Bandwidth management is the process of measuring and controlling the communications (traffic, packets) on a network link, to avoid filling the link to capacity or overfilling the link,
[https://www.internetsociety.org/wp-content/uploads/2017/08/BWroundtable_report-1.0.pdf Internet Society on Bandwidth Management] which would result in
network congestion
Network congestion in data networking and queueing theory is the reduced quality of service that occurs when a network node or link is carrying more data than it can handle. Typical effects include queueing delay, packet loss or the blocking of ...
and poor performance of the network. Bandwidth is described by
bit rate
In telecommunications and computing, bit rate (bitrate or as a variable ''R'') is the number of bits that are conveyed or processed per unit of time.
The bit rate is expressed in the unit bit per second (symbol: bit/s), often in conjunction ...
and measured in units of bits per second (bit/s) or bytes per second (B/s).
Bandwidth management mechanisms and techniques
Bandwidth management mechanisms may be used to further engineer performance and includes:
*
Traffic shaping
Traffic shaping is a bandwidth management technique used on computer networks which delays some or all datagrams to bring them into compliance with a desired ''traffic profile''. Traffic shaping is used to optimize or guarantee performance, improv ...
(
rate limiting
In computer networks, rate limiting is used to control the rate of requests sent or received by a network interface controller. It can be used to prevent DoS attacks and limit web scraping.
Research indicates flooding rates for one zombie machin ...
):
**
Token bucket
The token bucket is an algorithm used in packet-switched and telecommunications networks. It can be used to check that data transmissions, in the form of packets, conform to defined limits on bandwidth and burstiness (a measure of the unevenne ...
**
Leaky bucket
The leaky bucket is an algorithm based on an analogy of how a bucket with a constant leak will overflow if either the average rate at which water is poured in exceeds the rate at which the bucket leaks or if more water than the capacity of th ...
** TCP rate control - artificially adjusting TCP window size as well as controlling the rate of ACKs being returned to the sender
*
Scheduling algorithms
In computing, scheduling is the action of assigning resources to perform tasks. The resources may be processors, network links or expansion cards. The tasks may be threads, processes or data flows.
The scheduling activity is carried out by ...
:
**
Weighted fair queuing
Weighted fair queueing (WFQ) is a network scheduling algorithm. WFQ is both a packet-based implementation of the generalized processor sharing (GPS) policy, and a natural extension of fair queuing (FQ). Whereas FQ shares the link's capacity i ...
(WFQ)
**
Class based weighted fair queuing
**
Weighted round robin (WRR)
**
Deficit weighted round robin (DWRR)
**
Hierarchical Fair Service Curve (HFSC)
* Congestion avoidance:
**
RED,
WRED - Lessens the possibility of
port queue buffer tail-drops and this lowers the likelihood of
TCP global synchronization
TCP global synchronization in computer networks is a pattern of each sender decreasing and increasing transmission rates at the same time as other senders. It can happen to Transmission Control Protocol (TCP) flows during periods of congestion b ...
** Policing (marking/dropping the packet in excess of the committed traffic rate and burst size)
**
Explicit congestion notification
** Buffer tuning - allows you to modify the way a router allocates buffers from its available memory, and helps prevent packet drops during a temporary burst of traffic.
* Bandwidth reservation protocols / algorithms
**
Resource reservation protocol (RSVP) - is the means by which applications communicate their requirements to the network in an efficient and robust manner.
**
Constraint-based Routing Label Distribution Protocol (CR-LDP)
**
Top-nodes algorithm
*
Traffic classification - categorising traffic according to some policy in order that the above techniques can be applied to each class of traffic differently
Link performance
Issues which may limit the performance of a given link include:
*
TCP determines the capacity of a connection by flooding it until packets start being dropped (
slow start)
* Queueing in routers results in higher
latency and
jitter
In electronics and telecommunications, jitter is the deviation from true periodicity of a presumably periodic signal, often in relation to a reference clock signal. In clock recovery applications it is called timing jitter. Jitter is a signifi ...
as the network approaches (and occasionally exceeds) capacity
*
TCP global synchronization
TCP global synchronization in computer networks is a pattern of each sender decreasing and increasing transmission rates at the same time as other senders. It can happen to Transmission Control Protocol (TCP) flows during periods of congestion b ...
when the network reaches capacity results in waste of bandwidth
*
Burstiness of web traffic requires spare bandwidth to rapidly accommodate the bursty traffic
* Lack of widespread support for
explicit congestion notification and
quality of service
Quality of service (QoS) is the description or measurement of the overall performance of a service, such as a telephony or computer network, or a cloud computing service, particularly the performance seen by the users of the network. To quantitat ...
management on the Internet
*
Internet Service Provider
An Internet service provider (ISP) is an organization that provides a myriad of services related to accessing, using, managing, or participating in the Internet. ISPs can be organized in various forms, such as commercial, community-owned, no ...
s typically retain control over queue management and quality of service at their end of the link
*
Window Shaping allows higher end products to reduce traffic flows, which reduce queue depth and allow more users to share more bandwidth fairly
Tools and techniques
*
Packet sniffer
A packet analyzer (also packet sniffer or network analyzer) is a computer program or computer hardware such as a packet capture appliance that can Traffic analysis, analyze and Logging (computing), log traffic that passes over a computer netwo ...
is a program or a device that eavesdrops on the network traffic by grabbing information traveling over a network
*
Network traffic measurement
See also
*
Bandwidth cap
A data cap, often referred to as a bandwidth cap, is a restriction imposed on data transfer over a network. In particular, it refers to policies imposed by an internet service provider to limit customers' usage of their services; typically, excee ...
* Bandwidth management is a subset of
network management
Network management is the process of administering and managing computer networks. Services provided by this discipline include fault analysis, performance management, provisioning of networks and maintaining quality of service. Network managem ...
and
performance management
Business performance management (BPM) (also known as corporate performance management (CPM) enterprise performance management (EPM),) is a management approach which encompasses a set of processes and analytical tools to ensure that a business o ...
* Bandwidth management using
NetFlow
NetFlow is a feature that was introduced on Cisco routers around 1996 that provides the ability to collect IP network traffic as it enters or exits an interface. By analyzing the data provided by NetFlow, a network administrator can determine thing ...
and IPFIX data
*
Bandwidth throttling
Bandwidth throttling consists in the limitation of the communication speed (bytes or kilobytes per second), of the ingoing (received) or outgoing (sent) data in a network node or in a network device such as computers and mobile phones.
The d ...
*
Customer service unit a device to balance the data rate on user's telecommunication equipment
*
INASP runs bandwidth management training workshops and produces reports
*
Network congestion avoidance lists some techniques for prevention and management of congestion on routers
*
Network traffic measurement is a subset of
network monitoring
Network monitoring is the use of a system that constantly monitors a computer network for slow or failing components and that notifies the network administrator (via email, SMS or other alarms) in case of outages or other trouble. Network monitor ...
*
Traffic shaping
Traffic shaping is a bandwidth management technique used on computer networks which delays some or all datagrams to bring them into compliance with a desired ''traffic profile''. Traffic shaping is used to optimize or guarantee performance, improv ...
and
rate limiting
In computer networks, rate limiting is used to control the rate of requests sent or received by a network interface controller. It can be used to prevent DoS attacks and limit web scraping.
Research indicates flooding rates for one zombie machin ...
are bandwidth management (traffic control) techniques
References
* "Deploying IP and MPLS QoS for Multiservice Networks: Theory and Practice" by John Evans, Clarence Filsfils (Morgan Kaufmann, 2007, )
External links
Bandwidth Management Tools, Strategies, and IssuesTechSoup for Libraries: Bandwidth Management
*The True Price of Bandwidth Monitoring
Sniffers Basics and Detection
{{DEFAULTSORT:Bandwidth Management
Network performance
de:Netzwerk-Scheduler