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 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 (
rate limiting):
**
Token bucket
**
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 the ...
** TCP rate control - artificially adjusting TCP window size as well as controlling the rate of ACKs being returned to the sender
*
Scheduling algorithms:
**
Weighted fair queuing (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 can happen to
TCP/ IP flows during periods of congestion because each sender will reduce their transmission rate at the same time when packet loss occurs.
Routers on the Internet normally have packe ...
** Policing (marking/dropping the packet in excess of the committed traffic rate and burst size)
**
Explicit congestion notification
Explicit Congestion Notification (ECN) is an extension to the Internet Protocol and to the Transmission Control Protocol and is defined in RFC 3168 (2001). ECN allows end-to-end notification of network congestion without dropping packets. ECN ...
** 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 The top-nodes algorithm is an algorithm for managing a resource reservation calendar. The algorithm has been first published in 2003, and has been improved in 2009. It is used when a resource is shared among many users (for example bandwidth in a te ...
*
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 signific ...
as the network approaches (and occasionally exceeds) capacity
*
TCP global synchronization
TCP global synchronization in computer networks can happen to
TCP/ IP flows during periods of congestion because each sender will reduce their transmission rate at the same time when packet loss occurs.
Routers on the Internet normally have packe ...
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
Explicit Congestion Notification (ECN) is an extension to the Internet Protocol and to the Transmission Control Protocol and is defined in RFC 3168 (2001). ECN allows end-to-end notification of network congestion without dropping packets. ECN ...
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 services for accessing, using, or participating in the Internet. ISPs can be organized in various forms, such as commercial, community-owned, non-profit, or otherwise priva ...
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 known as packet sniffer, protocol analyzer, or network analyzer, is a computer program or computer hardware such as a packet capture appliance, that can intercept and log traffic that passes over a computer network or ...
is a program or a device that eavesdrops on the network traffic by grabbing information traveling over a network
*
Network traffic measurement In computer networks, network traffic measurement is the process of measuring the amount and type of traffic on a particular network. This is especially important with regard to effective bandwidth management.
Techniques
Network performance cou ...
See also
*
Bandwidth cap
* 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
Performance management (PM) is the process of ensuring that a set of activities and outputs meets an organization's goals in an effective and efficient manner. Performance management can focus on the performance of a whole organization, a ...
* 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 thin ...
and IPFIX data
*
Bandwidth throttling
*
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 In computer networks, network traffic measurement is the process of measuring the amount and type of traffic on a particular network. This is especially important with regard to effective bandwidth management.
Techniques
Network performance cou ...
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 monito ...
*
Traffic shaping and
rate limiting 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 ManagementThe True Price of Bandwidth Monitoring
Sniffers Basics and Detection
{{DEFAULTSORT:Bandwidth Management
Network performance
de:Netzwerk-Scheduler