New Journal Publication

The paper entitled as SDN/NFV-enabled satellite communications networks: Opportunities, scenarios and challenges published online at Elsevier Phycom Journal with DOI doi:10.1016/j.phycom.2015.10.007.

The paper focuses in the context of next generation 5G networks, where the satellite industry is clearly committed to revisit and revamp the role of satellite communications. As major drivers in the evolution of (terrestrial) fixed and mobile networks, Software Defined Networking (SDN) and Network Function Virtualisation (NFV) technologies are also being positioned as central technology enablers towards improved and more flexible integration of satellite and terrestrial segments, providing satellite network further service innovation and business agility by advanced network resources management techniques.

Through the analysis of scenarios and use cases, in this paper a description of the benefits that SDN/NFV technologies can bring into satellite communications towards 5G is provided. Three scenarios are presented and analysed to delineate different potential improvement areas pursued through the introduction of SDN/NFV technologies in the satellite ground segment domain. Within each scenario, a number of use cases are developed to gain further insight into specific capabilities and to identify the technical challenges stemming from them.

The accepted version of the paper can be downloaded here.

Cisco Thor: a Royalty Free Video Codec

Jonathan Rosenberg recently posted on Cisco Blog for the release of the project Thor codec to the community some weeks ago (link to Thor project). The effort is being staffed by some of the world’s most foremost codec experts, including the legendary Gisle Bjøntegaard and Arild Fuldseth, both of whom have been heavy contributors to prior video codecs. Cisco decided to open source the code, which is available on Moreover, Thor was contributed as an input to the Internet Engineering Task Force (IETF) (contribution available here, Presentation slides available here), which has begun a standards activity to develop a next-gen royalty free video codec in its NetVC workgroup.

More documents on IETF NetVC are available also here.

As Jonathan describes, the patent licensing situation for H.265 is dependent on two distinct patent licensing pools that have formed so far, and unfortunately many license holders are not represented in either. On the contrary, for the case of H.264 there is only one license pool, which make H.264 much cheaper than H.265, where the total costs to license H.265 from these two pools is up to sixteen times more expensive than H.264, per unit. Moreover, H.264 had an upper bound on yearly licensing costs, whereas H.265 has no such upper limit, while at the same time the licensing terms preclude usage of H.265 in any kind of open source or freely distributed software application, such as web browsers.

Jonathan invites others to work on Thor by contributing to the codec development or contributing their own Intellectual Property Rights on a royalty free basis (you may contact

Although activity graphs from github are not really encouraging for the community involvement (see figure below) and that there are many basic features that are not implemented yet, the project progress may be ambitious within 2015, however the project is still promising.


The main Thor-exclusive feature is the 64×64 super block, which provide significant better performance for specific video content types according to the provided performance comparison data (available here).

Summarizing, we may say that currently Thor is a parallel draft to Daala. Daala is the code-name for a new video compression technology promoted by a collaboration between Mozilla Foundation, Xiph.Org Foundation and other contributors. The goal of Daala is to provide a free to implement, use and distribute digital media format and reference implementation with technical performance superior to H.265. IETF may standarddize only one codec within the NetVC activity, therefore the competition for the one codec to prevail will be very tough. Initial comparison to Daala is available (here) but it will be interesting to close monitor the performance competition between the two codecs in the next months.

Guest Editor at IEEE COMSOC MMTC E-Letter (July Issue) on SDN/NFV

The July Issue of IEEE COMSOC MMTC E-Letter has just been published on-line and is for downloading here. The issue has been guest editored by Xiaoqing Zhu (Cisco Systems) and Harilaos Koumaras and provides the latest advances on SDN/NFV. More specifically, the special issue brings to our readers a collection of invited articles that address various aspects of SDN/NFV-enabled architectures for media content delivery. Authors from academia and industry share their individual perspectives regarding the opportunities and challenges brought forth by the rapid spread of SDN/NFV technologies, outlooks for the future of media content delivery in an increasingly mobile and heterogeneous environment, as well as ongoing research efforts in leveraging SDN/NFV for enhanced media content delivery.

It was really a pleasure collaborating with Xiaoqing and I believe that the outcome of our collaboration on this special issue is very good. Happy reading!!