Aiming at the limitations of existing solutions for network bottleneck caused by the gap between the network transmission capacity and the processing capability of the current Internet architecture, this paper presents a novel cloud routing protocol named LD-CR based on limited deflection mechanism. A router running this protocol logically separates data forwarding and processing, which could share cloud processing resources with other nodes by using extra bandwidth. This method could effectively alleviate single-node congestion by leverage of the capability of electronic processing and optical transmission capacity at the same node. Analysis and simulation results show the simple LD-CR protocol could improve network performance in packet loss rate and network throughput obviously compared with OSPF protocol. Meanwhile, this method could also avoid performance rapid deterioration under the condition of heavy traffic load by using traditional deflection routing technology.
The rapid rise of cloud computing and mobile Internet has led to explosive growth in network traffic recently [
Trying to solve the limitations of existing technologies for network processing bottleneck, this paper proposes a novel cloud routing protocol based on the limited deflection mechanism (LD-CR). This method partitions data forwarding and processing logically, and, by utilizing deflection routing technology, it could forward those data beyond the single node processing capability transparently by extra transmission channel to more powerful or temporary free routing nodes. Compared with traditional deflection routing technology applied in OBS [
As a starting point, in Section
Typically, there is no partition between data processing and forwarding in traditional network routing or switching technologies. Data processing and forwarding usually overlap in the port physically and logically. In another word, one node would do the processing for all the traffic flow from a certain physical ingress belong to itself and then forward it to the relevant egress according to the carried address, like the OSPF routing protocol popularized in IP network [
Therefore, due to the overlap of the processing and forwarding port, the network throughput is limited by the maximum processing capability of any intermediate node. Hence, the basic principle of the cloud routing protocol is to enhance the network capacity by partitioning the overlap port. It could adopt dual-port access according to time-division or space-division for the partition mechanism, which divides the data into forwarding flow or processing flow. For forwarding flow, there is no need for any routing processing, just transmitting it from the corresponding forwarding port according to the given port-mapping method. Like the implementation in photo-electronic hybrid network, an extra wavelength channel could be added for the data beyond the capability of electronic processing, while, in the optical cross matrix (OXC) of the core node network, it could be implemented by assigning some certain wavelength channels for the data transparent forwarding, which reduces the complexity for electronic processing.
In Figure
The optical switching structure of cloud routing node.
Deflection routing technology is one of the common resolution policies for network congestion in optical network which is lack of buffering technology like OBS network [
A typical network domain supporting LD-CR consists of front-end nodes and tail-end nodes along the cloud path, as Figure
Example of cloud routing network.
Thus, for each node, the quantity of cloud paths needed to maintain equals the ingress port number of this node, and the forwarding egress port for the traffic flow from certain forwarding ingress port is determined by looking up the local cloud path set
The cloud path set could be configured statically or updated periodically according to the statistics information, which is flexible and also low processing overhead for the forwarding traffic. Furthermore, if we generate or change the cloud path according to the traffic long period statistic information, the forwarding accuracy could be enhanced; that is, the network performance would be improved. Limited by this paper’s length, the dynamic generation, maintenance, and update of the cloud path are not discussed here. Assuming for each routing node in Figure
input: output:
return return
return return
Given
The research has shown that it is quite complicated for the mathematical expression of the packet loss rate or average end-to-end delay, even if for the single node in the real network traffic. Therefore, the expressions based on these parameters are more complex or even hardly explicitly described for the whole network with complex topologies. Thus, we only present the simplified theoretical analysis here. In Figures
Network traffic model.
Given
In this paper, the random topology structure as shown in Figure
Network diagram in simulation.
In Figure
The results have shown the packet loss rate, delay, and network throughput comparison of the 3 kinds protocols, respectively, in Figure
Results for network performance with different protocol: (a) packet loss rate with different processing power configuration; (b) end-to-end delay with different processing power configuration; (c) average throughput with different processing power configuration.
In Figures
In addition, it is quite effective on solving the bottleneck of single node when using LD-CR protocol under normal traffic load. When traffic load is within
In Figure
Results for network performance under low traffic load: (a) packet loss rate with different protocol; (b) end-to-end delay with different protocol.
The internet data dramatic increase has exceeded the development speed of network data processing. Aiming to the gap between network transmission capacity and processing capability, a novel cloud routing protocol based on limited deflection mechanism is proposed in this paper, and the node architecture and algorithm are also presented to support the protocol implementation. As expected, the implementation is simple for the LD-CR protocol. It is only needed to add a static port-mapping processing module in current routing nodes to utilize the idle transmission capacity for network processing capability improvement, which is limited by the network bottleneck caused by the processing capability insufficient in single nodes. Both theoretical analysis and simulation results show that the performance on packet loss rate, network throughput, and so forth is obviously improved when using LD-CR protocol compared with OSPF. Simultaneously, LD-CR protocol also overcomes the traditional DR protocols drawback when traffic load increases the performance rapidly worsens.
For the future work, the performance would be evaluated in bigger network for LD-CR. At the same time, the study of the cloud paths dynamic generation would be done, and its impact on network safety is also under consideration.
The authors declare that there is no conflict of interests regarding the publication of this paper.
This work was supported by the National Natural Science Funds of China (Grant no. 61174152), the Key Program of the National Natural Science Funds of China (Grant no. 61331008), and the Key Science-Technology Project of the National of China (2010ZX03004-002).