Adaptive multicast streaming for videoconferences on software-defined networks

Abstract

Real-time applications, such as video conferences, have strong Quality of Service requirements for ensuring a decent Quality of Experience. Nowadays, most of these conferences are performed over wireless devices. Thus, an appropriate management of both heterogeneous mobile devices and network dynamics is necessary. Software Defined Networking enables the use of multicasting and stream layering inside the network nodes, two techniques able to enhance the quality of live video streams. In this paper, we propose two algorithms for building and maintaining multicast sessions in a software-defined network. The first algorithm sets up the initial multicast trees for a given call. It optimally places the stream layer adaptation function inside the core network in order to minimize the bandwidth consumption. This algorithm has two versions: the first one, based on shortest path trees is minimizing the latency, while the second one, based on spanning trees is minimizing the bandwidth consumption. The second algorithm adapts the multicast trees according to the network changes occurring during a call. It does not recompute the trees, but only relocates the stream layer adaptation functions. It requires very low computation at the controller, thus making our proposal fast and highly reactive. Extensive simulation results confirm the efficiency of our solution in terms of processing time and bandwidth savings compared to existing solutions such as multiple unicast connections, Multipoint Control Unit solutions and application layer multicast. Recompute all the bitrates 5 foreach Multicast tree T i do 6 RelocateUp(T i , r) 7 if Uplink Bandwidth of a sender decreases (B(s i ) ↓) then 8 Recompute the uplink bitrate of s i 9 RelocateDown(c) where {c} = C(s i ) 10 if Uplink Bandwidth of a sender increases (B(s i ) ↑) then 11 Recompute the uplink bitrate of s i 12 Recompute the downlink bitrates of each r i,j 13 foreach receiver r i,j of T i do 14 if the bitrate of r i,j increased after recomputation then 15 RelocateUP(T i , r i,j ) 16 if Downlink bandwidth of a receiver r increases (B(r) ↑) then 17 Recompute all the bitrates 18 foreach Tree T i do 19 if the bitrate of s i increases after recomputation then 20 foreach receiver r i,j of T i do 21 if the bitrate of r i,j increased after recomputation then 22 RelocateUp(T i , r i,j ) 23 else 24 RelocateUp(T i , r)

QoS Aware Multicast Routing Protocol for Video Transmission in Smart Cities

“…Thus, during a video call, all the participants send the highest bitrate streams allowed by other receivers. Then, this stream gets degraded (viz., highest layer is dropped) to adapt according to the participant with least downlink bandwidth capability [18]. After determining the channel condition and network topology with SDN global view, it becomes easy to find the location of switches, where there is a need for degrading the SVC stream.…”

“…The Closest Fixed Node F t (i) : This is a fixed node with minimal delay using i th vehicle at time t and is represented as F t (i) . As per (18), the nearby fixed node transmitted from j to vehicle i at time t is defined by regular transmission of beacon packet. The fixed nodes that respond to this packet with minimal delay is considered as a nearer one.…”

Modeling the Level of User Frustration for the Impaired Telemeeting Service Using User Frustration Susceptibility Index (UFSI)

“…The network heterogeneity problem was also analyzed in [8] by Al Hasrouty et al, who propose two algorithms for establishing and maintaining multicast sessions in a software-defined network. Li et al in [9] developed a scheme to maximize the overall video reception quality among all destinations during the multicast period. The scheme significantly improved the network multicast throughput and showed the flexibility to dynamic network changes.…”

“…In the work reviewed thus far [6][7][8][9], researchers focused on the network side of a telemeeting quality, i.e., they invested efforts in optimizing video transmission in different network ecosystems. However, as mentioned in the introduction, this is only one part of the QoE evaluation.…”