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- Causevic, Aida, 1983-, et al.
(författare)
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On incorporating security parameters in service level agreements
- 2019
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Ingår i: CLOSER 2019 - Proceedings of the 9th International Conference on Cloud Computing and Services Science. - : SciTePress. - 9789897583650 ; , s. 48-57
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Konferensbidrag (refereegranskat)abstract
- With development of cloud computing new ways for easy, on-demand, Internet-based access to computing resources have emerged. In such context a Service Level Agreement (SLA) enables contractual agreements between service providers and users. Given an SLA, service users are able to establish trust in that the service outcome corresponds to what they have demanded during the service negotiation process. However, an SLA provides a limited support outside of basic Quality of Service (QoS) parameters, especially when it comes to security. We find security as an important factor to be included in adjusting an SLA according to user defined objectives. Incorporating it in an SLA is challenging due to difficulty to provide complete and quantifiable metrics, thus we propose to focus on a systematic way of addressing security using the security process. In this paper we investigate ways in which security might be incorporated already in the service negotiation process and captured in an SLA. We propose a corresponding process to develop and maintain an SLA that considers both design-, and run-time. To demonstrate the approach we built upon the existing SLAC language and extend its syntax to support security. An example of a service being provided with security guarantees illustrates the concept.
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| 2. |
- Yedugundla, Kiran, 1982-, et al.
(författare)
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Handling Packet Losses in Cloud-Based Application Traffic
- 2019
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Ingår i: Proceedings of the 9th International Conference on Cloud Computing and Services Science - Volume 1: CLOSER. - : SciTePress. - 9789897583650 ; , s. 111-119
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Konferensbidrag (refereegranskat)abstract
- Internet traffic is comprised of data flows from various applications with unique traffic characteristics. For many cloud applications, end-to-end latency is a primary factor affecting the perceived user experience. As packet losses cause delays in the communication they impact user experience, making efficient handling of packet losses an important function of transport layer protocols. Multipath TCP (MPTCP) is a modification to TCP that enables simultaneous use of several paths for a TCP flow. MPTCP is known to improve throughput. However, the performance of MPTCP is not optimal when handling certain loss scenarios. Efficient packet loss recovery is thus important to achieve desirable flow completion times for interactive cloud-based applications. In this paper we evaluate the performance of MPTCP in handling tail losses using traffic traces from various cloud-based applications. Tail losses, losses that occur at the end of a flow or traffic burst, are particularly challenging from a latency perspective as they are difficult to detect and recover in a timely manner. Tail losses in TCP are handled by using a tail loss probe (TLP) mechanism which was adapted to MPTCP from TCP. We investigate the performance of TLP in MPTCP, comparing the standard implementation to a recently proposed, less conservative approach. Our experimental results show that a less conservative implementation of TLP performs significantly better than the standard implementation in handling tail losses, reducing the average burst completion time of cloud based applications when tail loss occurs by up to 50% in certain cases.
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