This document provides an overview of Quality of Service (QoS) in computer networks. It discusses several key IP QoS mechanisms including resource reservation using RSVP, admission control with bandwidth brokers, packet classification and marking, queuing disciplines like priority queuing and weighted fair queuing, traffic shaping using leaky bucket and token bucket algorithms, and policing. It also describes QoS frameworks like IntServ and DiffServ that systematically apply these mechanisms. Finally, it covers QoS in wireless networks, focusing on support in 802.11 networks and interactions with mobility protocols.
Fundamental of Quality of Service(QoS) Reza Farahani
This slide contains fundamental concept about Quality of Service (QoS) technolog, according to the latest version of Cisco books (CCIE R&S and CCIE SP) and i taught it at IRAN TIC company.In the next slide, i upload advanced topic about this attractive technology.
Fundamental of Quality of Service(QoS) Reza Farahani
This slide contains fundamental concept about Quality of Service (QoS) technolog, according to the latest version of Cisco books (CCIE R&S and CCIE SP) and i taught it at IRAN TIC company.In the next slide, i upload advanced topic about this attractive technology.
These slides cover a topic on Introduction to switching & circuit switching in Data Communication. All the slides are explained in a very simple manner. It is useful for engineering students & also for the candidates who want to master data communication & computer networking.
The TCP/IP protocol suite does not define any protocol in the data-link layer or
physical layer. These two layers are territories of networks that when connected
make up the Internet. These networks, wired or wireless, provide services to the upper
three layers of the TCP/IP suite. This may give us a clue that there are several standard
protocols in the market today. For this reason, we discuss the data-link layer in several
chapters. This chapter is an introduction that gives the general idea and common issues
in the data-link layer that relate to all networks.
❑ The first section introduces the data-link layer. It starts with defining the concept
of links and nodes. The section then lists and briefly describes the services provided
by the data-link layer. It next defines two categories of links: point-to-point
and broadcast links. The section finally defines two sublayers at the data-link layer
that will be elaborated on in the next few chapters.
❑ The second section discusses link-layer addressing. It first explains the rationale
behind the existence of an addressing mechanism at the data-link layer. It then
describes three types of link-layer addresses to be found in some link-layer protocols.
The section discusses the Address Resolution Protocol (ARP), which maps
the addresses at the network layer to addresses at the data-link layer. This protocol
helps a packet at the network layer find the link-layer address of the next node for
delivery of the frame that encapsulates the packet. To show how the network layer
helps us to find the data-link-layer addresses, a long example is included in this
section that shows what happens at each node when a packet is travelling through
the Internet.
switching techniques in data communication and networkingHarshita Yadav
it is a detailed presentation on switching techniques. it includes the three types of switching technique. it is described in such manner that you can learn switching without any difficulties.
description of the services to the networks .
how to apply quality of service
how to improve the networks
summary in personal point of view
please don't hesitate if you have further question
These slides cover a topic on Introduction to switching & circuit switching in Data Communication. All the slides are explained in a very simple manner. It is useful for engineering students & also for the candidates who want to master data communication & computer networking.
The TCP/IP protocol suite does not define any protocol in the data-link layer or
physical layer. These two layers are territories of networks that when connected
make up the Internet. These networks, wired or wireless, provide services to the upper
three layers of the TCP/IP suite. This may give us a clue that there are several standard
protocols in the market today. For this reason, we discuss the data-link layer in several
chapters. This chapter is an introduction that gives the general idea and common issues
in the data-link layer that relate to all networks.
❑ The first section introduces the data-link layer. It starts with defining the concept
of links and nodes. The section then lists and briefly describes the services provided
by the data-link layer. It next defines two categories of links: point-to-point
and broadcast links. The section finally defines two sublayers at the data-link layer
that will be elaborated on in the next few chapters.
❑ The second section discusses link-layer addressing. It first explains the rationale
behind the existence of an addressing mechanism at the data-link layer. It then
describes three types of link-layer addresses to be found in some link-layer protocols.
The section discusses the Address Resolution Protocol (ARP), which maps
the addresses at the network layer to addresses at the data-link layer. This protocol
helps a packet at the network layer find the link-layer address of the next node for
delivery of the frame that encapsulates the packet. To show how the network layer
helps us to find the data-link-layer addresses, a long example is included in this
section that shows what happens at each node when a packet is travelling through
the Internet.
switching techniques in data communication and networkingHarshita Yadav
it is a detailed presentation on switching techniques. it includes the three types of switching technique. it is described in such manner that you can learn switching without any difficulties.
description of the services to the networks .
how to apply quality of service
how to improve the networks
summary in personal point of view
please don't hesitate if you have further question
Four issues must be addressed to ensure quality of service:
Application Requirements.
Traffic shaping.
Packet scheduling.
Admission control.
Versions of quality of service for the Internet:
Integrated Services.
Differentiated Services.
A Comparative Analysis of the Performance of VoIP Traffic with Different Type...ijcnac
The key QoS parameters for VoIP are delay, jitter and loss. In the Internet, VoIP requires
the underlying packet switched network to minimize the impact of these parameters. A
major contributing factor in this regard is traffic engineering carried out by scheduling
algorithms. This paper studies the behavior of different types of scheduling algorithms on
the delay, jitter and loss QoS parameters. The performance evaluation involves
identifying the scheduling algorithms which are most suitable for VoIP communications.
The result from the analysis also shows the impact of the QoS parameters on VoIP over
the Internet.
QOS-BASED PACKET SCHEDULING ALGORITHMS FOR HETEROGENEOUS LTEADVANCED NETWORKS...ijwmn
The number of LTE (Long-Term Evolution) users and their applications has increased significantly in the
last decade, which increased the demand on the mobile network. LTE-Advanced (LTE-A) comes with many
features that can support this increasing demand. LTE-A supports Heterogeneous Networks (HetNets)
deployment, in which it consists of a mix of macro-cells, remote radio heads, and low power nodes such as
Pico-cells, and Femto-cells. Embedding this mix of base-stations in a macro-cellular network allows for
achieving significant gains in coverage, throughput and system capacity compared to the use of macrocells only. These base-stations can operate on the same wireless channel as the macro-cellular network,
which will provide higher spatial reuse via cell splitting. Also, it allows network operators to support
higher data traffic by offloading it to smaller cells, such as Femto-cells. Hence, it enables network
operators to provide their growing number of users with the required Quality of Service (QoS) that meets
with their service demands. In-order for the network operators to make the best out of the heterogeneous
LTE-A network, they need to use QoS-based packet scheduling algorithms that can efficiently manage the
spectrum resources in the HetNets deployment. In this paper, we survey Quality of Service (QoS) based
packet scheduling algorithms that were proposed in the literature for the use of packet scheduling in
Heterogeneous LTE-A Networks. We start by explaining the concepts of QoS in LTE, heterogeneous LTE-A
networks, and how traffic is classified within a packet scheduling architecture for heterogeneous LTE-A
networks. Then, by summarising the proposed QoS-based packet scheduling algorithms in the literature for
Heterogeneous LTE-A Networks, and for Femtocells LTE-A Networks. And finally, we provide some
concluding remarks in the last section.
QoS-based Packet Scheduling Algorithms for Heterogeneous LTE-Advanced Network...ijwmn
The number of LTE (Long-Term Evolution) users and their applications has increased significantly in the last decade, which increased the demand on the mobile network. LTE-Advanced (LTE-A) comes with many features that can support this increasing demand. LTE-A supports Heterogeneous Networks (HetNets) deployment, in which it consists of a mix of macro-cells, remote radio heads, and low power nodes such as Pico-cells, and Femto-cells. Embedding this mix of base-stations in a macro-cellular network allows for achieving significant gains in coverage, throughput and system capacity compared to the use of macrocells only. These base-stations can operate on the same wireless channel as the macro-cellular network, which will provide higher spatial reuse via cell splitting. Also, it allows network operators to support higher data traffic by offloading it to smaller cells, such as Femto-cells. Hence, it enables network operators to provide their growing number of users with the required Quality of Service (QoS) that meets with their service demands. In-order for the network operators to make the best out of the heterogeneous LTE-A network, they need to use QoS-based packet scheduling algorithms that can efficiently manage the spectrum resources in the HetNets deployment. In this paper, we survey Quality of Service (QoS) based packet scheduling algorithms that were proposed in the literature for the use of packet scheduling in Heterogeneous LTE-A Networks. We start by explaining the concepts of QoS in LTE, heterogeneous LTE-A networks, and how traffic is classified within a packet scheduling architecture for heterogeneous LTE-A networks. Then, by summarising the proposed QoS-based packet scheduling algorithms in the literature for Heterogeneous LTE-A Networks, and for Femtocells LTE-A Networks. And finally, we provide some concluding remarks in the last section.
Token Based Packet Loss Control Mechanism for NetworksIJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
Cisco Webex dictado por el Cisco Learning Partner en Fundación Proydesa a más de 20 Academias Locales del país, Bolovia y Paraguay. Realizada en marco del acuerdo entre Fundación Proydesa y la filial Argentina de SLS LATAM, con el objeto de investigar, desarrollar y promover la formación en y con tecnología. Más info. en http://proydesa.org/portal/
Essentials of Automations: Optimizing FME Workflows with ParametersSafe Software
Are you looking to streamline your workflows and boost your projects’ efficiency? Do you find yourself searching for ways to add flexibility and control over your FME workflows? If so, you’re in the right place.
Join us for an insightful dive into the world of FME parameters, a critical element in optimizing workflow efficiency. This webinar marks the beginning of our three-part “Essentials of Automation” series. This first webinar is designed to equip you with the knowledge and skills to utilize parameters effectively: enhancing the flexibility, maintainability, and user control of your FME projects.
Here’s what you’ll gain:
- Essentials of FME Parameters: Understand the pivotal role of parameters, including Reader/Writer, Transformer, User, and FME Flow categories. Discover how they are the key to unlocking automation and optimization within your workflows.
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- Optimization Strategies in FME Flow: Explore the creation and strategic deployment of parameters in FME Flow, including the use of deployment and geometry parameters, to maximize workflow efficiency.
- Pro Tips for Success: Gain insights on parameterizing connections and leveraging new features like Conditional Visibility for clarity and simplicity.
We’ll wrap up with a glimpse into future webinars, followed by a Q&A session to address your specific questions surrounding this topic.
Don’t miss this opportunity to elevate your FME expertise and drive your projects to new heights of efficiency.
Kubernetes & AI - Beauty and the Beast !?! @KCD Istanbul 2024Tobias Schneck
As AI technology is pushing into IT I was wondering myself, as an “infrastructure container kubernetes guy”, how get this fancy AI technology get managed from an infrastructure operational view? Is it possible to apply our lovely cloud native principals as well? What benefit’s both technologies could bring to each other?
Let me take this questions and provide you a short journey through existing deployment models and use cases for AI software. On practical examples, we discuss what cloud/on-premise strategy we may need for applying it to our own infrastructure to get it to work from an enterprise perspective. I want to give an overview about infrastructure requirements and technologies, what could be beneficial or limiting your AI use cases in an enterprise environment. An interactive Demo will give you some insides, what approaches I got already working for real.
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
Securing your Kubernetes cluster_ a step-by-step guide to success !KatiaHIMEUR1
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However, this ease of use means that the subject of security in Kubernetes is often left for later, or even neglected. This exposes companies to significant risks.
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The Art of the Pitch: WordPress Relationships and SalesLaura Byrne
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LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
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The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
3. Introduction
Page 3
Point 2 is
Imposiblle
1. Computer networking relies on sharing of limited network resources for
communications.
2. If communications resources were unlimited, a direct point-to-point link of
unlimited bandwidth would be possible between any two end-points that
wished to communicate.
Agree..!!
4. Page 4
In the real world, two end-points that wish to communicate, unless they are
connected to the same LAN, need to communicate through a network of links
that have the following characteristics:
1. The links are shared between
traffic from multiple sources to
multiple destinations
2. The links have limited bandwidth
3. The links have propagation
latency (i.e., time taken for data to
traverse the links)
4. The nodes directly connected to
each link have limited processing
power and memory capacity
Introduction
5. Page 5
How should these
limited resource
be shared?
FIFO (first in first out)
Introduction
6. Page 6
However, this simple treatment of packets is not sufficient for today’s
multiservice networks.
The different applications have different requirement on the communications
services provided by the network.
Voice
Video
1. Voice and Video have very stringent delay and latency
requirements, as already discussed in chapter 4.
2. File transfer, on the other hand, does
not have the same delay and latency
requirments.
Introduction
7. Page 7
Introduction
These kind of requirements, plus others such as “guaranteed” bandwidth
requirements, are know as QoS requirements, and the whole field that is
about these requirement and the ways they are met in networks, is known
as:
QoS
(Quality of Service)
9. Page 9
IP QoS Mechanisms
1.Introduction to IP QoS
2.Resource Reservation
3.Admission Control
4.Packet Classification and Marking
5.Queuing Disciplines
6.Traffic Shaping
7.Policing
8.Routing Control and Traffic Engineering
10. Page 10
Introduction to IP QoS
The existing internet is largely a best-effort network.
Internet
No guarantees are
provided that
packet will not loss
11. Page 11
Introduction to IP QoS
The IP QoS solution is predicated on three fundamental requirements:
1.To Provide mechanisms to offer different levels
of services to different users, even though some
users might get better service than others.
Thus, IP QoS is inherently “unfair”
2.The Service should not usually be completely
denied to lower-priority traffic.
3.The mechanisms are efficient, not wasteful of
valuable network resources.
12. Page 12
IP QoS Mechanism
Resource Reservation
Perhaps a natural first step in moving away from a purely best-effort-service
Internet is to Provide away to reserve resources for selected users while still
using traditional IP Routing. Resource reservation refers to dynamic
arrangements for QoS provisioning that can be made end-to-end over one or
more intermediate networks. Usually, a reservation is specified by a traffic
profile, a description of the rate, burst size, and other feature of the reserved
traffic.
13. Page 13
IP QoS Mechanism
Resource Reservation Protocol (RSVP)
RSVP is a signaling protocol that allows
resource reservation to be coordinated in a
network. RSVP signaling generally results in
resources being reserved in rsvp capable routers
in the transit path of a traffic flow. Each of these
routers maintains a soft state that needs to be
periodically refresh. RSVP is unidirectional-
resources are reserved in one direction from
source to destination only.
14. Page 14
IP QoS Mechanism
Resource Reservation Protocol (RSVP)
Resources are reserved using the following procedures. See figure 1
15. Page 15
IP QoS Mechanism
Admission
Admission control refers to the decision whether
to admit a certain flow or aggregation of flows into
a network, in response to a request for resource
reservation. It makes sense for admission control
decsions to be made by an entity with an overall
view of network resources.
16. Page 16
IP QoS Mechanism
Bandwidth Brokers
There are two basic choices for dynamic allocation of bandwidth
resources in the routers in a given network.
1. Each router makes its own decisions, perhaps as configured
manually or by policy.
2. A single entity makes the decisions for the network, taking into
account the dynamic conditions in the network. This entity is often
called a bandwidth broker
By the nature of its functions, it is typical that each domain would have
its own
bandwidth broker to control its bandwidth resources. It would be
involved in negotiations
(perhaps with another domain’s bandwidth broker) for resource
allocation
for interdomain traffic, making decisions on
17. Page 17
IP QoS Mechanism
Figure 2.shows an example of a bandwidth broker providing
admission control services to administrative domain
Bandwidth Brokers
18. Page 18
IP QoS Mechanism
Packet Classification and Marking
Packet classification is the separation of packets into
different classes based on some criteria
Example:
1. Classifacation may be port-based (the input and/or output port of the
packet)
2. Transport protocol-based (TCP or UDP),
3. Application-Based (such as HTTP-based)
4. Address –Based (Based on the source or destination address of the
packet).
It is also possible that out-of-profile packet are
reclassified, typically into a lower priority class.
19. Page 19
IP QoS Mechanism
Packet Classification and Marking
Marking is the setting of bits in the packet header
corresponding to the packet class. The bits marked could
be the three bits in the type of service (ToS) field and the
three bits in the precedence field of the IP header
Packet classification and marking allows differential
treatment of different, packet classes using
other, complementary QoS. Packet classification and
marking may be handled by external sources like a
customer or other network. When the packets enter a new
network, that network can accept the classification or
reclassify.
The decision depends on the QoS architecture and
policies used..
20. Page 20
IP QoS Mechanism
Queuing Disciplines
Queuing is fundamental to IP QoS schemes
because each router has one or more input
queues and one or more output queues that may
be where the bulk of “processing time” is spent.
The use of various queuing disciplines can be
used to change such functions as processing
times and flow rates. Most of the queuing
disciplines discussed here operate on router
output queues, although priority queuing could be
implemented to operate jointly on input/output
queues.
22. Page 22
IP QoS Mechanism
FIFO Queuing
FIFO queuing is the standard, basic queuing discipline. All packets
are treated equally without preference except that earlier arriving
packets leave before later arriving packets.
Advantages :
1. Highly optimized forwarding performance resulting from years of
experience by router manufacturers.
2. For lightly loaded networks with sufficient transmission and switching
capacity, queuing is necessary only for smoothing intermittent traffic
bursts. FIFO does this very efficiently.
Disadvantages :
1. For networks that are not lightly loaded, FIFO queuing may result in loss
of packets through discarding when the queues are full.
2. FIFO does not allow certain packets to receive priority/preference over
other packets.
23. Page 23
IP QoS Mechanism
Priority Queuing (PQ)
PQ (see Figure 3) is a non-FIFO queuing discipline. The router
examines the input queue, takes high-priority packets and places
them in the output queue ahead of normal packets. This effectively
reorders packets according to priority.
24. Page 24
IP QoS Mechanism
Fair Queuing (FQ), Weighted Fair Queuing (WFQ), and Class-Based
Queuing (CBQ)
Therefore, FQ results in preferential treatment to low-volume traffic
flows.
WFQ is a variation and generalization of FQ that weights the outputs
of the per-flow queues (according to the IP ToS field, for example) as
well.
Advantages of WFQ include:
1. It prevents a misbehaving TCP session from consuming a large
fraction of
resources at the expense of other flows.
2. The fairness aspect of this type of scheme prevents buffer
starvation.
Disadvantages of WFQ include:
1. WFQ is a way to approximate generalized processor sharing
(GPS), where
the link sharing between queues is accomplished by scheduling
alone.
25. Page 25
IP QoS Mechanism
Comparison of Queuing Disciplines
26. Page 26
IP QoS Mechanism
7.2.8 Traffic Shaping
Traffic shaping refers to controlling the rate of traffic passing through a
given
router. It is often used at the ingress points of a network as a form of
soft admission control.
1. Leaky bucket traffic shaping constrains the rate to be less than a
maximum
value, while
2. token bucket traffic shaping constrains the average rate to be less
than a
maximum value.
27. Page 27
IP QoS Mechanism
7.2.9 Policing
There are multiple definitions of policing in the literature, which all
have to do with treatment of packets that are nonconforming (with a
profile). According to one definition, policing refers to the process of
dropping packets from a flow that are nonconforming
28. Page 28
IP QoS Mechanism
7.2.10 Routing Control and Traffic Engineering
The basic functional requirements for traffic engineering are :
• Distribution of topology information, to allow nodes to build correct
topology maps and to assist in path selection;
• Path selection, to select a path based on some criteria, such as
bandwidth,
delay, shortest path;
• Directing traffic along computed paths, using forwarding tables
(computed
independently at each node using traditional IP routing protocols or
signaled
protocols such as MPLS).
29. IP QoS Framework
Page 29
The mechanisms discussed in Section 7.2 are often used in
combination in networks, in order to provide end-to-end QoS, or to
enforce some QoS policies in a network domain. Routers typically
combine some of these mechanisms, for example as shown in
Figures 7.6 and 7.7.
30. IP QoS Framework
Page 30
There should be ways to more systematically coordinate the various
QoS
mechanisms used in a network according to some kind of framework
to allow endto-end provision of QoS for a variety of network traffic,
consistent with some idea of network QoS policy.
IntServ and DiffServ are two such frameworks.
31. QoS in Wireless Networks
Page 31
In wireless networks, there are a number of issues related to providing
QoS. 1. there are the issues associated with all wireless networks
regardless of host mobility, because of the characteristics of the
wireless link, including relatively lower bandwidth, higher latency, and
higher errors than comparable wired links.
2. there are the additional complications that come with mobility.
32. QoS in Wireless Networks
Page 32
7.4.1 WLAN QoS Support
The 802.11 MAC consists of a distributed coordination function (DCF)
and a point coordination function (PCF). The DCF is implemented in
all stations and can be used in both ad hoc and infrastructure modes.
33. 7.5 Summary
Page 33
As introduced in this chapter, techniques are needed for providing
differentiated QoS because limited resources in networks are
shared, and because the network needs to be able to treat different
classes of traffic differently based on issues including different
application requirements and different subscriptions. We overview a
number of different mechanisms for IP QoS, including resource
reservation (using RSVP), admission control (e.g., using bandwidth
brokers), packet classification and marking (e.g., using bits in the ToS
field of the IP header), queuing (FIFO, priority queuing, WFQ, and
CBQ), traffic shaping (leaky bucket and token bucket), policing
(e.g., policing token bucket), and traffic engineering or QoS routing.
We touch upon the two QoS frameworks for IP networks, the IntServ
and DiffServ frameworks that provide ways to systematically apply
QoS mechanisms. Then we explore QoS in wireless networks, looking
at some length at QoS in 802.11, and the interactions of mobility
protocols with QoS mechanisms.
Larger traffic flows present more packets to queue inputs. With FIFO queuing, theseflows also comprise a proportionately larger portion of the outputs. Is it unfair forlarger traffic flows to “starve” smaller traffic flows in this way? FQ is based on thenotion that it is. It attempts to balance out traffic-flow volume at the queue outputregardless of flow volume at the input, by using per-flow queues and interleavingbetween the queues.
MPLS is a solution for the third requirement, whereas QoS routing (also knownas constraint-based routing) is based on the first two. MPLS is out of the scope ofthis book, but we briefly describe QoS routing here.
In Chapter 3, we introduced WLANs, and in particular the IEEE 802.11 WLANs,popularly known as wi-fi. We mentioned the hidden terminal and exposed terminalproblems in Chapter 3, and that the CSMA/CA medium access scheme is used in802.11 to handle medium access while taking care of these challenges. We are nowready to discuss the 802.11 MAC in more detail, including the CSMA/CA scheme.This is directly relevant to 802.11 QoS, as the 802.11e addendum to 802.11enhances the original 802.11 MAC to support QoS.