How long does priority marking take

The traffic policy containing if-match flow-id can be only applied to an interface, a VLAN, a card, or the system in the inbound direction. SA cards of the S series do not support the action of inheriting the A traffic policy is created and the traffic policy view is displayed, or the view of an existing traffic policy is displayed. If no matching order is specified when you create a traffic policy, the default matching order is config.

After a traffic policy is applied, you cannot use the traffic policy command to modify the matching order of traffic classifiers in the traffic policy. To modify the matching order, delete the traffic policy, and re-create a traffic policy and specify the matching order.

For details about the cards, see Cards in the Hardware Description. After you run the undo portswitch command to switch Layer 2 interfaces on the preceding series of cards into Layer 3 interfaces, you can configure Layer 3 sub-interfaces on the interfaces.

The SA series cards do not support sub-interface configuration and cannot forward IP traffic to sub-interfaces on other cards. You are advised to add a member interface to an Eth-Trunk and then configure an Eth-Trunk sub-interface. The Eth-Trunk sub-interface can be successfully configured only when the card on which the member interface locates supports sub-interface configuration.

Each direction on an interface can be configured with only one traffic policy. A single traffic policy can be applied to both directions on one or more interfaces. After a traffic policy is applied to an interface, the system performs traffic policing for all the incoming or outgoing packets that match traffic classification rules on the interface. You are advised not to use a traffic policy containing remark p , remark cvlan-id , or remark vlan-id in the outbound direction of an untagged interface.

This is because the configuration may cause packet errors. Applying traffic policies consumes ACL resources. If ACL resources are insufficient, some traffic policies will fail to be applied.

For example, an if-match rule in a traffic policy occupies an ACL. One ACL is occupied for each interface the traffic policy is applied to. The system applies traffic policing to the packets that belong to the VLAN and match traffic classification rules in the inbound or outbound direction.

However, the traffic policy does not take effect for packets in VLAN 0. Each direction can be configured with only one traffic policy globally or on an LPU. A traffic policy cannot be applied to the same direction in both the system and LPU. For example, if a traffic policy is applied to the inbound direction globally, it cannot be applied to the inbound direction on an LPU.

A good example of such behaviour is the adaptation mechanism defined in the DASH standard [ 7 ]. It can be described as a process of elimination of certain enhancement layers or as a change of Operation Point OP of a given SVC stream.

Removal of the individual enhancement layers leads to define the next OPs. Of course, the process of removal of certain layers must take into account the existing dependencies between them. For example, one cannot remove the layers which are used as references for any others. Switching between the OPs allows to adjust the the bit rate of SVC video stream to conditions on the transmission link.

In the case illustrated in Fig. The number 0 indicates the base layer. The Fig. This choice should not be changed by the adaptation process. According to the information mentioned above and our own research results, temporal layers should also be protected.

This leads to the solution in which the decoder should have, for each of temporary layer, at least a minimum set of video data base layer SNR0. Because each temporal layer is associated with a double number of frames per second, this assumption maintains a high level of video smoothness. This scheme to define the structure of the SVC stream allows to provide the best quality of received video content [ 40 , 41 ]. As was stated at the beginning, the illustration presented applies if the spatial and temporal layers are to be protected.

Of course, in the same way different sets of OPs can be created, preferring other layers of the SVC stream. Detailed analysis of quality gradation by OP section can be found in [ 41 ]. The illustrated exemplary structure of the video stream is analogous to the previous example includes three temporary layers and four SNR layers for each of them.

The combination of the need to determine the priority of the single NALU to protect the selected layers and the possibilities for creating OPs leads to defining a set of scalable SVC video streams which can potentially be transmitted over an IP network using DiffServ rules.

The video packets need to be classified into different priorities according to their relative importance before any pre-marking algorithm can be applied. We assign the weights to the individual layers by giving values 1, 2 and 3 to the most important scalability layer, less important scalability layer and the least important scalability layer, respectively.

Assigning weight values for each type of scalability layers of the video stream depends on the particular provider of video streaming service. This choice is important because it affects the priority of the subsequent extended layers. The higher the weight value, the quicker decreases the priority assigned to successive, extended layers, which represent a particular scalability.

In other words, this choice has a direct influence on the quality of the video. Therefore, Sect. Constructing the principle of such mapping, we took into account two main reasons:. A number of protected layers that are most important to preserve the best possible perceived quality of the received video, should grow with the increasing number of OPs,.

The even distribution of the packets between different groups colors should be a neutral solution from the point of view of the potential competition for the available bandwidth between the multiple data and video streams. Taking into account the above issues, we proposed the following solution. Let H be the highest value of priority calculated according to Formula 1 for a given structure of the OP. The priority after mapping can be obtained using the formula as follows.

The provider of the DASH streaming service must determine the structure of the SVC stream OP1 and the priorities attached to particular types of scalability weight values. Based on these assumptions, the highest value of priority is calculated value of H. Weight values and the parameter H are necessary for operation of the WPP algorithm. Each request generated by a client of the DASH streaming service leads to the necessity of sending the video fragment with specific parameters.

According to the principles of adaptation DASH these parameters can vary between successive requests. At this stage, the final structure of the video stream is known. The system is ready for the process of packet pre-marking according to the algorithm WPP. The main aim of the tests is to determine the properties of the proposed WPP algorithm in combination with different methods of packet pre-marking.

The packets belonging to these streams were then pre-marked colored. Finally, they were sent through the DiffServ domain, which uses the trTCM marker in colour-aware mode. Therefore, the video quality was analysed for following schemas:. The conclusion of these tests we used as a starting point for the comparative analysis of the proposed WPP algorithm. The best WPP configuration is compared with two other scenarios of the video transmission in the DiffServ domain.

The first one is the transmission of the pre-marked stream of single layer H. All the compared solutions were tested at the comparable network configuration and used the same video source. The coding part of the testbed system is built up on the basis of the JSVM [ 38 , 42 ]. This packet has also been used to estimate the quality of the transmitted video. The trTCM marker in color-aware mode was configured on the ingress router. The structure of the developed testbed is presented in Fig.

The test video was a Foreman sequence, which has frames with a GoP size of 8. The structure of the stream consists of the following layers:. The above video bit stream has competed with one ON-OFF background traffic flow, which had an exponential distribution with the mean packet size of bytes, burst time ms, idle time of 50 ms, and the rate of kbps.

The test network also transmitted one FTP traffic flow of kbps. The WRED parameters include a minimum threshold, a maximum threshold, and a maximum drop probability. In our simulations, these parameters were specified respectively as 2, 4, 0.

The final assessment of video quality was based on PSNR metrics. The selection of WPP configuration. At this phase, all three selected pre-marking strategies have been simulated for the AF PHB overload ranging from 1.

Analysing the results shown in the Fig. From the perspective of the typical IP network behaviour, it seems to be reasonable to concentrate on the area of small and medium-size congestions. With respect to the simulation performed, it is the range of congestion from 1. In this area the best quality guarantee methods of protecting data are associated mainly with the SNR and the spatial layers.

This is also true for OPs. The protection of SNR layers allows for maintaining a relatively small decline in the video quality for a few first OPs. Similarly, in the case of small and medium-sized congestion, adaptation mechanisms that operate on the OPs should mostly use the first few of them. That was confirmed by our separate research [ 41 ], when the standard DASH adaptation mechanism was configured for the same video configurations and network conditions, operating on the first three OPs.

Comparative analysis of proposed WPP algorithm. Based on results from previous tests, the weights in Eq. The last step was to apply the rules of marking presented in Sect. To justify our algorithm, the simulation results for the video transmission of the SVC stream with the WPP pre-marking have been compared to the transmission of the SVC sequence without pre-marking trTCM was configured in blind mode and the video coded by the H. In all the cases the Foreman video sequence was used.

The simulation results are shown in Table 1. In the case of using WPP pre-marking, the video quality improvement is observed for relatively small values of congestion especially in the range from 1. This is due to better protection of spatial and SNR layers. Without pre-marking, the mechanism inside the transmission system cannot protect the low and the lowest layers very well and at the same time losses of higher spatial and SNR layers are relatively high so end-user has little or no benefit from the SVC coding.

The transmission of the H. These phenomena very quickly for relatively small values of overload manifest themselves as important video quality degradation. The same can be said about the relationship between transmission with and without pre-marking. Even the WPP algorithm cannot prevent loss of a substantial part of video data. Practical aspects of the implementation of the algorithm WPP During all of the tests, the elements of a typical video streaming system were used.

This applies to both components responsible for the distribution of video and data transmission. The DiffServ domain was based on the operating system fully compatible with commercial systems used by the routers Cisco series. The algorithms of the packet marking, queuing and the rules of the dynamic routing are configured as recommended for typical network operators. Also, the video distribution system was based on the reference software JSVM [ 42 ]. For this reason, focusing on practical aspects of the implementation of the algorithm WPP, we can conclude that:.

WPP algorithm works fine with a typical network infrastructure that supports DiffServ mechanisms and the packet marking in accordance with the algorithm trTCM color-aware mode. In this paper the relationship between the relative importance of NALUs and the packet pre-marking for the H. This algorithm has been tested for different bit stream ordering and operation point scenarios. In contrast to other proposed solutions, our approach is consistent with the DiffServ model and does not require changing the marking schema at the edge of the DiffServ domain.

Thus, the proposed algorithm can be applied to any IP network using the principles of the service differentiation. By comparing the simulation results with the standard streaming solution based on single layer H. Blake, S. Zhang, F. Efficient streaming packet video over differentiated services networks. Article Google Scholar. Wu, D. Transporting real-time video over the Internet: Challenges and approaches. Proceedings of the IEEE , 88 2 , Google Scholar. Fan Zhai, Luna, C. A novel cost-distortion optimization framework for video streaming over dierentiated services networks.

Ziviani, A. Improving the delivery quality of MPEG video streams by using differentiated services. Schwarz, H. Overview of the scalable video coding extension of the H. This website works best with JavaScript switched on. Please enable JavaScript. Your grade can go down as well as up. A review is the standard speed service for any student.

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