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As customers demand more high-bandwidth, real-time Internet services with no degradation in network performance, service providers must turn to solutions that provide their clients superior online experiences. The singular needs of specific clients may also require a contractual Service Level Agreement (SLA) that specifies assurances for a network or protocol to provide a guaranteed level of performance based on mutually agreed measures, usually by prioritizing traffic.
IP Infusion’s ZebOS® Network Platform Quality of Service (QoS) module supports the control mechanisms that assign priority handling to different classes of users or types of service, for example, streaming multimedia, Voice over IP (VoIP), Video Teleconferencing (VTC), alarm signaling, online gaming, and IP-TV. By taking advantage of QoS features, network managers can avoid problems such as dropped packets, out-of-order delivery or delivery delays, and errors in data flows.
IP Infusion’s ZebOS Network Platform QoS module is based on the Differentiated Services (DiffServ) architecture, which stipulates that individual packets are classified upon entry into a network. In this model, packets are marked according to the type of service they need. Classification information is carried in a Layer 3 packet header or a Layer 2 frame. All switches and routers in the Internet depend on class information to give the same forwarding treatment to packets with the same classification. Packets are assigned QoS classifications as follows
- At end hosts or switches along a path, based on a configuration policy
- At or near the network edge by detailed examination of the packet; this method prevents overload of core routers and switches
- A combination of these two techniques
Class information can be used by routers or switches along specified paths to limit the allotted resources based on traffic class. IP standard or IP extended Access Control Lists (ACL) are used to classify traffic with the same characteristics. QoS classifies packets or frames by assigning priority-indexed Class of Service (CoS) values – 0 through 7, with 7 designating the highest priority – and gives preference to higher-priority traffic.
The ZebOS Network Platform QoS module maps packets or frames to a CoS queue. Egress ports can accommodate up to 8 queues, prioritized as 0 (lowest) through 7 (highest). Once packets are queued, they are scheduled. Scheduling forwards or conditions packets using one of the following methods
- Strict Priority-Based (SP), in which packets with the highest priority are transmitted first
- Weighted Round Robin (WRR), in which each queue us assigned a weight to control the number of packets relatively sent from each queue
- Combination of SP and WRR, in which both methods are used
The ZebOS Network Platform QoS module is managed using IP Infusion’s Network Services Manager (NSM).
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