interesting technology market notes ashwani nov 2015

7/23/2019 Interesting Technology Market Notes Ashwani Nov 2015

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25 Nov 2015 STORYBOARD

Data center network designmoves from tree to leaf

Leaf-spine designs are pushing out the hierarchical tree data center

networking model, thanks to the popularity of Ethernet fabric

networks.

Explained: Leaf-spine data center network

architecture

The old data centernetwork designshould make like a tree and leaf.

For many years,data center networkshave been built in layers that, when

diagrammed, suggest a hierarchical tree. As this hierarchy runs up against

limitations, a new model is taking its place.

In the hierarchical tree data center, the bottom of the tree is

theaccesslayer, where hosts connect to the network.

The middle layer is theaggregation,ordistribution, layer, to which the

access layer is redundantly connected. The aggregation layer provides

connectivity to adjacent access layer switches and data center rows, and in

turn to the top of the tree, known as thecore
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The core layer provides routing services to other parts of the data center, as

well as to services outside of the data center such as the Internet,

geographically separated data centers and other remote locations.

This model scales somewhat well, but it is subject to bottlenecks if uplinks

between layers are oversubscribed. This can come from latency incurred as

traffic flows through each layer and from blocking of redundant links

(assuming the use of thespanning tree protocol, STP).

Leaf-spine data center architectures

Inmodern data centers, an alternative to the core/aggregation/access layer

network topology has emerged known asleaf-spine. In a leaf-spine

architecture, a series ofleafswitches form the access layer. These

switches are fully meshed to a series ofspineswitches.

The mesh ensures that access-layer switches are no more than one hop

away from one another, minimizing latency and the likelihood of bottlenecks

between access-layer switches. When networking vendors speak of

anEthernet fabric, this is generally the sort of topology they have in mind.
http://searchnetworking.techtarget.com/definition/spanning-tree-protocolhttp://searchdatacenter.techtarget.com/guide/Modern-data-center-strategy-Design-hardware-and-ITs-changing-rolehttp://searchsdn.techtarget.com/tip/How-data-center-network-fabric-and-SDN-intersecthttp://searchnetworking.techtarget.com/definition/spanning-tree-protocolhttp://searchdatacenter.techtarget.com/guide/Modern-data-center-strategy-Design-hardware-and-ITs-changing-rolehttp://searchsdn.techtarget.com/tip/How-data-center-network-fabric-and-SDN-intersect


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Leaf-spine architectures can belayer 2orlayer 3, meaning that the links

between the leaf and spine layer could be eitherswitchedorrouted. In

either design, all links are forwarding; i.e., none of the links are blocked,

since STP is replaced by other protocols.

In a layer 2 leaf-spine architecture, spanning-tree is most often replaced

with either a version ofTransparent Interconnection of Lots of Links(Trill)

orshortest path bridging(SPB). Both Trill and SPB learn where all hosts areconnected to the fabric and provide a loop-free path to their Ethernet MAC

addresses via a shortest path first computation.

Brocade's VCS fabric and Cisco's FabricPath are examples of proprietary

implementations of Trill that could be used to build a layer 2 leaf-spine

topology. Avaya's Virtual Enterprise Network Architecture can also build a

layer 2 leaf-spine but instead implements standardized SPB.

In a layer 3 leaf-spine, each link is a routed link.Open Shortest Path Firstis

often used as the routing protocol to compute paths between leaf and spine

switches. A layer 3 leaf-spine works effectively when network virtual local

area networks are isolated to individual leaf switches or when a network

overlay is employed.

Network overlays such as VXLAN are common in highly virtualized, multi-tenant environments such as those found at Infrastructure as a Service
http://searchnetworking.techtarget.com/definition/layer-2http://searchunifiedcommunications.techtarget.com/definition/layer-3http://searchnetworking.techtarget.com/definition/Transparent-Interconnection-of-Lots-of-Links-TRILLhttp://searchnetworking.techtarget.com/definition/Shortest-path-bridginghttp://searchenterprisewan.techtarget.com/definition/OSPFhttp://searchnetworking.techtarget.com/definition/layer-2http://searchunifiedcommunications.techtarget.com/definition/layer-3http://searchnetworking.techtarget.com/definition/Transparent-Interconnection-of-Lots-of-Links-TRILLhttp://searchnetworking.techtarget.com/definition/Shortest-path-bridginghttp://searchenterprisewan.techtarget.com/definition/OSPF


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providers. Arista Networks is a proponent of layer 3 leaf-spine designs,

providing switches that can also act as VXLAN Tunnel Endpoints.

The merits of white box switching

Modern infrastructures are based on commodity, non-proprietary hardware.

People have used commodity servers for a long time, but now we are

seeing commodity switching gear too, on which we layer open network

operating systems. This is a promising area, writes Ethan Banks in "Why

White Box Switching?" An offshoot of software defined networking, "white

box switching might survive on its own merits -- even if SDN falls by the

wayside."

Modern infrastructures run on open source software, finds Ed Scannell in

"Opening Up to Open Source." The reasons for today's surge of open

source projects aren't the same as yesterday's -- whereas open source

used to be about saving money, now it's about exploiting "the latest Web-

based technologies for mobile, cloud and analytics platforms."

What makes one infrastructure "modern" and another not so much? That is

continually up for debate, but there are definitely some common themes.

Read on to learn more.

The case for a leaf-spine data

center topology

Three-layer network designs are last season's topology. The leaf-

spine model is coming in hot, but can the advantages made data

center designers forget about the weaknesses?


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Three-layer designs arefalling out of favorin modern data center networks,

despite their ubiquity and familiarity. What's taking over? Leaf-spine

topologies.

As organizations seek to maximize the utility and utilization of their

respective data centers, there's been increased scrutiny of mainstream

network topologies. "Topology" is the way in which network devices are

interconnected, forming a pathway that hosts follow to communicate with

each other.

The standard network data center topology was a three-layer architecture:

theaccess layer, where users connect to the network; the aggregation

layer, where access switches intersect; and the core, where aggregation

switches interconnect to each other and to networks outside of the data

center.

ETHAN BANKS

The traditional, three-layer network design

The design of this model provides a predictable foundation for a data center

network. Physically scaling the three-layer model involves identifying port

density requirements and purchasing an appropriate number of switches for

each layer. Structured cabling requirements are also predictable, as

interconnecting between layers is done the same way across the datacenter. Therefore, growing a three-layer network is as simple as ordering
http://searchdatacenter.techtarget.com/feature/Data-center-network-design-moves-from-tree-to-leafhttp://searchdatacenter.techtarget.com/definition/access-layerhttp://searchdatacenter.techtarget.com/feature/Data-center-network-design-moves-from-tree-to-leafhttp://searchdatacenter.techtarget.com/definition/access-layer


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more switches and running more cable against well-known capital and

operational cost numbers.

Why three-layer falls short

Yet there are many reasons that network architects explore new data center

topologies.

Perhaps the most significant is the change in data center traffic patterns. Most

network traffic moves along a north-south line--hosts are communicating with

hosts from other segments of the network. North-south traffic flows down the

model for routing service, and then ack up to reach its destination. Meanwhile,

hosts within the same network segment usually connect to the same switch,

keeping their traffic off the network interconnection points.

!owever, inmodern data centers, compute and storage infrastructures alterations

change the predominant network traffic patterns from north-south to east-west.

"neast-west traffic flows, network segments are spread across multiple access

switches, re#uiring hosts to traverse network interconnection points. $t least two

ma%or trends have contriuted to this east-west phenomenon& 'onvergence and

virtuali(ation.

'onvergence& )torage traffic often shares the same physical network as application

traffic. )torage traffic occurs etween hosts and arrays that are in the same network

segment, logically right next to each other.

*irtuali(ation& $s "T continues to virtuali(e physical hostsinto virtual

machines+*M, the aility to move workloads easily has ecome a mainstream,

normative function. *Ms move from physical host to physical host within a

network segment.

unning east-west traffic through a network data center topology that was

designed for north-south trafficcauses oversuscriptionof interconnection links

etween layers. "f hosts on one access switch need to communicate at a high speed
http://searchdatacenter.techtarget.com/guide/Building-with-modern-data-center-design-in-mindhttp://searchsdn.techtarget.com/answer/What-is-the-relationship-between-east-west-traffic-and-SDNhttp://searchservervirtualization.techtarget.com/tip/Understanding-the-many-facets-of-infrastructure-convergencehttp://searchservervirtualization.techtarget.com/definition/virtualizationhttp://searchservervirtualization.techtarget.com/tip/Understanding-the-benefits-of-a-virtual-machinehttp://searchservervirtualization.techtarget.com/tip/Understanding-the-benefits-of-a-virtual-machinehttp://searchdatacenter.techtarget.com/tip/Preventing-virtual-resource-oversubscription-with-capacity-managementhttp://searchdatacenter.techtarget.com/guide/Building-with-modern-data-center-design-in-mindhttp://searchsdn.techtarget.com/answer/What-is-the-relationship-between-east-west-traffic-and-SDNhttp://searchservervirtualization.techtarget.com/tip/Understanding-the-many-facets-of-infrastructure-convergencehttp://searchservervirtualization.techtarget.com/definition/virtualizationhttp://searchservervirtualization.techtarget.com/tip/Understanding-the-benefits-of-a-virtual-machinehttp://searchservervirtualization.techtarget.com/tip/Understanding-the-benefits-of-a-virtual-machinehttp://searchdatacenter.techtarget.com/tip/Preventing-virtual-resource-oversubscription-with-capacity-management


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with hosts attached to another access switch, the uplinks etween the access layer

and aggregation ecome a potential--and proale--congestion point. Three-tier

network designs often exacerate the connection issue. ecause spanning-tree

locks redundant links to prevent loops, access switches with dual uplinks are onlyale to use one of the links for a given network segment.

$dding more andwidth etween the layers in the form of faster inter-switch links

helps overcome congestion in the three-layer model scale, ut only to a point. The

prolems with host-to-host east-west traffic don/t occur one conversation at a time.

"nstead, hosts talk to other hosts all over the data center at any given time, all the

time. )o whileadding andwidthfacilitates these conversations, it/s only part of the

answer.

A new topology in town

The rest of the answer is to add switches at the layer elow the access layer, and

then spread the links from the access layer to the next, across the network. This

topology is a leaf-spine. $ leaf-spine design scales hori(ontally through theaddition of spine switches, which spanning-tree deployments with a traditional

three-layer design cannot do.

This is similar to the traditional three-layer design, %ust with more switches in the

spine layer. "n a leaf-spine topology, all links are used to forward traffic, often

using modern spanning-tree protocol replacements such asTransparent

"nterconnection of 0ots of 0inks+T"00 or)hortest Path ridging+)P. T"00

and )P provide forwarding across all availale links, while still maintaining a

loop-free network topology, similar to routed networks.
http://searchdatacenter.techtarget.com/tip/Increasing-network-bandwidth-available-to-virtual-machineshttp://searchdatacenter.techtarget.com/tip/Increasing-network-bandwidth-available-to-virtual-machineshttp://searchnetworking.techtarget.com/definition/Transparent-Interconnection-of-Lots-of-Links-TRILLhttp://searchnetworking.techtarget.com/definition/Transparent-Interconnection-of-Lots-of-Links-TRILLhttp://searchnetworking.techtarget.com/definition/Shortest-path-bridginghttp://searchnetworking.techtarget.com/definition/Shortest-path-bridginghttp://searchdatacenter.techtarget.com/tip/Increasing-network-bandwidth-available-to-virtual-machineshttp://searchnetworking.techtarget.com/definition/Transparent-Interconnection-of-Lots-of-Links-TRILLhttp://searchnetworking.techtarget.com/definition/Transparent-Interconnection-of-Lots-of-Links-TRILLhttp://searchnetworking.techtarget.com/definition/Shortest-path-bridging


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$ small leaf-spine network

The advantages of leaf-spine

0eaf-spine topologies are now the de facto standard --it/s difficult to find a design

other than leaf-spine among vendors/ various 1thernet faric designs. There are

good reasons for this--leaf-spine has several desirale characteristics that play into

the hands ofnetwork designerswho need to optimi(e east-west traffic&

All east-west hosts are equidistant.0eaf-spine widens the access and aggregation

layers. $ host can talk to another host on any other leaf switch and know that the

traffic will only traverse the ingress leaf switch, spine switch and egress leaf

switch. $s a result, applications running over this network infrastructure will

ehave predictaly, which is a key feature for organi(ations running multi-tiered

2e applications,high-performance computing clustersor high-fre#uency trading.

Leaf-spine uses all interconnection links.The traditional three-layer design uses

spanning-tree, a loop prevention protocol. $s mentioned earlier, spanning-tree

detects loops, and then lock links forming the loop. This means that dual-homed

access switches only use one of their two uplinks. Modern alternatives such as )P

and T"00 allow all links etween leaf and spine to forward traffic, allowing the

network to scale as traffic grows.

It supports fixed configuration switches.3ixed configuration switches ship witha specific numer of ports, compared with chassis switches, which feature modular
http://searchservervirtualization.techtarget.com/tutorial/Virtual-networking-design-configuration-and-management-guidehttp://searchenterpriselinux.techtarget.com/tutorial/Linux-clusters-High-performance-computinghttp://searchenterpriselinux.techtarget.com/tutorial/Linux-clusters-High-performance-computinghttp://searchservervirtualization.techtarget.com/tutorial/Virtual-networking-design-configuration-and-management-guidehttp://searchenterpriselinux.techtarget.com/tutorial/Linux-clusters-High-performance-computing


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slots that can e filled with line cards to meet port density re#uirements. 'hassis

switches tend to e costlycompared to fixed configuration switches. ut chassis

switches are necessary in traditional three-layer topologies where large numers of

switches from one layer connect to two switches at the next layer. 0eaf-spineallows for interconnections to e spread across a large numer of spine switches,

oviating the need for massive chassis switches in some leaf-spine designs. 2hile

chassis switches can e used in the spine layer, many organi(ations are finding a

cost savings in deploying fixed-switch spines.

0eaf-spine is currently the favored design for data center topologies of almost any

si(e. "t is predictale, scalale and solves the east-west traffic prolem. $ny

organi(ation whose "T infrastructure is moving towards convergence and high

levels of virtuali(ation should evaluate a leaf-spine network topology in their data

center.

The cons of leaf-spine

0eaf-spine isn/t without shortcomings. 4ne drawack is that the high switch countto gain the re#uired scale. 0eaf-spine topologies in the data center need to scale up

to the point that they can support the physical hosts that connect to them. The

larger the numer of leaf switches needed to uplink all of the physical hosts, the

wider the spine needs to e to accommodate them.

$ spine can only extend to a certain point efore either the spine switches are out

of ports and unale to interconnect more leaf switches, or the oversuscription rate

etween the leaf and spine layers is unacceptale. "n general, a 5&6

oversuscription rate etween leaf and spine layer is deemed acceptale. 3or

example, 78 hosts connecting to the leaf layer at 69:ps use a potential maximum

of 789:ps. "f the leaf layer connects to the spine layer using 7 79:ps uplinks,

the interconnect andwidth is 6;9:ps, for an oversuscription ratio of 5&6.


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4versuscription etween network layers

0eaf-spine networks also have significant caling re#uirements. The numer of

cales re#uired etween the leaf and spine layer increases with the addition of a

spine switch. The wider the spine, the more interconnects are re#uired. The

challenge for data center managers is structuring caling plants to have sufficient

fier optic strands to interconnect the layers. $lso, interconnecting switches do(ens

of meters apart re#uiresexpensive optical modules, adding to the overall cost of a

leaf-spine deployment. 2hile there are udget-priced copper modules useful for

short distances, optical modules are necessary and a significant cost in modern data

centers.

Modern data center strategy:

Design, hardware and IT'schanging role

Newer data centers look far different than they did just a decade

ago, and strategies for design and style continue to shift under the

weight of big data, cloud computing, mobility and other technology

trends.
http://searchdatacenter.techtarget.com/tip/Calculating-costs-of-data-center-cabling-infrastructurehttp://searchdatacenter.techtarget.com/tip/Calculating-costs-of-data-center-cabling-infrastructure


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Introduction


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Data center strategy for a hybrid environment

'ompanies now use the pulic cloud as an extension of their own data center, mixing pulic and private clouds

with colocation and on-premises "T to ecome as efficient as possile.'ontinue eading

News

Meet tomorrow's computing demands with new technologies

2e-scale "T organi(ations reap efficiency, agility and performance enefits over typical enterprise operations.

"t/s time to change that.'ontinue eading

News

Start with cloud, SDN and virtualization to modernize your data

center

'loud computing, flash storage, software-defined networks +)


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Tip

What's driving the DevOps movement?

The


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The latest in data center infrastructure

0ooking at emerging technology is important for the future of data centers, utwhat aout today/s data center@ These tips on cloud computing, converged

infrastructure and the data center show the current trends to follow.

3eature

Flashy innovations inside hyper-converged offerings

'onverged and hyper-converged infrastructures are getting a oost from all-flash storage components.'ontinue

eading

News

The many faces of converged infrastructure

"T vendors are riding the converged infrastructure wave into data centers y laeling their wares with the term,

ut very few platforms are truly converged.'ontinue eading

Tip

Cloud computing risks from a data center perspective

"T has three choices with pulic cloud& steering clear, maintaining its entire environment off-site in the cloud or

seeking the est of oth worlds with the hyrid cloud model.'ontinue eading

Tip

Become the cloud service provider your enterprise needs

The traditional data center needs to survive the cloud era -- y emracing it.'ontinue eading

Tip

Build a better private cloud than AWS

Most private clouds fail on the first deployment. Take these tips to heart when designing a cloud move.'ontinue

eading

4Crunching numbers

Big data, data center applications
http://searchdatacenter.techtarget.com/feature/Quick-guide-to-whats-inside-new-hyper-converged-systemshttp://searchdatacenter.techtarget.com/feature/Quick-guide-to-whats-inside-new-hyper-converged-systemshttp://searchdatacenter.techtarget.com/feature/Quick-guide-to-whats-inside-new-hyper-converged-systemshttp://searchdatacenter.techtarget.com/news/2240180224/The-many-faces-of-converged-infrastructurehttp://searchdatacenter.techtarget.com/news/2240180224/The-many-faces-of-converged-infrastructurehttp://searchdatacenter.techtarget.com/tip/Weighing-cloud-computing-risks-from-a-data-center-perspectivehttp://searchdatacenter.techtarget.com/tip/Weighing-cloud-computing-risks-from-a-data-center-perspectivehttp://searchcloudstorage.techtarget.com/tip/How-to-become-an-internal-hybrid-cloud-service-providerhttp://searchcloudstorage.techtarget.com/tip/How-to-become-an-internal-hybrid-cloud-service-providerhttp://searchcloudstorage.techtarget.com/tip/How-to-become-an-internal-hybrid-cloud-service-providerhttp://searchdatacenter.techtarget.com/tip/How-to-build-an-enterprise-private-cloud-that-looks-better-than-AWShttp://searchdatacenter.techtarget.com/tip/How-to-build-an-enterprise-private-cloud-that-looks-better-than-AWShttp://searchdatacenter.techtarget.com/tip/How-to-build-an-enterprise-private-cloud-that-looks-better-than-AWShttp://searchdatacenter.techtarget.com/feature/Quick-guide-to-whats-inside-new-hyper-converged-systemshttp://searchdatacenter.techtarget.com/feature/Quick-guide-to-whats-inside-new-hyper-converged-systemshttp://searchdatacenter.techtarget.com/feature/Quick-guide-to-whats-inside-new-hyper-converged-systemshttp://searchdatacenter.techtarget.com/news/2240180224/The-many-faces-of-converged-infrastructurehttp://searchdatacenter.techtarget.com/news/2240180224/The-many-faces-of-converged-infrastructurehttp://searchdatacenter.techtarget.com/tip/Weighing-cloud-computing-risks-from-a-data-center-perspectivehttp://searchdatacenter.techtarget.com/tip/Weighing-cloud-computing-risks-from-a-data-center-perspectivehttp://searchcloudstorage.techtarget.com/tip/How-to-become-an-internal-hybrid-cloud-service-providerhttp://searchcloudstorage.techtarget.com/tip/How-to-become-an-internal-hybrid-cloud-service-providerhttp://searchdatacenter.techtarget.com/tip/How-to-build-an-enterprise-private-cloud-that-looks-better-than-AWShttp://searchdatacenter.techtarget.com/tip/How-to-build-an-enterprise-private-cloud-that-looks-better-than-AWShttp://searchdatacenter.techtarget.com/tip/How-to-build-an-enterprise-private-cloud-that-looks-better-than-AWS


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ig data has estalished its place in the enterprise. )taying on top of the latest

software and hardware changes ensures that your company will make the most of

the data deluge.

News

Academics teach commercial enterprises about big data

ig data analytics was once an area of technology reserved for scientists, ut corporations now need the

technology to analy(e huge volumes of data for a host of usiness reasons.'ontinue eading

3eature

Big data = big changes in the data center

race yourself for ig data. "f it hasn/t already hit your data center, it will soon and it may place new demands

on your "T infrastructure, operations and data center strategy.'ontinue eading

3eature

Legacy applications in the cloud: What's ahead?

"T industry watchers predict that within aout five years, legacy apps that are currently difficult to deploy to the

cloud will ecome etter suited to a cloudy home.'ontinue eading

NewsHow cloud apps impact data center infrastructure and management

educing servers results in smaller data center facility concerns and costs, ut migrating apps to a )aa) model is

not without its own uni#ue hurdles.'ontinue eading

5Take the temperature

Data center cooling

$gility, efficiency and moility are three aspects of modern data centers, and the

facility is a ig part of it. 0earn how to monitor energy use, remain flexile and

save the environment.

Tip

Keep data center energy use in check with PUE metrics
http://searchdatacenter.techtarget.com/news/2240227726/Scientists-teach-enterprises-how-to-process-big-datahttp://searchdatacenter.techtarget.com/news/2240227726/Scientists-teach-enterprises-how-to-process-big-datahttp://searchdatacenter.techtarget.com/news/2240227726/Scientists-teach-enterprises-how-to-process-big-datahttp://searchdatacenter.techtarget.com/feature/Big-data-survey-reveals-why-IT-is-or-isnt-on-boardhttp://searchdatacenter.techtarget.com/feature/Big-data-survey-reveals-why-IT-is-or-isnt-on-boardhttp://searchcloudcomputing.techtarget.com/feature/Looking-to-the-future-of-legacy-applications-in-the-cloudhttp://searchcloudcomputing.techtarget.com/feature/Looking-to-the-future-of-legacy-applications-in-the-cloudhttp://searchdatacenter.techtarget.com/news/2240185250/Data-centers-move-to-cloud-apps-weigh-SaaS-pros-and-conshttp://searchdatacenter.techtarget.com/news/2240185250/Data-centers-move-to-cloud-apps-weigh-SaaS-pros-and-conshttp://searchdatacenter.techtarget.com/tip/PUE-metric-helps-keep-data-center-energy-use-in-checkhttp://searchdatacenter.techtarget.com/news/2240227726/Scientists-teach-enterprises-how-to-process-big-datahttp://searchdatacenter.techtarget.com/news/2240227726/Scientists-teach-enterprises-how-to-process-big-datahttp://searchdatacenter.techtarget.com/feature/Big-data-survey-reveals-why-IT-is-or-isnt-on-boardhttp://searchdatacenter.techtarget.com/feature/Big-data-survey-reveals-why-IT-is-or-isnt-on-boardhttp://searchcloudcomputing.techtarget.com/feature/Looking-to-the-future-of-legacy-applications-in-the-cloudhttp://searchcloudcomputing.techtarget.com/feature/Looking-to-the-future-of-legacy-applications-in-the-cloudhttp://searchdatacenter.techtarget.com/news/2240185250/Data-centers-move-to-cloud-apps-weigh-SaaS-pros-and-conshttp://searchdatacenter.techtarget.com/news/2240185250/Data-centers-move-to-cloud-apps-weigh-SaaS-pros-and-conshttp://searchdatacenter.techtarget.com/tip/PUE-metric-helps-keep-data-center-energy-use-in-check


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Metrics tools that examine energy efficiency provide road measurements that are helpful for enterprises that

want to minimi(e energy use.'ontinue eading

4pinion

The big green payoff

)ustainale data center operations are imperative for the era of ui#uitous computing. 4n a practical level, green

facilities can also save money.'ontinue eading

3eature

Q&A: How to keep up with massive Internet growth

Aevin essler, director of gloal product management for the enterprise networks division at T1 'onnectivity,

discusses the rise in employee device moility and how data centers must evolve to meet user

demands.'ontinue eading

Tip

Renew the data center

3or the largest, most power-hungry data centers, renewales like wind and solar are picking up some of the

power load.'ontinue eading

Tip

New technology, trends to cool off the data center

)tagnant strategies for data center cooling will keep energy ills climing ever higher, ut a more modern data

center strategy can ring them ack down to earth.'ontinue eading

3eature

An example of upgrading on-premises

2hen it came time for a new data center, *)1 decided -- after much research -- to uild rather than outsource,

and repurpose its old e#uipment for


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The total number of network-connected devices under management is

increasing significantly, which creates more data to store and process. Sowhat does this mean for your data center network architecture?

The TechTarget Networking Survey asked IT pros why they were upgrading

their data center network. Overall, 44% of respondents said the upgrade is

in response to increased applications and data. New information is likely

due in part to big data initiatives. In theTechTarget 2015 IT Priorities

Survey, 30% of respondents said they planned to implement big data

projects in the coming year. But with this upsurge of information, storage

and networking concerns are likely to arise.

A majority of respondents take to upgrades to handle the amount of data

coming in. While only 20% upgrade to move toward converged storage and

networking resources, it is likely that a large portion of those who upgrade

their data center network architecture to accommodate more data do so

with storage in mind.

"People attach an increasing amount of storage via the data network --

Ethernet -- as opposed to traditional fiber channel storage area networks,"

said John Burke, CIO and principal research analyst at Nemertes Research

in Mokena, Ill. Data center managers look for switches that handle low

latency and zero-loss Ethernet loads.

Enterprises have the option to store big data in the cloud. Significantpercentages of the TechTarget Networking Survey respondents said the

data center network needs an upgrade to support private (26%) or hybrid

(21%) cloud.Cloud storageoffers improved scalability and agility that

traditional in-house storage deployments can't match. In the future, more

enterprises might need a big data network to stream information to cloud-

hosted storage.
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18/41

Only 15% of respondents in the TechTarget Networking Survey intend to

upgrade to implementnetwork programmabilityorsoftware-defined

networking(SDN). Of those IT pros, 44% said they will consider purchasing

from an SDN vendor and 41% will evaluate a traditional network hardwarevendor that offers an SDN product. Despite major vendorsmaking a push

for SDN, a slightly higher percentage of respondents -- 46% -- don't plan to

consider an SDN vendor at all, and will look to vendors with technology

from a third party. Respondents could choose more than one option,

implying most are willing to entertain traditional as well as SDN-specific

vendors for this data center network architecture change.

Their choice will likely come down to price and vendors' technologicalofferings, but also existing relationships.
http://searchsdn.techtarget.com/opinion/Using-big-data-for-SDN-How-analytics-will-enable-programmabilityhttp://searchdatacenter.techtarget.com/tip/Its-time-for-a-software-defined-networking-architecturehttp://searchdatacenter.techtarget.com/tip/Its-time-for-a-software-defined-networking-architecturehttp://searchsdn.techtarget.com/feature/Major-SDN-vendor-strategies-at-a-glancehttp://searchsdn.techtarget.com/feature/Major-SDN-vendor-strategies-at-a-glancehttp://searchsdn.techtarget.com/opinion/Using-big-data-for-SDN-How-analytics-will-enable-programmabilityhttp://searchdatacenter.techtarget.com/tip/Its-time-for-a-software-defined-networking-architecturehttp://searchdatacenter.techtarget.com/tip/Its-time-for-a-software-defined-networking-architecturehttp://searchsdn.techtarget.com/feature/Major-SDN-vendor-strategies-at-a-glancehttp://searchsdn.techtarget.com/feature/Major-SDN-vendor-strategies-at-a-glance


19/41

"People are willing to look at their traditional network vendors now doing

SDN because a relationship has already been established and a trust

level found," Burke said. Purchasing SDN from a familiar vendor eliminates

the fear of a new company being acquired or disappearing.

Burke added that those looking to new SDN vendors are not concerned

with protecting existing relationships or trying to make SDN fit into a current

vendor's marketing or sales strategies.

"[New vendors] offer a way to make a dramatic change and to shift rapidly

to a network driven with and by orchestration tools and automation," he

said.

The Disaggregation of Networking, The Open Source UpstartsAnd Legacy Vendors' Business

Recently I wroteabout some announcements by upstartnetworking vendor Cumulus. To summarize what Cumulus

does it is important to explain the way networking

traditionally works. Existing networking vendors such as

Juniper and Ciscotake generally proprietary sotware and

tightly couple it with their own hardware. This! or so these

companies say! gives customer the best perormance and

ensures their networking works as expected " sotware iscreated to run perectly on highly tuned hardware.

Companies like Cumulus are disputing this claim and helping

move towards a disaggregated networking paradigm where

organizations can buy any hardware #be it rom the

traditional vendors or cheap commodity hardware suppliers$

and run open source sotware on top o that hardware. These

vendors point to cost savings! lexibility and the shit to one
http://www.forbes.com/sites/benkepes/2014/08/25/dell-and-vmware-find-sdn-happiness-cumulus-networks-acts-as-matchmaker/http://www.cisco.com/http://www.forbes.com/sites/benkepes/2014/08/25/dell-and-vmware-find-sdn-happiness-cumulus-networks-acts-as-matchmaker/http://www.cisco.com/


20/41

operating system being able to work across dierent

hardware platorms as the reason that this disaggregated

approach will become the status %uo in the uture.

&hen I covered a partnership between Dell! Cumulus

and VMwarearound networking! I received a airly lengthy

reply rom Cisco's (R olks disputing much o what I said. I

thought it worth revisiting the discussion and responding to

the dierent points Cisco makes. I'm not a networking

analyst! however mapping onto the networking world some o

the impacts that virtualization has had upon the servermarket! can inorm us o some possible outcomes. )tarting at

the top*

+$ ,etworks aren't servers. )erver virtualization thrived because servers were grossly

underutilized. ,etworks are oten oversubscribed and rarely underutilized. Customers don't

need better network utilization- they want inrastructure that responds to the needs o

applications. It's a dierent problem.a

There is some validity to what Cisco says here but it has to besaid that hardware in the networking space is becoming less

and less dierentiated today. Customers are oten looking to

the webscale companies like Facebookand GoogleGOOGL

+0.00%and seeking to emulate their approach delivering

complex applications on simple andor commodity

inrastructure. It is not about underutilization or not! it is

about being able to deploy and migrate workloads. Thenetworking has to match storage and compute and allow or

ast and lexible workload orchestration. It has to allow

hardware to rapidly be added or removed to allow or erratic

load proiles. /s 0an Conde rom another networking1

involved company! 2idokura! said to me regarding Cumulus*

The key thing about Cumulus 3inux it that it is not 43inux based5. It I) 3inux. This creates a

standard interace with which to program and conigure the devices using conventional3inux commands! and in theory enables you to load your own sotware on the devices.
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21/41

Cumulus 3inux switches are more o a server with an 6) that has capabilities to process

network packets and control the network processor 7 which can be aBroadcomBRCM

+0.00%chip! or example. The programmability provides the hidden beneit or users 7 you

can now conigure and manipulate switches en1masse 7 using scripts like (uppet! Che or

C8 Engine. )o rom the point o view o an )0, partner toCumulus

NetworksoVMwareVMW -1.69%! it means that the network device is also as programmable aspure sotware components.

9oing back to the Cisco response to my post! the company

stated that*

:$ The notion that disaggregating hardware rom sotware saves customers money is a myth.

; compared to white box

approaches when you consider the total cost o ownership.

I don't want to pit one analysis against another but last year

I wroteabout a Credit )uisse report that deeply investigated

what networking disaggregation would mean or

Cisco's businessgenerally! and networking business inparticular. )uice it to say that the report pointed to huge

margin pressure upon Cisco that will come rom networking

disaggregation. /dd to that the customer"beneit that users

can now reuse the same operational tools or networking that

they're using or their compute and you have a buy1side and a

sell1side economic impact that is hard to argue against.

D$ /s a related point! separating hardware rom sotware also complicates trouble1shooting.

&hether you have white boxes or Cisco switches! problems can occur anywhere in a network!

and with the dis1aggregated model! customers lose the ability to troubleshoot across their

entire network. /nd hardware matters when it comes to scale and perormance. That's

another huge limitation o the sotware1only model.

Cisco has a point here. &ith the aggregated model o

networking! customers have 4one throat to choke5. 6ne

vendor delivers both hardware and sotware and thus there is
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22/41

no doubt who is to blame when something goes wrong. ut

it's hard to argue this point as a continuing actor

as enterpriseIT rapidly moves towards a distributed!

disaggregated and composible paradigm across the board.Enterprise IT is becoming! by deinition! a more distributed

operation. /ny CI6 worth his salt has thought about trouble

shooting within a ar wider context than previously. /nd on to

the last point*

F$ 3astly! )0, is not a dire threat to Cisco. &e are embracing )0, " and leading in )0,. /s

I said above! what customers really want is IT inrastructure that is more automatically

adaptive to the needs o applications. They don't want sotware1deined anything or the sakeo it. &e've embraced that challenge with our /pplication Centric Inrastructure strategy!

which " by enabling policy1led! automatic inrastructure coniguration o both physical and

virtual networks " reduces the time it takes customers to deploy or migrate applications

rom months to mouse clicks. That's what customers really care about. ,ow! you may call

that more 4Cisco spin5 but we'll let the results speak or themselves* ater less than one

month o availability o our ull /CI suite! we have G< paying customers. It took some o our

more1hyped rivals hal a decade to reach such numbers.

Clearly Cisco isn't going away any time soon " enterprises

have too much invested in existing solutions to evencontemplate ripping them all out. ear in mind the number o

mission critical applications still running on mainrames

around the place. The %uestion isn't whether )0, will destroy

Cisco! but rather whether the margin and competitive

changes that )0, brings will prove suiciently corrosive to

Cisco #and it's ilk$ in terms o margin to cause some long term

systemic implications.

It's a ascinating progression to watch " expect more

ireworks! more argument and more heads to be raised above

the parapets on this one.
http://www.forbes.com/enterprise/http://www.forbes.com/enterprise/


23/41

A disaggregated server proves

breaking up can be a good thingSplit up and go your separate ways for cost efficiency. With

disaggregation, systems separate CPU, memory and I/O for more

flexibility, no hard feelings.

The frequency with which components of data center systems break up

could put some Hollywood couples to shame.

While the "in" thing in system design isconvergence, some forward-looking

technologists are aiming toward disaggregated servers. It's conscious

uncoupling, data-center style

Networking and storageare frequently purchased and configured

separately from servers. Disaggregating systems takes things a step further

and targets the processing, main memory, and the input/out (I/O)subsystem -- "the three piece suit" which makes up every system, said Dr.

Tom Bradicich, Hewlett-Packard vice president of engineering for servers.

Disaggregation is particularly attractive among hyperscalecloud service

providers, which see disaggregation as a way to achieve more flexible

systems and fewer underutilized resources.

"In the public cloud, you're playing a multi-billion dollar Tetris game," saidMike Neil, Microsoft general manager for Enterprise Cloud. "You have all

these resources manifested as physical systems, and the challenge is to be

as efficient as possible with those resources."

CPU: Memory: I/O
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24/41

"n today/s traditional servers, the ratios of 'PB to memory to "C4 are mostly

unchangeale. 2ith disaggregated servers, those systems are separated into

discrete pools of resources that are mixed and matched to create differently si(ed

and shaped systems.


25/41

the 2U M-Series chassis holds eight processing cartridges that contain

CPU and memory --connected to disaggregated storage and connectivity

resources via Cisco's Virtual Interface Card.

The holy grail of disaggregation is etween 'PB and main memory, so systems

vendors need to deliver etter, faster andwidthetween those components.

DThe iggest challenge of disaggregation is the interconnect,D said !P/s


26/41

distances, ut an expensive interconnect technology will eat into the potential

utili(ation enefits and derail the whole plan.

)ystems designers might find that emerging 1thernet standards provide sufficientperformance and low enough latency to support disaggregation. )everal systems

designed for hyperscale systems rely on 69:1. 2hen grouped with =uad )mall

3orm-factor Pluggale transceivers, 1thernet can go to 79:, said Aevin


27/41

orchestration framework to assemle and disassemle systems from the resource

pool, said "ntel/s Ayathsandra.

"ntel demonstrated the system within a single rack, and will share the results withthe 4pen 'ompute Pro%ectfor hardware designs and 4pen)tackfor cloud

orchestration, to encourage openness and adoption. DYou should e ale to have

different racks from different vendors, and get the same hardware-level

information from each rack,D Ayathsandra said. The goal is for different

orchestration layers to work together seamlessly. D"t shouldn/t matter whether you

are using *Mware or 4pen)tack,D he said.

Disaggregate in the face of danger


28/41

internally for pulic consumption. DThey/re saying /hey, we/ve already done the

heavy lifting. 0et/s ring this to the enterprise./D

'isco announced the B') M-)eries Modular )ervers, the first example of a

commercially availale disaggregated system, said rannon. The front of the GB

M-)eries chassis holds eight processing cartridges that contain 'PB and memory

--connected to disaggregated storage and connectivity resources via 'isco/s *irtual

"nterface 'ard.

Ericsson Radio

With the introduction of the Ericsson Radio System we are also introducing theindustry's most energy efficient and compact radio solution, maintainingperformance leadership at half the size and weight known as the Radio 2217.

This is the smallest and lightest macro coverage radio in the new portfolio with avolume of approimately !" liters and a weight of !# kg. $t is designed to support%TE and W&() and (ulti*standard mied mode with up to +" (z of %TE andup to - carriers of W&(), all within a +" (z of instantaneous andwidth/$0W1.

With +*way R diversity ecoming increasingly more important to improve the2plink performance in many systems, the new #R unit Radio 0208 provides an
http://www.cisco.com/c/en/us/products/servers-unified-computing/ucs-m-series-modular-servers/index.htmlhttp://www.cisco.com/c/en/us/products/servers-unified-computing/ucs-m-series-modular-servers/index.html


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easy and fleile way of e3uipping sites with W supporting this functionality.Radio "#"4 has small form factor or - liters and an weight of 4kg and integrateswell with any other radio to constitute a +R5#T system.

)nother new addition to the Ericsson Radio System portfolio is the smallest, most

powerful outdoor microcell on the market, the Radio 2203. $ts sleek, minimalisticScandinavian design complements any environment.

The radio e3uipment used for the R0S -""" family supports multi standardoperation, which means it can operate on any of the standards, either in singlemode /one standard at a time1 or in mied mode /simultaneous operation onmore than one standard1.

The radio e3uipment can e of two types6

Radio units for installation in macro cainets /R2s1 Remote radios for main*remote configurations. These can e either

remote radio units /RR2s1 or antenna integrated radio units /)$R1.

The RR2s are designed to e installed close to the antennas, and can e eitherwall or pole mounted. There are different versions of RR2s that support (acro or(icro configurations.

$n the )$R units on the other hand, the radio unit and the antenna are cominedinto one single unit and installed in the usual antenna location.

The radio e3uipment is multi standard capale, which means that the differentunits can operate on all standards 7S(, W&() and %TE. Two standards canoperate simultaneously.

M2M India Conclave 2014

Smartphone users in urban India will cross 1! million in "1! compared to #1 millionusers in "1$ %India is $G & !G 'ead( with a mobile subscriber)s base o* o+er ,# million% -ne o* the *astest growing & largest telecom market place in the world. /elco)s in Indiaare e0cited and ha+e realied importance o* machine-to-machine2M"M3 market whichis growing worldwide at a *ast pace. M"M technologies allow both wireless and wireds(stems to communicate with other de+ices 4 s(stems o* the same abilit(. Inno+ati+eapplications like smart cars5 connected homes5 smart metering5 remote management andindustrial data collection would be the ma6or re+enue dri+ers o* ser+ice pro+idersworldwide in the *uture.

M"M is touted as the ne0t big business opportunit( *or /elco)s and Vendors 7 8ccording toa 6oint stud( conducted b( GSM8 and Machina 'esearch5 the number o* total connectedde+ices would grow *rom more than , million toda( to "! million in "". 8ccording to

latest industr( reports5 India M"M modules market would reach 9S:,;.$; million b( "1


30/41

In India M"M market has now started e+ol+ing % India M"M market will be ma6orl( dri+enb( 8utomoti+e & Commercial /elematics5 =ousehold Monitoring & Control5 FinancialSer+ices & 'etail5 Smart =omes & Smart Metering5 Manu*acturing5 /ransportation and>ogistics.

In India market 8utomoti+e5 /ransport & >ogistics industries lead in terms o* M"Madoption. =owe+er5 9tilities will dri+e *uture market growth as the Go+ernment o* India isincreasingl( taking serious initiati+es to deplo( smart energ( meters to address theconcern o* increasing power the*t and round7the7clock monitoring o* power suppl(.

Bein India!" #i$"t Convention on M2M % No& into "'cce""('l 4th )dition 7 /he*orum will o?er a world class plat*orm *or understanding business +alue proposition o*M"M and how M"M technologies and applications will help businesses to *uel growth andproducti+it( in India market.

ual carrier S8)6 &*S8), &*S8)

* notes or tutorial of the asics of ual carrier S8), &*S8) whichutilises two carriers on the downlink * &*S8), or ual carrier S8).

*S+A T,TORIA INC,D)S

S8) $ntroduction

S8)

S8) channels

S8) categories

S28)

S28) categories

S28) channels

Evolved S8) 5 S8)9

Evolved S8) ($(:

ual &arrier S8)
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To further improve the S8) performance a scheme utilising two S8) carriers to increase the

peak data rates has een made availale. The scheme known under a variety of names and

acronyms * &*S8), ual carrier S8), ual &ell S8), and &*S8), ual cell S8),

also etter utilises the availale resources y multipleing carriers in the &E%% & state.

&*S8) or &*S8) enales etter utilisation of the resources, especially under poorchannel conditions where signal to noise ratios may not e as high as normally needed for high

data rate links.

&*S8) 5 &*S8) ackground

2(TS 5 W*&() was initially conceived as a circuit switched ased system and was not well

suited to $8 packet ased data traffic. :nce the asics 2(TS system was released and

deployed, the need for etter packet data capaility ecame clear, especially with the rapidly

increasing trend towards $nternet style packet data services which are particularly ursty in

nature.

The initial response to this was the development and introduction of S8), followed y S28)

for provide the comined S8) service. These were defined in ;788 Release < = -. %ater this

was further developed and deployed in some areas to provide even higher data transfer rates as

S8)9 which occurred in Release >.

) further release, Release 4 detailed the dual cell S8), or S8), and then a comination of

&*S8) and ($(: eing defined in Release ?.

&*S8) 5 &*S8) asics

The concept ehind &*S8) 5 &*S8) is to provide the maimum efficiency and

performance for data transfers that are ursty in nature * utilising high levels of capacity for a

short time. )s most of the traffic is in the downlink direction, dual carrier S8) is applied to the

downlink * i.e. S8) elements, and therefore dual carrier S8) is also known as &*S8).

The concept of packet data is that it data is split into packets with a destination tag, and these

are sent over a common channel * sharing the channel as data traffic from one source is not

there all the time.

&*S8) seeks to take apply this principle to the multiple carriers that may e availale to an

operator. :ften 2(TS licences are issued in paired spectrum of either !" (z or !< (z locks* two or three carriers, for uplink and downlink.

2sing 2(TS, S8), or even S8)9 these carriers operate independently, and dependent upon

the usage, one carrier could e fully utilised while the other is under used. &oordination etween

the carriers only takes place in terms of the connection management, and the dynamic load is

not alanced. &*S8) 5 &*S8) seeks to provide resource allocation and optimisation.

This @oint resource allocation over multiple carriers re3uires dynamic allocation of resources to

achieve the higher peak data*rates per S8) user within a single Transmission Time $nterval

/TT$1, as well as enhancing the terminal capailities. The use of &*S8) is aimed at providing

a consistent level of performance across the cell, and particularly at the edges where ($(: is

not as effective.


32/41

&hannels for &*S8)

When implementing &*S8), the channels present within the system need to e modified to

enale the system to operate as re3uired.

HS-DPCCH: While it would have een possile to utilise two S*8&&s, one on each

carrier, only one is used * the feedack information eing mapped to the single channel.

There are either < or !" &A$ * channel Auality $ndicator its that are used. Bive are used

when only one channel is utilised, and ten when two are in use. The compound &A$ is

made up from two independent &A$s6 one for each channel. Cew channel coding

schemes are defined for the overall )RA feedack format.

HS-SCCH: The S*S&& is transmitted on oth the anchor, or primary carrier as well

as the supplementary one, and the 2E has to monitor up to four S*S&& codes on

each carrier. owever the 2E is only re3uired to e ale to receive up to one S*S&&

on the serving or main cell and one S*S&& on the secondary cell.

&*S8) signalling = scheduling

:ne of the key processes re3uired within &*S8) is that of scheduling the data to e

transmitted as this has to e achieved across the two carriers. The scheduling algorithms

re3uired developing in a manner that provided ackwards compatiility for single carrier

transmissions while providing throughput speed improvements for the dual carrier scenarios.

The 3ueues for data to e transmitted are operated in a @oint fashion to provide the optimum

fleiility in operation * it enales the carrier with the least traffic 3ueued to e used /not all 2Eswill have the dual carrier facility and therefore one carrier may e loaded more heavily than the

other, etc..1

:ne area which did re3uire addressing was the operation of the ()&*ehs entity within the Code*

0 stack. Within S8) this was designed to support S*S& operation in more than one cell

served y the same Code*0 and therefore etending this for dual carrier operation re3uired only

minor changes.

Separate )RA entities are re3uired for each S*S&. $n this way the transmission is

effectively two separate transmissions over two separate S*S&s * each one has its own

uplink and downlink signalling.

Each carrier has a transport lock that uses a Transport Bormat Resource &omination /TBR&1

which is ased on the )RA and &A$ feedack sent over the uplink S*8&&. )ny

retransmissions re3uired y )RA will use the same modulation coding scheme as the first

transmission.

2E categories for &*S8)

2E categories were developed to enale the ase stations to e ale to 3uickly determine the

capailities of different 2Es. The numers re3uired etending for S8)9 and &*S8) 5 &*

S8).


33/41

2E&)TE7:RD

;788RE%E)SE

() C: :BS*S&&:ES

(:2%)T$:C

()$(2( R)W)T) R)TE

&:((ECTS

#! Rel 4 !< !-*A)( #;.+ &*S8)

## Rel 4 !< !-*A)( #4." &*S8)#; Rel 4 !< -+ A)( ; &*S8) 9($(:

#- Rel ? !< !- A)( ".- &*S8) 9($(:

#4 Rel ? !< -+ A)( 4+.+ &*S8) 9($(:

&*S28) and (ulticarrier S8)

The concepts ehind &*S8) can e taken further in a numer of areas to provide further

improvements in the performance of the overall S8)9 system.

The first of these is to utilise a similar dual carrier system for the uplink. 2sing dual carrier

S28), &*S28), would provide similar gains in the uplink as &*S8) provides for the

downlink. The road implementation would also e similar.

)nother way in which performance of the system can e further pushed is to utilise multiplecarriers, eyond the two used in &*S8). D aggregating further carriers the improvements

gained with &*S8) can e further improved along higher still peak data rates.

DC7=S9@8

igher performancefor the uplink.The popularity of smartphones has created significant demand

on uplink network capacity. 2plink traffic consists of user traffic

and application signaling. ) prime eample of uplink user traffic

is picture sharing, which generates significant uplink network

load particularly during special events, such as professional


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sports. While instant messaging status updates are an

eample of uplink application signaling which is sent

periodically or in response to user status changes that add to

uplink loading.

$n general, smartphone traffic is FurstyG which is particularly

suitale for multipleing on a shared data pipe. $t has een

demonstrated that significant capacity improvements can e

achieved for ursty smartphone data traffic y aggregating

multiple carriers into a single shared data pipe. &*S28) is a

carrier aggregation techni3ue for addressing the uplink

challenge using an operatorsH eisting carrier resources.

The following diagram illustrates the &*S28) concept6

In essence5 DC7=S9@8 combines two uplink carriers into

a larger data pipe with 6oint scheduling o* uplink traAc

across the two carriers. It allows mobile de+ices to

make use o* instantaneous spare capacit( a+ailable on

either carrier5 thus achie+ing multiple0ing gain and load

balancing. /he benet is a signicant eAcienc(

impro+ement which leads to higher s(stem capacit(.


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The following graph shows the gains achieved y &*S28)

over two standalone carriers. The vertical arrow shows that for

a given numer of users, for instance eight users per sector,

the uplink user urst rate is almost douled when &*S28) isenaled. This essentially reduces signaling and the data upload

time y half, which in turn improves the service response time.

Bor eample, the latency of picture sharing through instant

messaging can e significantly reduced y enaling &*

S28).

DC7=S9@8 can also impro+e cell capacit( *or a gi+enuser e0perience. /he horiontal arrow in the graphillustrates this concept. It shows that at the gi+en user

e0perience le+el5 DC7=S9@8 can impro+e sectorcapacit( b(


36/41

time can e reduced y +4I when &*S28) is enaled.

Similarly, wepage time*to*contents during uplink congestion

can e reduced y ;


37/41

0&*S8) was initially standardized in the ;788 Release

? to support the following and cominations6

Ca$$ie$ 1 Ca$$ie$ 2

Band I 2"1 M=3 Band VIII 2, M=3

Band II 21, M=3 Band IV 2"141E M=3

Band I 2"1 M=3 Band V 2;# M=3

$t was further etended in ;788 Release !" to support the

following new and cominations6


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Ca$$ie$ 1 Ca$$ie$ 2

Band I 2"1 M=3 Band I 21!# M=3

Band II 21, M=3 Band V 2;# M=3

2nder most of the aove and cominations, 0&*S8)

aggregates a high and carrier with a low and carrier. The

availaility of the low and carrier significantly enhances cell

edge and indoor performance compared to &*S8) with

two high and carriers. $n addition, field test results have

demonstrated more than #"I cell edge throughput gain and a

significant reduction in device power consumption from 0&*

S8) compared to &*S8).

D98> C>> =SD@8

$mproving capacity

and performance yaggregating downlinkcarriers.


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ual &ell S8) /&*S8)1 aggregates two ad@acent

downlink carriers to achieve higher downlink capacity and

etter user eperience. Burthermore, y comining two carriers

into a single data pipe, &*S8) increases the peakdownlink data rate to +#(ps. The following diagram illustrates

the &*S8) concept.

&*S8) was standardized in ;788 Release 4. Today, more

than !


40/41

Smartphone traffic is typically FurstyG which is particularly

suitale for multipleing on a shared data pipe. ;&*S8)

comines three downlink S8)9 carriers through @oint traffic

scheduling to form a larger data pipe. )s a result, it deliversetter system capacity and user eperience compared to three

carriers operating independently.

The diagram elow illustrates the high*

level ;&*S8) concept6

The following graph shows the system capacity and user

eperience gains from ;&*S8) compared to a comined

ual*&arrier /&1 S8) and Single*&arrier /S&1 S8)

deployment scenario. $n this analysis, user eperience is

measured y the user urst rate. $t is defined as the ratio of thedownlink data urst size in its to the total time it takes to

transmit the entire data urst to the user.

The vertical arrow shows that for a given numer of users per

sector per carrier, in this case eight, the user urst rate is more

than >"I higher compared to the &*S8) 9 S&*S8)

scenario. The horizontal arrow shows that for a given user

eperience, ;&*S8) can more than doule the carrier


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capacity in a sector. Cote that ;&*S8) achieves the

improvements without adding new spectrum resources.

#o'$ Ca$$ie$ *SD+A .4C-*SD+A

;788 R!" also enales the aggregation of four downlink

carriers in the same sector. (ore information to come.

interesting technology market notes ashwani nov 2015

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