Internet Engineering Task Force Gorry Fairhurst
Internet Draft University of Aberdeen, U.K.
Document: draft-fair-ipdvb-ule-00.txt Bernhard Collini-Nocker
University of Salzburg, A
Category: Draft May 2003
Ultra Lightweight Encapsulation (ULE) for transmission of
IP datagrams over MPEG-2/DVB networks
Status of this Draft
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
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progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
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Document history
This draft is intended as a study item for proposed future work by
the IETF in this area. Comments relating to this document will be
gratefully received by the author(s) and the ip-dvb mailing list at:
ip-dvb@erg.abdn.ac.uk
Abstract
This document contains an alternative Ultra Lightweight Encapsulation
(ULE) mechanism for the transport of IP Datagrams directly over ISO
MPEG-2 Transport Streams (TS) as TS private data. The MPEG-2 TS has
been widely accepted not only for providing digital TV services, but
also as a subnetwork technology for building IP networks.
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Table of Contents
1. Introduction
2. Conventions used in this document
3. Description of method
4. SNDU Format
4.1 Bridged Payload
4.2 IPv4 Encapsulation
4.3 Ipv6
5. Processing at the Encapsulator and Receiver
5.1 Encapsulator processing
5.2 Flushing the bitstream
5.3 Receiver Processing
6. Summary
7. Acknowledgments
8. Security Considerations
9. References
10. Authors' Addresses
11. IANA Considerations
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1. Introduction
This document describes an encapsulation for transport of IP
datagrams or other network layer packets over ISO MPEG-2 Transport
Streams [ISO-MPEG]. This is suited to services based on MPEG-2, for
example the Digital Video Broadcast (DVB) architecture, the Advanced
Television Systems Committee (ATSC) system [ATSC; ATSC-G], and other
similar MPEG-2 based transmission systems. Such systems typically
provide unidirectional (simplex) physical and link layer standards,
and have been defined for a wide range of physical media (e.g.
Terrestrial TV [ETSI-DVBT; ATSC-PSIP-TC], Satellite TV [ETSI-DVBS;
ATSC-S],Cable Transmission [ETSI-DVBC; ATSC-PSIP-TC]). Bi-
directional (duplex) links may also be established using these
standards (e.g., DVB defines a range of return channel technologies,
including the use of two-way satellite links [ETSI-RCS] and dial-up
modem links [RFC3077]).
Data for transmission over the MPEG-2 transport multiplex is passed
to an encapsulator that typically receives PDUs (Ethernet
Frames, IP datagrams or other network layer packets). It formats
each PDU into a series of TS Packets (usually after adding an
encapsulation header), which is sent over a TS logical channel.
The draft describes a mechanism aimed at a subset of the services
supported by [draft-unisal-ipdvb-enc-01.txt]. The format of this
document resembles this for ease of comparison and much of the
background text is common, although the encapsulation protocol is
different and more lightweight.
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2. Conventions used in this document
ADAPTATION FIELD: An optional variable-length extension field of the
fixed-length TS Packet header, intended to convey clock references
and timing and synchronization information as well as stuffing over
an MPEG-2 multiplex [ISO-MPEG].
AFC: Adaptation Field Control.
ATSC: Advanced Television Systems Committee [ATSC]. A set of
framework and associated standards for the transmission of video,
audio, and data, using the ISO MPEG-2 standard.
DSM-CC: Digital Storage Management Command and Control [ISO-DSMCC].
A formatting defined by the ISO MPEG-2 standard, which is carried in
an MPEG-2 private section.
DVB: Digital Video Broadcast [ETSI-DVB]. A set of framework and
associated standards for the transmission of video, audio, and data,
using the ISO MPEG-2 standard.
ENCAPSULATOR: A network device which receives PDUs (Ethernet frames
or IP datagrams) and formats these for output as a transport stream
of TS Packets.
MAC: Medium Access and Control of the Ethernet IEEE 802 standard of
protocols.
MPE: Multiprotocol Encapsulation [ETSI-DAT]. A scheme that
encapsulates Ethernet frames or IP Datagrams, creating a
DSM-CC Section. The Section will be sent in a series of TS Packets
over a TS logical channel.
MPEG-2: A set of standards specified by the Motion Picture Experts
Group (MPEG), and standardized by the International Standards
Organisation (ISO) [ISO-MPEG].
PES: Programme Elementary Scheme of MPEG-2 [ISO-MPEG].
PID: Packet Identifier. A field carried in the header of all MPEG-2
Transport Stream packets. This is used to identify the TS logical
channel to which it belongs [ISO-MPEG].
PUSI: Payload_Unit_Start_Indicator of MPEG-2 [ISO-MPEG]. A PUSI
value of zero indicates that the TS Packet does not carry the start
of a new payload. In this document, a PUSI value of one indicates
that the TS Packet does carry the start of a new payload. When the
PUSI bit is set to 1, in ULE this also indicates the presence of a
one byte pointer directly following the TS packet header.
PRIVATE SECTION: a syntactic structure used for mapping all service
information (e.g. an SI table) into TS Packets. A table may be
divided into a number of sections. All sections of a table must be
carried over a single TS logical channel.
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SI TABLE: Service Information Table. In this document, the term is
used to describe any table used to convey information about the
service carried in a TS Multiplex (e.g. [ISO-MPEG]). SI tables are
carried in MPEG-2 private sections.
SNDU: Subnetwork Data Unit, an IPv4 or IPv6 datagram (or other
subnetwork packet, e.g., an arp message or bridged Ethernet frame).
TS: Transport Stream [ISO-MPEG], a method of transmission at the
MPEG-2 level using TS Packets; it represents level 2 of the ISO/OSI
reference model. See also TS logical channel and TS Multiplex.
TS LOGICAL CHANNEL: a channel identified at the MPEG-2 level; it
represents level 2 of the ISO/OSI reference model. All packets sent
over a channel carry the same PID value
TS MULTIPLEX: A set of MPEG-2 transport stream channels sent over a
single common physical link (i.e. a transmission at a specified
symbol rate, FEC setting, and transmission frequency).
TS PACKET: A fixed-length 188B unit of data sent over an MPEG-2
multiplex [ISO-MPEG]; it corresponds to the cells, of e.g. ATM
networks, and is frequently also referred to as a TS_cell. Each TS
Packet carries a 4B header, plus optional overhead including an
adaptation field, encryption details and time stamp information to
synchronise a set of Transport Streams.
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3. Description of method
Routed IP packets and bridged Ethernet frames shall be encapsulated
to form a Subnetwork Data Unit (SNDU). The method encapsulates IP
packets, Ethernet frames or packets from other network protocols
within a SNDU. The SNDU transmitted over an MPEG-2 transmission
system, by placing it in the payload of a single TS Packet, or, if
required, the SNDU may be fragmented into a series of TS Packets.
Where there is sufficient space, the method allows a single TS
Packet to carry more than one SNDU (or part there of).
All packets from a SNDU shall be assigned the same PID, and shall
therefore form a part of the same logical TS channel.
The ULE encapsulation is limited to TS private streams only. In TS
private streams, one may define the use of PUSI, AFC, and adaptation
field as appropriate [ISO-MPEG].. The method relies upon use of the
Payload Unit Start Indicator (PUSI) carried in the 4 byte header of
each TS Packet.
The header of each TS Packet carries a one bit Payload Unit Start
Indicator (PUSI) field whose semantics is defined for PES and PSI
packets; for private data its use is not defined in the MPEG-2
standard. IN ULE, this bit is used by the encapsulation to identify
the start of a payload unit within the MPEG-2 TS Packet Payload.
Hence, when used with this encapsulation, the following PUSI values
are defined:
0 - the TS Packet does not contain the start of a SNDU but the
continuation or end of a SNDU;
1 the TS Packet contains the start of a SNDU, and a one byte
pointer follows the last byte of the 4 byte TS Packet Header.
The TS Packet Header also carries a two bit Adaptation Field Control
(AFC) value. This value is not used in this encapsulation method,
and TS packets from a ULE encapsulator will normally be sent with an
AFC value of '01'. Standard decoders shall discard TS Packets with
the adaptation_field_control field set to a value of '00'; in the
case of a null packet the value of the adaptation_field_control
shall be set to '01'. The purpose of the adaptation field is
primarily to carry timing and synchronisation information and
occasionally to include stuffing bytes.
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4. SNDU Format
The encapsulation format to be used for IP packets and bridged
Ethernet frames is shown below:
+---------------------------------------------------+--------+
| length | type | SNDU field | CRC-32 |
+---------------------------------------------------+--------+
Figure 1: SNDU Encapsulation
Note that the SNDU field might include a Òlabel or some other form
of discriminator field, which in combination with the PID value,
could be interpreted as a ÒLink-Level address.
Length Field
A 16-bit value indicates the length in bytes of the SNDU
(encapsulated Ethernet frame, IP datagram or other packet) counted
from the byte following the type field up to and including the CRC.
The special value 0x0000 indicates that there are no further SNDUs
within the current TS packet (see section 5.1). The maximum value is
65531 bytes.
Type Field
The 16-bit type field indicates the type of payload being sent.
Three types are suggested in this document. These are:
0x0800 : IPv4 Payload (according to IANA EtherTypes)
0x86DD : IPv6 Payload (according to IANA EtherTypes)
0x8847 : MPLS frame (according to IANA EtherTypes)
0x????: ROHC Compressed IPv4 Packet
0x????: ROHC Compressed IPv6 Packet
0x6558: Bridged Ethernet Frame (i.e. MAC header follows)
All other assignments should be coordinated with the values defined
for IANA EtherTypes encapsulations.
[AuthorÌs note: An assignment of one/two bits of the type field to
indicate the presence of a MAC header following the SNDU type field
may simplify receiving processing. This may necessitate the use of
alternate type codes to those described above. This is an area of
future study, to be confirmed in the next revision of this draft.]
[AuthorsÌ note: suitable values for bridged Ethernet Frames to be
determined; suitable values for ROHC types to be determined]
IPv4 SNDU
The payload shall be a complete IPv4 datagram.
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IPv6 SNDU
The payload shall be a complete IPv6 datagram.
Bridged SNDU
The payload shall be a bridged MAC frame (see section 4.1).
CRC
Each SNDU MUST have a CRC field carries a CRC value calculated by
the encapsulator and checked by the receiver this protects the
entire SNDU. A CRC-32 is recommended for SNDUs up to 12 KB in size.
The primary purpose of this CRC is to protect an IP payload from
undetected resassembly errors and errors introduced by unexpected
software / hardware operation at the IP encapsulation gateway and/or
the receiver. It may also be used to detect the presence of
uncorrected errors from the physical link (these however may, in
some case, also be detected by other means).
4.1 Bridged Payload
The Bridged Payload shall carry an SNDU field with the following
format shown in figure 2.
+-------------------------------+
| Length and Type fields (4B) |
+-------------------------------+
| MAC destination address (6B) |
+-------------------------------+
| MAC source address (6B) |
+-------------------------------+
| Ethernet (DIX) Type (2B) |
+-------------------------------+
| |
| (remainder of MAC frame) |
| |
+-------------------------------+
| CRC_32 (4B) |
+-------------------------------+
Figure 2: SNDU Format for a Bridged Payload
The MAC addresses shall be assigned according to the rules specified
by the IEEE and may denote unknown, unicast, broadcast, and
multicast link addresses. The type of frame shall be defined
according to Ethernet [DIX]. Note that Òarp messages relate to the
binding of MAC addresses to IP addresses are carried in this format
and are identified by the appropriate DIX Ethernet frame type.
In normal operation, it is expected that any padding appended to the
Ethernet frame will be removed prior to forwarding. This requires the
sender to be aware of such padding.
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32-bit CRC
The LAN FCS field, is in this case not forwarded by the
encapsulation, and is replaced by a CRC-32 calculated by the IP
encapsulator. Note: It is assumed the LAN FCS is checked prior to
removal.
4.2 IPv4 Encapsulation
IPv4 datagrams will be transported over the MPEG-2 Transport Stream
using the SNDU structure shown in figure 3.
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| Length (2B) | Type = 0x0800 |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| |
| IPv4 datagram |
| |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| (CRC_32) |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
Figure 3: SNDU Format for an IPv4 Datagram
4.3 IPv6 Encapsulation
IPv6 datagrams will be transported over the MPEG-2 Transport Stream
using the SNDU structure shown in figure 4.
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| Length (2B) | Type = 0x86DD |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| |
| IPv6 datagram |
| |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| (CRC_32) |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
Figure 4: SNDU Format for an IPv6 Datagram
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5. Processing at the Encapsulator and Receiver
5.1 Encapsulator processing
The encapsulator shall fragment the SNDU into a series of MPEG-2 TS
Packets belonging to the same logical TS channel (figure 5).
+-----------------------------------------+
|Encap Header| Subnetwork PU |
+-----------------------------------------+
/ / \ \
/ / \ \
/ / \ \
+------*----------* +------*----------* +------*----------+
|MPEG-2| MPEG-2 |..|MPEG-2| MPEG-2 |...|MPEG-2| MPEG-2 |
|Header| Payload | |Header| Payload | |Header| Payload |
+------+----------+ +------+----------+ +------+----------+
Figure 5: Encapsulation of a subnetwork Payload_Unit (SNDU) e.g. an
IP datagram into a series of TS Packets (each TS Packet carries a
header with a common Packet ID, PID, value).
The encapsulation layer will first wrap each payload unit (IP
datagram or Ethernet frame) to form a SNDU. (This is similar to an
AAL5 encapsulation in ATM networks). This SNDU will then be
segmented into payload units of TS Packets; the resulting set of TS
Packets will all use the same PID value and successive values for
the continuation counter. This set will then be sent as a sequence
over a TS multiplex or possibly as one burst over a satellite link.
Measurements of IP traffic have shown that the overwhelming majority
of the datagrams have lengths of 1500 or 576 bytes for data and 40
or 48 bytes for control traffic; for example, these values represent
almost 96% of the typical world-wide-web traffic.
The most frequent situations for the encapsulator are:
- a short control packet using only a fraction of the
TS payload of 184 bytes;
- a long data packet using a number of TS Packets with
the last one containing only a remainder.
Both of the most frequent values (576 and 1500) lead
to a fairly high overhead in the last TS Packet.
Since radio/satellite bandwidth is an expensive resource, as opposed
to bandwidth in LANs, it is necessary to look for improvements. One
possibility is header compression but this is outside the scope of
this proposal. Another one is to pack SNDUs densely into TS Packets,
i.e. whenever the encapsulator has more than one SNDU available it
fills the TS Packets completely by appending the data of the
following SNDU directly to the preceding one before segmentation.
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When the encapsulator has not previously sent a TS Packet for the
specified logical TS channel, or after an idle period, it will start
sending the SNDU in the first available TS Packet. This first TS
Packet MUST carry a value of one in the payload_unit_start_indicator
(PUSI) to indicate it contains the start of a SNDU. It will also
carry a Payload Pointer value of one to indicate that the SNDU
starts in the first available byte of the TS Packet payload.
The encapsulator will continue to fill subsequent TS Packets, until
the end of the SNDU.
If the TS Packet carrying the final part of a SNDU has either zero
or one byte of unused payload, the encapsulator will start
transmission of the next SNDU in a new TS Packet. For the case of
one remaining byte this MAY be assigned the value of 0x00, but this
value MUST NOT be required at the receiver.
+------------------+ +------------------+
| Subnetwork | | Subnetwork |
| DU 1 | | DU 2 |
+------------------+ +------------------+
\ \ / /
\ \ / /
\ \ / /
+------+--------+--------+----------+
|MPEG-2| Payload| end of | start of |
|Header| Pointer| SNDU 1 | SNDU 2 |
+------+--------+--------+----------+
| ^
PUSI=1 | |
+--------------+
Figure 6 A TS Packet carrying the end of SNDU 1, followed by SNDU 2
If more packets are waiting at the encapsulator, and a TS Packet has
more than two bytes of unused payload, it MAY start the next SNDU in
the next available byte of the TS Packet payload. The PUSI MUST be
set, if not already set. If the PUSI is set by this operation, the
payload pointer MUST be assigned to the position of the byte
following the end of the first SNDU in the TS Packet payload.
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+-------------+
| Subnetwork |
| DU 3 |
+-------------+
\ \
\ \
\ \
+------+--------+--------+----------+
|MPEG-2| end of | 0x0000 | Unused |
|Header| SNDU 3 | | |
+------+--------+--------+----------+
PUSI=0 End
Indicator
Figure 7 A TS Packet carrying the end of SNDU 3, followed by idle
If the TS Packet carrying the final part of a SNDU has two or more
bytes of unused payload, and an encapsulator does not start a new
SNDU to use this unused payload, it MUST directly follow the final
byte of the last SNDU with the value 0x00 00. This value
corresponds to a SNDU payload length of zero, and is an End
Indicator, informing the receiver that there are no more SNDUs in
this TS Packet payload.
When a SNDU is less than the size of a TS Packet payload, a TS
Packet may be formed which carries a PUSI value of one and also an
End Indicator.
5.2 Flushing the bitstream
MPEG-2 multiplexers do not usually flush their buffers, but store TS
Packets until the buffer fills, assuming that the data comes in a
more or less continuous stream. In the case of data traffic, this
assumption no longer holds, leading to the problem that the last IP
datagram will be only partly transmitted unless a special Òpush
packet is appended. This introduces additional overhead and is not
an appealing solution.
A further SNDU within the same TS Packet is only started if it is
already available in the encapsulatorÌs buffer at the time the
previous one is encapsulated. The encapsulator does not wait for
another SNDU to fill a TS Packet, because this would introduce
additional latency.
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5.3 Receiver Processing
Receipt of a TS Packet with a non-zero PUSI value indicates that the
TS Packet contains the start of a new SNDU. It also indicates the
presence of the Payload Pointer. The Payload Pointer value indicates
that there are payload ((Payload Pointer) 1) bytes of the SNDU
currently being reassembled at the start of the TS Packet payload. A
Payload Pointer value equal to 0 or greater than 183 is illegal in
ULE, and the SNDU reassembly MUST be aborted. This event may
generate an error message.
A receiver reassembles SNDUs from the TS Packets received from a
logical TS channel. To perform this reassembly, the receiver may use
a buffer to hold the partially assembled SNDU, referred to here as
the Current SNDU buffer. Other implementations may choose to use
other data structures, but must provide equivalent operations.
Initialisation
After initialisation or an idle period, the receiver discards the
contents of the Current SNDU buffer and waits for the start of the
next SNDU by waiting for a TS Packet with a PUSI value of 1. All
other TS Packets are discarded in this mode.
A PUSI value of 1, indicates the presence of a Payload Pointer. For
the first TS Packet received, the Payload Pointer will also normally
have a value of 1. Following a loss of synchronisation, values
between 2 and 183 are permitted, in which case the receiver MUST
discard ((Payload Pointer) 1) bytes, before starting reassembly of
the next SNDU.
Processing of received SNDUs
The receiver reads the SNDU Length field from the current SNDU. If
this Length is less than or equal to 3, the receiver discards the
Current SNDU and the remaining TS Packet payload and returns to a
search for the next TS Packet with a PUSI value of 1.
If the Length of the Current SNDU is greater than 4, it then accepts
bytes from the TS Packet payload to the Current SNDU buffer until
either Length bytes in total are received, or the end of the TS
Packet is reached. When Length bytes are received, the receiver MUST
calculate and verify the CRC value. SNDUs that contain an invalid
CRC value MUST be discarded. After receiving a valid SNDU, the
receiver MUST check the Type Field. The SNDU payload is then passed
to the next protocol layer specified. An SNDU with an unknown Type
value MUST be discarded.
The receiver then starts reassembly of the next SNDU. This may
directly follow the previously reassembled SNDU within the TS Packet
Payload.
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If there is either 0 or 1 byte of payload data remaining in the TS
Packet after completion of the Current SNDU, the receiver MUST
discard this remaining TS payload, and wait for the next TS Packet
with the PUSI value set to 1.
If there more than one byte of payload data remains in the TS Packet
after completion of the Current SNDU, the receiver MUST accept the
next bytes as the start of the next SNDU (or an End Indicator), and
continue processing the next SNDU.
Payload Pointer Checking
A receiver that has partially received a SNDU (in the Current SNDU
buffer) MUST also check the Payload Pointer, of any received packets
with a PUSI value of 1. A Payload Pointer value of 1 indicates that
the receiver MUST discard any previously unreassembled SNDU, and
start processing the new SNDU that directly follows the Payload
Pointer.
A Payload Pointer value greater than 1, indicates the receiver MUST
complete processing of the current SNDU, if there are ((Payload
Pointer)-1) bytes remaining to complete the ANDU. If the receiver
has not completed the current SNDU, and the Length Field indicates
that it is awaiting a greater number of bytes than the ((Payload
Pointer) 1), then the receiver has detected a delimiting error and
the partially received SNDU MUST be discarded. The receiver MUST
also discard ((Payload Pointer) 1) bytes prior to the first SNDU in
the TS Packet, where it shall restart reassembly.
Other Error Condistions
The receiver SHOULD also check the MPEG-2 Continuity Counter carried
in the TS Packet Header. This counter should increment by one for
each TS Packet received on a logical TS channel. If the value is not
incremented by one in successive packets (modulo 16), any partially
received SNDU MUST be discarded. The receiver then waits for the
next TS Packet with a PUSI value of 1.
The receiver SHOULD also check the MPEG-2 Transport Error indicator
carried in the TS Packet Header. This flag indicates a transmission
error for the logical TS channel. If the flag is set to a one, any
partially received SNDU MUST be discarded. The receiver then waits
for the next TS Packet with a PUSI value of 1.
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6. Summary
This document defines a Ultra Lightweight Encapsulation (ULE) to
perform efficient and flexible support for IPv4 and IPv6 network
services over networks built upon the MPEG-2 Transport Stream (TS).
7. Acknowledgments
This draft is based on a previous draft authored by: Horst D.
Clausen, Bernhard Collini-Nocker, Hilmar Linder, and Gorry
Fairhurst. The authors wish to thank the members of the ip-dvb
mailing list for the input provided. In particular, the many
comments received from Patrick Cipiere.
8. Security Considerations
Security issues are not addressed in this document.
9. References
[ATSC] A/53, "ATSC Digital Television Standard", Advanced Television
Systems Committee (ATSC), Doc. A/53, 1995.
[ATSC-DAT] A/90, "ATSC Data Broadcast Standard", Advanced Television
Systems Committee (ATSC), Doc. A/090, 26 July 00
[ATSC-DATG] A/91, "Recommended Practice: Implementation Guidelines
for the ATSC Data Broadcast Standard", Advanced Television Systems
Committee (ATSC),Doc. A/91. 10 June 2001
[ATSC-G] A/54, "Guide to the use of the ATSC Digital Television
Standard", Advanced Television Systems Committee (ATSC), Doc. A/54,
4 Oct 95
[ATSC-PSIP-TC] A/65A, "Program and System Information Protocol for
Terrestrial Broadcast and Cable", Advanced Television Systems
Committee (ATSC), Doc. A/65A, 23 Dec 1997, Rev. A 31 May 2000
[ATSC-S] A/80, "Modulation and Coding Requirements for Digital TV
(DTV) Applications over Satellite", Advanced Television Systems
Committee (ATSC), Doc. A/80, 17 July 99
[CLC99] Clausen, H., Linder, H., and Collini-Nocker, B., "Internet
over Broadcast Satellites", IEEE Commun. Mag. 1999, pp.146-151.
[ETSI-DAT] EN 301 192 Specifications for Data Broadcasting, European
Telecommunications Standards Institute (ETSI).
[ETSI-DVBC] EN 300 800 Digital Video Broadcasting (DVB); DVB
interaction channel for Cable TV distribution systems (CATV),
European Telecommunications Standards Institute (ETSI).
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[ETSI-DVBS] EN 301 421 Digital Video Broadcasting (DVB); Modulation
and Coding for DBS satellite systems at 11/12 GHz, European
Telecommunications Standards Institute (ETSI).
[ETSI-DVBT] EN 300 744 Digital Video Broadcasting (DVB); Framing
structure, channel coding and modulation for digital terrestrial
television (DVB-T), European Telecommunications Standards Institute
(ETSI).
[ISO-DSMCC] ISO/IEC IS 13818-6 Information technology -- Generic
coding of moving pictures and associated audio information -- Part
6: Extensions for DSM-CC is a full software implementation,
International Standards Organisation (ISO).
[ISO-MPEG] ISO/IEC DIS 13818-1 Information technology -- Generic
coding of moving pictures and associated audio information: Systems,
International Standards Organisation (ISO).
[ISO-VID] ISO/IEC DIS 13818-2 Information technology -- Generic
coding of moving pictures and associated audio information: Video,
International Standards Organisation (ISO).
[ISO-AUD] ISO/IEC 13818-3:1995 Information technology -- Generic
coding of moving pictures and associated audio information -- Part
3: Audio, International Standards Organisation (ISO).
[LLC] IEEE Logical Link Control (ANSI/IEEE Std 802.2/ ISO 8802.2),
1985
[RFC3077] E. Duros, W. Dabbous, H. Izumiyama, Y. Zhang, "A Link
Layer Tunneling Mechanism for Unidirectional Links", RFC3077.
[RFC3095] C. Bormann, et al, "RObust Header Compression (ROHC):
Framework and four profiles: RTP, UDP ESP and uncompressed",
RFC3095.
[SI-DAT] SI-DAT group, "Second Draft DVB Specification for Data
Broadcasting", Geneva, 15 Jan. 1997
10.Authors' Addresses
Godred Fairhurst
Department of Engineering
University of Aberdeen
Aberdeen, AB24 3UE
UK
Email: gorry@erg.abdn.ac.uk
Web: http://www.erg.abdn.ac.uk/users/gorry
Bernhard Collini-Nocker
Institute of Computer Sciences
Expires December 2003 [page 16]
INTERNET DRAFT Encapsulation for IP over MPEG-2/DVB May 2003
University of Salzburg
Jakob Haringer Str. 2
5020 Salzburg
Austria
Email: [bnocker]@cosy.sbg.ac.at
Web: http://www.cosy.sbg.ac.at/cs/
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11. IANA Considerations
This document will require IANA involvement.
The payload type field defined in this document must be aligned with
an existing IANA registry or the following values need to be
assigned by the IANA:
Payload Type Field
Expires December 2003 [page 17]