Internet DRAFT - draft-jeong-16ng-multicast-delivery
draft-jeong-16ng-multicast-delivery
Network Working Group S. Jeong
Internet-Draft ETRI
Expires: December 28, 2006 H. Jang
SAIT
June 26, 2006
IPv6 Multicast Packet Delivery over IEEE 802.16 Networks
draft-jeong-16ng-multicast-delivery-01
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Copyright Notice
Copyright (C) The Internet Society (2006).
Abstract
This memo describes the transmission of IPv6 multicast packets over
IEEE 802.16 networks, including methods to deliver various scoped
multicast packets. It also presents a method of forming multicast
CIDs on IEEE 802.16 networks.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Assumption and Scope . . . . . . . . . . . . . . . . . . . 3
1.2. Terminology and Abbreviations . . . . . . . . . . . . . . 4
2. Brief Description of Subnet Models . . . . . . . . . . . . . . 5
3. Subnet Model A . . . . . . . . . . . . . . . . . . . . . . . . 6
3.1. Multicast Packet from MS . . . . . . . . . . . . . . . . . 6
3.2. Multicast Packet from AR or Other Subnets . . . . . . . . 6
4. Subnet Model B . . . . . . . . . . . . . . . . . . . . . . . . 8
4.1. Multicast Packet from MS . . . . . . . . . . . . . . . . . 8
4.2. Multicast Packet from AR or Other Subnets . . . . . . . . 8
5. Subnet Model C . . . . . . . . . . . . . . . . . . . . . . . . 9
5.1. Multicast Packet from MS . . . . . . . . . . . . . . . . . 9
5.2. Multicast Packet from BS/AR or Other Subnets . . . . . . . 9
6. Subnet Model D . . . . . . . . . . . . . . . . . . . . . . . . 10
6.1. Multicast Packet from MS . . . . . . . . . . . . . . . . . 10
6.2. Multicast Packet from BS/AR or Other Subnets . . . . . . . 10
7. Considerations about mCID Format . . . . . . . . . . . . . . . 11
7.1. IPv6 scope-based mCID Format . . . . . . . . . . . . . . . 11
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
9. Security Considerations . . . . . . . . . . . . . . . . . . . 13
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14
Intellectual Property and Copyright Statements . . . . . . . . . . 15
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1. Introduction
IEEE 802.16 networks support mobile stations (MSs) to access
broadband wireless networks while moving at vehicular speed
[IEEE802.16e]. However, IEEE 802.16 networks do not provide link
layer native multicast capability because of point-to-multipoint
connection characteristic [IEEE802.16]. This feature restricts the
adoption of protocols or applications that need IPv6 multicast
capability. One of the prominent ways to solve the multicast support
problem is to use the built-in LAN emulation feature of IEEE 802.16
which is based on Convergence Sublayer [I-D.jee-16ng-ps-goals].
There is several previous work which was focused on the transport of
link local scope multicast packets over IEEE 802.16 network
[I-D.jeon-ipv6-ndp-ieee802.16] [I-D.jang-16ng-llm]. However, the
IPv6 multicast service requires not only the delivery of link local
scope multicast packets, but also the delivery of non-link local
scope multicast packets such as site local or global scope multicast
packets. Since it is not clear that which subnet models would be
used in IEEE 802.16 networks, we consider the transport of IPv6
multicast packets over various subnet models proposed in [I-D.ietf-
v6ops-802-16-deployment-scenarios].
This memo describes how the IPv6 multicast packets with various scope
can be delivered over four different types of subnet models.
1.1. Assumption and Scope
This document describes how to provide IPv6 CS based IPv6 multicast
packets delivery over IEEE 802.16 networks. We will consider
Ethernet CS based IPv6 multicast packet transport in the later
version of this document.
We classify the IPv6 multicast packet into link local scope and non-
link local scope multicast packet. Node-local scope multicast packet
is not considered in this memo. When a BS is separated from an
access router (AR), we assume that the BS is connected to the AR via
Ethernet. If Ethernet is not used between the BS and the AR,
tunneling may be used to apply our proposed approaches.
Our approaches are based on the use of multicast CID (mCID) to
distinguish between multicast and unicast packets, and to deliver the
multicast packets. This memo presents mCID based transport of IPv6
multicast packet not only link local scope, but also non-link local
scope. The initialization or distribution of mCID is not covered in
this document, but we may guess that the mCID will be initialized
during the establishment phase of host IPv6 connectivity.
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1.2. Terminology and Abbreviations
In this memo, a link local multicast packet indicates a multicast
packet with link local scope such as NS, RA, and so on. A non-link
local multicast packet means that the scope of the packet is neither
node local nor link local. The non-link local multicast packet also
includes a multicast data packet.
Terminology in this document follows that in [I-D.jee-16ng-ps-goals],
with the addition of a new terminology given here:
o mCID (multicast CID) : CID for IPv6 multicast packet transport
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2. Brief Description of Subnet Models
The relationship between a BS and an AR induces several IPv6 subnet
models in IEEE 802.16 networks. This document describes the
transport of IPv6 multicast packets with IPv6 CS over each subnet
models proposed in [I-D.ietf-v6ops-802-16-deployment-scenarios]. We
may deduce following four IPv6 subnet models from the IPv6 prefix
assignment methods and the relationship between the AR and the BS.
+--------+---------------------------+----------------------------+
| Subnet | Deployment architecture | Subnet components |
| model | | |
+--------+---------------------------+----------------------------+
| A | BS is separated from AR | single AR, multiple BSs, |
| | | multiple MSs |
+--------+---------------------------+----------------------------+
| B | BS is separated from AR | multiple BSs, multiple MSs |
+--------+---------------------------+----------------------------+
| C | BS is integrated with AR | single BS/AR, multiple MSs |
+--------+---------------------------+----------------------------+
| D | BS is integrated with AR | single BS/AR, single MS |
+--------+---------------------------+----------------------------+
Figure 1: IPv6 subnet models in IEEE 802.16 networks
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3. Subnet Model A
In this section, we discuss the transport of IPv6 multicast packets
over the 'Subnet Model A' shown in Figure 2 where a BS is separated
from an AR and a subnet consists of single AR, multiple BSs, and
multiple MSs. This scenario covers the current celluar-like
deployment models such as WiMax and WiBro.
+-----+
| MS1 |------+
+-----+ |
+-----+ | +-----+
| MS2 |<------+----| BS1 |---+
+-----+ +-----+ | +-----+ +--------+
|--->| AR |----| Edge | ISP
| +-----+ | Router +==>Network
+-----+ +-----+ | +--------+
| MS3 |<-----------| BS2 |---+
+-----+ +-----+
<---> IP termination
Figure 2: Subnet Model A
3.1. Multicast Packet from MS
In the Figure 2, when the BS1 receives a multicast packet which was
originated from the MS1, the BS1 multicasts the packet onto its
downlinks by using mCID. After then, BS1 converts the IEEE 802.16
MAC frame format to IEEE 802.3 Ethernet frame and transmits the frame
into the link connected to the AR. The BS2 which is on the same link
as the BS1, receives the IEEE 802.3 Ethernet frame sent from the BS1
and examines the IPv6 destination address. If the destination
address is a multicast address, the BS2 multicasts the received
packet to its downlinks with predefined mCID.
When the AR receives the IPv6 multicast packet transmitted by BS1, it
investigates the scope of the IPv6 multicast destination address. If
the multicast packet is destined to itself (i.e., link local scope
multicast packet), the AR processes the multicast packet. If the
multicast packet has non-link local scope, the AR performs the
multicast routing table lookup and forwards the received multicast
packet according to the lookup result.
3.2. Multicast Packet from AR or Other Subnets
When the AR receives an IPv6 multicast packet from the edge router,
it looks up the multicast routing table and checks whether there
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exists a receiver of the multicast packet in the AR's subnet. If
there is a receiver, the AR sends the packet to the BSs in the
downlinks. Each BS in the AR's subnet receives the multicast packet
sent from the AR and multicasts the packet to its downlinks by using
mCID.
In case of a link local multicast packet originated from the AR, the
BSs in the AR's subnet transmits the received multicast packet to
their downlinks with mCID
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4. Subnet Model B
In this section, we discuss the transport of IPv6 multicast packets
over the 'Subnet Model B' depicted in the Figure 3 where a BS is
separated from an AR, and a subnet consists of multiple BSs and
multiple MSs. This scenario covers the hot-zone deployment model in
IEEE 802.11.
+-----+ +-----+ +-----+ ISP 1
| MS1 |<-----+ +->| AR1 |----| ER1 |===>Network
+-----+ | | +-----+ +-----+
+-----+ | +-----+ |
| MS2 |<-----+-----| BS1 |--|
+-----+ +-----+ | +-----+ +-----+ ISP 2
+->| AR2 |----| ER2 |===>Network
+-----+ +-----+ | +-----+ +-----+
| MS3 |<-----------| BS2 |--+
+-----+ +-----+
<---> IP termination
Figure 3: Subnet Model B
4.1. Multicast Packet from MS
In the Figure 3, when the BS1 receives a multicast packet originated
from the MS1, the BS1 multicasts the packet onto its downlinks by
using mCID. After then, the BS1 transmits the packet into the link
connected to ARs through IEEE 802.3 Ethernet frame. The BS2 which is
on the same link as the BS1, receives the IPv6 multicast packet sent
from BS1 and multicasts the packet to its downlinks with predefined
mCID.
When an AR receives an IPv6 multicast packet transmitted by BSs, it
follows the same procedure as Subnet Model A scenario except that
both the AR1 and the AR2 simultaneously receive the link local scope
multicast packet. In case of non-link local scope multicast packet,
the AR1 and the AR2 look up their own multicast routing table and
forward the received multicast packet according to the lookup result.
4.2. Multicast Packet from AR or Other Subnets
The operation of the BSs and the ARs in this case follows the same
procedure as Subnet Model A scenario except that there are two ARs in
the network and these ARs have their own multicast routing tables.
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5. Subnet Model C
When a BS and an AR are integrated in a same box, there exist two
cases of IPv6 prefix allocation method. The one is to assign an IPv6
prefix to each BS/AR box and the other is to allocate an IPv6 prefix
to each MS, similar to 3GPP scenario [RFC 3314].
In this section, we discuss the delivery of IPv6 multicast packets
over 'Subnet Model C' shown in Figure 4 where a BS is integrated with
an AR, composing one box, and a subnet consisting of only single
BS/AR and multiple MSs.
+-----+
| MS1 |<------+
+-----+ |
+-----+ | +-------+ +--------+
| MS2 |<------+--->|BS/AR1 |---------| Edge | ISP
+-----+ +-------+ | Router +==>Network
+--------+
+-----+ +-------+ |
| MS3 |<---------->|BS/AR2 |-----------+
+-----+ +-------+
<---> IP termination
Figure 4: Subnet Model C
5.1. Multicast Packet from MS
After the BS/AR1 receiving a multicast packet from the MS1, the BS/
AR1 transmits the received packet to its downlinks by using mCID. If
the multicast packet is destined to itself (i.e., link local scope
multicast packet), the BS/AR1 processes the multicast packet.
In case of a non-link local multicast packet, the BS/AR1 looks up the
multicast routing table and forwards the packet to the Edge Router
according to the lookup result. The packet forwarded by the BS/AR1
is delivered to the BS/AR2 or the Edge Router by means of
conventional IPv6 multicast packet transport procedure.
5.2. Multicast Packet from BS/AR or Other Subnets
When the BS/AR1 needs to send a multicast packet to MSs in its
subnet, the BS/AR1 transmits the packet to its downlinks with mCID.
When the BS/AR1 receives a multicast packet from Edge Router, it
looks up the multicast routing table and checks whether the packet is
destined to its subnet. If there exists a receiver in the subnet,
the BS/AR1 sends the packet to its downlinks by using mCID.
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6. Subnet Model D
In this section, we discuss the delivery of IPv6 multicast packets
over 'Subnet Model D' depicted in Figure 5 where a BS is integrated
with an AR, composing one box in view of implementation. In this
subnet model, each subnet consists of single BS/AR and only one MS.
Thus, each MS has a unique IPv6 prefix. This scenario is similar to
3GPP scenario [RFC 3314].
+-----+
| MS1 |<-------------+
+-----+ v
+-----+ +-------+ +--------+
| MS2 |<---------->|BS/AR1 |---------| Edge | ISP
+-----+ +-------+ | Router +==>Network
+--------+
+-----+ +-------+ |
| MS3 |<---------->|BS/AR2 |-----------+
+-----+ +-------+
<---> IP termination
Figure 5: Subnet Model D
6.1. Multicast Packet from MS
If the BS/AR1 receives a link local multicast packet from the MS1,
the BS/AR1 has only to process the received multicast packet.
In case of a non-link local multicast packet, the BS/AR1 looks up the
multicast routing table and forwards the packet to the Edge Router
according to the lookup result. Then, the packet will follow a
conventional IPv6 multicast packet transport procedure.
6.2. Multicast Packet from BS/AR or Other Subnets
When the BS/AR1 needs to send a multicast packet to MSs in its
subnet, the BS/AR1 transmits the packet to its downlink by using
either mCID or unicast CID.
When the BS/AR1 receives a multicast packet from Edge Router, it
looks up the multicast routing table and checks whether the packet is
destined to its own subnet. If there exists a receiver in the
subnet, the BS/AR1 sends the packet to its downlink by using wither
mCID or unicast CID.
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7. Considerations about mCID Format
The allocation of mCID to IPv6 multicast packets needs to be
considered in IEEE. However, in this memo, we present a candidate.
7.1. IPv6 scope-based mCID Format
This section specifies a modification to the CID format as follows.
| 11 | 1 | 4 |
+------------------------------+---+----------+
| mCID prefix | CS| scop |
+------------------------------+---+----------+
Figure 6: IPv6 Scope based mCID Format
mCID consists of mCID prefix, CS, and scope field. mCID prefix is
used to indicate that a multicast packet is embedded in IEEE 802.16
frame. CS field implies that whether IPv6 CS or Ethernet CS is used
to encapsulate the IPv6 packet. CS field with its value 1 implies
that IPv6 CS is used and scope field be set to the same value as the
scope field of encapsulated IPv6 destination address. CS field with
its value 0 indicates that Ethernet CS is used and scope field be set
to the same value as the scope field of encapsulated IPv6 destination
address.
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8. IANA Considerations
This document requests no action by IANA.
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9. Security Considerations
TBD
10. References
[IEEE802.16]
"IEEE 802.16-2004, IEEE standard for Local and
metropolitan area networks, Part 16:Air Interface for
fixed broadband wireless access systems", October 2004.
[IEEE802.16e]
"IEEE 802.16e/D10 Draft, IEEE Standard for Local and
metropolitan area networks, Part 16: Air Interface for
Fixed and Mobile Broadband Wireless Access Systems
Amendment for Physical and Medium Access Control Layers
for Combined Fixed and Mobile Operation in Licensed
Bands", August 2005.
[I-D.jee-16ng-ps-goals]
Jee, J., "IP over 802.16 Problem Statements and Goals",
draft-jee-16ng-ps-goals-00 (work in progress),
February 2006.
[I-D.jeon-ipv6-ndp-ieee802.16]
Jeon, H. and J. Jee, "IPv6 NDP for Common Prefix
Allocation in IEEE 802.16",
draft-jeon-ipv6-ndp-ieee802.16-01 (work in progress),
March 2006.
[I-D.jang-16ng-llm]
Jang, H., "Link-local Multicast Packet Transmission in
802.16 Networks", draft-jang-16ng-llm-00 (work in
progress), February 2006.
[I-D.ietf-v6ops-802-16-deployment-scenarios]
Shin, M. and Y. Han, "ISP IPv6 Deployment Scenarios in
Wireless Broadband Access Networks",
draft-ietf-v6ops-802-16-deployment-scenarios-00 (work in
progress), May 2006.
[RFC3314] Wasserman, M., "Recommendations for IPv6 in Third
Generation Partnership Project (3GPP) Standards",
RFC 3314, September 2002.
[RFC3810] Vida, R. and L. Costa, "Multicast Listener Discovery
Version 2 (MLDv2) for IPv6", RFC 3810, June 2004.
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Authors' Addresses
Sangjin Jeong
ETRI
161 Gajeong-dong, Yusung-gu
Daejeon, 305-350
Korea
Phone: +82 42 860 1877
Email: sjjeong@gmail.com
Heejin Jang
SAIT
P.O. Box 111
Suwon 440-600
Korea
Email: heejin.jang@samsung.com
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