Network Virtualization is claimed to be a key component of the Future Internet, providing the dyn... more Network Virtualization is claimed to be a key component of the Future Internet, providing the dynamic support of different networks with different paradigms and mechanisms in the same physical infrastructure. A major challenge in the dynamic provision of virtual networks is the efficient embedding of virtual resources into physical ones. Since this problem is known to be NP-hard, previous research focused on designing heuristic-based algorithms; most of them either do not consider a simultaneous embedding of virtual nodes and virtual links, or apply link-path formulation, leading to non-optimal solutions. This paper proposes an integer linear programming (ILP) formulation to solve the online virtual network embedding problem as a result of an objective function striving for the minimization of resource consumption and load balancing. To this end 3 different objective functions are proposed and evaluated. This approach applies multi-commodity flow constraint to accomplish a node-link formulation that optimizes the allocation of physical network resources. This proposal is evaluated against state of the art heuristics. The performance of the heuristics related to Virtual Network (VN) request acceptance ratio is, at least, 30% below the one of the Virtual Network Embedding Node-Link Formulation (VNE-NLF) method. From the three cost functions evaluated, the Weighted Shortest Distance Path (WSDP) is the one which embeds more VNs and also requires, on average, less physical resources per embedding.
Abstract: Cloud computing presupposes on-demand network access to pool of computing resources. Ho... more Abstract: Cloud computing presupposes on-demand network access to pool of computing resources. However, network access through the WAN is usually not compliant with any kind of service guarantees, including reliability, security and performance. In this work, two types of network services able to fulfill cloud requirements are presented. In addition, an extension of the Virtual Private Cloud concept is proposed by integrating these network services.
Resumo Network Virtualization is claimed to be a key component of the Future Internet by enabling... more Resumo Network Virtualization is claimed to be a key component of the Future Internet by enabling the coexistence ofheterogeneous (virtual) networks on the same physical infrastructure [1], providing the dynamic creation and support of different networks with different paradigms and mechanisms. In order for virtualization to be used in a network operator's infrastructure, its impact on the network traffic must be studied.
Network Virtualization is claimed to be a key component of the Future Internet by enabling the co... more Network Virtualization is claimed to be a key component of the Future Internet by enabling the coexistence of heterogeneous (virtual) networks on the same physical infrastructure, providing the dynamic creation and support of different networks with different paradigms and mechanisms in the same physical network. A major challenge in the dynamic provision of virtual networks resides on the efficient embedding of virtual resources into physical ones. Since this problem is known to be NP-hard, previous research focused on designing heuristic-based algorithms; most of them do not consider a simultaneous optimization of the node and the link mapping, leading to non-optimal solutions. This paper proposes an integer linear programming formulation to solve the virtual network embedding problem, as a simultaneous optimization of virtual nodes and links placement, providing the optimal boundary for each virtual network mapping. A link-node formulation is used and the multi-commodity flow constrain is applied. In addition, a heuristic algorithm for virtual network embedding is also proposed and compared against the optimal formulation. The performance of the integer linear programming formulation and of the heuristic is evaluated by means of simulation. Simulation experiments show significant improvements of the virtual network acceptance ratio, in average additional 10% of the virtual network requests are accepted when using the integer linear programming formulation, which corresponds, in average, to more 7 virtual networks accommodated on the physical network.
Cloud computing is widely considered as an attractive service model since the users
commitments ... more Cloud computing is widely considered as an attractive service model since the users commitments for investment and operations are minimised, and costs are in direct relation to usage and demand. However, when networking aspects for distributed clouds are considered, there is little support and the effort is often underestimated. The project SAIL is addressing cloud networking as the combination of management for cloud computing and vital networking capabilities between distributed cloud resources involved to improve the management of both. This position paper presents new security challenges as considered in SAIL for ensuring legitimate usage of cloud networking resources and for preventing misuse.
With the growing trend of wireless technologies and the great need of being
always on (line) and... more With the growing trend of wireless technologies and the great need of being always on (line) and anywhere culminate with the development of a new standard the IEEE802.21, bythe IEEE group. This standard is designed to streamline the handoversbetween different technologies through normalized mechanisms and events, with the purpose of making the different technologies seamless to the upper-layers This thesis presents mobility mechanisms independent of the wireless technologies at this stage, particularly WiMAX technology with support for mobility and the WiFi technology. It is described how are processed heterogeneous handovers based on IEEE802.16 standard and the IEEE802.21 and are purposed some changes on it. It is then analyzed the network simulator, which was used to assess the performance of the handovers in heterogeneous networks through the new mechanisms established and purposed, and changes are made to support the signalling and features specified. On this Thesis are simulated several scenarios with handovers of intra-technology and inter-technology in order to obtain performance parameters. The obtained results with the changes produced in the simulator show that this new standard and the purposed mechanism of integration with the technologies 802.11 and 802.16, bring significant improvements on the time of handovers as well as on the support of QoS.
In the last few years, the concept of network virtualization has gained a lot of attention both f... more In the last few years, the concept of network virtualization has gained a lot of attention both from industry and research projects. This paper evaluates the potential of network virtualization from an operator's perspective, with the short-term goal of optimizing service delivery and rollout, and on a longer term as an enabler of technology integration and migration. Based on possible scenarios for implementing and using network virtualization, new business roles and models are examined. Open issues and topics for further ...
Network Virtualization is claimed to be a key component of the Future Internet, providing the dyn... more Network Virtualization is claimed to be a key component of the Future Internet, providing the dynamic support of different networks with different paradigms and mechanisms in the same physical infrastructure. A major challenge in the dynamic provision of virtual networks is the efficient embedding of virtual resources into physical ones. Since this problem is known to be NP-hard, previous research focused on designing heuristic-based algorithms; most of them either do not consider a simultaneous embedding of virtual nodes and virtual links, or apply link-path formulation, leading to non-optimal solutions. This paper proposes an integer linear programming (ILP) formulation to solve the online virtual network embedding problem as a result of an objective function striving for the minimization of resource consumption and load balancing. To this end 3 different objective functions are proposed and evaluated. This approach applies multi-commodity flow constraint to accomplish a node-link formulation that optimizes the allocation of physical network resources. This proposal is evaluated against state of the art heuristics. The performance of the heuristics related to Virtual Network (VN) request acceptance ratio is, at least, 30% below the one of the Virtual Network Embedding Node-Link Formulation (VNE-NLF) method. From the three cost functions evaluated, the Weighted Shortest Distance Path (WSDP) is the one which embeds more VNs and also requires, on average, less physical resources per embedding.
Abstract: Cloud computing presupposes on-demand network access to pool of computing resources. Ho... more Abstract: Cloud computing presupposes on-demand network access to pool of computing resources. However, network access through the WAN is usually not compliant with any kind of service guarantees, including reliability, security and performance. In this work, two types of network services able to fulfill cloud requirements are presented. In addition, an extension of the Virtual Private Cloud concept is proposed by integrating these network services.
Resumo Network Virtualization is claimed to be a key component of the Future Internet by enabling... more Resumo Network Virtualization is claimed to be a key component of the Future Internet by enabling the coexistence ofheterogeneous (virtual) networks on the same physical infrastructure [1], providing the dynamic creation and support of different networks with different paradigms and mechanisms. In order for virtualization to be used in a network operator's infrastructure, its impact on the network traffic must be studied.
Network Virtualization is claimed to be a key component of the Future Internet by enabling the co... more Network Virtualization is claimed to be a key component of the Future Internet by enabling the coexistence of heterogeneous (virtual) networks on the same physical infrastructure, providing the dynamic creation and support of different networks with different paradigms and mechanisms in the same physical network. A major challenge in the dynamic provision of virtual networks resides on the efficient embedding of virtual resources into physical ones. Since this problem is known to be NP-hard, previous research focused on designing heuristic-based algorithms; most of them do not consider a simultaneous optimization of the node and the link mapping, leading to non-optimal solutions. This paper proposes an integer linear programming formulation to solve the virtual network embedding problem, as a simultaneous optimization of virtual nodes and links placement, providing the optimal boundary for each virtual network mapping. A link-node formulation is used and the multi-commodity flow constrain is applied. In addition, a heuristic algorithm for virtual network embedding is also proposed and compared against the optimal formulation. The performance of the integer linear programming formulation and of the heuristic is evaluated by means of simulation. Simulation experiments show significant improvements of the virtual network acceptance ratio, in average additional 10% of the virtual network requests are accepted when using the integer linear programming formulation, which corresponds, in average, to more 7 virtual networks accommodated on the physical network.
Cloud computing is widely considered as an attractive service model since the users
commitments ... more Cloud computing is widely considered as an attractive service model since the users commitments for investment and operations are minimised, and costs are in direct relation to usage and demand. However, when networking aspects for distributed clouds are considered, there is little support and the effort is often underestimated. The project SAIL is addressing cloud networking as the combination of management for cloud computing and vital networking capabilities between distributed cloud resources involved to improve the management of both. This position paper presents new security challenges as considered in SAIL for ensuring legitimate usage of cloud networking resources and for preventing misuse.
With the growing trend of wireless technologies and the great need of being
always on (line) and... more With the growing trend of wireless technologies and the great need of being always on (line) and anywhere culminate with the development of a new standard the IEEE802.21, bythe IEEE group. This standard is designed to streamline the handoversbetween different technologies through normalized mechanisms and events, with the purpose of making the different technologies seamless to the upper-layers This thesis presents mobility mechanisms independent of the wireless technologies at this stage, particularly WiMAX technology with support for mobility and the WiFi technology. It is described how are processed heterogeneous handovers based on IEEE802.16 standard and the IEEE802.21 and are purposed some changes on it. It is then analyzed the network simulator, which was used to assess the performance of the handovers in heterogeneous networks through the new mechanisms established and purposed, and changes are made to support the signalling and features specified. On this Thesis are simulated several scenarios with handovers of intra-technology and inter-technology in order to obtain performance parameters. The obtained results with the changes produced in the simulator show that this new standard and the purposed mechanism of integration with the technologies 802.11 and 802.16, bring significant improvements on the time of handovers as well as on the support of QoS.
In the last few years, the concept of network virtualization has gained a lot of attention both f... more In the last few years, the concept of network virtualization has gained a lot of attention both from industry and research projects. This paper evaluates the potential of network virtualization from an operator's perspective, with the short-term goal of optimizing service delivery and rollout, and on a longer term as an enabler of technology integration and migration. Based on possible scenarios for implementing and using network virtualization, new business roles and models are examined. Open issues and topics for further ...
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Papers by Márcio Melo
commitments for investment and operations are minimised, and costs are in direct relation to
usage and demand. However, when networking aspects for distributed clouds are considered,
there is little support and the effort is often underestimated. The project SAIL is addressing cloud
networking as the combination of management for cloud computing and vital networking
capabilities between distributed cloud resources involved to improve the management of both.
This position paper presents new security challenges as considered in SAIL for ensuring
legitimate usage of cloud networking resources and for preventing misuse.
always on (line) and anywhere culminate with the development of a new
standard the IEEE802.21, bythe IEEE group. This standard is designed to
streamline the handoversbetween different technologies through normalized
mechanisms and events, with the purpose of making the different technologies
seamless to the upper-layers
This thesis presents mobility mechanisms independent of the wireless
technologies at this stage, particularly WiMAX technology with support for
mobility and the WiFi technology. It is described how are processed
heterogeneous handovers based on IEEE802.16 standard and the IEEE802.21
and are purposed some changes on it.
It is then analyzed the network simulator, which was used to assess the
performance of the handovers in heterogeneous networks through the new
mechanisms established and purposed, and changes are made to support the
signalling and features specified.
On this Thesis are simulated several scenarios with handovers of intra-technology and inter-technology in order to obtain performance parameters.
The obtained results with the changes produced in the simulator show that this
new standard and the purposed mechanism of integration with the technologies
802.11 and 802.16, bring significant improvements on the time of handovers as
well as on the support of QoS.
commitments for investment and operations are minimised, and costs are in direct relation to
usage and demand. However, when networking aspects for distributed clouds are considered,
there is little support and the effort is often underestimated. The project SAIL is addressing cloud
networking as the combination of management for cloud computing and vital networking
capabilities between distributed cloud resources involved to improve the management of both.
This position paper presents new security challenges as considered in SAIL for ensuring
legitimate usage of cloud networking resources and for preventing misuse.
always on (line) and anywhere culminate with the development of a new
standard the IEEE802.21, bythe IEEE group. This standard is designed to
streamline the handoversbetween different technologies through normalized
mechanisms and events, with the purpose of making the different technologies
seamless to the upper-layers
This thesis presents mobility mechanisms independent of the wireless
technologies at this stage, particularly WiMAX technology with support for
mobility and the WiFi technology. It is described how are processed
heterogeneous handovers based on IEEE802.16 standard and the IEEE802.21
and are purposed some changes on it.
It is then analyzed the network simulator, which was used to assess the
performance of the handovers in heterogeneous networks through the new
mechanisms established and purposed, and changes are made to support the
signalling and features specified.
On this Thesis are simulated several scenarios with handovers of intra-technology and inter-technology in order to obtain performance parameters.
The obtained results with the changes produced in the simulator show that this
new standard and the purposed mechanism of integration with the technologies
802.11 and 802.16, bring significant improvements on the time of handovers as
well as on the support of QoS.