Multiplex communications – Communication techniques for information carried in plural... – Combining or distributing information via time channels
Reexamination Certificate
2000-08-31
2004-08-03
Pham, Chi (Department: 2667)
Multiplex communications
Communication techniques for information carried in plural...
Combining or distributing information via time channels
Reexamination Certificate
active
06771673
ABSTRACT:
§ 1. BACKGROUND OF THE INVENTION
§ 1.1 Field of the Invention
The present invention concerns methods, apparatus and data structures for aggregating traffic, which may originate from various media transport types, for presentation to a router, such as an access router of a network. Further, the traffic aggregation performed by the present invention may be done such that customers can be identified and such that customer device addressing information is available. Moreover, the traffic aggregation performed by the present invention may be done such that the service provided to a group of customers may be monitored; multicast groups are secure; and the access router can control access to services, facilitate virtual private networks, and facilitate the provision of different quality of service and/or class of service levels.
§ 1.2 Related Art
The description of art in this section is not, and should not be interpreted to be, an admission that such art is prior art to the present invention.
§ 1.2.1 Communications Protocol Stack
Although networking software and network reference models are known to those skilled in the art, they are introduce here for the reader's convenience.
To reduce their complexity, networks may be organized as a series of layers, each one built upon the one below it as shown in FIG.
1
. Each layer functions to offer certain services to the higher layer, thereby shielding those higher layers from the details of how the offered services are actually implemented. The entities comprising the corresponding layers on different machines are called “peers”. Such peers use rules and conventions, also referred to as the layer n protocol, to communicate with each other as depicted by the dashed lines in FIG.
1
. Actually, no data are directly transferred from layer n on one machine to layer n on another machine. Rather, in the machine transmitting the data, each layer passes data and control information to the layer immediately below it, until the lowest layer (layer
1
) is reached. Below layer
1
, is a physical medium
110
through which actual communications take place. At the machine receiving the data, each layer passes data and control information to the layer immediately above it until the highest layer is reached. Thus, referring to
FIG. 1
, actual communications take place via the solid lines and the physical medium
110
, while virtual peer-to-peer communications occur via the dashed lines.
Still referring to
FIG. 1
, interfaces are arranged between adjacent layers. Each of these interfaces defines primitive operations and services that the lower layer offers to the upper layer.
The set of layers and protocols may be referred to as a “network architecture”. A list of protocols used by a system, one protocol per layer, may be referred to as a “protocol stack” or “protocol suite”.
§ 1.2.2 Network Architecture Reference Models
FIG. 2
illustrates a comparison of the Open Systems Interconnection (or “OSI”) reference model
210
for network architectures and the transfer control protocol/Internet protocol (or “TCP/IP”) reference model
220
for network architectures. Although those skilled in the art will be familiar with both reference models, each is introduced below for the reader's convenience.
§ 1.2.2.1 The OSI Reference Model
As shown in
FIG. 2
, the OSI reference model
210
has seven (7) distinct layers; namely, (i) a physical layer
211
, (ii) a data link layer
212
, (iii) a network layer
213
, (iv) a transport layer
214
, (v) a session layer
215
, (vi) a presentation layer
216
, and (vii) an application layer
217
. Each layer is briefly introduced below.
The physical layer
211
deals with transmitting raw bits over a communications channel. Thus, the physical layer is typically concerned with mechanical, electrical, optical, and procedural interfaces, as well as the physical transmission medium (e.g., twisted copper pair, co-axial cable, optical fiber, etc.) that lies below the physical layer.
The data link layer
212
functions to transform a raw communications facility into a line that appears free from undetected transmission errors to the network layer
213
. The data link layer
212
does this by having the sending host segment its data into “data frames”, transmitting these frames to the receiving host, and processing “acknowledgement frames” sent back from the receiver.
The network layer
213
functions to control the operation of a subnetwork between the hosts and controls the routing of packets between the hosts.
The transport layer
214
functions to accept data from the session layer
215
and segment this data into smaller units, if necessary, for use by the network layer
213
. The transport layer
214
also determines a type of service (e.g., error-free, point-to-point) to provide to the session layer
215
. Further, the transport layer
214
controls the flow of data between hosts. The transport layer
214
is a true “end-to-end” layer, from source host to destination host, since a program on the source machine converses with a similar program on the destination machine, using message headers and control messages.
The session layer
215
functions to allow different machines to establish sessions between them. The session layer
215
may manage dialog control and maintain synchronization.
The presentation layer
215
concerns the syntax and semantics of information transmitted.
The application layer
216
may function to define network virtual terminals that editors and other programs can use, and to transfer files.
§ 1.2.2.2 The TCP/IP Model
In recent decades, and in the past five (5) to ten (10) years in particular, computers have become interconnected by networks by an ever increasing extent; initially, via local area networks (or “LANs”), and more recently via LANs, wide area networks (or WANs) and the Internet. In 1969, the Advanced Research Projects Agency (ARPA) of the U.S. Department of Defense (DoD) deployed ARPANET as a way to explore packet-switching technology and protocols that could be used for cooperative, distributed, computing. Early on, ARPANET was used by the TELNET application that permitted a single terminal to work with different types of computers, and by the file transfer protocol (or “FTP”) which permitted different types of computers to transfer files from one another. In the early 1970s', electronic mail became the most popular application which used ARPANET.
This packet switching technology was so successful, that the ARPA applied it to tactical radio communications (Packet Radio) and to satellite communications (SATNET). However, since these networks operated in very different communications environments, certain parameters, such as maximum packet size for example, were different in each case. Thus, methods and protocols were developed for “internetworking” these different packet switched networks. This work lead to the transmission control protocol (or “TCP”) and the internet protocol (or “IP”) which became the TCP/IP protocol suite. Although the TCP/IP protocol suite, which is the foundation of the Internet, is known to those skilled in the art, it is briefly described below for the reader's convenience.
As shown in
FIG. 2
, the TCP/IP reference model
220
includes a physical layer
221
, a network access layer
222
, an internet layer
223
, a transport layer
224
, and an application layer
225
. Each of these layers is briefly introduced below.
The physical layer
221
defines the interface between a data transmission device (e.g., a computer) and a transmission medium (e.g., twisted pair copper wires, co-axial cable, optical fiber, etc.). It specifies the characteristics of the transmission medium, the nature of the signals, the data rate, etc.
The network access layer
222
defines the interface between an end system and the network to which it is attached. It concerns access to, and routing data across, a network. Frame relay is an example of a network access layer.
The internet layer
223
functions to permit hosts to inject packets into any network and have them trav
Baum Robert T.
Voit Eric A.
Jones Prenell
Pham Chi
Straub, Esq. Michael P.
Suchyta, Esq. Leonard C.
Verizon Communications Inc.
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