Multiplex communications – Channel assignment techniques – Details of circuit or interface for connecting user to the...
Reexamination Certificate
2000-04-03
2001-04-24
Hsu, Alpus H. (Department: 2662)
Multiplex communications
Channel assignment techniques
Details of circuit or interface for connecting user to the...
C370S465000, C341S051000, C341S110000
Reexamination Certificate
active
06222852
ABSTRACT:
COPYRIGHT NOTICE
Contained herein is material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction of the patent disclosure by any person as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all rights to the copyright whatsoever.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the field of baseband computer networks. Specifically, the present invention relates to a method and apparatus utilized by a dual speed 10/100 Mb/s physical layer device. The dual speed device provides support for transmitting waveshape information compatible with the Institute of Electrical and Electronic Engineers (IEEE) 802.3 Clause 14, 10 million bits per second (10 Mb/s) Physical Layer specification, i.e., IEEE 802.3 Standard 10BASE-T Ethernet, over a service interface in the physical layer.
Although not specified in IEEE 802.3, the interface can also be utilized in the implementation of 100 million bits per second (100 Mb/s) Local Area Network (LAN) physical layer devices compatible with the Physical Layer specifications defined in the IEEE 802.3u Supplement (excepting Clause 23 and 26), i.e., IEEE 802.3 Standard 100BASE-TX Ethernet.
2. Description of the Related Art
Overview of 10 MbAs and 100 Mb/s Baseband Networks
To better appreciate and understand the present invention, a brief overview of relevant aspects of 10 Mb/s and 100 Mb/s baseband local area networks follows. The operation of a Local Area Network (LAN) is often described in terms of the International Standards Organization (ISO) seven-layer Open Systems Interconnection (OSI) abstract reference model. Referring to
FIG. 1
, the relationship between the seven-layer OSI reference model
100
and the IEEE 802.3 architectural layers for 1 Mb/s to 20 Mb/s operation model
110
and 100 Mb/s operation model
115
are shown.
10BASE-T is an IEEE standard 802.3 and ISO/IEC standard 8802-3 Physical Layer specification for 10 Mb/s Ethernet LANs. 100BASE-T is an IEEE 802.3 standard supplement (802.3u ) Physical Layer specification for 100 Mb/s Ethernet LANs. The 802.3u standard extends the speed of the 802.3 Media Access Controller (MAC) to 100 Mb/s while utilizing the existing MAC service interface
102
of MAC
120
. MAC service interface
102
is connected through a Reconciliation sublayer
103
and a Media Independent Interface (MII)
130
to a Physical Layer Device (PHY) sublayer
104
. The MII is the IEEE 802.3 standard specification for a dual speed 10/100 Mb/s service interface in the Physical Layer
10
, although implementation of the MII is optional.
The PHY sublayer
104
may be specified for operation at data rates of either 10 Mb/s or 100 Mb/s. The specifics of a 10 Mb/s PHY sublayer connected to an MII are not explicitly defined by the 802.3 standard, but inferred to match the overall system performance objectives of the MAC
120
, PLS
121
, AUI
113
, PMA
114
, and MDI
111
architecture at 10 Mb/s.
Multiple PHY sublayers have been specified in IEEE standard supplement 802.3u (and later supplements) for operation at 100 Mb/s. The current list of 100 Mb/s PHY sublayer specifications includes 100BASE-T
4
, 100BASE-T
2
and 100BASE-X.
100BASE-T
4
specifies the use of four pairs of category 3, 4 or 5 Unshielded Twisted Pair (UTP) wire and supports only half duplex operation. 100BASE-T2 specifies the use of two pairs of category 3,4, or 5 UTP wire and supports full duplex operation. 100BASE-X supports two embodiments, both of which support full duplex operation: 100BASE-TX and 100BASE-FX. 100BASE-TX specifies the use of 2 pairs of category 5 UTP or shielded twisted pair (STP) wire. 100BASE-FX specifies the use of 2 optical fibers. Generally, the term 100BASE-X is used when referring to characteristics common to both 100BASE-TX and 100BASE-FX.
100BASE-X is an IEEE standard 802.3 Physical Layer specification for 100 Mb/s LANs that uses the FDDI signaling standards. 100BASE-X encompasses 100BASE-TX (which references ANSI X3T9.5 TP-PMD/312, Revision 2.2, FDDI Twisted Pair Physical Medium Dependent (PMD) sublayer), and 100BASE-FX (which references ISO 9314-3, 1990, Fiber Distributed Data Interface (FDDI)—Part 3: Token Ring PMD sublayer).
As described in clause 28 of IEEE standard 802.3u, Auto-Negotiation is an optional function that allows a network device, such as a workstation, switch or repeater, coupled to a point-to-point link segment, to advertise the modes of operation of which it is capable to a network device at the other end of the point-to-point link segment and detect corresponding operational modes that the other network device may be advertising. Auto-Negotiation provides the capability for future technology upgrades and can be modified to advertise such modes of operation as types of physical layer devices available, full -duplex communication, and flow control. Auto-Negotiation further provides, through the use of the Parallel Detect Algorithm, the ability to detect and interoperate with legacy, non-Auto-Negotiation, half duplex, 10BASE-T, 100BASE-TX and 100BASE-T
4
based nodes where applicable. Auto-Negotiation is designed for LANs implemented using unshielded twisted pair (UTP) copper wire and the well known, ISO/IEC 8802, eight-pin modular jack (RJ-45 connector). The signaling mechanism used in Auto-Negotiation is backwards compatible with the installed base of 10BASE-T baseband computer networks as defined in IEEE 802.3 Clause 14.
10BASE-T operation employs a discontinuous signaling method over the transmission medium. When data is not being sent over the medium, the voltage on the medium is zero, with the exception of an occasional Link Test Pulse
300
. The Link Test Pulse, as defined in IEEE standard 802.3 Clause 14, signals that an active link connection exists. The Link Test Pulse is generally a 100 nanosecond positive pulse that repeats approximately every 16 milliseconds. Clause 28 Auto-Negotiation refers to the 10BASE-T Link Test Pulse as the Normal Link Pulse (NLP). Auto-Negotiation uses multiple Link Test Pulses to form a burst referred to as a Fast Link Pulse (FLP) Burst, as a signaling mechanism. Auto-Negotiation substitutes the FLP Burst in place of the single 10BASE-T Link Test Pulse. This approach increases the signaling capability of the link identifier, while maintaining backwards compatibility with 10BASE-T. The FLP Burst encodes the data (identifying modes of operation) transmitted by the Auto-Negotiation function.
100BASE-T Architecture and Nomenclature
With reference to
FIG. 1
, the 100BASE-T standard extends the IEEE standard 802.3 Media Access Control (MAC) sublayer
120
to 100 Mb/s and couples the MAC sublayer to a 100 Mb/s Physical Layer
101
. The Physical Layer is comprised of additional sublayers including the Reconciliation Sublayer
103
, Media Independent Interface (MII) Sublayer
130
, Physical Coding Sublayer (PCS)
140
, Physical Medium Attachment (PMA) sublayer
150
, Physical Medium Dependent (PMD) sublayer
160
and, in a 100BASE-T
4
, 100BASE-T
2
or 100BASE-TX environment, an optional Auto-Negotiation (AutoNeg) sublayer
170
. The PMD sublayer
160
encompasses the Medium Dependent Interface (MDI)
180
. The MDI provides the medium attachment, including the connector, to the medium
190
, such as UTP or STP wiring.
Reconciliation Sublaver
The Reconciliation Sublayer maintains the same interface
102
to the MAC layer
120
for 100 Mb/s operation as for 1 Mb/s to 20 Mb/s operation by reconciling the differences between the Physical Layer architectures described in IEEE 802.3 clauses 5 through 20 utilizing the PMA
114
, AUI
113
, and MAU
112
sublayers, and the MII based architecture described in 802.3u.
Media Independent Interface (MII)
The MII sublayer provides, among other things, an interconnection between the MAC sublayer and Physical Layer devices. As the name implies, this layer was designed to clearly separate the MAC sublayer from medium dependent issues. Although optional in implementation, the MII is the dual speed, Physical Layer
Blakely , Sokoloff, Taylor & Zafman LLP
Ho Duc
Hsu Alpus H.
Nortel Networks Limited
LandOfFree
Method and apparatus for transmitting dual speed ethernet... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for transmitting dual speed ethernet..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for transmitting dual speed ethernet... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2471169