This document discusses the benefits of implementing Layer 3 intelligence at mobile cell sites through an integrated solution called SmartNode from Aviat Networks. SmartNode integrates microwave radios and routing functionality into a single system, simplifying network management and operations. It allows cell sites to efficiently deliver new services while supporting network densification goals through a more flexible, scalable and intelligent architecture. Implementing Layer 3 intelligence through unintegrated routers and radios can increase costs, complexity and management challenges for mobile operators. SmartNode provides a simpler approach through a nodal microwave solution with integrated Layer 3 routing capabilities.

1. SMARTER PERFORMANCE
MADE SIMPLE
THE CASE FOR LAYER 3 INTELLIGENCE
AT THE MOBILE CELL SITE
HOW TO BEST IMPLEMENT LAYER 3 INTELLIGENCE
IN YOUR NETWORK
AVIAT NETWORKS
WHITE PAPER

2. WHITE PAPER
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Mobile cell sites are transitioning from simple Layer 2
connected sites for voice and low-speed mobile data access
to multi-functional hubs for delivery of new services built on
Layer 3 intelligence. Existing Layer 2 based mobile backhaul
solutions make this transition difficult because regular
routers installed next to legacy microwave complicate cell
site configurations increase cost and add management
overhead. This white paper presents a new integrated cell site
architecture based on Layer 3 intelligence that promises to
transform the cell site and restructure the mobile backhaul
cost equation—making the new service-delivery cell-site
vision possible with fewer boxes and simplifying tomorrow’s
mobile network.

3. 3AVIAT NETWORKS 3AVIAT NETWORKS
WHITE PAPER
In the past, mobile networks were built to
deliver voice services with data connectivity
services as a secondary consideration.
Today’s mobile networks are being relied
on to support mission-critical business
objectives, which are far beyond the realm
of basic mobile connectivity. New enterprise,
government, videoconferencing, social media
and mobile commerce services place growing
demands on the network in terms of capacity,
security and reliability. The mobile network
infrastructure must be flexible enough to
deliver a growing number of new services with
ease and cost effectiveness.
Increase ARPU via
New Services
Improve Subscriber Retention Reduce Network CAPEX
and OPEX
Enterprise
VPN, enterprise access, enterprise
application acceleration
Performance
Improved network performance
for voice, video and data services
(including network densification)
Fewer Boxes
Common IP network infrastructure
Consumers
Optimized social media access,
M-commerce, Videoconferencing,
Security Services
Services
Specialized services increase
stickiness
Less Complexity
Simplified operations and network
management
Other
Public Safety, Government
Security
Security and privacy policies
Future Proof
Architecture to minimize ongoing
investments
Table 1: Mobile Operator Objectives
THE EXPANDING ROLE OF THE
MOBILE NETWORK
Moreover, capacity demands are driving
new levels of network densification by
leveraging small cell, Wi-Fi and Cloud-
based RAN (C-RAN) architectures. While
the densification “end game” is hard to
pin down, what is certain is the mobile
network needs to be flexible to support a
considerable amount of future uncertainty.
In summary, the cell site is undergoing
a transformation in order to meet
subscriber coverage goals and consumer
demand. Additionally, pressure comes
from the mobile network operators
(MNOs) and their desire to enrich service
offerings, lower costs and grow average
revenue per user (ARPU).

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Enterprise
Services
Small
Cell
2G, 3G, 4G
Services
Streaming, Video Conference,
Social Media, M-commerce
Transport (MW, OTN, etc)
Cell Site Router
COMPLEX, NON-INTEGRATED
and at lower cost over a routed network. For example,
Layer 3 VPN services often provide the most flexible
solution for enterprise access and connectivity services—
especially as service requirements expand. Many of these
transport connections will terminate directly at the cell
site. On-site routed infrastructure can provide optimum
flexibility to support the full range of access services
including IP VPN, L2 VPN, VPLS, MPLS VPN, etc. to ensure
overall business objectives are met.
LOWER COST
Layer 2 is often believed to be a lower CAPEX solution,
but many times requires higher OPEX—especially as the
network changes and grows and new services are offered.
Traditionally, IP routers have commanded a higher price
tag due to the higher cost of the silicon chips they required.
However, newer technologies coupled with a highly soft-
ware driven paradigm and the fact that cell sites do not
need the same level of performance found in traditional
routers makes routing at the cell site cost effective.
NETWORK DENSIFICATION
The network edge is constantly evolving, resulting in
today’s edge sites becoming aggregation nodes—where
IP and Multiprotocol Label Switching (MPLS) are now
commonplace. In addition, the network needs to be
flexible to support the evolving network topology. Layer 3
intelligence makes it easier to change the network
topology (e.g., add a site, mesh to rings). With a mesh of
L2 connections, for example, operational complexities
can result in huge costs and slow the pace of the network
evolution—meaning delays in new service offerings or
improving network performance.
THE MOBILE CELL SITE AS
A LAYER 3 CONNECTED
SERVICE DELIVERY HUB
Operators need to enrich their offerings to attract and
retain high value customers to offset the low ARPU for
traditional consumer-level mobile users. To support new
business initiatives, fast and flexible delivery of new ser-
vices is necessary. This fact, combined with the pending
network densification, means the cell site must evolve.
The mobile cell site needs to evolve from simply housing
a base station to supporting a network architecture that
accelerates the delivery of new services to achieve busi-
ness goals—the service delivery hub. IP is the only proven,
scalable, futureproof technology upon which to meet
these goals completely.
LAYER 3 INTELLIGENCE:
THE ESSSENTIAL INGREDIENT FOR
CELL SITE TRANSFORMATION
Traditional Carrier Ethernet (i.e., Layer 2) advocates
believe cell sites should be maintained at a Layer 2 (L2)
implementation, citing a lower cost and simpler network
infrastructure compared to Layer 3. IP (i.e., Layer 3)
intelligence at the cell site gives the operator flexibility to
support new scalable, high-quality services and the pend-
ing mobile network densification. Based on this, below are
some reasons why routers at the cell site are poised to
become the norm in future mobile network architectures.
NEW SERVICE DELIVERY
Many enterprise, government, videoconferencing and
banking services can be delivered much more efficiently

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MULTI-SERVICE CONNECTIVITY
New services, and network densification means the emer-
gence of a multitude of devices at the cell site. Many of
these devices are multi-service interfaces and many can
even include legacy interfaces such as TDM, ATM or even
FR/X25. Routers are the only proven solution to cost ef-
fectively converge multi-services interfaces onto a single
low cost IP transport. Also, with the migration to LTE/
HSPA+, native IP is the default transport technology.
SECURITY
Layer 3 intelligence at the cell site provides many security
benefits. Because mobile security requirements continue
to evolve, routers offer optimum flexibility (e.g., having
the ability to initiate and terminate IPsec) and the ability to
support ever-changing security requirements. Ultimately,
ensuring both control and bearer channels are carried in
the most secure fashion possible.
HIGHER CAPACITY AND NETWORK
SCALABILITY
IP routers at the cell site enable the network to better
deal with capacity challenges. By having the intelligence
to route around issues, routed intelligence at the cell site
can have a great effect on capacity. When compared to flat
Layer 2 networks, routers scale to vast numbers of nodes,
thus, giving flexibility to grow the network seamlessly with
a lower total cost of ownership.
X2 INTERFACE
The interface between eNodeBs in LTE architecture, X2
creates significant challenges for network architects.
Carrying up to 10 percent of an eNodeB’s total traffic,
X2 has extremely low latency requirements and is a key
connection to support mobile handoff. When eNodeBs
are on different subnets, a router is required to provide
X2 connectivity and avoid storms of broadcast traffic. A
more scalable X2 infrastructure is achieved by supporting
router functionality at the cell site.
Cell site routers are an essential investment to support
the expanding role of the mobile network.
BACKHAUL TRENDS:
WHAT OPERATORS SAY
ABOUT LAYER 3
NETWORK INTELLIGENCE
In the last three years, research has revealed a lot
about the changing intent of wireless network opera-
tors to deploy Layer 3 (L3) intelligent applications. In
many markets, and especially in emerging markets, a
plurality (42 percent) of operators see a need for Layer
3 functionality in access networks, according to a 2013
Heavy Reading report. Even more telling, in the same
report, a strong majority of operators (62 percent) said
that it was “very likely” that MPLS—a leading L3 tech-
nology—would need to be deployed in the aggregation
layer of their networks.
More recently in 2014, Heavy Reading research found
that mobile network operators (MNOs) see a new ap-
plication for L3 intelligence. Specifically, 73 percent
consider L3 “critical” or “very important” for delivering
new services to enterprises from current cell sites.
This sentiment goes hand in hand with the observation
that mobile operators consider enterprise services a
top strategic priority for growth.
Not only do MNOs see a role for L3 at the edges of
their networks but also private network operators. In
a proprietary study conducted by Aviat Networks in
November 2014, survey results of non-MNO operators
in North America reveal that 66 percent of respondents
believed it is “critical” or “very important” to adopt IP/
MPLS technology within their networks. In addition, a
nearly unanimous number (92 percent) of survey re-
spondents said end-to-end IP/MPLS provisioning was
“critical” or “very important.”
What all these L3 survey results share in common
is that operators of all persuasions believe that they
lack in-house experience to roll out L3 functionality.
Concomitantly, they feel they will need outside ex-
perts in order to implement the most highly intelligent
networks.

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POOR FAILURE DETECTION AND RECOVERY
In the above scenarios, the router generally does not
know what the microwave radio is doing in relation to
failure recovery. Separate boxes require complex
signaling/interworking that is not well coordinated.
Also, there is a lack of integrated failure recovery
across all layers including the IP/MPLS layer.
NON-INTEGRATED RF
The above options all involve Ethernet connections from
the router to the microwave device, either baseband
unit or ODU. This is a departure from traditional micro-
wave architectures—which have worked well for years
and represent 95 percent of all microwave deployments
today, where a microwave baseband unit is connected to
the RF unit with an intermediate frequency connection
over the COAX cable interface. With the router + Ethernet
RF unit options, the modem is in the ODU on the tower,
which requires a tower climb for any modem upgrades.
The multitude of protection options (e.g. 1+1, N+0, SD, FD)
gets extremely complex, and many configurations are not
supported. The cabling is also a challenge. Existing COAX
cable infrastructure cannot be reused, and many new
cables are often required (RJ45 Ethernet has limited dis-
tances so optical cables need to be run in addition). Power
over Ethernet (PoE) injectors are also generally required
often necessitating purchase, deployment and ongoing
maintenance of a separate box. In summary, the lack of
RF integration on these router + Ethernet radio configura-
tions spells trouble for mobile network operator (MNO)
operations teams.
ADDING LAYER 3 INTELLIGENCE TO LEGACY MICROWAVE
WITH REGULAR ROUTERS MAKES NETWORKS MORE
COMPLEX, LESS INTEGRATED
Despite all the benefits, the addition of the router adds
a completely new level of complexity to the transport
network of microwave connected cell sites.
Routers can be deployed alongside a microwave indoor
unit in a split-mount microwave scenario or connected
directly to an ODU (outdoor unit) in an all-outdoor Ethernet
scenario. In either case, routers are not well integrated
into the microwave transport network, which can cause a
host of challenges for operators.
Key challenges are listed below:
MANAGEMENT COMPLEXITY
Separate devices, with different management
interfaces, create a multitude of operational challenges.
End-to-end configuration, provisioning, fault and
performance management can be difficult especially
in IP/MPLS configuration.
LACK OF DYNAMIC BANDWIDTH AWARENESS
The router does not have awareness into the microwave
radio’s link bandwidth. Without this knowledge, traffic en-
gineering and L2/L3 routing become very difficult. In addi-
tion, Adaptive Coding and Modulation (ACM), which results
in dynamic reduction of link bandwidth, makes matters
worse. Network performance is drastically affected in the
above scenarios where routers are “flying blind” and not
aware of the actual bandwidth available in the network.
DUMB
MICROWAVE
INDOOR UNIT
ROUTER
IF Connected
ODU
All Outdoor
Ethernet Radio
DUMBER
ROUTER
OR

7. 7AVIAT NETWORKS
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LACK OF INTEGRATED SYNCHRONIZATION,
SECURITY AND QOS
Router + Ethernet ODU solutions lack an integrated
security policy across all layers and boxes. They also
lack automatic alignment of QoS policy across all layers
leading to a complex operations effort to manage and
maintain end-to-end QoS policy. Also, because of the lack
of integration, clock source change on router results in a
network wide microwave outage.
TOO MANY BOXES
Unintegrated solutions currently deliver L2/L3 intelligence
at the cell site using external routers. This means that ex-
ternal boxes have to be separately configured, externally
connected and functionally tested, especially for solutions
from different vendors. The use of external boxes not only
increases management complexity, operational expenses
and energy consumption but also network performance
degradation. This is especially true if the router providing
L2 VPN or MPLS-TE functionality is not aware of underly-
ing wireless fluctuations. These RF propagation fluctua-
tions can lead the microwave equipment to run at lower
capacity (i.e., lower modulation), something of which the
L2/L3 equipment may not be aware. All these issues cre-
ate a more expensive and inefficient solution.
In the same way that consumer devices like cellphones
have integrated items such as cameras, video players,
and voice to create a more powerful “Swiss Army” knife
device. The integration of microwave IDU, switch, router
and TDM mux functionality in one device simplifies cell
site deployments reducing installation complexity and
improving network performance.
SERVICE DELIVERY IS TOO SLOW
As the need that operators have for new revenue streams
intensifies new services are deployed at faster speeds in
the core of the network. Only to be delayed by the RAN
deployment. A big part of this is the unautomated and
labor-intensive deployment of backhaul.
The use of an integrated nodal solution like the CTR
family with a single management interface that can
integrate L1, L2 and L3 aspects of the microwave router
can significantly reduce configuration time. This can be
complemented by using a powerful event driven platform
like Aviat OS (part of SmartNode) for automating network
functions. This kind of platform should be able to use a
scripting language to automate labor-intensive backhaul
deployments and reduce service delivery time.

8. THE INDUSTRY’S ONLY NODAL
MICROWAVE SOLUTION WITH
INTEGRATED LAYER 3 INTELLIGENCE
SmartNode is a single split mount nodal system with
virtualized high performance radio nodes and integrated
IP/MPLS routing capability.
The SmartNode solution
consists of any radio (IRU
600, ODU 600, STR 600,
WTM 3300, etc) deployed
with any router/switch
(CTR 8500, 8300, 8400, 8600 series models). Regardless
of the number of radios, or whether the radios are IF or
Ethernet connected, the SmartNode solution behaves as
one system with one IP address and one configuration—
just like a traditional split mount nodal microwave radio—
simplifying operations and lowering costs.
Aviat SmartNode features include:
Nodal Microwave
Being one single system, SmartNode is easy to manage,
configure and upgrade. This is in stark contrast to outdoor
radios that are independently managed entities having
separate IP address and
QoS configurations for each
device. These solutions
complicate operations
especially at nodal sites.
Integrated Microwave Router
Because of CTR’s Integrated L2 and L3 intelligence,
SmartNode reduces the number of boxes to buy, deploy,
and maintain. This results in faster and more efficient
service delivery and new revenue opportunities right from
the transport network. In addition, the system is media
aware all the way to Layer 3 so the routing protocols
understand what’s happening over microwave links for
better performing networks.
WHITE PAPER
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Aviat SmartNode is the simplest,
smartest way to add Layer 3
Intelligence to your mobile network
ADDING LAYER 3 INTELLIGENCE
WITH AVIAT SMARTNODE

9. WWW.AVIATNETWORKS.COM
Aviat, Aviat Networks, and Aviat logo are trademarks or registered trademarks of Aviat Networks, Inc.
ProVision is a registered trademark of Aviat U.S., Inc.
© Aviat Networks, Inc. [2015). All Rights Reserved. Data subject to change without notice. _wp_IntelligenceLayer3_23Mar15
SPLIT-MOUNT OR OUTDDOR RADIOS +
REGULAR ROUTER
AVIAT SMARTNODE
SMARTER
MEDIA
AWARENESS
POOR
Microwave not integrated with L3
EXCELLENT
Adaptive media awareness -
common protocol across all devices
SERVICES POOR
Separate devices required
EXCELLENT
Implemented with fewer boxes, integrated
PERFORMANCE
CAPACITY
EXCELLENT
Double header available today
(but tower climb to add channel 50% of the time)
EXCELLENT
Meets today’s needs and evolves to future
RELIABILITY
POOR
50 minutes more downtime per site per year.
Unproven MTBF (double header)
EXCELLENT
No PoE injectors, no single point of failure.
Electronics inside—lower MTTR
MADE SIMPLE
OPERATIONS
COMPLEX
Many separate devices to manage: multiple
management platforms, complex power
management, complex demarcations
SIMPLE
Single virtualized device (1 QoS policy for entire node).
Single EMS
TCO
HIGH
More boxes, complex operations, lower reliability.
40% higher TCO
SIMPLE
Fewer boxes, simpler, more reliable
Single Management Interface - Nodal Managment
Regardless of the number of radios and router/switches
at a SmartNode location, all assets can be managed with
a single IP address. This single user interface is a radical
departure from other solutions that require separate man-
agement solutions for the radio, L2 switch and routers.
SmartNode is an integrated solution for seamless opera-
tion and lower TCO.
Aviat SmartNode combines the proven advantages of nodal
microwave with the latest innovation of integrated micro-
wave router, with support for both IF-connected ODUs and
Ethernet-connected ODRs, with built-in PoE.
Zero Footprint
For locations where indoor space is not available,
Aviat’s Zero Footprint SmartNode is available with
an outdoor CTR product.
As the network densifies, today’s edge sites will be
tomorrow’s nodal sites so with Zero Footprint SmartNode
not only do you get all the benefits of SmartNode in an
outdoor package but also future proof yourself for pending
network expansion.
Aviat SmartNode is SMARTER (service flexibility, media
aware), PERFORMANCE (high capacity, best reliability),
MADE SIMPLE (deployment and operations simplicity
and lowest total cost of ownership).