MPEG-2
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... architecture for the
transport of IP Datagrams over ISO MPEG-2 Transport Streams
[ISO-MPEG]. The prime focus is the efficient and flexible delivery ...
... architecture is designed to be compatible with services based on
MPEG-2, for example the Digital Video Broadcast (DVB) architecture ...
... ATSC) system [ATSC,ATSC-G], and other similar MPEG-2-based transmission systems. Such
systems typically provide unidirectional (simplex) physical ...
... |t|o|o|r| r | | r |a |r | native |
|e| | | | | | |b | | over |
|x| | | | | +---+----+-+ |l | |MPEG-2 TS|
|t| | | | | | | MPE ...
... ATM | |Sect. |Section| |
+-------+----------+---+------+-------+---------+
| MPEG-2 TS |
+---------+-------+----------------+------------+
...
... +---------+-------+----------------+------------+
Figure 1: Overview of the MPEG-2 protocol stack
Although many MPEG-2 ...
... MPEG-2 protocol stack
Although many MPEG-2 systems carry a mixture of data types, MPEG-2
components may be, and are, also used to build IP-only networks ...
...
Although many MPEG-2 systems carry a mixture of data types, MPEG-2
components may be, and are, also used to build IP-only networks.
...
... interoperability and larger deployment. However, some MPEG-2
networks do not implement all parts of a DVB ...
... architecture defined in this document describes a set of
protocols that support transmission of IP packets over the MPEG-2 TS.
Key characteristics of these networks ...
... Some, or all, of these protocols may also be applicable to other
subnetworks, e.g., other MPEG-2 transmission networks, regenerative
satellite links [ETSI-BSM ...
... IP services.
Since a majority of MPEG-2 transmission networks are bandwidth-
limited, encapsulation ...
... provided in a dynamic way, allowing transparent integration with
other IP-layer protocols. Collectively, these will form an MPEG-2 TS
Address Resolution ...
... and timing and synchronization information as well as stuffing over
an MPEG-2 Multiplex [ISO-MPEG].
...
... a set of associated standards for the transmission of video, audio,
and data using the ISO MPEG-2 standard [ISO-MPEG].
...
... ISO-DSMCC]. A
format for transmission of data and control information defined by
the ISO MPEG-2 standard that is carried in an MPEG-2 Private Section.
...
... format for transmission of data and control information defined by
the ISO MPEG-2 standard that is carried in an MPEG-2 Private Section.
DVB ...
... ETSI) for the transmission of
video, audio, and data, using the ISO MPEG-2 Standard [ISO-MPEG].
...
... TS Logical
Channel.
MPEG-2: A set of standards specified by the Motion Picture Experts
Group (MPEG ...
... PAT: Program Association Table [ISO-MPEG]. An MPEG-2 PSI control
table that associates program numbers with the PID value ...
... PES: Packetized Elementary Stream [ISO-MPEG]. A format of MPEG-2 TS
packet payload usually used for video or audio information.
...
... private information (i.e., not defined by [ISO-MPEG]) relating to one
or more elementary streams, or a specific MPEG-2 program, or the
entire TS. Other Standards bodies (e.g., ETSI ...
... Data Unit. An encapsulated PDU sent as an MPEG-2
Payload Unit.
STB: Set-Top Box. A consumer equipment (Receiver ...
... ISO-MPEG], a method of transmission at the
MPEG-2 level using TS Packets; it represents level 2 of the ISO/OSI ...
... Logical Channel. In this
document, this term identifies a channel at the MPEG-2 level
[ISO-MPEG]. It exists at level 2 of the ISO ...
... (this value is unique within a specific TS Multiplex). According to
MPEG-2, some TS Logical Channels are reserved for specific
...
...
The following sections introduce the components of the MPEG-2
Transmission Network and relate these to a networking framework.
...
... MPEG-2 Transmission Networks ...
...
There are many possible topologies for MPEG-2 Transmission Networks.
A number of example scenarios are briefly described below, and the
following text relates specific functions to this set of scenarios.
...
... the broadcast transmission, including allocation of PIDs and
generation of appropriate MPEG-2 control information (e.g., DVB and
ATSC ...
... sized groups of Receivers. MPEG-2 transmission technology provides
the forward direction physical and link layers ...
... Point-to-Point connectivity may be provided using a pair of transmit
and receive interfaces supporting the MPEG-2 physical and link
layers. Typically, the transmission from a sender ...
... direction at the physical and link layers is MPEG-2, which may also
be used in the return direction. Such systems also usually include a
control plane ...
...
Scenarios A-D employ unidirectional MPEG-2 Transmission Networks.
For satellite-based networks ...
... RFC3077].
Note that only Scenarios A-B actually carry MPEG-2 video and audio
(intended for reception by digital Set Top Boxes (STBs)) as the
...
... control plane.
Scenarios E-F provide two-way connectivity using the MPEG-2
Transmission Network. Such networks provide direct support for
bidirectional ...
... IP layer.
The complete MPEG-2 transmission network may be managed by a
transmission service operator. In such cases, the assignment of
...
... service operator. Examples include a TV operator
(Scenario A), or an ISP (Scenarios B-F). MPEG-2 transmission
networks are also used for private networks. These typically involve
a smaller number of Receivers ...
... PID) value that is carried
in the header of each MPEG-2 TS Packet. The PID value is a 13 bit ...
... TS Logical Channels are independently numbered on each MPEG-2 TS
Multiplex (MUX). In most cases, the data sent over the TS Logical
Channels ...
... multicast content that needs
to be received by Receivers tuned to either MPEG-2 TS; unicast data
...
... where the Receiver may be in either/both of two potentially
overlapping MPEG-2 transmission cells). In figure 2, each multiplex
carries 3 MPEG-2 TS ...
... overlapping MPEG-2 transmission cells). In figure 2, each multiplex
carries 3 MPEG-2 TS Logical Channels. These TS ...
... TS Logical Channels are processed by
an MPEG-2 multiplexor, resulting in a TS Multiplex. The TS Multiplex
...
... In a more complex example, the same TS may be fed to multiple MPEG-2
multiplexors and these may, in turn, feed other MPEG-2 multiplexors
...
... TS may be fed to multiple MPEG-2
multiplexors and these may, in turn, feed other MPEG-2 multiplexors
(remultiplexing). Remultiplexing may occur in several places (and is
common in Scenarios A and B of Section 3.1). One example is a
...
... SI Tables | | |
+-------+-------+ ->+------+--------+ |
| -->| MPEG-2 | . . .
+------------>+ Multiplexor | |
MPEG-2 ...
... MPEG-2 | . . .
+------------>+ Multiplexor | |
MPEG-2 TS +------+--------+ |
Logical Channel ...
... +------+--------+ +------+-----+
|Physical Layer | | MPEG-2 |
|Modulator +---------->+ Receiver |
...
...
Packet data for transmission over an MPEG-2 Transport Multiplex is
passed to an Encapsulator ...
... PID value of a logical link). It is common for
a number of MPEG-2 TS Logical Channels to carry SNDUs ...
... concurrent reception of IP Packets over other media that may not
necessarily use MPEG-2 transmission.
Bidirectional ...
...
Bidirectional (duplex) transmission can be provided using an MPEG-2
Transmission Network by using one of a number of alternate return
channel schemes [ETSI-RC ...
... ETSI-RC]. Duplex IP paths may also be supported
using non-MPEG-2 return links (e.g., in Scenarios B-D of section
3.1). One example of such an application is that of UniDirectional ...
... architecture will provide:
(i) Guidance on which MPEG-2 features are pre-requisites for the
IP service, and identification of any optional fields that
...
... broadcast. To make the schemes robust to loss and
state changes within the MPEG-2 transmission network, a soft-
state approach may prove desirable.
...
... state approach may prove desirable.
(v) Standards to associate the capabilities of an MPEG-2 TS
Logical Channel with IP flows. This includes mapping of QoS ...
... (vi) Guidance on Security for IP transmission over MPEG-2. The
framework must permit use of IPsec ...
... architecture and techniques should be suited to a range
of systems employing the MPEG-2 TS, and may also suit other
(sub)networks ...
... PDU (e.g., IPv4 or IPv6
packet) to form an MPEG-2 Payload Unit.
Examples of existing encapsulation ...
... / / \ \
+------+----------+ +------+----------+ +------+----------+
|MPEG-2| MPEG-2 |..|MPEG-2| MPEG-2 ...
... +------+----------+ +------+----------+ +------+----------+
|MPEG-2| MPEG-2 |..|MPEG-2| MPEG-2 |...|MPEG-2 ...
... a Table Section (with the format used by the control plane associated
with the MPEG-2 transmission). The MPE specification includes a set
of optional header ...
... A combination of the PUSI and a Length Indicator (see below) allows
an efficient MPEG-2 convergence protocol to receive accurate
delineation of packed SNDUs ...
... convergence protocol to receive accurate
delineation of packed SNDUs. The MPEG-2 standard [ISO-MPEG] does not
specify how private data ...
... the core of the current Internet. This would seem a suitable maximum
size for an MPEG-2 transmission network.
...
... throughput on links that have a limited capacity.
Since many MPEG-2 Transmission Networks are wireless, the ROHC
...
... If it is required to address an individual Receiver in an MPEG-2
transport system, this can be achieved either at the network ...
... links).
Mechanisms exist in MPEG-2 Transmission Networks that may assist in
detecting loss (e.g., the 4-bit continuity counter ...
... In some cases (e.g., ATM, X.25, MPEG-2 and many more), AR involves
finding other information than the MAC address ...
... Multicast address resolution is not required for many L2 networks,
but is required where MPEG-2 transmission networks carry IP multicast
packets using more than one TS Logical Channel.
...
... Address Resolution for MPEG-2 ...
...
Elements (ii) and (iii) need to be de-referenced when the MPEG-2
Transmission Network includes (re)multiplexors that renumber the PID
values of the TS Logical Channels ...
... PID
values of the TS Logical Channels that they process. In MPEG-2
[ISO-MPEG], this dereferencing ...
... \-----/
Figure 6: MPEG-2 Transmission Network with 2 Receivers
...
... If the Hub is an L2 bridge, then case 2 still has to relay the IP
packet back to the outbound MPEG-2 channel. The AR protocol needs to
...
... AR information in three distinct ways:
(i) An MPEG-2 signalling table transmitted at the MPEG-2 level
(e.g., within the control plane ...
...
(i) An MPEG-2 signalling table transmitted at the MPEG-2 level
(e.g., within the control plane using a Table);
...
... control plane using a Table);
(ii) An MPEG-2 signalling table transmitted at the IP level (no
implementations of this are known);
...
... TS Logical Channels as they pass through the
MPEG-2 transmission network (as in Scenario A of Section 3.1).
(ii) Tuner configuration(s) that are fixed or controlled by some
...
... MPEG-2 networks, information about the set
of MPEG-2 TS Logical Channels carried over a TS Multiplex ...
... control plane by processing the SI table information
(carried in MPEG-2 section format [ISO-DSMCC]). The scheme reflects
the complexity of delivering and coordinating the various TS ...
... for IP services is to integrate additional information into the
existing MPEG-2 tables, or to define additional tables specific to
the IP service. The DVB ...
... networks. It also is advantageous for networks that use the MPEG-2
TS, but do not necessarily support audio/video ...
... ND protocol). The AR
protocol may operate over an MPEG-2 TS Logical Channel using a
previously agreed PID ...
...
In some cases, an MPEG-2 Transmission Network may support multiple IP
networks. When this is the case, it is important to recognize the
context ...
... address to be used.
The MPEG-2 Transmission Network may also require access control to
prevent unauthorized use ...
... multicast [RFC1112] over MPEG-2 Transmission Networks. The primary
goal of multicast support will be efficient filtering ...
... MPEG-2 Encapsulator may forward multicast
traffic on the MPEG-2 TS Multiplex using a static or dynamic set of
groups ...
... (ii) Mapping IP multicast groups to the underlying MPEG-2 TS
Logical Channel (PID) and the MPEG-2 ...
... services over
networks built upon the MPEG-2 Transport Stream (TS). It also
describes existing approaches. The focus is on IP ...
... dynamic configuration of the sender and Receiver
using an MPEG-2 transmission link/network. These support IPv4 and
IPv6 ...
... security mechanisms only within a subnetwork (e.g., an
MPEG-2 Transmission Network). Several security mechanisms that can
be used end-to-end ...
... security mechanisms at the application layer, or
within the MPEG-2 transmission network, are the concerns of
organisations beyond the IETF. The complexity of any such security
mechanisms ...
... Unidirectional Lightweight Encapsulation (ULE) for transmission of IP datagrams over an MPEG-2 Transport Stream", Work in Progress, June 2005. ...
... Fairhurst, G. and M-J. Montpetit, "Address Resolution for IP datagrams over MPEG-2 networks", Work in Progress, 2005. ...
... Appendix A: MPEG-2 Encapsulation Mechanisms ...
...
Transmitting packet data over an MPEG-2 transmission network requires
that individual PDUs (e.g., IPv4 ...
... convergence protocol. The following
encapsulations are currently standardized for MPEG-2 transmission
networks:
(i) Multi-Protocol Encapsulation ...
... broadcast descriptor table [ETSI-DAT] sent
separately over another MPEG-2 TS within the TS multiplex.
...
... MPE is currently a widely deployed scheme. Due to
Investments in existing systems, usage is likely to continue
in current and future MPEG-2 Transmission Networks. ATSC
provides a scheme similar to MPE ...