< draft-ietf-nemo-basic-support-00.txt   draft-ietf-nemo-basic-support-01.txt >
NEMO Working Group Vijay Devarapalli NEMO Working Group Vijay Devarapalli
INTERNET DRAFT Nokia INTERNET DRAFT Nokia
21 June 2003 Ryuji Wakikawa Category: Standards Track Ryuji Wakikawa
Category: Standards Track Keio University Expires March 2004 Keio University
Alexandru Petrescu Alexandru Petrescu
Motorola Motorola
Pascal Thubert Pascal Thubert
Cisco Systems Cisco Systems
September 2003
Nemo Basic Support Protocol Nemo Basic Support Protocol
draft-ietf-nemo-basic-support-00.txt draft-ietf-nemo-basic-support-01.txt
Status of This Memo Status of This Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is subject to all provisions
all provisions of Section 10 of RFC2026. of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at and may be updated, replaced, or obsoleted by other documents at
any time. It is inappropriate to use Internet- Drafts as reference any time. It is inappropriate to use Internet- Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at: The list of current Internet-Drafts can be accessed at:
http://www.ietf.org/ietf/1id-abstracts.txt http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at: The list of Internet-Draft Shadow Directories can be accessed at:
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
Abstract Abstract
This document describes a protocol to support network mobility as the This document describes the Nemo Basic Support protocol to support
mobile network attaches to different points in the Internet. The network mobility as the mobile network attaches to different points
protocol allows for session continuity for every node in the mobile in the Internet. The protocol is based on extensions to Mobile
IPv6 and allows for session continuity for every node in the mobile
network as the network moves. It also allows every node in the network as the network moves. It also allows every node in the
mobile network to be reachable while moving around. The protocol is mobile network to be reachable while moving around. The Mobile
based on extensions to Mobile IPv6 [1]. The Mobile Router [2] which Router, which connects the network to the Internet, runs the NEMO
connects the network to the Internet runs the NEMO protocol with its Basic Support protocol with its Home Agent. The protocol is designed
Home Agent. The protocol is designed in such a way that network in such a way that network mobility is transparent to the nodes
mobility is transparent to the nodes inside the mobile network. inside the mobile network.
Contents Contents
Status of This Memo 1 Status of This Memo 1
Abstract 1 Abstract 1
1. Introduction 4 1. Introduction 4
2. Terminology 5 2. Terminology 5
3. Overview of the NEMO Protocol 7 3. Overview of the Nemo Protocol 6
4. Message Formats 10 4. Message Formats 9
4.1. Binding Update . . . . . . . . . . . . . . . . . . . . . 10 4.1. Binding Update . . . . . . . . . . . . . . . . . . . . . 9
4.2. Binding Acknowledgement . . . . . . . . . . . . . . . . . 10 4.2. Binding Acknowledgement . . . . . . . . . . . . . . . . . 9
4.3. Mobile Network Prefix Option . . . . . . . . . . . . . . 11 4.3. Mobile Network Prefix Option . . . . . . . . . . . . . . 10
4.4. Mobile Network Prefix Length Option . . . . . . . . . . . 12 4.4. Mobile Network Prefix Length Option . . . . . . . . . . . 11
5. Mobile Router Operation 14 5. Mobile Router Operation 13
5.1. Data Structures . . . . . . . . . . . . . . . . . . . . . 14 5.1. Data Structures . . . . . . . . . . . . . . . . . . . . . 13
5.2. Sending Binding Updates . . . . . . . . . . . . . . . . . 15 5.2. Sending Binding Updates . . . . . . . . . . . . . . . . . 13
5.3. Receiving Binding Acknowledgements . . . . . . . . . . . 15 5.3. Receiving Binding Acknowledgements . . . . . . . . . . . 14
5.4. Error Processing . . . . . . . . . . . . . . . . . . . . 16 5.4. Error Processing . . . . . . . . . . . . . . . . . . . . 15
5.5. Establishment of Bi-directional Tunnel . . . . . . . . . 17 5.5. Establishment of Bi-directional Tunnel . . . . . . . . . 16
5.6. Neighbour Discovery for Mobile Router . . . . . . . . . . 18 5.6. Neighbour Discovery for Mobile Router . . . . . . . . . . 17
5.7. Multicast Groups for Mobile Router . . . . . . . . . . . 18 5.7. Multicast Groups for Mobile Router . . . . . . . . . . . 17
6. Home Agent Operation 19 6. Home Agent Operation 18
6.1. Prefix Table . . . . . . . . . . . . . . . . . . . . . . 19 6.1. Data Structures . . . . . . . . . . . . . . . . . . . . . 18
6.1.1. Binding Cache . . . . . . . . . . . . . . . . . . 18
6.1.2. Prefix Table . . . . . . . . . . . . . . . . . . 18
6.2. Mobile Network Prefix Registration . . . . . . . . . . . 19 6.2. Mobile Network Prefix Registration . . . . . . . . . . . 19
6.3. Advertising Mobile Network Reachability . . . . . . . . . 21 6.3. Advertising Mobile Network Reachability . . . . . . . . . 20
6.4. Establishment of Bi-directional Tunnel . . . . . . . . . 21 6.4. Establishment of Bi-directional Tunnel . . . . . . . . . 21
6.5. Forwarding Packets . . . . . . . . . . . . . . . . . . . 21 6.5. Forwarding Packets . . . . . . . . . . . . . . . . . . . 21
6.6. Sending Binding Acknowledgements . . . . . . . . . . . . 22 6.6. Sending Binding Acknowledgements . . . . . . . . . . . . 22
6.7. Mobile Network Prefix De-Registration . . . . . . . . . . 23 6.7. Mobile Network Prefix De-Registration . . . . . . . . . . 22
7. Extended Home Network 24
8. Support for Dynamic Routing Protocols 26 7. Support for Dynamic Routing Protocols 23
9. Use of IPsec to protect the Signaling Messages 27 8. Security Considerations 25
10. Security Considerations 28 9. IANA Considerations 25
11. IANA Considerations 28 10. Contributors 25
12. Contributors 28 11. Acknowledgements 26
13. Acknowledgements 28 A. Examples of Operation 28
A. Examples of Operation 31 B. Changes from Previous Version 31
Addresses 34 Addresses 32
1. Introduction 1. Introduction
This document describes protocol extensions to Mobile IPv6 (MIPv6) This document describes protocol extensions to Mobile IPv6 (MIPv6)
[1] to enable support for network mobility. The extensions provide [1] to enable support for network mobility. The extensions provide
a backward compatibility with Mobile IPv6, and in particular, a Nemo backward compatibility with Mobile IPv6, and in particular, a Nemo
compliant Home Agent can operate as a MIPv6 Home Agent as well. compliant Home Agent can operate as a MIPv6 Home Agent as well.
The Nemo Basic Support works in such a way that session continuity is The Nemo Basic Support works in such a way that session continuity is
ensured for all the nodes in the mobile network even as the Mobile ensured for all the nodes in the mobile network even as the Mobile
Router changes its point of attachment to the Internet. It also Router changes its point of attachment to the Internet. It also
provides connectivity and reachability for all nodes in the mobile provides connectivity and reachability for all nodes in the mobile
network as the network moves. The solution supports both Local Fixed network as the network moves. The solution supports both Local Fixed
Nodes [2] and Mobile Nodes in the Mobile Metwork. Nodes [8] and Mobile Nodes in the Mobile Network.
Within the context of this document, the definition of a Mobile Within the context of this document, the definition of a Mobile
Router extends that of a Mobile IPv6 [1] Mobile Node, by adding Router extends that of a Mobile IPv6 [1] Mobile Node, by adding
the capability of routing between its point of attachment (Care-of the capability of routing between its point of attachment (Care-of
Address) and a subnet which moves with the Mobile Router. Address) and a subnet which moves with the Mobile Router.
The solution described in this document requires setting up a The solution described in this document requires setting up a
bi-directional tunnel between the Mobile Router and its Home Agent. bi-directional tunnel between the Mobile Router and its Home Agent.
This tunnel is set up when the Mobile Router sends a successful This tunnel is set up when the Mobile Router sends a successful
Binding Update to its Home Agent, informing the Home Agent of its Binding Update to its Home Agent, informing the Home Agent of its
current point of attachment. current point of attachment.
All traffic between the nodes in the Mobile Network and Correspondent All traffic between the nodes in the Mobile Network and Correspondent
Nodes passes through the Home Agent. This document does not describe Nodes passes through the Home Agent. This document does not describe
how to route optimize this traffic. Route Optimization will be dealt how to route optimize this traffic.
with in later specifications.
IPsec is used to secure all signalling messages between the Mobile
Router and its Home Agent. The use of IPsec to protect the signaling
messages is described in [3]. This document does not introduce any
additional requirements as far as the use of IPsec is concerned.
The terminology document [2] describes Nested Mobility as a scenario The terminology document [8] describes Nested Mobility as a scenario
where a Mobile Router allows another Mobile Router to attach to its where a Mobile Router allows another Mobile Router to attach to its
mobile network. There could be arbitrary levels of nested mobility. mobile network. There could be arbitrary levels of nested mobility.
The operation of each Mobile Router remains the same whether the The operation of each Mobile Router remains the same whether the
Mobile Router attaches to another Mobile Router or to a fixed Access Mobile Router attaches to another Mobile Router or to a fixed Access
Router on the Internet. The solution described here does not place Router on the Internet. The solution described here does not place
any restriction on the number of levels for nested mobility. But any restriction on the number of levels for nested mobility. But it
it should be noted that this might introduce important overhead on should be noted that this might introduce significant overhead on
the data packets as each level of nestedness introduces another IPv6 the data packets as each level of nestedness introduces another IPv6
header encapsulation. header encapsulation.
2. Terminology 2. Terminology
There is a separate NEMO terminology document [2], which defines the
terms related to Network Mobility used in the document.
The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [2]. document are to be interpreted as described in RFC 2119 [2].
There is a separate NEMO terminology document [8], which defines the
terms related to Network Mobility used in the document.
Prefix Table Prefix Table
It is a list of a mobile network prefixes indexed It is a list of a Mobile Network Prefixes indexed
by the extended Home Address of a Mobile Router. The by the Home Address of a Mobile Router. The prefix table
prefix table is managed by the Home Agent. When a Home is managed by the Home Agent and is used by the Home Agent
Agent receives a Binding Update without any options, to determine which Mobile Network Prefixes are owned
it searches a correspondent Mobile Network prefix in a particular Mobile Router. This is an optional data
the prefix table, keying with the Home Address of the
requesting Mobile Router. This is an optional data
structure. structure.
Mobile Network Prefix 3. Overview of the Nemo Protocol
The IPv6 prefix advertised in the Mobile Network
by one or more Mobile Routers. There could be multiple
prefixes in the Mobile Network.
extended Home Network Prefix
The aggregation of one or more Home Network and
Mobile Network prefixes. The extended Home Network
is generally the granularity that is exposed by the
Home Agents to the routing infrastructure over routing
protocols.
extended Home Network
The network associated with the extended Home
Network Prefix. The extended Home Network may be physical
or virtual.
extended Home Address
The Home Address is derived from the Home Network
prefix. The extended Home Address is taken from the
extended Home Network. More precisely, the extended Home
Address can be either from the Home Network or from one of
the Mobile Router's Mobile Network prefixes. The extended
Home Address inherits from the properties of the Home
Address and can be used for registration to the Home Agent
as described in this document.
3. Overview of the NEMO Protocol
A Mobile Network is a network segment or subnet which can move A Mobile Network is a network segment or subnet which can move
and attach to arbitrary points in the Internet. A Mobile Network and attach to arbitrary points in the Internet. A Mobile Network
does not allow any transit traffic and can only be accessed via does not allow any transit traffic and can only be accessed via
specific Gateways called Mobile Routers that manage its movement. specific gateways called Mobile Routers that manage its movement.
A Mobile Router does not distribute the Mobile Network routes to A Mobile Router does not distribute the Mobile Network routes to
the infrastructure at its point of attachment (i.e. in the visited the infrastructure at its point of attachment (i.e. in the visited
network). Instead, it maintains a bidirectional tunnel to a Home network). Instead, it maintains a bidirectional tunnel to a Home
Agent that advertises an aggregation of Mobile Networks to the Agent that advertises an aggregation of Mobile Networks to the
infrasructure. The Mobile Router is also the default gateway for the infrasructure. The Mobile Router is also the default gateway for the
Mobile Network. Mobile Network.
A Mobile Network can also consist of multiple and nested subnets. In A Mobile Network can also consist of multiple and nested subnets. A
particular, a router with no support for mobility may be permanently router with no support for mobility may be permanently attached to
attached to a Mobile Network for local distribution. Also, Mobile a Mobile Network for local distribution. Also, Mobile Routers may
Routers may be attached to Mobile Networks owned by different Mobile be attached to Mobile Networks owned by different Mobile Routers and
Routers and form a graph. In particular, with Basic Nemo Support, form a graph. In particular, with Basic Nemo Support, each Mobile
each Mobile Router is attached to another Mobile Network by a single Router is attached to another Mobile Network by a single interface,
interface, and if loops are avoided, the graph is a tree. and if loops are avoided, the graph is a tree.
A Mobile Router has an unique Home Address through which it is always A Mobile Router has an unique Home Address through which it is always
reachable. The Home Address is configured from a prefix that is reachable. The Home Address is configured from a prefix that is
aggregated and advertised by its Home Agent. The prefix could either aggregated and advertised by its Home Agent. The prefix could either
be the prefix advertised on the home link or the prefix delegated be the prefix advertised on the home link or the prefix delegated to
to the Mobile Router. This is described in detail in Section 7. the Mobile Router. The Mobile Router can have more than one Home
The Mobile Router can have more than one Home Address if there Address if there are multiple prefixes in the home link. The Mobile
are multiple prefixes in the home link. The Mobile Router also Router also advertises one or more prefixes in the mobile network
advertises one or more prefixes in the mobile network attached to it. attached to it. The actual mechanism for allocating these Mobile
The actual mechanism for allocating these Mobile Network Prefixes is Network Prefixes is outside the scope of this specification.
outside the scope of this specification. However, it is recommended
that these prefixes are allocated in such a manner that they can be
aggregated under the home link.
When the Mobile Router moves away from the home link and attaches When the Mobile Router moves away from the home link and attaches
to a new access router, it acquires a Care-of Address from the to a new access router, it acquires a Care-of Address from the
visited link. The Mobile Router at any time can appear and behave visited link. The Mobile Router at any time can appear and behave
as a Mobile Host or a Mobile Router. If the Mobile Router wants as a Mobile Host or a Mobile Router. If the Mobile Router wants
connectivity, rechability and session continuity for nodes in the connectivity, reachability and session continuity for nodes in the
Mobile Network, it acts as a Mobile Router. In either case, as soon Mobile Network, it acts as a Mobile Router. In either case, as soon
as the Mobile Router acquires a Care-of Address, it immediately sends as the Mobile Router acquires a Care-of Address, it immediately sends
a Binding Update to its Home Agent as described in [1]. When the a Binding Update to its Home Agent as described in [1]. When the
Home Agent receives this Binding Update it creates a binding cache Home Agent receives this Binding Update it creates a binding cache
entry binding the Mobile Router's Home Address to its Care-of address entry binding the Mobile Router's Home Address to its Care-of address
at the current point of attachment. at the current point of attachment.
If the Mobile Router wishes to act as a Mobile Router and provide If the Mobile Router wishes to act as a Mobile Router and provide
connectivity to nodes in the Mobile Network, it indicates this to connectivity to nodes in the Mobile Network, it indicates this to
the Home Agent by setting a flag 'R' in the Binding Update. It also the Home Agent by setting a flag 'R' in the Binding Update. It MAY
includes information about the Mobile Network Prefix in the Binding also include information about the Mobile Network Prefix in the
Update using one of the modes described in Section 5.2, so that Binding Update using one of the modes described in section 5.2, so
the Home Agent can forward packets meant for nodes in the mobile that the Home Agent can forward packets meant for nodes in the mobile
network to the Mobile Router. Two new Mobility Header Options are network to the Mobile Router. Two new Mobility Header Options are
described in this document to carry prefix information. These new described in this document to carry prefix information. These new
options are described in Section 4.3 and section 4.4. If the Mobile options are described in section 4.3 and section 4.4. If the Mobile
Network has more than one IPv6 prefix and wants the Home Agent to Network has more than one IPv6 prefix and wants the Home Agent to
setup forwarding for all these prefixes, it includes multiple prefix setup forwarding for all these prefixes, it includes multiple prefix
information options in a single Binding Update. The Home Agent sets information options in a single Binding Update. The Home Agent sets
up forwarding for each of these prefixes to the Mobile Router's up forwarding for each of these prefixes to the Mobile Router's
Care-of Address. In some scenarios the Home Agent already knows Care-of Address. In some scenarios the Home Agent already knows
which prefixes are owned by a Mobile Router. In these scenarios, the which prefixes are owned by a Mobile Router. In these scenarios, the
Mobile Router does not include any prefix information in the Binding Mobile Router does not include any prefix information in the Binding
Update. The Home Agent sets up forwarding for all prefixes owned by Update. The Home Agent sets up forwarding for all prefixes owned by
the Mobile Router, when it receives a Binding Update from the mobile the Mobile Router, when it receives a Binding Update from the mobile
router. router with the router flag 'R' set.
If the Home Agent successfully processes the Binding Update and The Home Agent acknowledges the Binding Update by sending a Binding
sets up forwarding for the Mobile Network Prefix, it sends a Acknowledgement to the Mobile Router. A positive acknowledgement
Binding Acknowledgement to the Mobile Router. Once the binding means that the HA has set up forwarding for the Mobile Network.
process completes, a bi-directional tunnel is established between Once the binding process completes, a bi-directional tunnel is
the Home Agent and the Mobile Router. The tunnel end points are established between the Home Agent and the Mobile Router. The tunnel
Mobile Router's Care-of Address and the Home Agent's address. If end points are Mobile Router's Care-of Address and the Home Agent's
a packet with a source address belonging to the Mobile Network address. If a packet with a source address belonging to the Mobile
Prefix is received from the Mobile Network, the Mobile Router Network Prefix is received from the Mobile Network, the Mobile Router
reverse-tunnels the packet to the Home Agent through this tunnel. reverse-tunnels the packet to the Home Agent through this tunnel.
This reverse-tunneling is done by using IP-in-IP encapsulation [4]. This reverse-tunneling is done by using IP-in-IP encapsulation [3].
The Home Agent decapsulates this packet and forwards it to the CN. The Home Agent decapsulates this packet and forwards it to the
The Mobile Router is however free to use route optimization as Correspondent Node. The Mobile Router is however free to use route
described in [1] for packet originated by the Mobile Router itself. optimization as described in [1] for packet originated by the Mobile
Router itself.
When a data packet is sent by a Correspondent Node to a node in the When a data packet is sent by a Correspondent Node to a node in the
Mobile Network, it gets routed to the Home Agent which currently Mobile Network, it gets routed to the Home Agent which currently
has the binding for the Mobile Router. It is expected that the has the binding for the Mobile Router. It is expected that the
Mobile Router's network prefix would be aggregated at the Home Mobile Router's network prefix would be aggregated at the Home Agent,
Agent, which advertises the resulting aggregation. Alternatively, which advertises the resulting aggregation. Alternatively, the Home
the Home Agent may receive the data packets meant for the Mobile Agent may receive the data packets meant for the Mobile Network
Network by advertising routes to the Mobile Network prefix. The by advertising routes to the Mobile Network prefix. The actual
actual mechanism by which these routes are advertised is outside mechanism by which these routes are advertised is outside the scope
the scope of this document for now. When the Home Agent receives a of this document. When the Home Agent receives a data packet meant
data packet meant for a node in the mobile network, it tunnels the for a node in the mobile network, it tunnels the packet to Mobile
packet to Mobile Router's current Care-of address. The Mobile Router Router's current Care-of address. The Mobile Router decapsulates
decapsulates the packet and forwards it onto the link where the the packet and forwards it onto the interface where the Mobile
Mobile Network is connected. Network is connected. The Mobile Router before decapsulating the
tunneled packet, has to check if the Source address on the outer IPv6
header is the Home Agent's address. It also has to make sure the
destination address on the inner IPv6 header belongs to one of its
Mobile Network Prefixes before forwarding the packet to the Mobile
Network.
The Mobile Network could consist of nodes which are Local Fixed The Mobile Network could consist of nodes which are Local Fixed
Nodes, Local Mobile Nodes and Visiting Mobile Nodes [2]. The Nodes, Local Mobile Nodes and Visiting Mobile Nodes [8]. The
protocol described here ensures complete transparency of network protocol described here ensures complete transparency of network
mobility to the Local Fixed Nodes. Visiting Mobile Nodes are those mobility to the Local Fixed Nodes. Visiting Mobile Nodes are those
nodes which are Mobile Nodes as described in Mobile IPv6. Visiting nodes which are Mobile Nodes as described in Mobile IPv6. Visiting
Mobile Nodes treat the Mobile Network as just a normal IPv6 access Mobile Nodes treat the Mobile Network as just a normal IPv6 access
network and run the Mobile IPv6 protocol. network and run the Mobile IPv6 protocol.
It is also possible for the Mobile Router and the Home Agent to It is also possible for the Mobile Router and the Home Agent to run
run a routing protocol through the bi-directional tunnel. The a routing protocol through the bi-directional tunnel. In that case,
Mobile Router need not include prefix information in the Binding the Mobile Router need not include prefix information in the Binding
Update. Instead the Home Agent uses the routing protocol updates to Update. Instead the Home Agent uses the routing protocol updates to
setup forwarding for the Mobile Network. When running the routing setup forwarding for the Mobile Network. When running the routing
protocol it is required that the bi-directional tunnel be treated as protocol it is required that the bi-directional tunnel be treated as
a tunnel interface. The tunnel interface is included as the list of a tunnel interface. The tunnel interface is included as the list of
interfaces on which routing protocol is active. The Mobile Router interfaces on which routing protocol is active. The Mobile Router
should be careful to not run the routing protocol on its egress should be configured not to run the routing protocol on its egress
interface when it is away from the home link. interface when it is away from the home link.
Finally, the Home Agent(s) may be configured with static routes to Finally, the Home Agent may be configured with static routes to the
the Mobile Network Prefix via the Mobile Router home address.. In Mobile Network Prefix via the Mobile Router's Home Address. In that
that case, the routes are set independently of the binding flows and case, the routes are set independently of the binding flows and the
the returning Home of a Mobile Router. The benefit is that such returning Home of a Mobile Router. The benefit is that such movement
movement does not induce any additional signalling in the form of does not induce any additional signalling in the form of routing
routing updates in the Home Network. The drawback of that model is updates in the Home Network. The drawback of that model is that the
that the routes are present even if the Mobile Routers that are not routes are present even if the related Mobile Routers that are not
reachable (at Home or bound) at a given point of time. reachable (at Home or bound) at a given point of time.
4. Message Formats 4. Message Formats
4.1. Binding Update 4.1. Binding Update
A new flag `R' is included in the Binding Update to indicate to the A new flag `R' is included in the Binding Update to indicate to the
Home Agent if the Binding Update is coming from a Mobile Router Home Agent if the Binding Update is coming from a Mobile Router
and not from a mobile node. The rest of the Binding Update format and not from a mobile node. The rest of the Binding Update format
remains the same as defined in [1]. remains the same as defined in [1].
skipping to change at page 10, line 28 skipping to change at page 9, line 28
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A|H|L|K|R| Reserved | Lifetime | |A|H|L|K|R| Reserved | Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
. . . .
. Mobility options . . Mobility options .
. . . .
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Mobile Router Flag(R) Mobile Router Flag (R)
The Mobile Router Flag is set to indicate to the Home Agent The Mobile Router Flag is set to indicate to the Home Agent
that the Binding Update is from a Mobile Router. If the flag that the Binding Update is from a Mobile Router. If the flag
is set to 0, the Home Agent assumes that the Mobile Router is is set to 0, the Home Agent assumes that the Mobile Router is
just behaving as a Mobile Node, and should not forward packets just behaving as a Mobile Node, and MUST NOT forward packets
destined for the mobile network to the Mobile Router. destined for the mobile network to the Mobile Router.
Mobility Options Mobility Options
Variable length field which can include zero or more mobility Variable length field which can include zero or more mobility
options. This document defines two new mobility options in options. This document defines two new mobility options in
addition to what is defined [1]. The receiver MUST skip and addition to what is defined in [1]. The receiver MUST skip and
ignore any options which it does not understand. ignore any options which it does not understand.
4.2. Binding Acknowledgement 4.2. Binding Acknowledgement
There is no change in the Binding Acknowledgement format from what There is no change in the Binding Acknowledgement format from what
is used in Mobile IPv6 [1]. However, this document introduces the is used in Mobile IPv6 [1]. However, this document introduces the
following new status values for the binding acknowledgement. following new status values for the binding acknowledgement.
Status Status
2 Mobile Router Binding Update accepted
140 Mobile Router Operation not permitted 140 Mobile Router Operation not permitted
141 Invalid Prefix 141 Invalid Prefix
142 Not Authorized for Prefix 142 Not Authorized for Prefix
143 Mobile Network Prefix information unavailable. 143 Forwarding Setup failed
Status values less than 128 indicate that the Binding Update was Status values less than 128 indicate that the Binding Update was
processed successfully by the receiving nodes. Values greater than processed successfully by the receiving nodes. Values greater than
128 indicate that the Binding Update was rejected by the receiving 128 indicate that the Binding Update was rejected by the receiving
node. node.
4.3. Mobile Network Prefix Option 4.3. Mobile Network Prefix Option
The Mobile Network Prefix Option is included in the Binding Update The Mobile Network Prefix Option is included in the Binding Update
to indicate to the Home Agent the prefix information for the mobile to indicate to the Home Agent the prefix information for the mobile
skipping to change at page 11, line 45 skipping to change at page 10, line 47
+ + + +
| | | |
+ Mobile Network Prefix + + Mobile Network Prefix +
| | | |
+ + + +
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
TBD TBA
Length Length
8 bit unsigned integer indicating the length in octets of the 8 bit unsigned integer indicating the length in octets of the
option excluding the type and length fields. Set to 18. option excluding the type and length fields. Set to 18.
Reserved Reserved
Set to 0. Ignored for now. This field is unused for now. The value MUST be initialized to
zero by the sender, and MUST be ignored by the receiver.
Prefix Length Prefix Length
8 bit unsigned integer indicating the length of the IPv6 prefix 8 bit unsigned integer indicating the prefix length of the IPv6
contained in the option. prefix contained in the option.
Mobile Network Prefix Mobile Network Prefix
A 16 byte field contains the Mobile Network Prefix. A 16 byte field contains the Mobile Network Prefix.
4.4. Mobile Network Prefix Length Option 4.4. Mobile Network Prefix Length Option
The Mobile Network Prefix Length Option can be used by the Mobile The Mobile Network Prefix Length Option can be used by the Mobile
Router if the Mobile Network Prefix can be deduced from the Home Router if the Mobile Network Prefix can be deduced from the Home
Address of the Mobile Router. If there is only one Mobile Network Address of the Mobile Router. If there is only one Mobile Network
skipping to change at page 12, line 44 skipping to change at page 11, line 45
Update if this option is present. Update if this option is present.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved | Prefix Length | | Type | Length | Reserved | Prefix Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type
TBD TBA
Length Length
8 bit unsigned integer indicating the length in octets of the 8 bit unsigned integer indicating the length in octets of the
option excluding the type and length field. Set to 2. option excluding the type and length field. Set to 2.
Reserved Reserved
Set to 0. Ignored for now. This field is unused for now. The value MUST be initialized to
zero by the sender, and MUST be ignored by the receiver.
Prefix Length Prefix Length
8 bit unsigned integer indicating the length of the IPv6 prefix 8 bit unsigned integer indicating the prefix length of the IPv6
contained in the option prefix from which the Home Address included in the Binding
Update was configured.
5. Mobile Router Operation 5. Mobile Router Operation
Mobile Router operation is derived largely from the combined Mobile Router operation is derived largely from the combined
behaviors of a Host, of a Router [8], and of a Mobile Node [1] (also behaviors of a Host, of a Router [6], and of a Mobile Node [1] (also
please see definition of a Mobile Host in [2] and the definition of please see definition of a Mobile Host in [8]).
an IPv4 Mobile Node [10]).
A Mobile Node can act in two different ways: (1) as a Mobile Host A Mobile Node can act in two different ways: (1) as a Mobile Host
(in which case the Mobile IPv6 Home Agent doesn't maintain any prefix (in which case the Mobile IPv6 Home Agent doesn't maintain any prefix
information related to the Mobile Host's Home Address, but does information related to the Mobile Host's Home Address, but does
maintain a binding cache entry related to the Mobile Host's Home maintain a binding cache entry related to the Mobile Host's Home
Address) and (2) as a Mobile Router (in which case, in addition to Address) and (2) as a Mobile Router (in which case, in addition to
maintaining the binding cache entry corresponding to the Mobile maintaining the binding cache entry corresponding to the Mobile
Router Home Address, the Mobile IPv6 Home Agent also maintains Router Home Address, the Mobile IPv6 Home Agent also maintains
forwarding information related to prefixes assigned to the Mobile forwarding information related to prefixes assigned to the mobile
Network). The distinction between the the two modes is represented network). The distinction between the the two modes is represented
by the value of the 'R' bit. by the value of the Mobile Router flag 'R'.
Mobile Router uses various data structures, exchanges specific
binding messages with Home Agent, performs a specific Neighbour
Discovery behavior and joins certain multicast groups.
5.1. Data Structures 5.1. Data Structures
Like a Mobile Host, a Mobile Router also maintains a Binding Update Like a Mobile Host, a Mobile Router also maintains a Binding Update
List, described in section 11.1 of Mobile IPv6 specification[1]. The List, described in section 11.1 of Mobile IPv6 specification[1]. The
Binding Update list is a conceptual data structure which records Binding Update list is a conceptual data structure which records
information that is sent in the Binding Updates. There is one entry information that is sent in the Binding Updates. There is one entry
per each destination that the Mobile Router is currently sending per each destination that the Mobile Router is currently sending
Binding Updates to. Binding Updates to.
This document introduces a new Prefix Information field in the This document introduces a new Prefix Information field in the
Binding Update list structure. This field is used to store any Binding Update list structure. This field is used to store any
prefix information that the Mobile Router includes in the Binding prefix information that the Mobile Router includes in the Binding
Update. If the Mobile Router sets the 'R' bit in the Binding Update, Update. If the Mobile Router sets the Mobile Router flag 'R' in the
but does not include any prefix information in it (implicit mode), Binding Update, but does not include any prefix information in it
this field is set to null. (implicit mode), this field is set to null.
Similar to a Mobile Host, a Mobile Router also stores the information Similar to a Mobile Host, a Mobile Router stores the information
regarding status of flags of the Binding Update, in the corresponding regarding status of flags of the Binding Update, in the corresponding
Binding Update List entry. Additionally, this document introduces a Binding Update List entry. This document introduces a new mobile
new mobile router flag 'R' for this entry. The status of this flag router flag 'R' for this entry. The status of this flag is stored in
is stored in the Binding Update list whenever a Binding Update is the Binding Update list whenever a Binding Update is sent.
sent.
Similarly to a Mobile Host, a Mobile Router maintains a Home Agent A Mobile Router also maintains a Home Agent list populated according
list populated according to the same procedure as a Mobile Host. to the same procedure as a Mobile Host.
5.2. Sending Binding Updates 5.2. Sending Binding Updates
A Mobile Router will send Binding Updates to its Home Agent according A Mobile Router sends Binding Updates to its Home Agent according to
to the same procedures that a Mobile Host uses. The Mobile Router the same procedures that a Mobile Host uses. The Mobile Router uses
MUST use one of the following modes to instruct the Home Agent to one of the following modes to instruct the Home Agent to determine
determine the Mobile Network prefix. In all three modes, the Mobile the prefixes owned by the Mobile Router. In all three modes, the
Router sets the 'R' bit to 1. Mobile Router sets the Mobile Router flag 'R'.
Implicit: Implicit:
In this mode, the Mobile Router does not include either a In this mode, the Mobile Router does not include either a
Mobile Network Prefix Option or a Mobile Network Prefix Length Mobile Network Prefix Option or a Mobile Network Prefix Length
Option in the Binding Update (but it does include the Home Option in the Binding Update (but it does include the Home
Address Option in the Destination Options header, as all Mobile Address Option in the Destination Options header, as all Mobile
Hosts do). The Home Agent can use any mechanism (not defined Hosts do). The Home Agent can use any mechanism (not defined
in this document) to determine the Mobile Network Prefix(es) in this document) to determine the Mobile Network Prefix(es)
owned the Mobile Router. One of the well known mechanisms is owned by the Mobile Router and setup forwarding for the Mobile
where the Home Agent maintains a Pre-configured Prefix Table Network. One example would be manual configuration at the
listing all the Mobile Network prefixes owned by a particular Home Agent mapping the Mobile Router's Home Address to the
Mobile Router. This table is keyed on the Home Address of the information required for setting up forwarding for the Mobile
Mobile Router. Network.
Explicit: Explicit Network:
In this mode, the Mobile Router includes one or more Mobile In this mode, the Mobile Router includes one or more Mobile
Network Prefix Options in the Binding Update. These options Network Prefix Options in the Binding Update. These options
contain information about the Mobile Network Prefix(es) contain information about the Mobile Network Prefix(es)
configured on the Mobile Network. configured on the mobile network.
Explicit combined: Explicit Prefix Length:
In this mode, the Mobile Router instructs the Home Agent to In this mode, the Mobile Router instructs the Home Agent to
derive the Mobile Network Prefix by using: (1) the Home derive the Mobile Network Prefix by using: (1) the Home
Address in the Home Address Option carried in the Destination Address in the Home Address Option carried in the Destination
Options header of the same packet that carries the Mobility Options header of the same packet that carries the Mobility
Header containing this Binding Update and (2) the prefix length Header containing this Binding Update and (2) the prefix length
carried in the Mobile Network Prefix Length Option. In this carried in the Mobile Network Prefix Length Option. In this
case, Mobile Router includes one and only one Mobile Network case, Mobile Router includes one and only one Mobile Network
Prefix Length Option. It MUST not include a Mobile Network Prefix Length Option. It MUST NOT include a Mobile Network
Prefix Option if this method is used. Prefix Option if this method is used.
If the Mobile Router flag is set, The Mobile Router MUST also set the If the Mobile Router flag is set, Home Registration flag 'H' MUST be
Home Registration flag 'H'. set.
5.3. Receiving Binding Acknowledgements 5.3. Receiving Binding Acknowledgements
The Mobile Router receives Binding Acknowledgements from the Home The Mobile Router receives Binding Acknowledgements from the
Agent, corresponding to the Binding Updates it sent. If the Binding Home Agent, corresponding to the Binding Updates it sent. If the
Acknowledgement status is set to a value less than 128, the Mobile Binding Acknowledgement status is set to '2' (Mobile Router Binding
Router assumes that the Binding Update was processed succesfully Update accepted), the Mobile Router assumes that the Home Agent has
by the Home Agent. The Mobile Router can then start using the successfully processed the Binding Update and has set up forwarding
for the Mobile Network.The Mobile Router can then start using the
bi-directional tunnel for reverse tunneling traffic from the mobile bi-directional tunnel for reverse tunneling traffic from the mobile
network. network.
5.4. Error Processing 5.4. Error Processing
If the Binding Acknowledgement status is set to a value between 128 If the Binding Acknowledgement status is set to a value between 128
and 140, the Mobile Router takes necessary actions as described in and 140, the Mobile Router takes necessary actions as described in
the Mobile IPv6 specification [1]. the Mobile IPv6 specification [1].
If the Binding Acknowlegement status is set to '0' (Binding Update
accepted), the Mobile Router concludes that the Home Agent which
processed the Binding Update is a MIPv6 Home Agent that has not
implemented support for Mobile Routers. It should send a similar
Binding Update to another Home Agent on the link. If no Home Agent
replies positively then the Mobile Router MUST refrain from sending
any Binding Update with the Mobile Router flag set to any home agent
on the home link and log the information.
If the Mobile Router sent a Binding Update to the Home Agent in If the Mobile Router sent a Binding Update to the Home Agent in
implicit mode (i.e. the prefix field in the Binding Update list implicit mode (i.e. the prefix field in the Binding Update list
entry is null) then the Mobile Router interprets only the error entry is null) then the Mobile Router interprets only the error
status '140' (Mobile Router Operation not permitted) and '143' status '140' (Mobile Router Operation not permitted) and '143'
(Mobile Network Prefix information unavailable). For this Binding (Forwarding Setup failed) For this Binding Update, the Mobile Router
Update, the Mobile Router will discard Binding Acknowledgements with MUST discard Binding Acknowledgements with codes '141' and '142'.
codes '141' and '142', and log the information.
For the same Binding Update, if the status is '140', Mobile Router For the same Binding Update, if the status is '140', then the Mobile
SHOULD send a similar Binding Update (implicit mode) to another Home Router should send a similar Binding Update (implicit mode) to
Agent on the same home link. If no Home Agent replies positively another Home Agent on the same home link. If no Home Agent replies
then the Mobile Router MUST refrain from sending any Binding Update positively then the Mobile Router MUST refrain from sending any
with the 'R' bit set to any Home Agent on the home link, and log the Binding Update with the Mobile Router flag set to any Home Agent on
information. the home link, and log the information.
For the same Binding Update, if the status is '143', Mobile Router For the same Binding Update, if the status is '143', then the Mobile
SHOULD send a similar Binding Update (implicit mode) to another Home Router should send a similar Binding Update (implicit mode) to
Agent on the same home link. If no Home Agent replies positively another Home Agent on the same home link. If no Home Agent replies
then Mobile Router SHOULD refrain from sending this Binding Update positively then Mobile Router SHOULD refrain from sending this
to any Home Agent on the home link, and MAY send Binding Updates in Binding Update to any Home Agent on the home link, and MAY send
another mode (e.g. explicitly include a prefix) to a Home Agent on Binding Updates in another mode (e.g. explicitly include a prefix)
the same home link. to a Home Agent on the same home link.
If the Mobile Router sent a Binding Update to Home Agent in any other If the Mobile Router sent a Binding Update to Home Agent in any other
mode than implicit mode (i.e. the prefix field in the Binding Update mode than implicit mode (i.e. the prefix field in the Binding Update
list entry is not null) then the Mobile Router interprets only the list entry is not null) then the Mobile Router interprets only the
error status '141' (Invalid Prefix) and '142' (Not Authorized for error status '141' (Invalid Prefix) and '142' (Not Authorized for
Prefix). For this Binding Update, the Mobile Router will discard Prefix). For this Binding Update, the Mobile Router MUST discard
Binding Acknowledgements with codes '140' and '143', and log the Binding Acknowledgements with codes '140' and '143'.
information.
For the same Binding Update, if the status is set to '141', then the For the same Binding Update, if the status is set to '141', then the
Mobile Router should send a similar Binding Update (same explicit Mobile Router should send a similar Binding Update (same explicit
prefix(es) or prefix lens) to another Home Agent on the same home prefix(es) or prefix lengths) to another Home Agent on the same home
link. If no Home Agent replies positively then Mobile Router SHOULD link. If no Home Agent replies positively then Mobile Router SHOULD
refrain from sending this Binding Updates to any Home Agent on the refrain from sending this Binding Updates to any Home Agent on the
home link. At this point, Mobile Router MAY try try to obtain and home link. At this point, Mobile Router MAY try to obtain and own a
own a prefix by the same means that it initially got attributed the prefix by the same means that it initially got attributed the Invalid
Invalid Prefix in question. Alternatively, Mobile Router MAY send Prefix in question. Alternatively, Mobile Router MAY send Binding
Binding Updates in another mode (e.g. implicit mode) to a Home Agent Updates in another mode (e.g. implicit mode) to a Home Agent on the
on the same home link. same home link.
For the same Binding Update, if the status is set to '142', then the For the same Binding Update, if the status is set to '142', then the
Mobile Router should send a similar Binding Update (same explicit Mobile Router should send a similar Binding Update (same explicit
prefix(es) or prefix lens) to another Home Agent on the same home prefix(es) or prefix lens) to another Home Agent on the same home
link. If no Home Agent replies positively then Mobile Router SHOULD link. If no Home Agent replies positively then Mobile Router SHOULD
refrain from sending this Binding Updates to any Home Agent on the refrain from sending this Binding Updates to any Home Agent on the
home link. Additionally, the Home Agent MUST stop advertising home link. Additionally, the Home Agent MUST stop advertising
the respective prefix(es) in the mobile network with associated the respective prefix(es) in the mobile network with associated
Router Advertisements, and modify its own forwarding information Router Advertisements, and modify its own forwarding information
accordingly. Following this, the Mobile Router MAY send Binding accordingly. Following this, the Mobile Router MAY send Binding
Updates in another mode (e.g. implicit) to a Home Agent on the same Updates in another mode (e.g. implicit) to a Home Agent on the same
home link. home link.
If at the end of this Error Processing procedure the Mobile Router If at the end of this Error Processing procedure the Mobile Router
has tried every available modes of sending Binding Updates and still has tried every available modes of sending Binding Updates and still
has not received a positive Binding Acknowledgement (status valued 0) has not received a positive Binding Acknowledgement (status value
for this Home Address from any Home Agent on its home link, then the between 0 and 127) for this Home Address from any Home Agent on its
Mobile Router MUST stop sending Binding Updates with the 'R' bit set home link, then the Mobile Router MUST stop sending Binding Updates
for this Home Address and log the information. with the Mobile Router flag set for this Home Address and log the
information.
In all the above cases, the Mobile Router should assume that the Home In all the above cases, the Mobile Router MUST conclude that the Home
Agent did not create a binding cache entry for the Mobile Router's Agent did not create a binding cache entry for the Mobile Router's
home address. Home Address.
5.5. Establishment of Bi-directional Tunnel 5.5. Establishment of Bi-directional Tunnel
Only when a successful Binding Acknowledgement ('Status' field valued When a successful Binding Acknowledgement with status set to '2'
0) is received will the Mobile Router set up its endpoint of the (Mobile Router Binding Update accepted) is received, the Mobile
bi-directional tunnel. Router set up its endpoint of the bi-directional tunnel.
The bi-directional tunnel between Mobile Router and Home Agent allows The bi-directional tunnel between Mobile Router and Home Agent allows
packets to flow in both directions between these entities, while the packets to flow in both directions between these entities, while the
Mobile Router is connected to a Visisted Link. The bi-directional Mobile Router is connected to a Visited Link. The bi-directional
tunnel involves two virtual links [4]: one virtual link has the tunnel involves two virtual links [3]: one virtual link has the
address of the tunnel entry point as the Care-of Address of the address of the tunnel entry point as the Care-of Address of the
Mobile Router and the tunnel exit point as the address of the Home Mobile Router and the tunnel exit point as the address of the
Agent; the other virtual link has as tunnel entry point the Home Home Agent; the other virtual link has as tunnel entry point the
Agent address and as tunnel exit point the Care-of Address of the Home Agent address and as tunnel exit point the Care-of Address
Mobile Router. Both addresses are unicast addresses. of the Mobile Router. Both addresses are unicast addresses. All
IPv6 traffic to and from the Mobile Network is sent through this
Packets sent by the nodes in the mobile network (including the Mobile bi-directional tunnel.
Router) and addressed to any nodes other than nodes in the mobile
network are encapsulated by Mobile Router and decapsulated by the
Home Agent. Packets sent by any nodes other than nodes in the mobile
network and addressed to nodes in the mobile network are encapsulated
by the Home Agent and decapsulated by the Mobile Router.
A Mobile Router MAY limit the number of mobile routers that attach to A Mobile Router MAY limit the number of mobile routers that attach to
its mobile network (the number of levels in the nested aggregation) its mobile network (the number of levels in the nested aggregation)
by means of setting the Tunnel Encapsulation Limit field of the by means of setting the Tunnel Encapsulation Limit field of the
Tunnel Encapsulation option. Tunnel Encapsulation option.
A Mobile Router uses the Tunnel Hop Limit that is normally assigned A Mobile Router uses the Tunnel Hop Limit that is normally assigned
to routers (not to hosts); see IANA numbers. to routers (not to hosts). See [3].
Following the successful setup of the bi-directional tunnel on the
Mobile Router, the forwarding information on the Mobile Router is
updated such as to allow forwarding of packets as described above.
5.6. Neighbour Discovery for Mobile Router 5.6. Neighbour Discovery for Mobile Router
A Mobile Router MAY be configured to send Router Advertisements and A Mobile Router MAY be configured to send Router Advertisements and
reply to Router Solicitations on the interface attached to the home reply to Router Solicitations on the interface attached to the home
link. The value of the Router Lifetime field MUST be set to zero to link. The value of the Router Lifetime field MUST be set to zero to
prevent other nodes from configuring the Mobile Router as the default prevent other nodes from configuring the Mobile Router as the default
router. router.
A Mobile Router SHOULD NOT send unsolicited Router Advertisements A Mobile Router SHOULD NOT send unsolicited Router Advertisements
and SHOULD NOT reply to Router Solicitations on any egress interface and SHOULD NOT reply to Router Solicitations on any egress interface
when that interface is attached to any other link than the home link. when that interface is attached to a visited link. However, the
However, the Mobile Router SHOULD reply with Neighbor Advertisements Mobile Router SHOULD reply with Neighbor Advertisements to Neighbor
to Neighbor Solicitations received on the egress interface, for Solicitations received on the egress interface, for topologically
topologically correct addresses. correct addresses.
A Mobile Router MAY use the received Router Advertisements on the A Mobile Router MUST NOT ignore Router Advertisements received on
interface connected to the home link, but only for logging and the egress interface. The received Router Advertisements MAY be
administrative purposes. Only when that interface is connected to used for address configuration, default router selection or movement
a visisted link, the Mobile Router uses information in the received
Router Advertisements for purposes other than logging; this includes
address configuration, setting up a default route and movement
detection. detection.
5.7. Multicast Groups for Mobile Router 5.7. Multicast Groups for Mobile Router
When at home, the Mobile Router joins the multicast group All Routers When at home, the Mobile Router joins the multicast group All Routers
Address with scopes '1' interface-local (on the home-advertising Address with scopes '1' interface-local (on the home-advertising
interface), '2' link-local and '5' site-local on any of its egress interface) and '2' link-local on any of its egress interfaces. When
interfaces. When in a visited network, the Mobile Router MUST NOT in a visited network, the Mobile Router MUST NOT join the above
join any of the above groups on the respective interface. multicast groups on the corresponding interface.
6. Home Agent Operation 6. Home Agent Operation
In order for a Mobile Router to operate correctly, the home agent In order for a Mobile Router to operate correctly, the Home Agent
MUST satisfy all the requirements listed in Section 8.4 of [1]. MUST satisfy all the requirements listed in section 8.4 of [1]. The
Home Agent MUST implement all the modes described in Section 5.2.
6.1. Prefix Table 6.1. Data Structures
In some scenarios, the Home Agent might need to maintain a Prefix 6.1.1. Binding Cache
Table of Mobile Routers and the IPv6 prefixes owned by Mobile
Routers. The Home Agent MUST maintain this table if the Mobile The Home Agent maintains Binding Cache Entries for each Mobile Router
Routers operate under the implicit mode where they do not include any that is currently registered with the Home Agent. The Binding Cache
prefix information in the Binding Updates. is a conceptual data structure described in detail in [1].
The Home Agent might need to store the Mobile Network Prefixes
associated with a Mobile Router in the corresponding Binding Cache
Entry. This is required if the Binding Update (that created the
Binding Cache Entry) contained explicit prefix information. This
information can be used later to cleanup routes installed in explicit
mode, when the Binding Cache Entry is removed, and to maintain the
routing table, for instance should the routes be manually removed.
The Home Agent also stores the status of the Mobile Router Flag 'R'
in the Binding Cache entry.
6.1.2. Prefix Table
In some deployment scenarios it may be necessary for the Home Agent
to prevent a misbehaving Mobile Router from claiming mobile network
prefixes belonging to another Mobile Router. The Home Agent can
prevent such attacks if it maintains a Prefix Table and verifies the
Prefix Information provided by the Mobile Router against the entries
in the Prefix Table. However, this verification is done only if the
Binding Update contained explicit prefix information in the form of
either the Mobile Network Prefix Option or the Mobile Network Prefix
Length Option.
Each entry in the Prefix Table conceptually contains the following Each entry in the Prefix Table conceptually contains the following
fields: fields:
- The Home Address of the Mobile Router. This field is used as the - The Home Address of the Mobile Router. This field is used as the
key for searching the pre-configured prefix table. key for searching the pre-configured prefix table.
- The Mobile Network prefix of the Mobile Router associated with - The Mobile Network Prefix of the Mobile Router associated with
the Home Address. the Home Address.
In some deployment scenarios it is important that the Home Agent
prevents a misbehaving Mobile Router from claiming Mobile Network
Prefixes belonging to another Mobile Router. The Home Agent can
prevent such attacks if it maintains the Prefix Table and verifies
the Prefix Information provided by the Mobile Router against the
entries in the Prefix Table.
6.2. Mobile Network Prefix Registration 6.2. Mobile Network Prefix Registration
The Home Agent processes the Binding Update as described in Section The Home Agent processes the Binding Update as described in section
10.3.1 of the Mobile IPv6 specification. This section describes the 10.3.1 of the Mobile IPv6 specification [1]. This section describes
processing of the Binding Update if the Mobile Router (R) flag is the processing of the Binding Update if the Mobile Router (R) flag is
set. The Home Agent performs the following check in addition. set. The Home Agent performs the following check in addition.
- The Binding Update MUST be authenticated by IPsec according to - The Home Registration (H) flag MUST be set. If not, the
Section 5.1 of [1].
- The Home Registration (H) bit MUST be set. If not, the
Home Agent MUST reject the Binding Update and send a Binding Home Agent MUST reject the Binding Update and send a Binding
Acknowledgement with status set to 140. Note: The basic support Acknowledgement with status set to 140. Note: The basic support
does not allow sending Binding Update for a Mobile Network prefix does not allow sending Binding Update for a Mobile Network Prefix
to correspondent nodes (for route optimization).. to correspondent nodes (for route optimization).
- If the Mobile Network Prefix Length option is present in - If the Mobile Network Prefix Length option is present in
the Binding Update, then there MUST be only one instance of the Binding Update, then there MUST be only one instance of
this option in the Binding Update. Also the Mobile Network this option in the Binding Update. Also the Mobile Network
Prefix Option MUST not be present in the same Binding Update. Prefix Option MUST NOT be present in the same Binding Update.
Otherwise, the Home Agent MUST discard the Binding Update and Otherwise, the Home Agent MUST discard the Binding Update and
send an ICMP Parameter Problem, Code 0, message to the Mobile send an ICMP Parameter Problem, Code 0, message to the Mobile
Router Router.
If the home agent does not reject the Binding Update as described If the Home Agent does not reject the Binding Update as described
above, then it retrieves the Mobile Network Prefix information as above, then it retrieves the Mobile Network Prefix information as
described below. described below.
- If a Mobile Network Prefix Length Option is present in the - If a Mobile Network Prefix Length Option is present in the
Binding Update, the Home Address in the Home Address destination Binding Update, the Home Address in the Home Address destination
option MUST be an extended Home Address. In that case, the option MUST be an Home Address. In that case, the Mobile Network
Mobile Network Prefix is obtained from that Home Address and the Prefix is obtained from that Home Address and the prefix length
prefix length in the Mobile Network Prefix Length Option. in the Mobile Network Prefix Length Option.
If the Home Agent verfies the prefix information with the Prefix If the Home Agent verfies the prefix information with the Prefix
Table and the check fails, the Home Agent MUST discard the Table and the check fails, the Home Agent MUST discard the
Binding Update and send a Binding Acknowldegement with status set Binding Update and send a Binding Acknowldegement with status set
to 142 (Not Authorized for Prefix). to 142 (Not Authorized for Prefix).
- If a Mobile Network Prefix Option is present in the Binding - If a Mobile Network Prefix Option is present in the Binding
Update, the prefix information for the mobile network prefix is Update, the prefix information for the mobile network prefix is
retrieved from the Mobile Network Prefix field and the Prefix retrieved from the Mobile Network Prefix field and the Prefix
Length field of the option. If the Binding Update contains more Length field of the option. If the Binding Update contains more
than one option, the Home Agent MUST set up forwarding for all than one option, the Home Agent MUST set up forwarding for all of
of the Mobile Network Prefixes. Otherwise the Home Agent MUST the Mobile Network Prefixes. If the Home Agent fails to setup
not forward traffic to any of the prefixes, reject the Binding forwarding to all the prefixes listed in the Binding Update, then
Update and send a Binding Acknowledgement with status set to 141 it MUST NOT forward traffic to any of the prefixes, reject the
(Invalid Prefix). Binding Update and send a Binding Acknowledgement with status set
to 141 (Invalid Prefix).
If the Home Agent verfies the prefix information with the Prefix If the Home Agent verifies the prefix information with the Prefix
Table and the check fails, the Home Agent MUST discard the Table and the check fails, the Home Agent MUST discard the
Binding Update and send a Binding Acknowldegement with status set Binding Update and send a Binding Acknowldegement with status set
to 142 (Not Authorized for Prefix). to 142 (Not Authorized for Prefix).
- If there are no options in the Binding Update, the Home Agent - If there are no options in the Binding Update, the Home Agent
MUST figure out which prefixes are assigned to the Mobile Router uses manual pre-configured information to determine the prefixes
from the Pre-configured Prefix Table. If the home agent can not assigned to the Mobile Router and for setting up forwarding for
find the correspondent Mobile Network prefix, it MUST reject the the Mobile Network. If there is no information that the Home
Binding Update and send a Binding Acknowledgement with the Status Agent can use, it MUST reject the Binding Update and send a
field set to 143 (Prefix Information unavailable). Binding Acknowledgement with status set to 143 (Forwarding Setup
failed).
If the Lifetime specified in the Binding Update is zero or the If the Lifetime specified in the Binding Update is zero or the
specified care-of address matches the home address for the binding, specified Care-of address matches the Home Address in the Binding
then this is a request to delete the cached binding for the home Update, then this is a request to delete the cached binding for
address and specified mobile network prefixes. The Binding Update is the home address and specified Mobile Network Prefixes. The
processed according to the procedure described in Section 6.7. Binding Update is processed according to the procedure described in
section 6.7.
If all checks are passed, the home agent creates a binding cache If all checks are passed, the Home Agent creates a binding cache
entry for Mobile Router's home address, or updates the binding cache entry for Mobile Router's Home Address, or updates the binding cache
entry if it already exists. Otherwise, the home agent MUST NOT entry if it already exists. Otherwise, the Home Agent MUST NOT
register the binding of the Mobile Router's home address. register the binding of the Mobile Router's Home Address.
The home agent also creates a bi-directional tunnel to the mobile The Home Agent defends the Mobile Router's Home Address through Proxy
router for the requested Mobile Network prefix, or update an existing Neighbor Discovery by multicasting onto the home like a Neighbor
bi-directional tunnel as described in Section 6.4 Advertisement message on behalf of the mobile router. All fields in
each such Neighbor Advertisement message SHOULD be set in the same
way they would be set by the mobile router itself if sending this
Neighbor Advertisement while at home, as described in [7], with the
exception that the Router (R) bit in the Advertisement MUST be set if
the Mobile Router (R) flag has been set in the Binding Update.
The Home Agent also creates a bi-directional tunnel to the mobile
router for the requested Mobile Network Prefix, or update an existing
bi-directional tunnel as described in section 6.4.
6.3. Advertising Mobile Network Reachability 6.3. Advertising Mobile Network Reachability
In order to be able to receive packets meant for the Mobile Network, In order to be able to receive packets meant for the mobile network,
the Home Agent advertises reachability to the Mobile Network. If the the Home Agent advertises reachability to the mobile network. If the
Mobile Network Prefix can be aggregated under the Home Link prefix, Home Link is configured with a prefix that is an aggregation and if
then the routing updates advertising reachability to the Mobile the Mobile Network Prefix is aggregated under that prefix, then the
Network are sent only on the Home Link. If the Home Agent is the routing updates advertising reachability to the mobile network are
only router on the Home Link, routes to the Mobile Network Prefix sent only on the Home Link. If the Home Agent is the only default
gets aggregated naturally under the Home Agent and the Home Agent router on the Home Link, routes to the Mobile Network Prefix get
does not have to do anything special. aggregated naturally under the Home Agent and the Home Agent does not
have to do anything special.
If the Home Agent receives routing updates through a dynamic routing If the Home Agent receives routing updates through a dynamic routing
protocol from the Mobile Router, those routes are propogated by protocol from the Mobile Router, those routes are propagated by
the routing protocol running on the Home Agent on the relevant the routing protocol running on the Home Agent on the relevant
interfaces. interfaces.
6.4. Establishment of Bi-directional Tunnel 6.4. Establishment of Bi-directional Tunnel
The establishment and operation of the bi-directional tunnel is The establishment and operation of the bi-directional tunnel is
implementation specific. However, all implementations MUST be implementation specific. However, all implementations MUST be
capable of the following operations. capable of the following operations.
- The Home Agent can tunnel packets meant for the Mobile Network - The Home Agent can tunnel packets meant for the mobile network
Prefix to the Mobile Router's current location, the Care-of prefix to the Mobile Router's current location, the Care-of
Address of the Mobile Router. Address of the Mobile Router.
- The Home Agent can accept packets tunneled by the Mobile Router - The Home Agent can accept packets tunneled by the Mobile Router
with source address of the outer IPv6 header set to the Care-of with source address of the outer IPv6 header set to the Care-of
Address of the Mobile Router. Address of the Mobile Router.
6.5. Forwarding Packets 6.5. Forwarding Packets
When the Home Agent receives a data packet destined for the mobile When the Home Agent receives a data packet destined for the mobile
network, it fowards the packet to the Mobile Router through the network, it fowards the packet to the Mobile Router through the
bi-directional tunnel. The Home Agent either uses only the routing bi-directional tunnel. The Home Agent either uses only the routing
table, only the Binding Cache or a combination of routing table table, only the Binding Cache or a combination of routing table
and Binding Cache to route packets to the Mobile Network. This is and Binding Cache to route packets to the mobile network. This is
implementation specific. Two examples are shown below. implementation specific. Two examples are shown below.
1. The Home Agent maintains a route to the Mobile Network Prefix 1. The Home Agent maintains a route to the Mobile Network Prefix
with the next hop set to the Mobile Router's Home Address. When with the next hop set to the Mobile Router's Home Address. When
the Home Agent tries to forward the packet to the next hop, it the Home Agent tries to forward the packet to the next hop, it
finds a binding cache entry for the home address. Then the Home finds a binding cache entry for the home address. Then the Home
Agent extracts the Mobile Router's Care-of address and tunnels Agent extracts the Mobile Router's Care-of address and tunnels
the packet to the Care-of address. the packet to the Care-of address.
2. The Home Agent maintains a route to the Mobile Network Prefix 2. The Home Agent maintains a route to the Mobile Network Prefix
skipping to change at page 22, line 31 skipping to change at page 22, line 12
the Home Agent's address and the Mobile Router's Care-of address, the Home Agent's address and the Mobile Router's Care-of address,
respectively. respectively.
6.6. Sending Binding Acknowledgements 6.6. Sending Binding Acknowledgements
A Home Agent serving a Mobile Router sends Binding Acknowledgements A Home Agent serving a Mobile Router sends Binding Acknowledgements
according to the same rules it uses for sending Binding according to the same rules it uses for sending Binding
Acknowledgements to Mobile Hosts, with the following enhancements. Acknowledgements to Mobile Hosts, with the following enhancements.
The Home Agent sets the status code in the Binding Acknowledgement The Home Agent sets the status code in the Binding Acknowledgement
to '0' (Binding Update accepted) in order to indicate to the Mobile to '2' (Mobile Router Binding Update accepted) in order to indicate
Router that it accepted the Binding Update, set up the tunnel to the Mobile Router that it accepted the Binding Update, set up the
endpoint and the necessary forwarding information. tunnel endpoint and the necessary forwarding information.
If the Home Agent is configured not to support mobile routers, it If the Home Agent is configured not to support mobile routers, it
sets the status code in the Binding Acknowledgement to '140' (Mobile sets the status code in the Binding Acknowledgement to '140' (Mobile
Router Operation not permitted). Router Operation not permitted).
If one or more prefixes received in the Binding Update are invalid If one or more prefixes received in the Binding Update are invalid
and the Home Agent cannot setup forwarding for the prefixes, the Home and the Home Agent cannot setup forwarding for the prefixes, the Home
Agent sets the status code in the Binding Acknowledgement to '141' Agent sets the status code in the Binding Acknowledgement to '141'
(Invalid Prefix) in order to indicate this to the Mobile Router. (Invalid Prefix) in order to indicate this to the Mobile Router.
If the Mobile Router is not authorized to use this Home Address to If the Mobile Router is not authorized to use this Home Address to
forward packets for one or more prefixes that are present in the forward packets for one or more prefixes that are present in the
Binding Update, the Home Agent sets the status code in the Binding Binding Update, the Home Agent sets the status code in the Binding
Acknowledgement to '142' (Not Authorized for Prefix) in order to Acknowledgement to '142' (Not Authorized for Prefix) in order to
indicate this. indicate this.
The Home Agent sets the status code in the Binding Acknowledgement The Home Agent sets the status code to 143 (Forwarding Setup
to '143' (Mobile Network Prefix information unavailable) in order failed) if it is unable to determine the information needed to setup
to indicate the Mobile Router that the received Home Address in the forwarding for the Mobile Network. This is used in the Implicit mode
Binding Update does not match any prefix entry in the pre-configured where the Mobile Router does not include any prefix information in
prefix table. This is used in the Implicit case where the Mobile the Binding Update.
Router does not include any prefix information in the Binding Update.
6.7. Mobile Network Prefix De-Registration 6.7. Mobile Network Prefix De-Registration
The Mobile Router de-registers with the Home Agent by sending The Mobile Router de-registers with the Home Agent by sending a
a Binding Update with the lifetime set to zero. This Binding Binding Update with the lifetime set to zero. When the Home Agent
Update MUST be secured as described in [3]. When the Home Agent
successfully processes the de-registration BU, it deletes the Binding successfully processes the de-registration BU, it deletes the Binding
Cache Entry for the Mobile Router's Home Address and stops proxying Cache Entry for the Mobile Router's Home Address and stops proxying
the Home Address. This is described in detail in the Mobile IPv6 the Home Address. This is described in detail in the Mobile IPv6
specification [1]. specification [1].
In addition, the Home Agent also removes the bi-directional tunnel In addition, the Home Agent also removes the bi-directional tunnel
and stops forwarding packets to the Mobile Network. and stops forwarding packets to the mobile network. The HA should
keep all necessary information to clean up whichever routes it
7. Extended Home Network installed, whether they come from implicit or explicit source.
With MIPv6, the Home Network is generally a physical network
interconnecting the Home Agents, and the Mobile Nodes that are at
Home. The Network Mobility concept introduces the extended Home
Network that aggregates the Home Network(s) and the Mobile Network(s)
in a single, shorter prefix.
For most practical situations, it is expected that:
- There is a single Home Network and multiple Mobile Networks
- The Home Network and Mobile Network prefixes are tailored to
allow for IPv6 Stateless Address Autoconfiguration with typical
interface identifier length for the type of interface.
- The prefix length of the extended Home Network is shorter than
the Home Network and the Mobile Network prefixes, since it is an
aggregation.
- The Home Agents collectively advertise the extended Home Network
aggregation only. The dichotomy of the extended Home Network is
kept within the Home Agents and the Mobile Nodes, as opposed to
advertised by means of routing protocols to other parties.
The Home Network is configured on a physical interface as defined in
MIPv6. A Mobile Router may own a Home Address that is built out of
the Home Network prefix and use it for Nemo registration and to come
back Home. In that case, the Home Network Prefix and prefix length
are used in the Binding Update.
A Mobile Router owns one or several Mobile Networks. It may form
extended Home Addresses from the prefixes of its Mobile Network(s)
and register them to the Home Agent using the extended Home Network
prefix and prefix length. An extended Home Address may be used for
only one registration that it identifies uniquely, regardless of the
Home Agent, as for normal Home Addresses.
An extended Home Network may be configured on a virtual or a physical
interface of the Home Agent. It is partitioned in Mobile Networks
and Home Networks. If the extended Home Network is configured on a
physical Network, a Mobile Router that registers using an extended
Home Address may come back home by:
- Autoconfiguring a Care-of Address from the Home Network and
providing Proxy Neighbor Discovery for its Mobile Network
Prefixes
or
- Attaching directly by its Ingress Link if it has only one of
them.
Multihoming, and in particular the associated coordination of
the Home Agents, is out of the scope of this document. Yet, this
specification does not prevent that:
- More than one Mobile Network may be connected to a Mobile Router
- A Mobile Network Prefix may be shared between Mobile Routers and
registered by some of them
- An Mobile Network Prefix may be registered several times to
several Home Agents using different (extended) Home Addresses for
each registration.
This description is open to a:
- Mobile Router autoconfiguring one or several extended Home
Address to carry out many registrations in parallel. It owns the
full prefix so it may use any address in there for a MNLP based
registration, and several of them for multihoming.
- Mobile Node autoconfiguring one or several Care-of Addresses from
the Mobile Network Prefix
- Mobile Host autoconfiguring one or several Home Addresses from
the Home Network.
Mobile Nodes' Home Addresses may still be configured manually from
the Home Network Prefix as described in Mobile IPv6.
8. Support for Dynamic Routing Protocols 7. Support for Dynamic Routing Protocols
In the solution described so far, forwarding to the Mobile Network In the solution described so far, forwarding to the Mobile Network
at the Home Agent is set up when the Home Agent receives a Binding at the Home Agent is set up when the Home Agent receives a Binding
Update from the Mobile Router. An alternative to this is for the Update from the Mobile Router. An alternative to this is for the
Home Agent and the Mobile Router to run a intra-doamin routing Home Agent and the Mobile Router to run a intra-domain routing
protocol like RIPng [6] and OSPF [7] through the bi-directional protocol like RIPng [10] and OSPF [11] through the bi-directional
tunnel. The Mobile Router can continue running the same routing tunnel. The Mobile Router can continue running the same routing
protocol that it was running when it was attached to the home link. protocol that it was running when it was attached to the home link.
This feature is very useful when the Mobile Network is large with This feature is very useful when the Mobile Network is large with
multiple subnets containing different IPv6 prefixes. Routing changes multiple subnets containing different IPv6 prefixes. Routing changes
in the Mobile Network are propagated to the Home Agent quickly. in the Mobile Network are propagated to the Home Agent quickly.
Routing changes in the home link are also propogated to the Mobile Routing changes in the home link are also propogated to the Mobile
Router very quickly. Router very quickly.
When the Mobile Router is attached to the home link, it runs a When the Mobile Router is attached to the home link, it runs a
skipping to change at page 26, line 49 skipping to change at page 23, line 49
filled with the Mobile Router's link local address with the outgoing filled with the Mobile Router's link local address with the outgoing
interface set to the bi-directional tunnel. interface set to the bi-directional tunnel.
Similary, the Home Agent also sends routing updates through the Similary, the Home Agent also sends routing updates through the
bi-directional tunnel to the Mobile Router. The Mobile Router bi-directional tunnel to the Mobile Router. The Mobile Router
processes these routing protocol messages and updates its routing processes these routing protocol messages and updates its routing
table. For all routes advertised by the Home Agent, the Mobile table. For all routes advertised by the Home Agent, the Mobile
Router sets the outgoing interface to the bi-directional tunnel to Router sets the outgoing interface to the bi-directional tunnel to
the Home Agent. the Home Agent.
The tunneled routing messages MUST be authenticated and encrypted by When the Mobile Router and the Home Agent exchange routes through
using IPsec ESP [5] in tunnel mode. a dynamic routing protocol, the Mobile Router should be careful in
including the same mobile network prefixes in the Binding Update to
the HA and in the routing protocol updates. The HA depending on its
configuration might not add routes based on the prefix information in
the Binding Updates at all, and might use only the routing protocol
updates. Moreover, including the same prefix information in both the
Binding Update and the routing protocol update is redundant.
9. Use of IPsec to protect the Signaling Messages The tunneled routing messages MUST be authenticated and encrypted by
using IPsec ESP [4] in tunnel mode.
The use of IPsec to protect to Mobile IPv6 signaling messages is 8. Security Considerations
described in detail in HA-MN IPsec specification [3]. This document
does not require any changes or anything more that what is described
in the HA-MN IPsec specification.
10. Security Considerations All signaling messages between the Mobile Router and the Home Agent
MUST be authenticated by IPsec [5]. The use of IPsec to protect
Mobile IPv6 signaling messages is described in detail in the HA-MN
IPsec specification [2]. The signaling messages described in this
document just extend Mobile IPv6 messages and do not require any
changes to what is described in the HA-MN IPsec specification.
The Home Agent has to verify that packets received through the The Home Agent has to verify that packets received through the
bi-directional tunnel belong to the Mobile Network. This check is bi-directional tunnel belong to the Mobile Network. This check is
necessary in order to prevent nodes from using the Home Agent to necessary in order to prevent nodes from using the Home Agent to
launch attacks that would have otherwise been prevented by ingress launch attacks that would have otherwise been prevented by ingress
filtering. The source address of the outer IPv6 header MUST be set filtering. The source address of the outer IPv6 header MUST be set
the Mobile Router's current Care-of address. The source address of the Mobile Router's current Care-of address. The source address of
the inner IPv6 header MUST belong to the Mobile Network Prefix owned the inner IPv6 header MUST belong to the Mobile Network Prefix owned
by the Mobile Router. by the Mobile Router.
When the Mobile Router is running a dynamic routing protocol as When the Mobile Router is running a dynamic routing protocol as
described in Section 8, it injects routing update messages into the described in section 7, it injects routing update messages into the
Home Link. The Home Agent MUST verify that the Mobile Router is Home Link. The Home Agent MUST verify that the Mobile Router is
allowed to send routing updates before processing the messages and allowed to send routing updates before processing the messages and
propagating the routing information. propagating the routing information.
Please refer to the Mobile IPv6 specification [1] for security Please refer to the Mobile IPv6 specification [1] for security
considerations when the Mobile Router operates as a Mobile Host. considerations when the Mobile Router operates as a Mobile Host.
11. IANA Considerations 9. IANA Considerations
This document defines two new Mobility Header Options. This document defines two new Mobility Header Options.
- Mobile Network Prefix Option - Mobile Network Prefix Option.
- Mobile Network Prefix Length Option. - Mobile Network Prefix Length Option.
These options are described in section 4.3 and section 4.4. The type These options are described in section 4.3 and section 4.4. The type
values for these options need to assigned from the same space used by values for these options need to assigned from the same space used by
the mobility options defined in [1] the mobility options defined in [1]
12. Contributors 10. Contributors
We would like to acknowledge Thierry Ernst, Miguel Catalina-Gallego, We would like to acknowledge Ludovic Bellier, Claude Castelluccia,
Christophe Janneteau, T.J. Kniveton, Hong-Yon Lach, Jari T. Malinen, Thierry Ernst, Miguel Catalina-Gallego, Christophe Janneteau, T.J.
Koshiro Mitsuya, Charles E. Perkins and Keisuke Uehara, for their Kniveton, Hong-Yon Lach, Jari T. Malinen, Koshiro Mitsuya, Alexis
work on earlier proposals for Network Mobility. This document Olivereau, Charles E. Perkins and Keisuke Uehara, for their work on
inherits a lot of ideas from these earlier proposals. earlier proposals for Network Mobility. This document inherits a lot
of ideas from these proposals.
13. Acknowledgements 11. Acknowledgements
We also thank all members of the NEMO Working Group, and of the We thank all members of the NEMO Working Group, and of the preceding
preceding MONET BoF for fruitful discussions on the mailing list and MONET BoF for fruitful discussions on the mailing list and at IETF
at IETF meetings. meetings.
Tim Leinumeller for many insightful remarks and implementation Kent Leung, Marco Molteni and Patrick Wetterwald for their work on
Network Mobility for IPv4 and IPv6.
Tim Leinmueller for many insightful remarks and implementation
aspects. aspects.
References Normative References
[1] D. Johnson, C. Perkins and J. Arkko. Mobility Support [1] D. Johnson, C. Perkins and J. Arkko. Mobility Support in IPv6.
in IPv6 (work in progress). Internet Draft, IETF. Internet Draft, IETF. draft-ietf-mobileip-ipv6-24.txt (work in
draft-ietf-mobileip-ipv6-22.txt. May 2003. progress). June 2003.
[2] T. Ernst and H.-Y. Lach. Network Mobility Support [2] J. Arkko, V. Devarapalli and F. Dupont. Using IPsec to Protect
Terminology (work in progress). Internet Draft, IETF. Mobile IPv6 Signaling between Mobile Nodes and Home Agents.
draft-ietf-nemo-terminology-00.txt. May 2003. Internet Draft, IETF. draft-ietf-mobileip-mipv6-ha-ipsec-06.txt
(work in progress). June 2003.
[3] J. Arkko, V. Devarapalli and F. Dupont. Using IPsec to [3] A. Conta and S. Deering. Generic Packet Tunneling in IPv6
Protect Mobile IPv6 Signaling between Mobile Nodes and Specification. RFC 2473, IETF. December 1998.
Home Agents (work in progress). Internet Draft, IETF.
draft-ietf-mobileip-mipv6-ha-ipsec-05.txt May 2003.
[4] A. Conta and S. Deering. Generic Packet Tunneling in IPv6 [4] S. Kent and R. Atkinson. IP Encapsulating Security Payload
Specification. RFC 2473, IETF. December 1998. (ESP). RFC 2402, IETF. November 1998.
[5] S. Kent and R. Atkinson. IP Encapsulating Security Payload (ESP). [5] S. Kent and R. Atkinson. Security Architecture for the Internet
RFC 2402, IETF. November 1998. Protocol. RFC 2401, IETF. November 1998.
[6] G. Malkin and R. Minnear. RIPng for IPv6. RFC 2080, IETF. January [6] S. Deering and R. Hinden. Internet Protocol, Version 6 (IPv6)
1997. Specification. RFC 2460, IETF. December 1998.
[7] R. Coltun, D. Ferguson and J. Moy. OSPF for IPv6. RFC 2470, IETF. [7] T. Narten, E. Nordmark and W. Simpson. Neighbour Discovery for
December 1999. IP Version 6 (IPv6). RFC 2461, IETF. December 1998.
[8] S. Deering and R. Hinden. Internet Protocol, Version 6 (IPv6) Informative References
Specification. RFC 2460, IETF. December 1998.
[9] T. Narten, E. Nordmark and W. Simpson. Neighbour Discovery for IP [8] T. Ernst and H.-Y. Lach. Network Mobility Support Terminology.
Version 6 (IPv6). RFC 2461, IETF. December 1998. Internet Draft, IETF. draft-ietf-nemo-terminology-00.txt (work
in progress). May 2003.
[10] C. Perkins, ed. IP Mobility Support for IPv4. RFC 3344, IETF. [9] T. Ernst. Network Mobility Support Goals and Requirements.
August 2002. Internet Draft, IETF. draft-ietf-nemo-requirements-01.txt (work
in progress). May 2003.
[10] G. Malkin and R. Minnear. RIPng for IPv6. RFC 2080, IETF.
January 1997.
[11] R. Coltun, D. Ferguson and J. Moy. OSPF for IPv6. RFC 2470,
IETF. December 1999.
A. Examples of Operation A. Examples of Operation
This section tries to illustrate the NEMO protocol using a Mobile This section tries to illustrate the NEMO protocol using a Mobile
Router and a Mobile Node belonging to different administrative Router and a Mobile Node belonging to different administrative
domains. The Mobile Router's mobile network consists of a Local domains. The Mobile Router's mobile network consists of a Local
Fixed Node (LFN) and a Local Fixed Router (LFR) [2]. The LFR has Fixed Node (LFN) and a Local Fixed Router (LFR) [8]. The LFR has
an access link to which other Mobile Nodes or Mobile Routers could an access link to which other Mobile Nodes or Mobile Routers could
attach to. attach to.
Figure 1 depicts the scenario where both the Mobile Router and the Figure 1 depicts the scenario where both the Mobile Router and the
Mobile Node are at home. Mobile Node are at home.
+----+ +-------+ +----+ +-------+
| MN | | HA_MN | | MN | | HA_MN |
+--+-+ 1:: +---+---+ +--+-+ 1:: +---+---+
2+-------------+3 2+-------------+3
skipping to change at page 33, line 21 skipping to change at page 30, line 21
+-------+ +-------+
| HA_MN | 1::2->6::2 | HA_MN | 1::2->6::2
1:: +---+---+ 1:: +---+---+
---------|3 ---------|3
| |
| |
+-------+2 2:: +-------------------+ 3:: 2+-------+ +-------+2 2:: +-------------------+ 3:: 2+-------+
| CN_MN |------| Internet |------| CN_MR | | CN_MN |------| Internet |------| CN_MR |
+-------+ ++------------------+ +-------+ +-------+ ++------------------+ +-------+
3::2->6::2 | 7:: 4:: | 4::2->7::2 1::2->6::2 | 7:: 4:: | 4::2->7::2
| | | |
2+ +3 2+ +3
+--+-+ +---+---+ +--+-+ +---+---+
| MR | | HA_MR | 4::2->7::2 | MR | | HA_MR | 4::2->7::2
+--+-+ +-------+ 5::/prefixlen -> forward +--+-+ +-------+ 5::/prefixlen -> forward
5:: |1 to MR 5:: |1 to MR
---------- 6::/prefixlen -> forward ---------- 6::/prefixlen -> forward
2| |3 to MR 2| |3 to MR
+--+-+ +--+-+ +--+-+ +--+-+
| LFN| | LFR| | LFN| | LFR|
skipping to change at page 34, line 5 skipping to change at page 31, line 5
6:: |1 6:: |1
--------+- --------+-
|2 |2
+--+-+ +--+-+
| MN | | MN |
+----+ +----+
Figure 3: Mobile Node attached to Mobile Figure 3: Mobile Node attached to Mobile
Router on a Visited Link Router on a Visited Link
B. Changes from Previous Version
The following changes have been made to this document from version 00
- Clarified that Router flag must be set in the Proxy Neighbor
Advertisement sent for a Mobile Router by the Home Aagent.
(Issue 1).
- Clarified that if the Router flag in the Binding Update is set,
then the HA should assume that the Mobile Router wants to be
treated as a mobile node. (Issue 3).
- Added text to make it clear that the Home Agent must perform
ingress filtering on all packets reverse tunneled by the Mobile
Router. (Issue 3).
- Extended Home Network concept has been removed from this
document. (Issue 5).
- Added text to clarify differences between Implicit mode and
running a dynamic routing protocol. (Issue 6).
- Clarified that Prefix Table is used only in explicit mode. In
Implicit mode the Prefix Table is not used. (Issue 7 and 12).
- Added text to specify the Home Agent must support all modes. The
Mobile Router needs to support only one mode. (Issue 11).
- Added text to support interoperability between a Mobile Router
and a legacy MIPv6 Home Agent. (Issue 15).
Authors Addresses Authors Addresses
Vijay Devarapalli Vijay Devarapalli
Nokia Research Center Nokia Research Center
313 Fairchild Drive 313 Fairchild Drive
Mountain View, CA 94043 Mountain View, CA 94043
USA USA
Email: vijay.devarapalli@nokia.com Email: vijay.devarapalli@nokia.com
Ryuji Wakikawa Ryuji Wakikawa
Keio University and WIDE Keio University and WIDE
5322 Endo Fujisawa Kanagawa 5322 Endo Fujisawa Kanagawa
252-8520 Japan 252-8520 Japan
Email: ryuji@sfc.wide.ad.jp Email: ryuji@sfc.wide.ad.jp
Alexandru Petrescu Alexandru Petrescu
Motorola Labs Motorola Labs
Espace Technologique de St Aubin Parc les Algorithmes Saint Aubin
Gif-sur-Yvette 91193 Gif-sur-Yvette 91193
France France
Email: Alexandru.Petrescu@motorola.com Email: Alexandru.Petrescu@motorola.com
Pascal Thubert Pascal Thubert
Cisco Systems Technology Center Cisco Systems Technology Center
Village d'Entreprises Green Side Village d'Entreprises Green Side
400, Avenue Roumanille 400, Avenue Roumanille
Biot - Sophia Antipolis 06410 Biot - Sophia Antipolis 06410
France France
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