3.5 Proof-of-concept prototype results
3.6.2 Reality check: Practical issues
During the implementation, deployment and evaluation a set of practical issues arose that hindered the operation of the presented framework as it was initially designed. These aspects are presented in this section.
3.6. Discussion 91 with the foreign network architectures.
What type of resources are convertible: Studying the cases where content conversion is suitable and how such conversion impacts the actual content is a key aspect for future research. Deciding whether or not to convert resource identifiers inside content can be divided into:
❼ Security issues: For example, converting identifiers inside content invalidates integrity checking mechanisms enforced by the resource provider (e.g., content hash and signatures). To mitigate this issue, the FIXP may act as a trusted entity enforcing its own integrity check mechanisms.
❼ Technical issues: For example, due to the fact that the FIXP may not recognize the content type or its semantics, thus being unable to change the identifiers within the content.
❼ Management issues: For example, consumer and providers of resources may want to retain the original content.
Lack/maturity of real applications: The years of evolution and maturity of the current IP architecture allowed the definition of a multitude of well-defined protocols for different use cases. In the case of new network architectures, specific and/or mature higher-layer protocols targeting different use cases was still lacking. Thus, in this work the protocols in the IP architectures were mapped with the generic operation of the studied ICN architectures. The existence of consolidated mechanisms/protocols for the different use cases for each network architecture may enable an easier and more efficient mapping and retrieval of resources across different architectures.
❼ Video parameters in live video streaming: During the implementation of the live video streaming use case, the question arose on which parameters should be used for providing the video via the RTP stream on the IP network architecture. If, in an interaction between PURSUIT and NDN, each PURSUIT Publish Data message was mapped into a new NDN chunk, the lack of a well- defined and mature higher-level protocol (e.g., a protocol to establish or control media sessions) hindered the session setup of the RTSP session, since the video parameters were unknown during this setup process. As such, the FIXP freely defined the parameters to be used (independently of the real parameters of the received video stream) and re-encoded it to match the parameters defined during the RTSP session establishment. However, by doing this, the original video stream is being modified, which is not desirable in a general solution.
❼ User-specific content retrieval: The same resource may vary depending on the user requesting it (e.g., premium access to contents), information that usually goes along with the request as metadata (e.g., cookies in HTTP protocol). The lack/maturity of higher-level protocols in the new network architectures that support this information to go along with the request also imposes a new problem while using the presented framework. The presented framework needs to handle the resources for each user as being different resources, which not only impacts the scalability of the solution, but also affects the control of which users have access to each resource when accessed by a foreign network architecture.
Note that these practical issues can in some way be expected to be solvable in production-level code and more mature Future Internet architectures.
In this chapter, a way on how to enable the interoperation between different network architectures was presented. Specifically, a novel interoperability framework for the Future Internet, named FIFu (Future Internet Fusion), was presented. FIFu allows the current Internet and new (clean-slate) network architectures to share resources between one another, in a transparent way to end-user, network devices and applications. In doing so, each network architecture can be developed and evolved independently of the others. Such framework leverages the coexistence of different network architectures, which can be seen as an evolution strategy that will further facilitate the initial roll out of new network architectures by promoting its incremental deployment over time. This framework was implemented and evaluated through simulation, in a web browsing use case, and through a proof-of-concept prototype, in a web browsing, live video streaming and video on-demand scenarios. These scenarios allowed to demonstrate the feasibility of the proposed framework in enabling resource sharing among different network architectures, as well as the impact that the inherent conversion procedures have in the overall communication when accessing resources deployed in a different network architecture. Results showed that it was able to achieve a similar performance when compared with native approaches in the evaluated scenarios. Moreover, the provision of a given resource on the foreign network architectures allowed the capabilities of each architecture (e.g., caching and request aggregation) to be applied to the resource, as if it is originally deployed on each network architecture. However, a set of issues arose during the implementation and evaluation of the proposed framework, such as the anchoring-related issues, sub-optimal mapping of features among different architectures and concerns about content compatibility
3.7. Concluding Remarks 93 across different network architectures. Nevertheless, some of the encountered issues are expected to be mitigated as each network architecture evolves and matures with new protocols and mechanisms targeting specific use case scenarios.
Supporting Mobility in Future
In the previous chapter a framework that enables entities to access resources deployed in different architectures was proposed, which may leverage the incremental deployment of new network architectures. Nevertheless, mobility in these architectures is still a key requirement that needs to be addressed on each individual architecture for its adoption being considered as a potential Future Internet architecture. Thus, this chapter addresses this subject and contributes to the development of mobility management mechanisms in both evolutionary SDN-based and clean-slate ICN network architectures, as well as in scenarios where mobility crosses different network architectures.
The increasing proliferation of mobile devices equipped with multiple wireless interfaces (such as, smartphones) created heterogeneous scenarios where network operators need to provide connectivity for different kinds of access networks. At the same time, it opens space for a new set of opportunities taking advantage of the different technologies to provide an always best connected experience to the user. In this way, the capability of handling mobility efficiently in Future Internet network architectures is a key requirement that needs to be addressed by those architectures.
Furthermore, the traffic generated by mobile devices is continuously increasing and, by 2021, traffic from wireless and mobile devices will account for more than 63% of the total IP traffic . The dynamics of the wireless environments, and the associated heterogeneity, pose a complex challenge for assuring that the content reaches the user in an optimized way.
As such, supportive mechanisms to ensure that the content is sent to the requester
in the most optimal way (i.e., best available point of attachment or best suitable wired/wireless technology) are required. Aspects related to the conditions of the wireless networks, both the currently connected or neighboring networks, are factors that can help to decide how to best deliver the content to the user. Considering this scenario, IEEE developed the IEEE 802.21 standard for Media Independent Handover . Its main purpose is to facilitate and optimize inter-technology handover processes by providing a set of media-independent primitives, thus creating an abstraction regarding the link layer, not only for obtaining link information and controlling link behavior, but also for assisting the different steps of the handover procedure.
In this chapter, the mechanisms defined in IEEE 802.21 are integrated into two different frameworks, one focusing on SDN-based and the other on ICN architectures. By being aware of the link conditions at each moment and by having control over the different phases of the handover procedure, the proposed frameworks optimize the handover procedures in both Future Internet architectures, decreasing handover delay and packet loss. Additionally, with the edge of the network being a potential location for the initial deployment of new network architectures, an heterogeneous environment where access networks support either IP and/or ICN architectures can be expected. In doing so, a novel mobility framework that tackles the mobility of MN across different network architectures is proposed, allowing resources to continue being reached even if deployed in a different network architectures after the handover of MNs.