traffic engineering methods

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traffic engineering methods

There are a variety of traffic engineering methods that are used to regulate network traffic. Mostly dealing with queuing, they ensure that transmitted data are received in a timely manner. Following are the common methods. See traffic engineering, traffic shaping and traffic policing.

First-In, First-Out (FIFO) Queuing
First-Come, First-Served (FCFS) Queuing
The simplest queuing method. Packets are placed into a single queue and serviced in the order they were received.

Priority Queuing (PQ)
Each packet is assigned a priority and placed into a hierarchy of queues based on priority. When there are no more packets in the highest queue, the next-lower queue is serviced. The problem with this method is that lower-priority packets may get little attention.

Fair Queuing (FQ)
Each packet is assigned a type (flow) and placed into the queue for that type. All queues are serviced round-robin: a packet from one queue, a packet from the next and so on. FQ provides a more uniform service to all packet types than priority queuing (PQ).

Weighted Fair Queuing (WFQ)
Similar to fair queuing (FQ), except that queues are given priorities and can support variable-length packets.

Hierarchical Weighted Fair Queuing (HWFQ)
Similar to WFQ, but monitors traffic and evaluates current conditions to adjust queues. Uses worst-case packet delay as its evaluation metric.

Weighted Round Robin (WRR)
Class-Based Queuing (CBQ)
Custom Queuing (CQ)
Similar to fair queuing, packets are assigned a class (real time, file transfer, etc.) and placed into the queue for that class of service. Packets are accessed round-robin style, but classes can be given priorities. For example, four packets from a high-priority class might be serviced, followed by two from a middle-priority class and then one from a low-priority class.

Deficit Weighted Round Robin (DWRR)
A weighted round-robin (WRR) method that uses a deficit counter. A maximum packet size number is subtracted from the packet length, and packets that exceed that number are held back until the next visit of the scheduler.

TCP Rate Shaping (TRS)
This non-queuing method dynamically adjusts the TCP window size based on real-time evaluation of the traffic flows.
References in periodicals archive ?
To overcome the above limitations and to provide fair sharing of resources, many other types of scheduling methods, such as Priority Queuing (PQ), Weighted Round Robin (WRR), Weighted Fair Queuing (WFQ), Custom Queuing (CQ) and Class-Based Weighted Fair Queuing (CB-WFQ) have been proposed [6].
It uses the scheduling techniques of weighted fair queuing (WFQ), for assigning weight to different class of service.
Budnikas Analysis of QoS assurance using weighted fair queuing (WFQ) scheduling discipline with low latency queue (LLQ)"
We evaluated VPQ with Contention-Aware Temporally fair Scheduling (CAT) Decentralized-CATS, Decentralized-CATS+ and controlled access phase scheduling (CAPS), and Temporally Weighted Fair Queuing (T-WFQ).
In Weighted Fair Queuing, packets from different connections are stored in a FIFO queue.
In general, to implement weighted fair queuing, we can choose Queue i with a probability of occurrence that is proportional to the weight associated with that of Queue i.
The router vendors are adding some QoS capabilities to their backbone equipment in the form of weighted fair queuing (WFQ), priority queuing or custom queuing.
The Cisco 2600 series' new data compression Advanced Integration Module (AIM) allows customers to deploy new network services such as voice without increasing WAN bandwidth and maximizes the benefit of advanced Cisco IOS software bandwidth management features such as the Resource Reservation Protocol (RSVP), Weighted Fair Queuing (WFQ) and IP Precedence.
6Gbps with a non-blocking single chip switching architecture, the SMC6128PL2 and SMC6152L2 provide cost-effective, Ethernet switching for demanding networks that advanced switching features, including Quality of Service (QoS) with four levels of priority, weighted fair queuing and L2/3/4 IP capabilities.
In this section, some well-known scheduling algorithms in WiMAX wireless network are investigated including Round-Robin (RR), Self-Clocked-Fair (SCF), Strict-Priority (SP), Weighted Fair Queuing (WFQ) and Weighted Round Robin (WRR).
The DSLAS supports QoS and a common bandwidth allocation scheme called weighted fair queuing (WFQ), both of which are necessary to provision voice over the DSL local loop.
1x, IP filtering, Quality of Service (QoS) with four levels of priority and weighted fair queuing to ensure smooth transmission of mission critical data and VLANs based on frame tags or ports and spanning tree for loop detection and prevention.

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