
Cell Site Access
Source: VzW
4 QoS, p bits, Q-in-Q,
shaping, L2CP blocking;
80.1ag CFM; SLA
monitoring per EVC,
High burst -PIR
Transport
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100-150 cell
sites per
MSC
MSC Access
Ethernet Backhaul Service Requirements

Cost effective scalable solution for Ethernet bandwidth up
to 150-300 Mbps per cell site

Initial requirements from carriers is for guaranteed bandwidth between
cell site and MSC location



Maintains the current model of using TDM based transport “pipes”
Expected evolution to multiple classes of service to better match traffic
characteristics to the transport need
Circuit emulation support for TDM/ATM/FR

Migration of cell sites with existing TDM/ATM/FR interfaces on a
common Ethernet backhaul network

Coexistence of TDM and Ethernet backhaul expected for sometime
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Ethernet Backhaul Service Requirements – cont.

Low latency, jitter and packet loss transport

Multiple classes of service

Transport network reliability 5 9’s

50 ms restoration desired

Timing and frequency synchronization

Performance monitoring and Real time SLAs

Comprehensive Network management and OAM capability
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Present Backhaul Technologies

Leased T1 lines over copper

Most prevalent for cell site backhaul today


Up to 8-10 T1s used per cell site

Widely available

High cost

Not scalable to meet projected high bandwidth demands

Optimized for voice traffic with dedicated bandwidth with little flexibility
for bursty traffic
High capacity Microwave Ethernet backhaul

Better bandwidth scalability compared to leased T1 lines

Use of licensed spectrum

Somewhat limited reach and line of sight requirements

Susceptible to interferences
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Present Backhaul Technologies

Ethernet over SONET (Ethernet Private Line)

Point-to-Point Ethernet transport

Can scale to very high bandwidth to meet the current and projected
bandwidth demand

Network bandwidth can be increased at STS1 granularity

50 ms restoration capability in the access and transport network

Significant upfront cost for dedicated fiber facilities and optical
equipment
Transport
NGADM
Access
MSC
OTP
OTP
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OTP
9
Present Backhaul Technologies

Switched Ethernet Network

Provide flexible bandwidth options with multiple class of services to
support voice, video and data traffic

Point to point Ethernet virtual connection (EVC)

Use of Dedicated dark fiber pair or CWDM

Limited availability in cell site locations

Providing redundancy in the access can be expensive

Dedicated pair of fiber required for every cell site


Could also use access CWDM infrastructure
Desire for dedicated bandwidth from wireless carrier reduces the
attractiveness of cost effective shared backbone network
NID
Edge
Aggregation/Core
MSC
NGADM
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Why GPON?

GPON (Gigabit Passive Optical Network) provides high bandwidth
capacity which can be used in effective “pay as you grow” model

2.4 Gbps in downstream and 1.2 Gbps in upstream generally shared across 32
customers

Cost efficient point–to–multipoint utilization of fiber without need for dedicated
fiber infrastructure


Only ~25% cell site are currently passed with fiber
NG PON will be able to support up to 10 Gbps

Growing availability of GPON deployment in cell site locations

Highly reliable with no active components in outside plant

Ability to provide smooth migration from current TDM based backhaul
to scalable Ethernet backhaul using hybrid TDM and Ethernet backhaul
model

Convergence of residential and business services over common
infrastructure
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Ethernet Backhaul over GPON
Converged access
for TDM and
Ethernet
Aggregated
handoff at the
Hub location
Shared feeder fiber and
PON across multiple
cell sites and customers
Bypass of IP/MPLS network
depending on traffic
characteristics for more cost
effective solution
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Implementation of Ethernet
Backhaul over GPON

GPON ONT can cost effectively support from 10Mbps to
potentially 100s of Mbps to a cell site

Bandwidth can be added on as needed basis

Support for guaranteed bandwidth to emulate current
guaranteed “pipe” model with TDM based backhaul

Evolution to model with multiple classes of services to
optimize bandwidth need to the traffic characteristics for
more cost efficient backhaul


Class of service differentiation based on 802.1p (p-bits) in VLAN header
or DSCP in IP header
GPON provides support for carrying both Ethernet and
TDM traffic
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Implementation of Ethernet
Backhaul over GPON – cont.

Synchronization options with Ethernet backhaul over GPON

Outside of the Ethernet transport network



Packet Based synchronization using dedicated packet flow



Via GPS at base station
Retention of a T1 circuit for synchronization
IEEE 1588 v2
Clock carried by circuit emulated data (e.g. T1) over Ethernet Transport
Synchronous Ethernet


GPON Transmission Convergence (GTC) layer supports the transport of an 8
kHz clock via 125 ms framing
Transfer of synchronization over Ethernet interface on ONT

Redundancy can be supported at the cell site by providing
dual connections from diverse PONs

Encryption of traffic with in GPON for additional layer of
security
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Concluding Remarks

Increase in bandwidth demand for mobile backhaul with
new data and multimedia mobile applications and evolution
to 4G technologies is creating significant opportunity for
Ethernet backhaul

Wireless carriers are looking for cost effective, scalable and flexible
solution to meet expected bandwidth demand

TDM and Ethernet will coexist for some time and backhaul
solution should provide converged access to support this
hybrid model with easy migration to Ethernet backhaul

GPON can provide scalable and cost effective “pay as grow”
solution for Ethernet backhaul as the bandwidth demand for
wireless backhaul grows overtime with evolution of wireless
networks towards 4G technologies
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