Network Working Group Tat-Chee. Wan
Internet-Draft Way-Chuang. Ang
Intended status: Standards Track Chee Hong. Teh
Expires: August, 2008 Universiti Sains Malaysia
19 March, 2008
Robust Header Compression over Unidirectional Lightweight Encapsulation
(ULE) and MPEG2 Transport Stream (TS) frames
draft-wan-ipdvb-rohc-00.txt
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Copyright Notice
Copyright (C) The IETF Trust (2008).
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Abstract
This paper introduces approach to carry ROHC packets over ULE and
MPEG2-TS frames. For completeness, ROHC Channel Parameters
Negotiation Protocol (RCPNP) is also presented.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminologies . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Packet Format of ROHC Packet . . . . . . . . . . . . . . . . . 7
3.1. ROHC over ULE . . . . . . . . . . . . . . . . . . . . . . 7
3.1.1. Dedicated EtherType Fields for ROHC Compressed
Packet . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1.2. ROHC Compressed Packet as Payload of Ethernet
Packet . . . . . . . . . . . . . . . . . . . . . . . . 8
3.2. ROHC over MPEG2-TS . . . . . . . . . . . . . . . . . . . . 8
4. Establishing ROHC Channel . . . . . . . . . . . . . . . . . . 10
4.1. ROHC Channel Parameters Negotiation Protocol (RCPNP) . . . 10
4.1.1. Compressor Advertisement . . . . . . . . . . . . . . . 12
4.1.2. Compressor Solicitation . . . . . . . . . . . . . . . 12
4.1.3. Request . . . . . . . . . . . . . . . . . . . . . . . 13
4.1.4. Reply . . . . . . . . . . . . . . . . . . . . . . . . 15
4.1.4.1. Medium Information . . . . . . . . . . . . . . . . 16
4.1.4.1.1. MPEG-2 TS Medium . . . . . . . . . . . . . . . 16
4.1.4.1.2. ULE Medium . . . . . . . . . . . . . . . . . . 17
4.1.5. Acknowledgement/Negative Acknowledgement . . . . . . . 18
4.1.6. Compressor Shutdown . . . . . . . . . . . . . . . . . 18
4.1.7. Decompressor Shutdown . . . . . . . . . . . . . . . . 18
4.2. Interaction of RCPNP . . . . . . . . . . . . . . . . . . . 19
5. Bidirectional ROHC Channels . . . . . . . . . . . . . . . . . 20
6. IANA Consideration . . . . . . . . . . . . . . . . . . . . . . 21
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 22
8. Security Considerations . . . . . . . . . . . . . . . . . . . 23
9. Normative References . . . . . . . . . . . . . . . . . . . . . 24
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 25
Intellectual Property and Copyright Statements . . . . . . . . . . 26
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1. Introduction
This paper introduces approach to carry ROHC packets over ULE and
MPEG2-TS frames. For completeness, ROHC Channel Parameters
Negotiation Protocol (RCPNP) is also presented.
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2. Terminologies
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
DVB
Digital Video Broadcast. A framework and set of associated
standards published by the European Telecommunications Standards
Institute (ETSI) for the transmission of video, audio, and data
using the ISO MPEG-2 Standard [ISO-MPEG2].
MAC
Medium Access Control [IEEE-802.3]. A link-layer protocol defined
by the IEEE 802.3 standard (or by Ethernet v2 [DIX]).
MPEG-2
A set of standards specified by the Motion Picture Experts Group
(MPEG) and standardized by the International Standards
Organisation (ISO/IEC 13818-1) [ISO-MPEG2], and ITU-T (in H.222
[ITU-H222]).
PDU
Protocol Data Unit. Examples of a PDU include Ethernet frames,
IPv4 or IPv6 datagrams, and other network packets.
Receiver
Equipment that processes the signal from a TS Multiplex and
performs filtering and forwarding of encapsulated PDUs to the
network-layer service (or bridging module when operating at the
link layer).
Transmitter
Router or host that sends data.
SNDU
SubNetwork Data Unit. An encapsulated PDU sent as an MPEG-2
Payload Unit.
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TS
Transport stream (TS) is a format specified in MPEG-2 Part 1,
Systems (ISO/IEC standard 13818-1). Its design goal is to allow
multiplexing of digital video and audio and to synchronize the
output. Transport stream offers features for error correction for
transportation over unreliable media, and is used in broadcast
applications such as DVB and ATSC.
ULE stream
An MPEG-2 TS Logical Channel that carries only ULE encapsulated
PDUs. ULE Streams may be identified by definition of a
stream_type in SI/PSI [ISO-MPEG2].
ROHC
Robust Header Compression. A framework of compression headers of
IP packet as defined in [RFC3095].
ROHC channel
A logical unidirectional point-to-point channel carrying ROHC
packets from one compressor to one decompressor, optionally
carrying ROHC feedback information on the behalf of another
compressor-decompressor pair operating on a separate ROHC channel
in the opposite direction.
ROHC profile
A logical unidirectional point-to-point channel carrying ROHC
packets from one compressor to one decompressor, optionally
carrying ROHC feedback information on the behalf of another
compressor-decompressor pair operating on a separate ROHC channel
in the opposite direction.
MRRU
Maximum Reconstructed Reception Unit as defined in [RFC3095].
Context Identifier
[RFC3095] provides a definition for context identifiers.
MSB
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Most significant bit.
LSB
Least significant bit.
ACK
Acknowledgement.
NACk
Negative acknowledgement.
CID
Contect Identifier.
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3. Packet Format of ROHC Packet
This section briefly describes the notation used in all diagrams. ":"
in a diagram indicates that the part is optional. Likewise, "~" in a
diagram indicates the number of octets by the part is not presented
in a precise manner. This situation appears when a field or part
spans multiple or variable number of bytes.
3.1. ROHC over ULE
The packet format for ROHC packet encapsulated can be in one the
following two formats:
3.1.1. Dedicated EtherType Fields for ROHC Compressed Packet
MSB LSB
0 1 2 3 4 5 6 7
+-----+-----+-----+-----+-----+-----+-----+-----+
| D | |
+-----+ Length +
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
+ Type=ROHC +
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
: :
~ Dest Address* (6 octets) ~
: :
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
~ ROHC compressed packet (variable length) ~
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
~ CRC-32 (4 octets) ~
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
Figure 1: ROHC compressed packet encapsulated using dedicated
EtherType
The semantics of D-bit, Length, Type, Destination Address and CRC-32
fields are defined in section 4 of [RFC 4326]. However, the Type
fields requires a new IANA assigned EtherType value to indicate the
presence of ROHC compressed packet in PDU.
In the absence of multiple receivers, a transmitter can send an SNDU
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without Destination Address Field (D bit marked). However, when
multiple receivers are listening to the same transmitter, destination
address must be included in SNDU.
3.1.2. ROHC Compressed Packet as Payload of Ethernet Packet
MSB LSB
0 1 2 3 4 5 6 7
+-----+-----+-----+-----+-----+-----+-----+-----+
| D=1 | |
+-----+ Length +
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
+ Type=Ether +
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
~ Dest MAC (6 octets) ~
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
~ Source MAC (6 octets) ~
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
+ EtherType=ROHC +
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
~ ROHC compressed packet (varible length) ~
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
~ CRC-32 (4 octets) ~
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
Figure 2: ROHC compressed packet encapsulated in SNDU bridged frame
This packet format should be used when there are multiple
transmitters and receivers over a DVB link. The value of EtherType
field is similar to Type Field in section 3.1.1.
3.2. ROHC over MPEG2-TS
This encapsulation format is the smallest packet format in terms of
packet size. The format of SNDU is the following format:
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+------+------------------------+--------+
|Length| ROHC compressed packet | CRC-32 |
+------+------------------------+--------+
Figure 3: ROHC compressed packet compressed encapsulated direct
within MPEG2-TS frames' payload
The meaning of each fields is specified below:
Length
This field indicates the ROHC compressed packet field only. This
field can be either 1 or 2 octets depending on the the most
significant bit. If the most significant bit is cleared, the
length of this field is 1 octet and may represents values from 0
until 127. Otherwise, the length of this field is 2 octets and
may represents values from 128 until 61566.
ROHC Compressed Packet
ROHC compressed packet as defined in section 5.2 of [RFC3095].
CRC-32
The 32-bit CRC is calculated over Length filed and ROHC compressed
packet. The polynomial used to calculate the CRC is 0x104C11DB7.
Like ULE, ROHC over MPEG2-TS also supports packing and padding
mode. The mechanism of encapsulating this SNDU is similar to
encapsulation of ULE packet within MPEG2-TS. This approach
requires that separate PID dedicated to a ROHC channel.
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4. Establishing ROHC Channel
This standard presents two approaches to setup a ROHC channel over a
DVB link. The first approach is to setup ROHC channel manually.
This requires that the operators at the every transmitters and
receivers to manually configure the ROHC channel parameters. When
the size of network is small, this approach is favourable.
But the former approach becomes nonviable if the network is dynamic
and is not scalable as the size of the network grows. Henceforth, we
presents a negotiation protocol to create ROHC channel in the next
section.
4.1. ROHC Channel Parameters Negotiation Protocol (RCPNP)
The approach presented in this section can only work if compressor
site and decompressor site are connected through two dedicated
unidirectional DVB links, with a unidirectional link originating from
each of the sites, configured to form a bidirectional network link
between the two sites. This protocol works through ULE packets only.
It is possible to extend this protocol to work over Generic Stream
Encapsulation [GSE] in the future. While it is possible to extend
this protocol to work over asymmetrical link, this draft doesn't try
to address this issue. Since new EtherType is allocated, this
protocol can be extended to asymmetrical link via Link-Layer
Tunneling Mechanism [RFC3077] with little modifications.
The basic format of ULE SNDU packet is as such:
+---+--------+------------+----------+--------+
|D=1| Length |Type=ROHCNeg| Body | CRC-32 |
+---+--------+------------+----------+--------+
Figure 4: Minimal format of RCPNP message
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MSB LSB
0 1 2 3 4 5 6 7
+-----+-----+-----+-----+-----+-----+-----+-----+
| D=1 | |
+-----+ Length +
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
+ Type=Ether +
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
~ Dest MAC (6 octets) ~
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
~ Source MAC (6 octets) ~
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
+ EtherType=ROHCNeg +
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
~ Body (varible length) ~
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
~ CRC-32 (4 octets) ~
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
Figure 5: RCPNP message encapsulated in bridged frame
Type field requires a new separate IANA assigned EtherType number for
ROHC Channel Negotiation Protocol. The types of message in this
protocol is defined in the Body field. The following subsections
will explain the type of messages for this protocol. Compressor
Advertisement and Compressor Solicitation uses packet format depicted
in Figure 4. While other forms of messages uses packet format
depicted in Figure 5.
The basic format for these messages is depicted is as such:
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MSB LSB
0 1 2 3 4 5 6 7
+-----+-----+-----+-----+-----+-----+-----+-----+
| Version | Operation | X |
+-----+-----+-----+-----+-----+-----+-----+-----+
Figure 6: Basic format of RCPNP Body field
Currently, version number is 0. Operation field defines the type of
message contained in the Body field. The content of X-bit depends on
operation type.
4.1.1. Compressor Advertisement
MSB LSB
0 1 2 3 4 5 6 7
+-----+-----+-----+-----+-----+-----+-----+-----+
| Version=0 | Operation=0 | X |
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
~ Address (6 octets) ~
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
Figure 7: Format of Compressor Advertisement message
This message is used by the compressor site to advertise the
availability of ROHC Compressor. Out of concern for bandwidth and
energy consumption, compressor site should limit the broadcast of
this message for a few times when it first join the network. This
message should also be broadcasted when a Compressor Solicitation
message is received. The decompressor site will use the value
specified in the Address field when addressing compressor site.
X-bit is unused and should be ignored.
4.1.2. Compressor Solicitation
MSB LSB
0 1 2 3 4 5 6 7
+-----+-----+-----+-----+-----+-----+-----+-----+
| Version=0 | Operation=1 | X |
+-----+-----+-----+-----+-----+-----+-----+-----+
Figure 8: Format of Compressor Solicitation message
This message is broadcasted by decompressor to solicit for
compressor. X-bit is unused and should be ignored. Decompressor
site should rate-limit the frequency of solicitation if it is doesn't
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receive any Compressor Advertisement to avoid flooding DVB link.
4.1.3. Request
MSB LSB
0 1 2 3 4 5 6 7
+-----+-----+-----+-----+-----+-----+-----+-----+
| Version=0 | Operation=2 | X |
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
+ Maximum CID +
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
~ MRRU (4 octets) ~
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
| Number of Media | |
~-----+-----+-----+ Medium Types ~
: :
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
+ Num of profiles +
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
+ Profile ID 1 +
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
: :
+ Profile ID 2 +
: :
+-----+-----+-----+-----+-----+-----+-----+-----+
: :
+ Profile ID N +
:| :
+-----+-----+-----+-----+-----+-----+-----+-----+
Figure 9: Format of Request message
This message is sent by decompressor site to compressor site when it
wishes to establish a ROHC channel. The meaning of each fields in
the message are described below:
Maximum CID
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Maximum Context Identifier tolerated by decompressor.
MRRU
Maximum Reconstructed Reception Unit tolerated by decompressor.
Value of 0 indicates the negotiated channel doesn't allow for
segmentation of ROHC compressed packet.
Number of Media
The number of medium types carried in Medium Types field.
Medium Types
This field consists of all supported medium types by the
decompressor. Each medium type consists of 3 bits and corresponds
to Medium field described in Medium Information (Section 4.1.4.1)
section. The number of bits used by Medium Types and Number of
Media fields must be expanded to multiple of 8 if actual number of
required bits is not multiple of 8. The unused bits for such case
should be ignored by Compressor site.
Number of profiles
Number of profiles supported by decompressor.
Profile IDs
ROHC Profile IDs supported by decompressor. Each profile ID
occupy 2 octets.
X-bit is unused and should be ignored.
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4.1.4. Reply
MSB LSB
0 1 2 3 4 5 6 7
+-----+-----+-----+-----+-----+-----+-----+-----+
| Version=0 | Operation=3 | X |
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
+ Maximum CID +
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
~ MRRU (4 octets) ~
| |
+===============================================+
| Num of profiles |
+-----+-----+-----+-----+-----+-----+-----+-----+
| |
+ Profile ID 1 +
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
: :
+ Profile ID 2 +
: :
+-----+-----+-----+-----+-----+-----+-----+-----+
: :
+ Profile ID N +
: :
+-----+-----+-----+-----+-----+-----+-----+-----+
Figure 10: Format of Reply message
This message is sent by compressor site to decompressor site in
response to request message sent by decompressor site. The meaning
of each fields in the message are described below:
Maximum CID
Maximum CID tolerated by compressor. This value of this field
should be less than or equal to its counterpart in request
message. Decompressor site should send a NACK if it receives
Maximum CID that is higher than the initial negotiated value.
MRRU
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Maximum Reconstructed Reception Unit tolerated by compressor.
Likewise, decompressor site should send a NACK if it is receives
higher MRRU than what it requested.
Number of profile IDs
Note that this field is 1 octet instead of 2 because there can be
only 256 active profiles at any given ROHC channel. Decompressor
site should send a NACK if it receives more profile IDs than it
can support.
Profile IDs
Profile Identifiers of the ROHC profiles that will be used for the
negotiated ROHC channel. Decompressor site should send a NACK if
it receives any profile ID that it doesn't support.
X-bit is unused and should be ignored.
4.1.4.1. Medium Information
The following notation depicted in the previous figure 10 indicates
the presence of medium information.
+===============================================+
Medium information conveys how compressor is to send ROHC compressed
packets to decompressor. Currently only 2 media are supported,
namely MPEG2-TS and ULE. The details of packet format for ROHC over
MPEG2-TS/ULE is described in section 3. Medium type is conveyed by
Medium field. Other media may be supported in the future and the
support for these media will specified in other documents.
Decompressor receiving unsupported medium type should send a NACK.
When an unrecognized medium type is received, decompressor site
should send an NACK message to compressor.
4.1.4.1.1. MPEG-2 TS Medium
MSB LSB
0 1 2 3 4 5 6 7
+-----+-----+-----+-----+-----+-----+-----+-----+
| Medium=0 | |
+-----+-----+-----+ PID +
| |
+-----+-----+-----+-----+-----+-----+-----+-----+
Figure 12: Medium information for ROHC over MPEG2-TS
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PID
Packet Identifier of MPEG2-TS frames that will carry ROHC
compressed packet.
4.1.4.1.2. ULE Medium
MSB LSB
0 1 2 3 4 5 6 7
+-----+-----+-----+-----+-----+-----+-----+-----+
| Medium=1 | ULE Type | Reserved |
+-----+-----+-----+-----+-----+-----+-----+-----+
Figure 13: Medium information for ROHC over ULE
ULE Type:
0
No MAC address will be sent in ULE packets. This option should
only be used if the compressor site is certain that there is only
one receiver and one transmitter over DVB link.
1
Only destination MAC address will be sent in ULE packets that
carry ROHC compressed packet. This means that Destination Absent
bit in ULE header will be cleared. This option is used only if
there is one transmitter and many receivers listening to that
transmitter via DVB link.
2
ROHC packets will be encapsulated in Ethernet bridged frame. This
option is used when there multiple transmitters and receivers over
a DVB link.
3
Not used. Receiver should treat it as corrupted packet, silently
discard the message and wait for a valid Reply message or until a
timeout occur at which the decompressor site will start the
negotiation afresh by sending a Request message.
Reserved field is not used and should be ignored.
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4.1.5. Acknowledgement/Negative Acknowledgement
MSB LSB
0 1 2 3 4 5 6 7
+-----+-----+-----+-----+-----+-----+-----+-----+
| Version=0 | Operation=4 | Ack |
+-----+-----+-----+-----+-----+-----+-----+-----+
Figure 14: Format of Acknowledgement message
Decompressor site should send either an acknowledgement or negative
acknowledgement if it receives a valid Reply message. If Ack bit is
set, then the message is an acknowledgement. Otherwise, it is a
negative acknowledgement. If compressor site doesn't receive ACK nor
NACK within a reasonable interval, it should discard any information
of negotiated ROHC channel parameters. An acknowledgement must be
sent to decompressor site when compressor site receives Decompressor
Shutdown message.
4.1.6. Compressor Shutdown
MSB LSB
0 1 2 3 4 5 6 7
+-----+-----+-----+-----+-----+-----+-----+-----+
| Version=0 | Operation=5 | X |
+-----+-----+-----+-----+-----+-----+-----+-----+
Figure 15: Format of Compressor Shutdown message
This message is sent by the compressor site to notify the
decompressor site that it is about to stop compressing IP packets.
Upon receiving this message, decompressor should release all
resources that are being held.
Compressor must wait for an acknowledgement from decompressor site
before freeing its resource. If it doesn't an acknowledgement within
a reasonable interval, it should keep sending a shutdown message for
a number of times before freeing its resource.
X-bit is unused and should be ignored.
4.1.7. Decompressor Shutdown
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MSB LSB
0 1 2 3 4 5 6 7
+-----+-----+-----+-----+-----+-----+-----+-----+
| Version=0 | Operation=6 | X |
+-----+-----+-----+-----+-----+-----+-----+-----+
Figure 16: Format of Decompressor Shutdown message
This message is sent by the decompressor site to notify the
compressor that it is about to stop decompressing IP packets. Upon
receiving this message, compressor should release all resources that
are being held and stop sending compressed IP packets.
Decompressor must wait for an acknowledgement from compressor site
before freeing its resource. If it doesn't an acknowledgement within
a reasonable interval, it should keep sending a shutdown message for
a number of times before freeing its resource.
X-bit is unused and should be ignored.
4.2. Interaction of RCPNP
The following diagram depicts a possible interaction between
compressor site and decompressor site in negotiating ROHC channel
parameters.
Compressor Site Decompressor Site
|<---------------- Solicit ---------------|
| |
|-------------- Advertise --------------->|
| |
|<-------------- Request -----------------|
| |
|---------------- Reply ----------------->|
| | Create instance
| | of decompressor
Create |<---------------- ACK -------------------|
compressor | |
| |
|= (Compression can begin at this point) =|
| |
| |
Destroy |<------- Decompressor Shutdown ----------|
compressor | |
|----------------- ACK --- -------------->| Destroy
| | decompressor
Figure 17: Packets flow of RCPNP
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5. Bidirectional ROHC Channels
While establishing bidirectional ROHC channels allows for the use of
ROHC bidirectional optimistic mode and bidirectional reliable mode,
RCPNP doesn't concern itself with the establishment of bidirectional
ROHC channels. Therefore, it is up to implementers of this protocol
to support bidirectional ROHC channels. The implementation should be
as straightforward as mapping correct pair of ROHC channels.
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6. IANA Consideration
Two EtherTypes should be assigned. One of it is for RCPNP and the
other is to indicate the presence of ROHC compressed packet.
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7. Acknowledgements
We would like to thank Rod Walsh (Nokia) for his valuable input and
feedback.
We also want to extend our gratitude to Dr. Gorry Fairhurst for his
guidance.
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8. Security Considerations
- None -
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9. Normative References
[DIX] Digital Equipment Corp, Intel Corp, Xerox Corp, "Ethernet
Local Area Network Specification Version 2.0",
November 1982.
[GSE] Digital Video Broadcasting, ""Generic Stream Encapsulation
(GSE) Protocol", DVB Document A116, 2007.
[IEEE-802.3]
IEEE 802.3, "Local and metropolitan area networks-Specific
requirements Part 3: Carrier sense multiple access with
collision detection (CSMA/CD) access method and physical
layer specifications", IEEE Computer Society, (also ISO/
IEC 8802-3), 2000.
[ISO-MPEG2]
ISO 13818-1, "Information technology -- Generic coding of
moving pictures and associated audio information -- Part
1: Systems", International Standards Organisation (ISO),
2000.
[ITU-H222]
H.222.0, "Information technology - Generic coding of
moving pictures and associated audio information: Systems,
International Telecommunication Union, (ITU-T)", 1995.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3077] Duros, E., "A Link-Layer Tunneling Mechanism for
Unidirectional Links", RFC 3077, 2001.
[RFC3095] Borman, C., "RObust Header Compression (ROHC): Framework
and four profiles: RTP, UDP, ESP, and uncompressed",
RFC 3095, 2001.
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Authors' Addresses
Tat-Chee Wan
Universiti Sains Malaysia
School of Computer Science
Universiti Sains Malaysia
Penang
Malaysia
Phone: +6 04 653 4633
Email: tcwan@nav6.org
URI: http://nrg.cs.usm.my/~tcwan
Way-Chuang Ang
Universiti Sains Malaysia
School of Computer Science
Universiti Sains Malaysia
Penang
Malaysia
Email: wcang@nav6.org
Chee-Hong Teh
Universiti Sains Malaysia
School of Computer Science
Universiti Sains Malaysia
Penang
Malaysia
Email: chteh@nav6.org
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