The document discusses how software defined networking (SDN) could be applied to cellular networks to simplify network management and enable new services. It proposes several extensions to SDN controllers, switches, and base stations to address challenges in supporting mobility, scalability, and real-time control in cellular networks. Specifically, it suggests expressing policies based on subscriber attributes rather than addresses, using local switch agents for real-time control, and enabling remote control of virtualized base station resources from the SDN controller.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Reducing handoff delay by adaptive thresholdijistjournal
In wireless networks data are sent and received with impressive speed and ease. Mobile WiMAX is a
broadband wireless solution that enables coverage of mobile and fixed broadband networks with flexible
network architecture. Devised as a truly broadband access solution, the WiMAX technology offers
promising features in terms of high bandwidth, extended coverage area and low cost. Despite having
many advantages, WiMAX faces major research issues like QoS based bandwidth allocation, Roaming,
Internetworking with other technologies, security and handoff. Handoff occurs when a mobile user goes
from one cell to another without interruption of ongoing session. Many approaches have been proposed
for reducing handoff delay. In this paper, we propose a new approach by which a critical area, an area
far away from serving base station but still inside the coverage of serving base station, is found. And then
overlapping area between serving base stations and neighboring base station are found and tabulated.
According to the size of overlapping area, different weights are assigned where handoff threshold is
changed adaptively to reduce handoff delay.
we find out various power aware and data packet rate control with-collision-avoidance (CSMA/CA)-based ad hoc wireless network communication. And identifies that CSMA
Investigation of Clock Synchronization Techniques and its Performance Impact ...ijctet
Mobile ad hoc Network (MANET) is an assortment of mobile nodes that area unit needed to transmit packets on behalf of every alternative. The mobile nodes maintain the topology data during a dynamic network among a selected vary. All nodes should remember of its neighbors that area unit directly approachable. The every node in network maintained next hop data of close neighbor nodes. The routing protocols area unit routed knowledge packets in between sender and receiver during a specific time instant. The time synchronization is maintained the communication clock cycle between the nodes. Time synchronization is an important element of a MANET. Time synchronization during a network aims at providing a typical duration for local clocks of nodes within the network. Since all hardware clocks area unit imperfect, local clocks of nodes could alienate from one another in time, thus determined time or durations of your
Minimizing network delay or latency is a critical factor in delivering mobile broadband services; businesses and users expect network response will be close to instantaneous. Excess latency can have a profound effect on user experience—from excess delay during a simple phone conversation, reducing throughput at edge of cell coverage areas by reducing effectiveness of RAN optimization techniques, to slow- loading webpages and delays with streaming video. Response delays negatively impact revenue. In financial institutions, low latency networks have become a competitive advantage where even a few extra microseconds, can enable trades to execute ahead of the competition.
The direct correlation between delay and revenue in the web browsing experience is well documented. Amazon famously claimed that every 100 millisecond reduction in delay led to a one percent increase in sales. Google also stated that for every half second delay, it saw a 20 percent reduction in traffic.
For LTE network operators, control of latency is growing in importance as both an operational and business issue. Low latency is not only critical to maintaining the quality user experience (and therefore, the operator competitive advantage) of growing social, M2M, and real-time services, but latency reduction is fundamental to meeting the capacity expectations of LTE-A, where latency budgets will be cut in half and X2 will need to perform at microsecond speed.
Total network latency is the sum of delay from all the network components, including air interface, the processing, switching, and queuing of all network elements (core and RAN) along the path, and the propagation delay in the links. With ever tightening latency expectations, the relative contribution of any individual network element, such as a security gateway, must be minimized. For example, when latency budgets were targeting 150ms, a network node providing packet processing at 250μs was only adding 0.17% to the budget. However, in LTE-A, with latency targets slashed to 10ms, that same network node will consume almost 15x more of the budget. More important, when placed on the S1 with a target of only 1ms, 250 μs is 25% of the entire S1 latency allocation, and endangers meeting the microsecond latency needed at the X2. Clearly, operators need to apply stringent latency requirements for all network nodes, when designing LTE and LTE-A networks.
Motivation and results coverage enhancment for 3GPP NR Rel.17 Eiko Seidel
In this paper we would like to emphasize once again the need to look at large coverage scenarios for 5G NR and express our support for the creation of a Rel.17 work item. Furthermore, we provide first system-level simulation results to further motivate work on coverage enhancements and prove our commitment to contribute to a study item in the working groups in Rel.17 with independent performance evaluation.
Quantative Analysis and Evaluation of Topology Control Schemes for Utilizing ...ijsrd.com
By virtue of their robustness, cost-effectiveness, self-organizing and self-configuring nature, WMNs have emerged as a new network paradigm for a wide range of applications, such as public safety and emergency response communications, intelligent transportation systems, and community networks. It is anticipated that WMNs will not only resolve the limitations of wireless ad hoc networks, local area networks (WLANs), personal area networks (WPANs), and metropolitan area networks (WMANs) but also significantly improve such networks’ performance. One fundamental problem of WMNs with a limited number of radio interfaces and orthogonal channels is that the performance degrades significantly as the network size grows. This results from increased interference between nodes and diminished spatial reuse over the network. In this paper, it is proposed to evaluate the performance of two different channel assignment schemes namely common channel assignment (CCA) and centralized tabu-based search algorithm under WCETT routing protocols for varying traffic load in terms of packet delivery ratio, throughput, average end to end delay and routing overhead using NS2 network simulator. WCETT protocol uses the weighted sum of the cumulative expected transmission time and the maximal value of efficient channels among all channels.
Design and implementation of new routingIJCNCJournal
Energy consumption is a key element in the Wireless Sensor Networks (WSNs) design. Indeed, sensor nodes are really constrained by energy supply. Hence, how to improve the network lifetime is a crucial and challenging task. Several techniques are available at different levels of the OSI model to maximize the WSN lifetime and especially at the network layer which uses routing strategies to maintain the routes in the network and guarantee reliable communication. In this paper we intend to propose a new protocol called
Combined Energy and Distance Metrics Dynamic Routing Protocol (CEDM-DR). Our new approach considers not only the distance between wireless sensors but also the energy of node acting as a router in order to find the optimal path and achieve a dynamic and adaptive routing.
The performance metrics exploited for the evaluation of our protocol are average energy consumed, network lifetime and packets lost. By comparing our proposed routing strategy to protocol widely used in WSN namely Ad hoc On demand Distance Vector(AODV), simulation results show that CEDM-DR strategy might effectively balance the sensor power consumption and permits accordingly to enhance the network
lifetime. As well, this new protocol yields a noticeable energy saving compared to its counterpart.
A novel architecture for sdn based cellular network ijwmn
In this paper, we propose a novel SDN-based cellular network architecture that will be able to utilize the
opportunities of centralized administration of today’s emerging mobile network. Our proposed architecture
would not depend on a single controller, rather it divides the whole cellular area into clusters, and each
cluster is controlled by a separate controller. A number of controller services are provided on top of each
controller to manage all the major functionalities of the network and help to make the network
programmable and more agile, and create opportunities for policy-driven supervision and more
automation.
Xin Jin
Princeton University
Research Track Part 1
ONS2015: http://bit.ly/ons2015sd
ONS Inspire! Webinars: http://bit.ly/oiw-sd
Watch the talk (video) on ONS Content Archives: http://bit.ly/ons-archives-sd
Reducing handoff delay by adaptive thresholdijistjournal
In wireless networks data are sent and received with impressive speed and ease. Mobile WiMAX is a
broadband wireless solution that enables coverage of mobile and fixed broadband networks with flexible
network architecture. Devised as a truly broadband access solution, the WiMAX technology offers
promising features in terms of high bandwidth, extended coverage area and low cost. Despite having
many advantages, WiMAX faces major research issues like QoS based bandwidth allocation, Roaming,
Internetworking with other technologies, security and handoff. Handoff occurs when a mobile user goes
from one cell to another without interruption of ongoing session. Many approaches have been proposed
for reducing handoff delay. In this paper, we propose a new approach by which a critical area, an area
far away from serving base station but still inside the coverage of serving base station, is found. And then
overlapping area between serving base stations and neighboring base station are found and tabulated.
According to the size of overlapping area, different weights are assigned where handoff threshold is
changed adaptively to reduce handoff delay.
we find out various power aware and data packet rate control with-collision-avoidance (CSMA/CA)-based ad hoc wireless network communication. And identifies that CSMA
Investigation of Clock Synchronization Techniques and its Performance Impact ...ijctet
Mobile ad hoc Network (MANET) is an assortment of mobile nodes that area unit needed to transmit packets on behalf of every alternative. The mobile nodes maintain the topology data during a dynamic network among a selected vary. All nodes should remember of its neighbors that area unit directly approachable. The every node in network maintained next hop data of close neighbor nodes. The routing protocols area unit routed knowledge packets in between sender and receiver during a specific time instant. The time synchronization is maintained the communication clock cycle between the nodes. Time synchronization is an important element of a MANET. Time synchronization during a network aims at providing a typical duration for local clocks of nodes within the network. Since all hardware clocks area unit imperfect, local clocks of nodes could alienate from one another in time, thus determined time or durations of your
Minimizing network delay or latency is a critical factor in delivering mobile broadband services; businesses and users expect network response will be close to instantaneous. Excess latency can have a profound effect on user experience—from excess delay during a simple phone conversation, reducing throughput at edge of cell coverage areas by reducing effectiveness of RAN optimization techniques, to slow- loading webpages and delays with streaming video. Response delays negatively impact revenue. In financial institutions, low latency networks have become a competitive advantage where even a few extra microseconds, can enable trades to execute ahead of the competition.
The direct correlation between delay and revenue in the web browsing experience is well documented. Amazon famously claimed that every 100 millisecond reduction in delay led to a one percent increase in sales. Google also stated that for every half second delay, it saw a 20 percent reduction in traffic.
For LTE network operators, control of latency is growing in importance as both an operational and business issue. Low latency is not only critical to maintaining the quality user experience (and therefore, the operator competitive advantage) of growing social, M2M, and real-time services, but latency reduction is fundamental to meeting the capacity expectations of LTE-A, where latency budgets will be cut in half and X2 will need to perform at microsecond speed.
Total network latency is the sum of delay from all the network components, including air interface, the processing, switching, and queuing of all network elements (core and RAN) along the path, and the propagation delay in the links. With ever tightening latency expectations, the relative contribution of any individual network element, such as a security gateway, must be minimized. For example, when latency budgets were targeting 150ms, a network node providing packet processing at 250μs was only adding 0.17% to the budget. However, in LTE-A, with latency targets slashed to 10ms, that same network node will consume almost 15x more of the budget. More important, when placed on the S1 with a target of only 1ms, 250 μs is 25% of the entire S1 latency allocation, and endangers meeting the microsecond latency needed at the X2. Clearly, operators need to apply stringent latency requirements for all network nodes, when designing LTE and LTE-A networks.
Motivation and results coverage enhancment for 3GPP NR Rel.17 Eiko Seidel
In this paper we would like to emphasize once again the need to look at large coverage scenarios for 5G NR and express our support for the creation of a Rel.17 work item. Furthermore, we provide first system-level simulation results to further motivate work on coverage enhancements and prove our commitment to contribute to a study item in the working groups in Rel.17 with independent performance evaluation.
Quantative Analysis and Evaluation of Topology Control Schemes for Utilizing ...ijsrd.com
By virtue of their robustness, cost-effectiveness, self-organizing and self-configuring nature, WMNs have emerged as a new network paradigm for a wide range of applications, such as public safety and emergency response communications, intelligent transportation systems, and community networks. It is anticipated that WMNs will not only resolve the limitations of wireless ad hoc networks, local area networks (WLANs), personal area networks (WPANs), and metropolitan area networks (WMANs) but also significantly improve such networks’ performance. One fundamental problem of WMNs with a limited number of radio interfaces and orthogonal channels is that the performance degrades significantly as the network size grows. This results from increased interference between nodes and diminished spatial reuse over the network. In this paper, it is proposed to evaluate the performance of two different channel assignment schemes namely common channel assignment (CCA) and centralized tabu-based search algorithm under WCETT routing protocols for varying traffic load in terms of packet delivery ratio, throughput, average end to end delay and routing overhead using NS2 network simulator. WCETT protocol uses the weighted sum of the cumulative expected transmission time and the maximal value of efficient channels among all channels.
Design and implementation of new routingIJCNCJournal
Energy consumption is a key element in the Wireless Sensor Networks (WSNs) design. Indeed, sensor nodes are really constrained by energy supply. Hence, how to improve the network lifetime is a crucial and challenging task. Several techniques are available at different levels of the OSI model to maximize the WSN lifetime and especially at the network layer which uses routing strategies to maintain the routes in the network and guarantee reliable communication. In this paper we intend to propose a new protocol called
Combined Energy and Distance Metrics Dynamic Routing Protocol (CEDM-DR). Our new approach considers not only the distance between wireless sensors but also the energy of node acting as a router in order to find the optimal path and achieve a dynamic and adaptive routing.
The performance metrics exploited for the evaluation of our protocol are average energy consumed, network lifetime and packets lost. By comparing our proposed routing strategy to protocol widely used in WSN namely Ad hoc On demand Distance Vector(AODV), simulation results show that CEDM-DR strategy might effectively balance the sensor power consumption and permits accordingly to enhance the network
lifetime. As well, this new protocol yields a noticeable energy saving compared to its counterpart.
A novel architecture for sdn based cellular network ijwmn
In this paper, we propose a novel SDN-based cellular network architecture that will be able to utilize the
opportunities of centralized administration of today’s emerging mobile network. Our proposed architecture
would not depend on a single controller, rather it divides the whole cellular area into clusters, and each
cluster is controlled by a separate controller. A number of controller services are provided on top of each
controller to manage all the major functionalities of the network and help to make the network
programmable and more agile, and create opportunities for policy-driven supervision and more
automation.
Xin Jin
Princeton University
Research Track Part 1
ONS2015: http://bit.ly/ons2015sd
ONS Inspire! Webinars: http://bit.ly/oiw-sd
Watch the talk (video) on ONS Content Archives: http://bit.ly/ons-archives-sd
Voici ma présentation intitulée "Soigner sa E-réputation" faite dans le cadre de l'atelier "Comment construire son avenir via les réseaux sociaux ?" réalisé le 16 Avril 2014, à la Centrale DG.
Le but de cet atelier est de sensibiliser les étudiants à l'utilisation des réseaux sociaux afin d'accroitre leur chance à trouver une bonne offre d'emploi.
Bonne découverte.
TECHNIQUES FOR OFFLOADING LTE EVOLVED PACKET CORE TRAFFIC USING OPENFLOW: A C...IJCNCJournal
Cellular users of today have an insatiable appetite for bandwidth and data. Data-intensive applications, such as video on demand, online gaming and video conferencing, have gained prominence. This, coupled with recent innovations in the mobile network such as LTE/4G, poses a unique challenge to network
operators in how to extract the most value from their deployments while reducing their Total Cost of Operations(TCO). To this end, a number of enhancements have been proposed to the “conventional” LTE mobile network. Most of these recognize the monolithic and non-elastic nature of the mobile backend and propose complimenting core functionality with concepts borrowed from Software Defined Networking
(SDN). In this paper, we will attempt to explore some existing options within the LTE standard to address traffic challenges. We then survey some SDN-enabled alternatives and comment on their merits and drawbacks.
Introduction to SDN: Software Defined NetworkingAnkita Mahajan
SDN is the next big thing in networking. It focuses on separating the intelligence from the hardware. OpenFlow is one of the ways (currently the open standard followed by all Datacenters) to implement SDN.
AN ADAPTIVE DIFFSERV APPROACH TO SUPPORT QOS IN NETWORK MOBILITY NEMO ENVIRON...IJCNCJournal
Network Mobility Basic Support (NEMO BS) protocol (RFC 3963) is an extension of Mobile IPv6. The NEMO BS embraced by IETF working group to permit any node in the portable network to be accessible to the Internet despite the fact the network itself is roaming. This protocol likewise Mobile IPv6 doesn’t deliver any kind of Quality of Service (QoS) guarantees to its clients. It can barely offer the same level of services (i.e. Best-Effort) to all the users without obligation to the application’s needs. This propositions a challenge to real-time applications that demand a precise level of QoS pledge. The Differentiated Services has recently come to be the most widely used QoS support technology in IP networks due to its relative simplicity and scalability benefits. This paper proposes a new scheme to provide QoS to mobile network nodes within NEMO context. The proposed scheme intends to reduce handover latency for the users of MNN as well as alleviates packet losses. The feasibility of the proposed enhancement is assessed by measuring its performance against the native NEMO BS standard protocol using NS-2 simulator. The obtained results in the simulation study have demonstrated that the proposed scheme outperforms the standard NEMO BS protocol.
A Quality of Service Strategy to Optimize Bandwidth Utilization in Mobile Net...IDES Editor
The mobile network that supports network mobility
is an emerging technology. It is also referred as NEMO
(NEtwork MObility). It is more appropriate for mobile
platforms such as car, bus, train, air plane, etc. It is a great
challenge to provide Quality of Service (QoS) in NEMO. QoS
is a set of service requirements to be met by the network.
There are various parameters by which QoS is provided. This
paper concentrates on providing optimum bandwidth for data
traffic. The objective of this paper is to propose a strategy to
use Virtual Circuit (VC) approach in NEMO. It helps to
utilize the bandwidth effectively, to consume minimum time to
transfer the data and also to reduce overload of the mobile
router due to the minimum size of the header. Ultimately, it
gives better results to enhance the QoS in mobile networks.
Towards achieving-high-performance-in-5g-mobile-packet-cores-user-plane-functionEiko Seidel
White Paper Intel SK Telekom
This paper presents the architecture for a user plane function (UPF) in the mobile packet core (MPC) targeting 5G deployments.
Survey of optimizing dynamic virtual local area network algorithm for softwar...TELKOMNIKA JOURNAL
Software-defined network (SDN) is one of the most predominant technologies for networking in the existing and next-generation networks. Therefore, this paper is conducted to introduce a survey for researchers who are interested in exploiting the dynamic tunneling technique to optimize software-defined wide area network (SD-WAN). The main purpose of this survey is not only to investigate the related works of dynamic tunneling with SD-WAN but also to classify this related work according to the aim of each research into the practicable categories and present the most dominated employments for tunneling with SD-WAN, specifically virtual local area network (VLAN). The performed classification accompany dynamic tunneling in SDN can be summarized into four categories as following: exploring VLAN in SDN; management of multi VLAN in SDN; recover link failure of SDN; and development of SDN by using VLAN. Finally,
the intensive study of the literature in this paper discovers that the dominant path of research falls in the class that covers SDN’s link failure. This class takes full advantage of SD-WANs due to offering more robust networking and restoring most communication failures. In the event of a fault, the controller could respond and recover quickly by switching to a pre-computed backup route.
I AM SUDANESE,MASTER OF TELECOM FROM SUDAN UNEVERSITY ,THIS IS MY DOCUMENT I INVESTIGATE IN LTE WITH MORE THAN 50 REFERENCE , GOD BLESS US ,PLEASE FEEL FREE TO ASK ABOUT ANY THING IN THIS TOPIC
MY EMAIL khalidaam2015@hotmail,khalidaa@sudatel.sd
دعواتكم لى وللوالدين ولاهلى , الحمد لله فبنعمته تتم الصالحات اللهم احفظ الدول الاسلامية من كل كيد واغدق عليهم الرخاء
Web Server for Remote Monitoring and Controliosrjce
IOSR Journal of Computer Engineering (IOSR-JCE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of computer engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in computer technology. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Active Network is a novel approach of networking to mobile users in which the nodes are programmed to perform custom operations on the messages that pass through the node. It provides an architectural support for dynamically deploying new protocols in an existing network topology. The routers in an active network can download and execute code that is contained in the packets passing through them, thus rendering the node recognized and run totally new protocols without making any changes to the architecture of the network. Because the network's behavior can be altered at any time, active networks could be used to provide dynamic quality of service (QoS) or to support dynamic solutions to traffic congestion. This research implements and tests such specialized Active Networks security service known as the firewall and the ping service in Active Network. Active Network environment will be implemented on a small scale test scenario in order to study the performance and characteristics of active networks
Improvements for DMM in SDN and Virtualization-Based Mobile Network Architectureijmnct
The (r)evolution of wireless access infrastructure can be described as the convergence of the available radio communication systems towards a harmonized, more flexible and reconfigurable access system to match the current and upcoming demands. In recent years Softwarization and Virtualization technologies have moved from server and network domains to wireless domain and provides new perspectives of managing mobile networks functionalities. This paper provides evolution of the mobile network architecture in Software Defined Networking (SDN) and virtualization context and realizes it through the use of distribution of gateway function approach. Key improvements with proposed approach are to support efficient mobility management in heterogeneous access environments, remove the chains of IP preservation and optimal data path management according to application needs. A functional setup validates and assays the proposed evolution in terms of inter-system handover preparation, interruption and completion time relative to control plane delay requirements of the 5G networks.
2. to packet-processing rules based on IP addresses and network
locations.
Scalability through local switch agents: The need for fast
and frequent updates to a large amount of data-plane state
would put tremendous pressure on a central controller. Instead,
switches should run software agents that perform simple local
actions (such as polling traffic counters and comparing against
thresholds), at the behest of the controller.
Flexible switch patterns and actions: Today’s OpenFlow
already supports flexible packet classification and actions. That
said, cellular networks would benefit from support for deep-
packet inspection, header compression, and message-based
control protocols like SCTP [2].
Remote control of virtualized base-station resources:
Fig. 2. Simplified LTE network architecture Virtualizing the base station by time slot and subcarriers can
makes the equipment very expensive (e.g., more than 6 million give different applications, traffic classes, or virtual operators
dollars for a Cisco packet gateway). Centralizing data-plane the illusion of a dedicated base station. An open API between
functions at the cellular-Internet boundary forces all traffic the controller and base station can enable remote control
through the P-GW, including traffic between users on the same of radio resource allocation, admission control, handoff, and
cellular network, making it difficult to host popular content paging.
inside the cellular network. In addition, the network equipment For prototyping our architecture, we are encouraged by the
has vendor-specific configuration interfaces, and communicate availability of the open source LTE base station code provided
through complex control-plane protocols, with a large and by openairinterface.org and the open source LTE packet core
growing number of tunable parameters (e.g., several thousand code provided by openepc.net.
parameters for base stations). As such, carriers have (at best)
indirect control over the operation of their networks, with little II. C ONTROLLER A PPLICATIONS
ability to create innovative services. In this section, we identify several major challenges in
cellular data networks, and how Software Defined Networking
B. SDN for Cellular Data Networks can enable better solutions.
Cellular data networks are ripe for the introduction of Soft-
ware Defined Networking (SDN), where the network equip- A. Directing Traffic Through Middleboxes
ment performs basic packet-processing functions at the behest
Cellular network operators offer many fine-grained services
of applications running on a logically-centralized controller.
implemented in network appliances, or middleboxes. In a
In the next section, we discuss how SDN could give cellular
dynamic environment, cellular providers need to adapt video
operators greater control over their equipment, simplify net-
quality in real time based on cell tower congestion, device
work management, and introduce value-added services. SDN
type, and the subscriber’s service plan [3]. To improve security
can enable carriers to distribute data-plane rules over multiple,
for enterprise customers, providers direct traffic through intru-
cheaper network switches, reducing the scalability pressure on
sion detection and prevention systems. Certain legacy devices
the packet gateway and enabling flexible handling of traffic
need in-network support for echo cancellation for VoIP calls.
that stays within the cellular network.
However, today’s cellular carriers do not have fine-grained
Supporting real-time updates to many fine-grained packet-
control over routing, forcing them to either direct excess traffic
handling rules raises significant scalability challenges. Fre-
through unnecessary middleboxes or manage an unwieldy set
quent user mobility can require forwarding state at the level
of tunnels.
of individual subscribers, and the state must change quickly to
SDN provides fine-grained packet classifier and flexible
avoid service disruptions. To detect when subscribers exceed
routing, which can easily direct a chosen subset of traffic
their usage caps, the switches must perform fine-grain mon-
through a set of middleboxes. As a result, middleboxes will
itoring of traffic volumes. The network must adapt quickly
handle much less traffic, making them much cheaper. In addi-
to the measurement data to adapt QoS policies, or transcode
tion, with support for deep-packet inspection, SDN switches
content to offer good service during times of congestion. To
could support some middlebox functionality directly, reducing
address these challenges, we propose four main extensions to
the number of extra devices in the network.
controllers, switches, and base stations:
Flexible policies on subscriber attributes: Many controller
applications need to apply policy based on the properties of B. Monitoring for Network Control & Billing
cellular subscribers, including the network provider, device Due to frequent user mobility, and changing channel condi-
type, subscriber type, and recent usage. The controller should tions, cellular networks are subject to rapid changes in traffic
automatically translate policies based on subscriber attributes demands, and frequent signaling messages to migrate connec-
tions. Real-time traffic monitoring is crucial for triggering fast
8
3. adaptation. This includes load balancing data traffic from base E. Virtual Cellular Operators
stations to a different S-GW, and from a different S-GW to a Today’s cellular networks have relatively limited support
different P-GW, load balancing control traffic from the base for virtualization. LTE can isolate different enterprise cus-
station and S-GW to a different MME. Real-time monitoring tomers’ traffic into virtual private networks using traditional
also enables rapid per-application content adaptation (e.g., BGP/MPLS VPN technologies. However, LTE does not allow
video conferencing, or streaming from Netflix) to meet per- different carriers to share the infrastructure to offer a complete
subscriber QoS. Existing traffic-monitoring solutions [4] re- virtual LTE network to their customers. Virtual operators
quire additional equipment that captures every packet at every may want to innovate in mobility management, policy, and
interface of a S-GW, and provides a summary to a backend charging, without investing the substantial resources necessary
SQL server every few minutes. These measurements provide to build and manage a wireless network. For example, content
no real-time visibility into the eNodeB, S-GW, and MME. providers like Akamai could leverage a virtual infrastructure
The packet-handling rules in SDN switches include byte to better deliver content to mobile users.
and packet counters. By adjusting these rules over time, the Virtualization would also be useful to provide isolation and
cellular provider can efficiently monitor traffic at different separate control for different classes of traffic. For example, a
levels of granularity to drive real-time control loops on the carrier may want to carry traffic for roaming subscribers on a
SDN controller. In addition, associating packet classifiers different virtual network from its own customers, for security
with traffic counters is useful to drive billing decisions and reasons.
determine whether a subscriber has reached a usage cap. The SDN makes it relatively easy to support network virtu-
recent interest in allowing content providers to cover usage alization by partitioning the “flow space” of packet head-
charges for mobile users will put even more pressure on ers. Different controller applications can manage rules acting
cellular providers to collect fine-grained measurements. on each portion of flow space, enabling customized control
while ensuring isolation [5]. Virtualizing the cellular network
C. Seamless Subscriber Mobility requires virtualizing the base stations [6], [7], by slicing
Cellular networks must respond quickly to subscriber mo- resources at the physical layer (physical channels), link layer
bility to avoid disruptions in service. Yet, today’s cellular (scheduling), or network layer (traffic shaping).
providers do not have direct control over routing, or common
protocols for controlling forwarding across different cellular F. Inter-Cell Interference Management
technologies (e.g., 3G, LTE, WiMax, and WiFi). As a result, In LTE, every base station can use all subcarriers. However,
handoff across technologies involves complex procedures that base stations need to coordinate their subcarrier allocations to
lead to longer delays and higher packet loss rates. avoid harmful interference among users. Currently, inter-cell
SDN would provide a common control protocol (e.g., Open- interference management is done in a distributed fashion. A
Flow) that works across different cellular technologies, making base station tells its neighboring base stations if it needs to
mobility management much easier. In addition, rather than use a higher power to transmit to a UE using a subset of
performing hop-by-hop signaling to create a new session, the subcarriers. Alternatively, upon perceiving high interference on
controller can push new forwarding rules to multiple switches certain subcarriers, the base station can notify its neighboring
at the same time for a lower set-up delay. base stations to lower their transmission power. Inter-cell
interference management algorithm is related to graph coloring
D. QoS and Access Control Policies algorithm. Due to the lack of a global view, distributed graph
In today’s networks, the packet gateway is the central point coloring algorithms with a limited number of rounds are highly
for fine-grained policy enforcement and charging based on the suboptimal [8].
subscriber profile, application, and usage. The P-GW classifies SDN enables centralized control of base stations. A SDN
packets based on the 5-tuple of the TCP/IP header and either controller will have a global view of the current power and
drops packets (if they violate a firewall policy) or map them subcarrier allocation profile of base stations. In addition, a
into QoS classes. These QoS classes further map into the SDN controller running on a commodity server would have
Diff-Serve Code Points (DSCP) when the packets traverses much more computing resources than most base stations. As
IP networks en route to the base station. At the base station, a result, a SDN controller can make a more efficient allocation
only simple policies such as a maximum rate are enforced. of radio resources to handle new users.
This leads to scalability problems at the P-GW, and missed
opportunities to optimize the use of bandwidth inside the III. C ELLULAR SDN A RCHITECTURE
cellular network. Cellular networks need an SDN architecture that offers fine-
SDN would enable the distributed enforcement of QoS and grain, real-time control without sacrificing scalability. Working
firewall policies based on a network-wide view. Distributed our way down from the controller platforms to the base
enforcement is especially important for handling any traffic stations, we propose four main extensions to enable SDN
that stays within the cellular network. A controller application in cellular networks. The cellular SDN architecture is shown
running on the controller can spread access-control rules over in Figure 3. First, controller applications should be able to
multiple switches, and manage the scheduling of traffic by express policy in terms of subscriber attributes, rather than
QoS classes across multiple hops in the network. IP addresses or physical locations, as captured in a subscriber
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4. information base. Second, to improve control-plane scalability, identifiers1 . The controller can also dynamically divide the
each switch should run a local control agent that performs network into “slices” that handle all traffic matching some
simple actions (such as polling traffic counters and comparing predicate on the subscriber attributes. This allows the cellular
against a threshold), at the behest of the controller. Third, provider to isolate roaming traffic, isolate dumb phone traffic
switches should support more flexible data-plane functional- or phone traffic using legacy protocols. To enable scalable
ity, such as deep packet inspection and header compression. slicing of semantic space, the controller can instruct ingress
Fourth, base stations should support remote control of virtu- switches to mark incoming packets (e.g., using an MPLS label
alized wireless resources to enable flexible cell management. or VLAN tag) sent to or from subscribers with particular
attributes.
B. Switch Software: Local Control Agents
Cellular data networks face significant scalability chal-
lenges, in terms of the number of subscribers, frequent changes
in user location, fine-grain access-control and quality-of-
service policies, and real-time adaptation to network condi-
tions. For example, the switches may need to direct a video
stream through a transcoding proxy if the network becomes
congested, or give certain traffic lower priority if the user
exceeds his usage cap. These measurement and control func-
tions could easily overwhelm a logically-centralized controller.
Fig. 3. Cellular SDN architecture In addition, the controller may not be able to respond as
quickly to local events as the underlying switches themselves.
This argues for having some control-plane functionality on the
underlying switches, though arguably not the same complex
A. Controller: Policies on Subscriber Attributes software that runs on the switches in today’s cellular networks.
The SDN controller consists of a Network Operating System In particular, each switch can run an agent that performs
(NOS) running a collection of application modules, such simple local actions, under the command of the controller.
as radio resource management, mobility management, and For example, the controller could offload simple measurement
routing. The handling of individual packets often depends on tasks to the local agents, such as periodically polling the traffic
multiple modules. For example, the flow of traffic through counters and notifying the controller if a counter exceeds a
the network depends on the subscriber’s location (determined threshold. The local agent could also perform simple control
by the mobility manager) and the paths between pairs of operations, such as automatically changing the weight or
network elements (determined by infrastructure routing), and priority of a queue when traffic counts exceed a threshold,
traffic monitoring and packet scheduling depend on the policy or pushing a tag on a packet to direct the traffic through
and charging rule function. As such, the NOS should support an intermediate middlebox. Performing these operations on
composition to combine the results of multiple modules into the local agents would reduce the load on the controller, and
a single set of packet-handling rules in each switch [9]. enable faster responses to critical events.
Many of the controller application modules need to apply Supporting local agents on the switches raises many inter-
policy based on the properties of cellular subscribers, including esting research problems. Partitioning functionality between
the cellular network provider (e.g., whether the user is roaming the controller and the agents requires ways for application
or not), device type (e.g., whether the user has a legacy phone modules to expose the inherent parallelism across agents and
that requires echo cancellation), subscriber type (e.g., usage the necessary aggregation of information at the controller. In
cap, parental controls, etc.), and recent usage (e.g., whether the addition, the partitioning of functionality must work in the
user is near exceeding the usage cap). Yet, the switches match presence of multiple modules that form a single application.
packets and perform actions based on packet header fields, Network updates must be kept consistent amid the partitioning
based on ephemeral identifiers such as a subscriber’s current of functionality and user equipment mobility. We plan to
IP address and location. To bridge the gap, the controller can explore the design of the local agent and techniques for
maintain a Subscriber Information Base (SIB) that stores and partitioning functionality in our future work.
maintains subscriber information, including relatively static
subscriber attributes as well as dynamic data like the user’s C. Switch Hardware: Flexible Packet Processing
current IP address, location, and total traffic consumption. Today’s OpenFlow [11] switches already support many fea-
The NOS can translate policies expressed in terms of tures needed in cellular networks. Flexible packet classification
subscriber attributes into switch rules that match on packet based on Ethernet, IP, and TCP and UDP header fields enables
headers. Similarly, the NOS can translate network measure-
1 This is similar to the way Ethane [10] supports access-control policies
ments (such as traffic counters) to the appropriate (sets of)
based on named principals, rather than IP addresses and network locations,
subscribers, to allow the application modules to focus on though cellular networks must support a much wider range of attributes and
subscribers and their attributes rather than ephemeral network control actions.
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5. fine-grain quality-of-service, access control, and monitoring. (RRM) on top of a logically-centralized controller makes it
The forwarding actions in today’s OpenFlow switches would much easier to innovate in admission control, radio resource
enable carriers to direct selective traffic through middleboxes, allocation, and interference management. For example, the
change the paths to and from a mobile user, and mark and RRM can redirect a UE to a nearby lightly loaded base
schedule traffic according to QoS policies. The byte and station or increase the transmission power of a congested
packet counters associated with each rule would support traffic base station. If the base station has multiple antennas, the
measurement, real-time adaptation based on congestion or control plane can decide whether the antennas should be used
exceeding a subscriber’s usage cap, and usage-based billing. for boosting signals (combining diversity to boost signals
Still, these switches may need larger rule tables, or more for delay-sensitive applications) or for spatial multiplexing
stages of tables, than today’s commodity switches to efficiently (multiple parallel transmissions). Although 3G base stations
support fine-grained policies. are controlled by a central entity, the radio network controller
That said, software-defined cellular networks would benefit (RNC) couples control-plane and data-plane functionality,
from new switch capabilities. TCP/UDP port numbers are including fine-grained tasks like packet scheduling. In contrast,
no longer a sufficiently reliable way to identify applications. the RRM module should only perform control-plane functions,
Instead, support for deep packet inspection (DPI) would enable and instruct the base station to perform any data-plane opera-
finer-grain classification based on the application, such as tions.
Web, peer-to-peer, video, and VoIP traffic. This is important to Virtualization: Today’s SDN virtualization solutions like
divide traffic into separate traffic classes for different packet- FlowVisor [5] can share a single switch data plane among mul-
scheduling and routing policies, as commonly done in today’s tiple virtual networks. Much as a hypervisor resides between
cellular networks [12]. DPI would also help support intrusion software and hardware on a PC, FlowVisor uses OpenFlow as
detection and prevention systems that analyze packet contents a hardware abstraction layer to sit logically between control
to identify malicious traffic. and forwarding paths on a network device. FlowVisor is
To support DPI, the OpenFlow protocol must be extended to transparent to both the network hardware and the controller
add and remove rules where the pattern is a regular expression. managing the virtual networks. FlowVisor defines a slice
To avoid having the DPI module inspect every packet, SDN as a set of flows running on a topology of switches. The
controller can jointly manage the flow table and the DPI rule virtualization layer enforces strong isolation between slices.
table. For example, the switch could first match a packet with Resources that can be sliced are bandwidth, topology, traffic,
a flow-table rule, which includes a flag indicating whether device CPU, and forwarding tables.
the packet should proceed directly to the output port(s) or go Technologies like FlowVisor can be extended to slice base
through the DPI table. To contain cost, we do not envision that station resources, e.g., to create virtual base stations. A virtual
every switch would support DPI. Instead, the controller must base station’s resource can be a combination of time slots, sub-
place packet-classification rules in the appropriate locations in carriers, and power. For example, a virtual base station can be
the underlying network. allocated a subset of time slots, and transmission in each time
In addition to DPI, switches could also support techniques slot can use maximum transmission power allowed or a subset
like header compression and decompression to reduce the of subcarriers across all time slots and transmission in each
overhead for applications with small packet payloads. For time slot uses a fraction of the maximum transmission power.
example, VoIP packets are typically small, making the headers A slice can ask for base stations with a specific MAC protocol.
a relatively high fraction of the traffic. Compressing these To support base station virtualization, without modifying the
packets before transmission on low-bandwidth links substan- physical-layer protocols, the controller can convey high-level
tially lowers the overhead. VoIP packet sizes range from 20 to information like the identity of the virtual provider through the
150 bytes, and the combined overhead of the RTP, UDP, and control plane. This would allow the UE software to display
IP headers is 40 bytes. Robust header compression (ROHC) the virtual provider (rather than the physically broadcasted
reduces the 40-byte overhead to 1 byte. As with DPI, this provider information) without requiring explicit broadcasting
functionality may not be available on every switch, but instead of the provider information and cell ID.
mainly on switches with links to and from low-bandwidth
regions of the network. IV. R ELATED W ORK
Our work is heavily inspired and follows the high-level
vision of OpenRoads (OpenFlow wireless) [7], which is a
D. Base Station: Remote Control and Virtualization platform for innovation and realistic deployment of services
Remote control: In LTE, base stations participate in dis- for wireless networks. OpenRoads is the first software-defined
tributed control protocols to manage radio resource allocation, wireless network. It is mainly based on WiFi and offers no
session setup/reconfiguration/teardown, handoff, and paging. special support for cellular networks. In contrast, our work
Radio resources are inherently shared among base stations. addresses specific cellular network requirements such as real-
The lack of central control makes it difficult to optimize tasks time session management which runs on top of SCTP instead
related to radio access. We decouple the control plane from the of TCP, paging, UE (User Equipment) state tracking, policy
radio hardware. We envision that that the SDN radio hardware enforcement, charging and radio resource management.
exposes a well-defined API which can be controlled by the Our work focuses on the design of a programmable con-
control plane. Running Radio Resource Management Module trol plane for cellular networks. It can benefit from a pro-
11
6. grammable data plane [13]. A programmable data plane en-
ables physical layer customization of virtual base stations that
traditional MAC scheduling based virtualization techniques [6]
can not. For example, each LTE virtual base station can pick
a different FFT size to balance multipath effects against peak-
to-average-power ratio (PAPR) inefficiencies.
V. C ONCLUSION AND F UTURE W ORK
In this paper, we argue that software defined networking can
make cellular networks much simpler and easier to manage,
introduce new services, and inter-operate with other wireless
network technologies and other operator networks. We sketch
out changes and extensions to controller platforms, network
switches, and base stations to enable software defined cellular
networks. The complete design of an SDN architecture for
cellular networks is an exciting avenue for future work.
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