Collaborative QoS Architecture between DiffServ and
802.11e Wireless LAN
Seyong Park
*
, Kyungtae Kim
*
, Doug C. Kim
*
, Sunghyun Choi
+
, Sangjin Hong
*
*
Mobile Systems Design Laboratory
Department of Electrical and Computer Engineering
State University of New York at Stony Brook
Stony Brook, NY 11794-2350, USA
{seyong,kyungtae,dougkim,snjhong}@ece.sunysb.edu
+
Multimedia & Wireless Networking Laboratory
School of Electrical Engineering
Seoul National University
Seoul 151-744, KOREA
schoi@snu.ac.kr
Abstract- As the multimedia applications such as Voice over
IP (VoIP) and Audio/Visual (AV) streaming across the
Internet emerge, many are working on the network
architecture to extend such applications to the wireless
networking domain. The emerging IEEE 802.11e Quality-of-
Service (QoS)-enabled Wireless LAN (WLAN) is considered
a strong candidate for the air interface for such multimedia
applications thanks to the IP-centric network paradigm
along with its inherent high-speed transmission capability.
This paper provides an integrated wired/wireless network
architecture interfacing QoS between user level traffic over
IP using Differentiated Service (DiffServ) and transport
level traffic using IEEE 802.11e WLAN. Our study
investigates the correlations in end-to-end traffic
management between DiffServ and 802.11e, and presents the
hierarchical QoS signaling interface between DiffServ and
802.11e, in terms of traffic classifying, shaping and policing.
Keywords- IEEE 802.11, IEEE 802.11e, WLAN, DiffServ,
Quality-of-Service (QoS)
I. INTRODUCTION
As broadband Internet access becomes pervasive, many
multimedia applications such as VoIP, AOD and VOD
have been serviced via Internet Service Providers (ISPs).
In order to maintain a required performance for such
applications, Internet network systems have been
facilitating Quality-of-Service (QoS) to enable the
network systems to prioritize traffic according to the
application’s service types. To our best knowledge, the
IETF Differentiated Service (DiffServ) [10] is at the
center of such efforts. As the portable devices such as
laptops and palmtops become more and more popular, the
interest to have a level of services similar to those
available from the conventional wired networks using
those portable devices without wires is growing very fast
these days.
On the other hand, the IEEE 802.11 Wireless LAN
(WLAN) has become a prevailing broadband wireless
technology in recent years. Today, the IEEE 802.11
WLAN is considered a “wireless Ethernet” by virtue of its
best effort service provisioning based on Ethernet-like
medium access control (MAC) protocol and up to 54
Mbps transmissions rates. However, the 802.11 WLAN is
also evolving to support QoS currently, and a new QoS-
enabled MAC called IEEE 802.11e is emerging [3].
For the multimedia applications to work properly, the
end-to-end QoS should be in place. That is, for example,
neither IEEE 802.11e WLAN alone nor the DiffServ
without a proper QoS support from the air interface is
enough for the full-fledged wireless multimedia
applications. We, in this paper, consider an end-to-end
QoS architecture across wired WAN, wired LAN, and
wireless LAN, which are based on DiffServ, IEEE
802.1D/Q, and IEEE 802.11e, respectively.
This paper explores DiffServ, 802.11e and 802.1D/Q
architectures in Sections III and IV. Section V presents
two methodologies coordinating traffic QoS between
DiffServ and 802.11e over the air interface, between
802.11e and 802.1D in Ethernet LAN interface, and
DiffServ Per Hop Behavior (PHB) traffic control in IP
WAN. Finally, this paper concludes with Section VI.
II.
SYSTEM MODELING AND BACKGROUND
From the overall network service perspective, QoS
should provide end-to-end traffic control so that users’
applications can be properly served according to the
allowable quality requirements such as latency, jitters and
packet loss rate. To comply with the service quality
requirements, user level traffic of the applications should
coordinate QoS traffic control with transport level QoS at
the network interfaces.
Gateway Access Point IP router Mobile Station Server
IEEE802.11e
Radio Bearer Services
Radio Access Bearer Services
RF
IP over Ethernet
Public IP Backbone
End
-
to
-
End User Bearer Services
Wireline Bearer Service
IEEE 802.1D/Q
Ethernet Interconnect
Managed IP network
RFC2474/2475 IP DiffServ
Fig. 1. End-to-end QoS network structures
As illustrated in Fig. 1, the user traffic QoS specifies
end-to-end network traffic delay, jitter and policing. Since
most data service accessing remote servers carries user
traffic through multiple heterogeneous networking
environments, the user level QoS should be decomposed
into each network interface segment as follows:
(a) Radio Access network: air interface between mobile
station (STA) and access point (AP) defined by IEEE
802.11e. Under the prioritized QoS paradigm, the
802.11e provides differentiated channel access to
traffic with 8 different priority levels.
(b) Ethernet LAN: Ethernet between AP and Gateway
terminating subnet traffic including traffic through
other MAC bridges. 802.1D/Q defines the QoS
mechanisms, which can be used in the Ethernet LAN.
Similar to the DiffServ, it also classifies the traffic
type and prioritizes upon the traffic class at the
bridge.
(c) Managed IP WAN: wireline interface managed by
network service providers such as Competitive Local
Exchange Carrier (CLEC) and Incumbent Local
Exchange Carrier (ILEC). The IP WAN is normally
managed by Service Level Agreement (SLA). User
traffic’s DiffServ parameters can be directly reflected
into the IP routers to be prioritized over other traffic.
The IEEE 802.11e is an emerging standard for QoS-
enabled MAC for the popular IEEE 802.11 WLAN. As of
today, the 802.11e standardization is at the final stage [3],
and there have been some reports about the utility of this
emerging technology, e.g., [6][7]. However, these reports
have been focused on QoS issues at the layer-2 single hop,
i.e., wireless link between a STA and an AP. Since most
user traffic in application layer traverses multiple
networks as depicted in Fig. 1, the end-to-end QoS also
becomes crucial to offer various network services in the
real networks. Even though there was also a paper dealing
with an end-to-end QoS paradigm based IntServ over
IEEE 802.11e WLAN [8], to our best knowledge, today
DiffServ is considered a dominant QoS protocol in the
network layer that supports across different network
interfaces. However, in wireless and wired LAN,
DiffServ cannot function to traffic control for QoS.
Instead, IEEE 802.11e and IEEE 802.1D are QoS in
MAC layer. Since 802.11e and 801.1D are non-DiffServ
domains, end-to-end QoS environment cannot be properly
provided unless these different QoS techniques are
coordinated under common QoS specifications.
Our study is to propose a methodology translating the
DiffServ Per Hop Behavior (PHB) to the 802.11e and
802.1D.
III.
DIFFERENTIATED SERVICE (DIFFSERV)
The DiffServ architecture [10] provides a scalable
QoS framework for service providers that offer
differentiated services under heterogeneous network
environment. Each IP datagram carries a Differentiated
Service CodePoint (DSCP) value in its Differentiated
Service (DS) field, which supercedes the IPv4 Type of
Service (TOS) octet and IPv6 Traffic Classifier octet. A
network node supporting DiffServ consists of functional
elements including Per Hop forwarding behavior, traffic
classification, and conditioning function. Depending on
the type of the network interface, normally, different
functional elements are actually used. That is, as
presented in the following subsections, the traffic
classification and conditioning are conducted at the
ingress network node while the PHB forwarding is
conducted at the intermediate network node.
A. Ingress network node
Ingress network nodes such as edge routers or
gateways perform the packet classification and
conditioning. A packet classifier is a logical function to
select packets based on packet information via either
Behavior Aggregate (BA) Classifier searching the DSCP
value or Multi-Field (MF) Classifier searching multiple
fields including source and destination addresses, DSCP,
port ID, etc. When a packet is classified, it is forwarded to
the traffic conditioner that consists of meter, market,
shaper and dropper. Meter measures the packet stream
based on the traffic profile defined by Traffic
Conditioning Agreement (TCA) that is typically part of
network provisioning contract. Packet marker sets the
DSCP value given by classifier and meter. Shaper and
Dropper function to police the packet traffic according to
the temporal traffic conditions.
B. Intermediate network node
An intermediate network node performs a Per Hop
Behavior (PHB), which is a logical instantiation
performing traffic forward behavior. The forward
behavior normally follows the traffic resource allocation
per link based on the priority defined in DSCP. The traffic
resource is determined based on packet loss rate,
propagation delay and jitter. The PHB should maintain a
mapping table between DSCP and forward behavior
functions. DiffServ defines four available standard PHBs:
• Default PHB [9]
• Class-Selector PHB[9]
• Assured Forwarding (AFxy) PHB [12]
• Expedited Forwarding (EF) PHB [11]
The Default PHB is a best-effort service traffic that never
assures any traffic parameters such as delay, jitter and
throughput. It is typically implemented using the first-in
first-out (FIFO) queuing. Most non-real-time data traffic
is served using this PHB. The Class-Selector PHB is used
for the backward compatibility with the existing IP
precedence scheme current used in the IP network. The
AF PHB is defined to support controlled traffic
management at the QoS network node. The AF PHB is
expressed as “AFxy.” The ‘x’ represents AF class number
and ‘y’ represents the drop precedence. For example, in
case of traffic congestion, AF13 should be dropped before
AF12. AF classes are typically controlled by prioritized
queues and traffic bandwidth following the Service Level
Agreement (SLA). The EF PHB is the highest traffic
class supporting for the real-time traffic such as VoIP or
real-time video that require low delay and jitter. PHB may
also include a specification for traffic conditioning
described in Section III.A.
IV.
802.11E AND 802.1D FOR QOS-ENABLED LANS
A. Legacy 802.11 WLAN
The 802.11 MAC protocol [1] consists of two
coordination functions, which are a mandatory distributed
coordination function (DCF) built on Carrier Sense
Multiple Access with Collision Avoidance (CSMA/CA)
and an optional point coordination functions (PCF) built
on a poll-and-response protocol. Today, most 802.11
devices implement the mandatory DCF mode only. The
DCF functions traffic control based on non-preemptive
service (i.e., FIFO). When the MAC frame arrives at the
queue, it shall wait until the channel becomes idle, and
defers another fixed time interval, called DCF Inter-
Frame Space (DIFS), to avoid the potential collision with
other network nodes. When the channel stays idle for the
DIFS interval, it starts the random backoff (BO) counter.
When the BO counter expires, the frame is transmitted
over the air. When a frame arrives at an empty queue and
the medium has been idle longer than the DIFS time
interval, the frame is transmitted immediately.
Each STA maintains a contention window (CW), which
is used to select the random backoff count. The backoff
count is determined as a pseudo-random integer drawn
from a uniform distribution over the interval [0,CW]. If
the channel becomes busy during a backoff process, the
backoff is suspended. When the channel becomes idle
again, and stays idle for an extra DIFS time interval, the
backoff process resumes with the suspended backoff
counter value. The timing of DCF channel access is
illustrated in Fig. 2.
Busy
Medium
SIFS
DIFS
Backoff Window
Slot Time
Defer Access
Select Slot and decrement backoff
as long as medium stays idle
DIFS
Contention Window
Immediate access when
medium is idle >= DIFS
Next Frame
PIFS
Fig. 2. 802.11 DCF Channel Access
B. QoS-Enabled 802.11e WLAN
The IEEE 802.11e defines a single coordination
function, called the hybrid coordination function (HCF),
for the QoS provisioning. The HCF combines functions
from the DCF and PCF with some enhanced QoS-specific
mechanisms and QoS data frames in order to allow a
uniform set of frame exchange sequences to be used for
QoS data transfers. The HCF uses a contention-based
channel access, called the enhanced DCF (EDCF), which
operates concurrently with a controlled channel access
based on a poll-and-response protocol. In this paper, only
EDCF is enclosed in the scope.
The emerging EDCF is designed to provide
differentiated, distributed channel accesses for frames
with 8 different priorities (from 0 to 7) by enhancing the
legacy DCF. Each frame from the higher layer arrives at
the MAC along with a specific priority value. Each QoS
data frame also carries its priority value in the MAC
frame header. In the context of the 802.11e, the priority
value is called Traffic Category Identification (TCID). An
802.11e STA shall implement four access categories
(ACs), where an AC is an enhanced variant of the DCF
with a single FIFO queue, as shown in Fig. 4. Each frame
arriving at the MAC with a priority is mapped into an AC
as shown in T
ABLE I. Note the relative priority of priority
0 is placed between 2 and 3. This relative priority is
rooted from IEEE 802.1D bridge specification [4].
TABLE I. TCID TO ACCESS CATEGORY MAPPINGS
TCID / Priority Access Category Traffic Type
1 0 Best Effort
2 0 Best Effort
0 0 Best Effort
3 1 Video Probe
4 2 Video
5 2 Video
6 3 Voice
7 3 Voice
Basically, an AC uses AIFSD [AC], CWmin[AC], and
CWmax[AC] instead of DIFS, CWmin, and CWmax, of
the DCF, respectively, for the contention to transmit a
frame belonging to access category AC. AIFSD[AC] is
determined by
[] []
A
IFSD AC SIFS AIFS AC SlotTime=+ ⋅
,
where AIFS[AC] is an integer greater than zero. Fig. 3
shows the timing diagram of the EDCF channel access.
The values of AIFS[AC], CWmin[AC], and
CWmax[AC], which are referred to as the EDCF
parameters, can be determined and announced by the AP
via beacon frames, which are transmitted periodically, say
every 100 msec typically. The AP can adapt these
parameters dynamically depending on network conditions.
Basically, the smaller AIFS[AC] and CWmin[AC], the
shorter the channel access delay, and hence the more
bandwidth share for a given traffic condition. These
parameters can be used in order to differentiate the
channel access among different priority traffic.
Busy
Medium
SIFS
AIFSD[AC]
Backoff Window
SlotTime
Defer Access
Select Slot and decrement backoff as
long as medium stays idle
AIFSD[AC]
+SlotTime
Contention Window
from [1,CWmin[AC]+1]
Immediate access when
medium is idle >=
AIFSD[AC] + SlotTime
Next Frame
PIFS
Fig. 3. IEEE 802.11e EDCF channel access.
Fig. 4 shows the 802.11e MAC with four transmission
queues, where each queue behaves as a single enhanced
DCF contending entity, i.e., an AC, where each queue has
its own AIFS and maintains its own Backoff Counter
(BC). When there is more than one AC finishing the
backoff at the same time, the collision is handled in a
virtual manner. That is, the highest priority frame among
the colliding frames is chosen and transmitted, and the
others perform a backoff with increased CW values.
AC 0 AC 1
AC 2 AC3
Virtual Collision Handler
Backoff
AIFS[0]
BC[0]
Backoff
AIFS[1]
BC[1]
Backoff
AIFS[2]
BC[2]
Backoff
AIFS[3]
BC[3]
Transm ission
Attem pt
Fig. 4. Four Access Categories (ACs) for EDCF
C. QoS-Enabled Wired LAN via 802.1D/Q
The IEEE 802.1D MAC bridge specification allows
different MAC layers in the IEEE 802 family to interwork.
Note that the 802.11 AP typically implements an 802.1D
bridge connecting the 802.11 MAC and 802.3 (or
Ethernet) MAC. The 802.1D bridge supports up to 8 user
priorities by implementing multiple FIFO transmission
queues between two MAC entities. By default, a priority
queuing can be used for these multiple queues. That is, a
frame can be forwarded to the egress MAC only if there is
no frame in the higher priority queues. As shown in Fig.
5
and Fig. 6, the 802.1Q Virtual LAN (VLAN) tag extends
the existing 802.3 frame format, and it specifies the user
priority of the frame. Note that the 802.3 MAC itself does
not support any differentiated channel access to different
priority traffic, but via the 802.1Q VLAN tag, the 802.3
MAC frames can carry the corresponding priority value,
which in turn can be used by the 802.1D MAC bridge for
a prioritized forwarding. Since the 802.11e EDCF QoS
scheme roots in 802.1D, priority parameters of 802.11e
and 802.1D are interoperable. The User_Priority shown in
Fig. 6 can be used for TCID valued that is defined in
T
ABLE II.
Fig. 5. IEEE 802.3 frame format with 802.1Q VLAN tag
Fig. 6. Tag Control Information (TCI) format within VLAN tag
TABLE II. 802.1D TRAFFIC TYPE [4]
User Priority Acronym Traffic Type
1 BK Background
2 - Spare
0 (Default) BE Best Effort
3 EE Excellent Effort
4 CL Controlled Load
5 VI Video < 100 ms latency and jitter
6 VO Voice < 10 ms latency and jitter
7 NC Network Control
When the 802.11e MAC frame is received at the
ingress of the VLAN bridge supporting 802.1D/Q, it is
classified by VLAN ID, filtered via filtering ID (FID),
and forwarded based on the traffic class that is mapped by
user priority [5]. When the traffic class is mapped by user
priority, 802.1D/Q frames are allocated into specific
priority queues according to the traffic classes. When the
traffic frames are dequeued from the forwarding process,
it is transmitted to the next bridge via egress. 802.1Q [5]
has a recommended mapping table between user priorities
that are defined in 3 bits of TCI in 802.1Q, and traffic
classes that specify the priority queue in traffic
forwarding process in VLAN Bridge.
V.
END-TO-END QOS COORDINATION BASED DIFFSERV
It is typical that a single STA simultaneously services
multiple sessions under different applications such as
VoIP, streaming video, email or FTP. According to the
service type, traffic should be differently treated at the
network node. As depicted in Fig. 1, three network
interfaces were defined in our study as an end-to-end
network. Each network interface has independent QoS
coordination functions. However, the DSCP is a single
point of traffic control across multiple network interfaces
so that the end-to-end QoS can be transparently provided
over all networks.
A. Over the Air
In the wireless network, STA performs the packet
classification and conditioning in the network layer and
forwards the packet to the AP. As illustrated in Fig. 1, a
STA should map QoS in IP layer to the 802.11e. In STA
supporting DiffServ and 802.11e, the DSCP value should
be mapped to the TCID placed in 802.11e MAC QoS
Control field. T
ABLE III depicts an example mapping
between DSCP and TCID. DSCP values are
recommended by standards [11][12]. According to the
traffic control structure, two QoS architectures can be
considered as follows: Direct mapped QoS between
DSCP and TCID and Hierarchical QoS architecture.
TABLE III. QOS MAPPING TABLE BETWEEN DSCP AND TCID
Traffic Class Example DSCP TCID
Class 1 VoIP (101)xxx for
EF
7
Class 2 Video Streaming (100)xxx
(AF4x)
5
Class 3 Signaling bearer (010)xxx
(AF2x)
3
Class 4 Normal Data
service (e.g.
Web, E-mail)
(000)000
default best-
effort delivery
1
Direct mapped QoS between DSCP and TCID:
This
architecture might be simple to map between DSCP and
TCID via interface between IEEE 802.2 Logical Link
Control (LLC)
1
Service Access Point (SAP) and PHB. In
this model, every IP packet will be placed into 802.11e
MAC priority queues with no preemption. As illustrated
in Fig. 7, IP packets are arrived to MAC layer with non-
preemptive mode. Fig. 7 shows that regardless the DSCP
values of IP packets, IP packets are forwarded to the
802.11e MAC layer according to the arrival times, which
are in order of AF2 (1), AF4 (2), EF (3), and default (4).
When the IP packets are encapsulated in MAC frames,
each frame should be allocated to a priority queue, or an
AC, in MAC layer according to its TCID value. Since the
TCID field of 802.11e MAC is 3-bit long and the DSCP
field of DiffServ is 6-bit long, a single TCID value may
represent multiple DSCP values. Due to the different QoS
field lengths, the granularity of traffic control should
conform to the 802.11e MAC.
Virtual Collision Handler
EFEF
AF4AF4
AF2AF2
defaultdefault
1
2
3
4
Backoff
AIFS [0]
BO[0]
Backoff
AIFS [1]
BO[1]
Backoff
AIFS [2]
BO[2]
Backoff
AIFS [3]
BO[3]
Fig. 7. Direct mapping between DiffServ and 802.11e
Hierarchical QoS from DSCP and TCID: This
architecture uses hierarchical architecture from PHB to
the 802.11e Prioritized QoS. The DiffServ engine is a
logical entity that performs packet classification and
conditioning in the network layer.
As illustrated in Fig. 8, when the IP packets arrive at
the DiffServ engine, called Traffic Conditioner (TC),
which consists of Classifier, Meter, Marker and
Shaper/Dropper, they are classified, marked into DSCP
values, and shaped in accordance with the priority of the
DSCP values. When DiffServ TC completes the traffic
shaping, it encapsulates IP packets into 802.11e MAC
frames, and forwards them to 802.11e priority queues in
accordance with the TCID values. For example, as shown
in Fig. 8, when the IP packets arrive at DiffServ TC in
order of DSCP values, AF4, AF2, EF and default, they
are shaped to EF, AF4, AF2 and default according to the
1
In the 802 LAN devices, the 802.2 LLC sits on top of the MAC.
priority. After completing the traffic shaping, IP packets
are encapsulated in 802.11e MAC frame and placed into
the 802.11e priority queue.
In this architecture, since IP packets are policed and
shaped in the network layer, traffic control can support
full range of DiffServ QoS as well as 802.11e. This
enables the network system to manage accurate end-to-
end QoS traffic control required by user applications.
DiffServ TC
EFEF
AF4
AF2AF2
defaultdefault
EFEF
AF4AF4
AF2
defaultdefault
1’
2’
3’
4’
Virtual Collision Handler
1
2
3
4
classifier
Meter
Marker
dropper
Backoff
AIFS [0]
BO[0]
Backoff
AIFS [1]
BO[1]
Backoff
AIFS [2]
BO[2]
Backoff
AIFS [3]
BO[3]
Fig. 8. Combined QoS of DiffServ and 802.11e
B. Ethernet Local Area Network
As illustrated in Fig. 1, when the AP receives either an
Ethernet (i.e., IEEE 802.1D/Q) or a WLAN (i.e., IEEE
802.11e) frame in the local area network, the 802.11e AP
shall convert the Ethernet frame into the 802.11e frame,
and vice versa. Since User Priority in 802.1D/Q and
TCID in 802.11e have the identical field size and
meaning, they can seamlessly coordinate the QoS
parameters. That is, when the 802.11e prioritized QoS
service is used, the first three bits of the 802.1Q TCI field
is conveyed in the TCID field of the 802.11e QoS Control
field. Note that both sets of three bits indicate the priority
value of the frame. Further, the TCID of 802.11e in AP
should be coordinated with the User Priorities specified in
IEEE 802.1D MAC bridge standard depicted in T
ABLE II.
C. Managed IP Wide Area Network
When the 802.3 MAC frames are terminated at a
gateway, as illustrated in Fig. 1, IP packets are
reassembled and forwarded to the destination. When the
IP packets arrive at the intermediate IP router supporting
DiffServ, PHBs are enforced based on the DSCP values.
Delay sensitive IP packets in EF class are entered in high
priority queue and forwarded with preemption as
specified in RFC 2598 [11]. When the IP packets in AF
class enter in the IP router supporting QoS, DiffServ
engine performs AF PHB. Each AF class (e.g. AF1x,
AF2x, AF3x and AF4x) allocates different forwarding
resources, which are typically priority buffer size and
bandwidth. Once the IP router experiences the traffic
congestion, IP packets with AF class will be determined
whether or not to be dropped with accordance to the drop
precedence values that represents ‘x’ above. When the
network congestion occurs, IP packets in EF class are
always protected for low-jitter, low-loss and low-latency
that are defined in SLA. When the SLA defines the QoS
traffic control requirements, network administration
should configure every IP router under the DiffServ
Domain where a single QoS framework is managed. In
case of multiple DiffServ Domains, DSCP values can be
modified at the Ingress node where the IP packets arrive
across network service area.
VI.
CONCLUSION
This paper has presented an end-to-end network QoS
architecture engaged with IEEE 802.11e MAC, which is
an emerging QoS standard accompanying with the IEEE
802.11 Wireless Local Area Network (WLAN) standard.
Each transport level QoS scheme is presented with
associated network interfaces, including DiffServ in
network and 802.11e and 802.1D/Q in link layer. From
the study, it is realized that every QoS scheme has three
distinctive processes, which are traffic classification,
marking and forwarding. Based on this commonality,
end-to-end QoS architecture can be defined with minimal
coordination amongst QoS traffic parameters such as
DSCP in DiffServ, TCID in 802.11e MAC, and User
Priority of TCI in 802.1D/Q.
It should be emphasized that different QoS granularity
between DiffServ and 802.11e should be resolved by
hierarchical QoS structure using two-level priority queues.
This enables the service providers offering multimedia
service via WLAN for their subscribers to manage
sophisticated QoS over the end-to-end network.
Performance verification remains as a future work.
It should be noted that the 802.11e supports a
parameterized QoS paradigm along with the prioritized
QoS paradigm considered in this paper [3]. The
parameterized QoS characterizes the QoS level with a set
of parameters. It will be our future research to study the
DiffServ with accordance to the parameterized QoS of the
802.11e.
R
EFERENCES
[1] IEEE Std. 802.11-1999, Part 11: Wireless LAN Medium Access
Control (MAC) and Physical Layer (PHY) specifications,
Reference number ISO/IEC 8802-11:1999(E), IEEE Std. 802.11,
1999 edition, 1999.
[2] IEEE Std. 802.11b, Supplement to Part 11: Wireless LAN Medium
Access Control (MAC) and Physical Layer (PHY) specifications:
Higher-speed Physical Layer Extension in the 2.4 GHz Band,
IEEE Std. 802.11b-1999, 1999.
[3] IEEE 802.11e/D4.0, Draft Supplement to Part 11: Wireless
Medium Access Control (MAC) and physical layer (PHY)
specifications: Medium Access Control (MAC) Enhancements for
Quality of Service (QoS), November 2002.
[4] IEEE 802.1D-1998, Part 3: Media Access Control (MAC) Bridges,
ANSI/IEEE Std. 802.1D, 1998 edition, 1998.
[5] IEEE 802.1Q-1998, Virtual Bridge Local Area Networks,
ANSI/IEEE Std. 802.1Q, 1998 edition, 1998.
[6] Stefan Mangold, Sunghyun Choi, Peter May, Ole Klein, Guido
Hiertz, and Lothar Stibor, “IEEE 802.11e Wireless LAN for
Quality of Service,” in Proc. European Wireless’02, Florence,
Italy, February 2002.
[7] Sunghyun Choi, Javier del Prado, Stefan Mangold, and Sai
Shankar, “IEEE 802.11e Contention-Based Channel Access
(EDCF) Performance Evaluation,” to appear in Proc. IEEE
ICC’03, Anchorage, Alaska, USA, May 2003.
[8] Sai Shankar and Sunghyun Choi, "QoS Signaling for
Parameterized Traffic in IEEE 802.11e Wireless LANS," Lecture
Notes in Computer Science, vol. 2402, pp. 67-84, August 2002.
[9] RFC 2474, Definition of the Differentiated Services Field (DS
Field) in the IPv4 and IPv6 Headers, December 1998.
[10] RFC 2475, An Architecture for Differentiated Services, December
1998.
[11] RFC 2598, An Expedited Forwarding PHB, June 1999.
[12] RFC 2597, Assured Forwarding PHB Group, June 1999.
![TABLE II. 802.1D TRAFFIC TYPE [4]](/figures/table-ii-802-1d-traffic-type-4-3qd4l0q7.webp)
