draft-ietf-nemo-home-network-models-01.txt   draft-ietf-nemo-home-network-models-02.txt 
Network Mobility P. Thubert Network Mobility P. Thubert
Internet-Draft Cisco Internet-Draft Cisco
Expires: April 5, 2005 R. Wakikawa Expires: August 8, 2005 R. Wakikawa
Keio University Keio University
V. Devarapalli V. Devarapalli
Nokia Nokia
October 5, 2004 February 7, 2005
NEMO Home Network models NEMO Home Network models
draft-ietf-nemo-home-network-models-01 draft-ietf-nemo-home-network-models-02
Status of this Memo Status of this Memo
By submitting this Internet-Draft, I certify that any applicable By submitting this Internet-Draft, I certify that any applicable
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and any of which I become aware will be disclosed, in accordance with and any of which I become aware will be disclosed, in accordance with
RFC 3668. RFC 3668.
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
skipping to change at page 1, line 37 skipping to change at page 1, line 37
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This Internet-Draft will expire on April 5, 2005. This Internet-Draft will expire on August 8, 2005.
Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2004). All Rights Reserved. Copyright (C) The Internet Society (2005). All Rights Reserved.
Abstract Abstract
This paper documents some usage patterns and the associated issues This paper documents some usage patterns and the associated issues
when deploying a Home Network for NEMO-enabled Mobile Routers, when deploying a Home Network for NEMO-enabled Mobile Routers,
conforming the NEMO Basic Support draft [8]. The aim here is conforming the NEMO Basic Support draft [8]. The aim here is
specifically to provide some examples of organization of the Home specifically to provide some examples of organization of the Home
Network, as they were discussed in NEMO related mailing lists. Network, as they were discussed in NEMO related mailing lists.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology and concepts . . . . . . . . . . . . . . . . . . . 4 2. Terminology and concepts . . . . . . . . . . . . . . . . . . . 5
3. General Expectations . . . . . . . . . . . . . . . . . . . . . 5 3. General Expectations . . . . . . . . . . . . . . . . . . . . . 6
4. Extended Home Network . . . . . . . . . . . . . . . . . . . . 6 4. MIP Home Network . . . . . . . . . . . . . . . . . . . . . . . 7
4.1 Configuration . . . . . . . . . . . . . . . . . . . . . . 6 5. NEMO Extended Home Network . . . . . . . . . . . . . . . . . . 8
4.2 Returning Home . . . . . . . . . . . . . . . . . . . . . . 7
4.3 Applicability . . . . . . . . . . . . . . . . . . . . . . 7
5. Aggregated Home . . . . . . . . . . . . . . . . . . . . . . . 8
5.1 Configuration . . . . . . . . . . . . . . . . . . . . . . 8 5.1 Configuration . . . . . . . . . . . . . . . . . . . . . . 8
5.2 Returning Home . . . . . . . . . . . . . . . . . . . . . . 9 5.2 Returning Home . . . . . . . . . . . . . . . . . . . . . . 9
5.2.1 Returning Home by egress . . . . . . . . . . . . . . . 9 5.3 Home Address from MNP . . . . . . . . . . . . . . . . . . 9
5.2.2 Returning Home by ingress . . . . . . . . . . . . . . 10 5.4 Deployment Caveats . . . . . . . . . . . . . . . . . . . . 10
5.3 Applicability . . . . . . . . . . . . . . . . . . . . . . 10 5.4.1 MR side . . . . . . . . . . . . . . . . . . . . . . . 10
6. Virtual Home Network . . . . . . . . . . . . . . . . . . . . . 11 5.5 Applicability . . . . . . . . . . . . . . . . . . . . . . 10
6. NEMO Aggregated Home Network . . . . . . . . . . . . . . . . . 11
6.1 Configuration . . . . . . . . . . . . . . . . . . . . . . 11 6.1 Configuration . . . . . . . . . . . . . . . . . . . . . . 11
6.2 Applicability . . . . . . . . . . . . . . . . . . . . . . 12 6.2 Returning Home . . . . . . . . . . . . . . . . . . . . . . 11
7. Mobile Home . . . . . . . . . . . . . . . . . . . . . . . . . 13 6.2.1 Returning Home by egress . . . . . . . . . . . . . . . 12
7.1 Configuration . . . . . . . . . . . . . . . . . . . . . . 13 6.2.2 Returning Home by ingress . . . . . . . . . . . . . . 12
7.2 Applicability . . . . . . . . . . . . . . . . . . . . . . 14 6.3 Applicability . . . . . . . . . . . . . . . . . . . . . . 13
8. Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 6.4 Deployment Caveats . . . . . . . . . . . . . . . . . . . . 13
8.1 Changes from version 00 to 01 . . . . . . . . . . . . . . 16 6.4.1 HA Side . . . . . . . . . . . . . . . . . . . . . . . 13
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 17 6.4.2 MR side . . . . . . . . . . . . . . . . . . . . . . . 14
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 17 7. Virtual Home Network . . . . . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 18 7.1 Configuration . . . . . . . . . . . . . . . . . . . . . . 15
A. Returning Home emulation in the virtual case . . . . . . . . . 19 7.2 Applicability . . . . . . . . . . . . . . . . . . . . . . 16
Intellectual Property and Copyright Statements . . . . . . . . 20 8. Mobile Home . . . . . . . . . . . . . . . . . . . . . . . . . 17
8.1 Configuration . . . . . . . . . . . . . . . . . . . . . . 17
8.2 Applicability . . . . . . . . . . . . . . . . . . . . . . 18
9. Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
9.1 Changes from version 00 to 01 . . . . . . . . . . . . . . 20
9.2 Changes from version 01 to 02 . . . . . . . . . . . . . . 20
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 21
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 21
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 22
A. Returning Home emulation in the virtual case . . . . . . . . . 23
Intellectual Property and Copyright Statements . . . . . . . . 24
1. Introduction 1. Introduction
This document assumes that the reader is familiar with IPv6 Mobility This document assumes that the reader is familiar with IPv6 Mobility
as defined in [7], with the NEMO Basic Support [8] and with the NEMO as defined in [7], with the NEMO Basic Support [8] and with the NEMO
terminology document [10]. terminology document [9].
In order to read this document properly, the distinction between the In order to read this document properly, the distinction between the
concepts of Home Link and of Home Network must be very clear. A Home concepts of Home Link and of Home Network must be very clear. A Home
Link is a physical or a virtual Link, attached to a Home Agent. A Link is a physical or a virtual Link, attached to a Home Agent. A
Home Network is an aggregation that can be further subnetted. As a Home Network is an aggregation that can be further subnetted. As a
result, the Home Network is not necessarily contained on a Home Link. result, the Home Network is not necessarily contained on a Home Link.
In fact, the Mobile Network Prefixes are subnets of the Home Network. In fact, the Mobile Network Prefixes are subnets of the Home Network.
How the two concepts relate in a given deployment depend on the How the two concepts relate in a given deployment depend on the
organization of the Home Network, as described below. organization of the Home Network, as described below.
Four different organizations of the Home Network including a Five different organizations of the Home Network including a
hierarchical construction are documented: hierarchical construction are documented:
Extended Home Network: In this disposition, the Home Network is only MIPv6 Home Network: A short reminder of what the Home Network is with
one subnet of a larger aggregation that encompasses the Mobile Mobile IP, in order to help the reader figure out the evolution
Networks, called extended Home Network. When at Home, a Mobile towards NEMO.
Router performs normal routing between the Home Link and the
Mobile Networks. More in Section 4.
Aggregated Home Network: In this disposition, the Home Network NEMO Extended Home Network: In this disposition, the Home Network is
only one subnet of a larger aggregation that encompasses the
Mobile Networks, called extended Home Network. When at Home, a
Mobile Router performs normal routing between the Home Link and
the Mobile Networks. More in Section 5.
NEMO Aggregated Home Network: In this disposition, the Home Network
actually overlaps with the Mobile Networks. When at Home, a actually overlaps with the Mobile Networks. When at Home, a
Mobile Router acts as a bridge between the Home Link and the Mobile Router acts as a bridge between the Home Link and the
Mobile Networks. More in Section 5. Mobile Networks. More in Section 6.
Virtual Home Network: In this disposition, there is no physical Home Virtual Home Network: In this disposition, there is no physical Home
Link at all for the Mobile Routers to come back Home to. More in Link at all for the Mobile Routers to come back Home to. More in
Section 6. Section 7.
Mobile Home Network: In this disposition, there is a bitwise NEMO Mobile Home Network: In this disposition, there is a bitwise
hierarchy of Home Networks. A global Home Network is advertised hierarchy of Home Networks. A global Home Network is advertised
to the infrastructure by a head Home Agent and further subnetted to the infrastructure by a head Home Agent and further subnetted
into Mobile Networks. Each subnet is owned by a Mobile Router into Mobile Networks. Each subnet is owned by a Mobile Router
that registers it in a NEMO fashion while acting as a Home Agent that registers it in a NEMO fashion while acting as a Home Agent
for that network. More in Section 7. for that network. More in Section 8.
In all cases, the Home Agents collectively advertise only the In all cases, the Home Agents collectively advertise only the
aggregation of the Mobile Networks. The dichotomy is kept within the aggregation of the Mobile Networks. The dichotomy is kept within the
Home Agents and the Mobile Routers, as opposed to advertised by means Home Agents and the Mobile Routers, as opposed to advertised by means
of routing protocols to other parties. of routing protocols to other parties.
The examples provided here aim at illustrating the NEMO Basic Support The examples provided here aim at illustrating the NEMO Basic Support
draft [8] but do not aim at limiting its scope of application, and [8] but do not aim at limiting its scope of application, and
additional cases may be added in the future. additional cases may be added in the future.
2. Terminology and concepts 2. Terminology and concepts
The key words MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, The key words MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL in this document are to be SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL in this document are to be
interpreted as described in RFC2119 [1]. interpreted as described in RFC2119 [1].
The following terms used in this document are defined in the IPv6 The following terms used in this document are defined in the IPv6
Addressing Architecture document [5]: Addressing Architecture document [5]:
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link-local unicast address link-local unicast address
link-local scope multicast address link-local scope multicast address
Most of the mobility related terms used in this document are defined Most of the mobility related terms used in this document are defined
in the Mobility Related Terminology document [6] and in the Mobile in the Mobility Related Terminology document [6] and in the Mobile
IPv6 (MIP6) specification [7]. IPv6 (MIP6) specification [7].
Additionally, some terms were created or extended for NEMO. These Additionally, some terms were created or extended for NEMO. These
specific terms are defined in the Mobile Network Terminology document specific terms are defined in the Mobile Network Terminology document
[10]: [9]:
Home Link Home Link
Home Network Home Network
Home Address Home Address
MRHA Tunnel MRHA Tunnel
Mobile Aggregated Prefix Mobile Aggregated Prefix
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be to configure the Aggregation of Mobile Networks as the subnet on be to configure the Aggregation of Mobile Networks as the subnet on
the Home Link, and let the Mobile Routers manage the overlapping the Home Link, and let the Mobile Routers manage the overlapping
networks. Finally, the aggregation could be configured on a virtual networks. Finally, the aggregation could be configured on a virtual
network, with no physical Home Link at all, in which case Home means network, with no physical Home Link at all, in which case Home means
topologically and administratively close to the Home Agent that owns topologically and administratively close to the Home Agent that owns
the virtual network. the virtual network.
The following sections provide additional information on these forms The following sections provide additional information on these forms
of Home Network. of Home Network.
4. Extended Home Network 4. MIP Home Network
4.1 Configuration With Mobile IPv6 (MIP6) specification [7] Mobile Nodes are at Home
when they are connected to their Home Link, where they recognize
their Home Prefix in Router Advertisement messages. Also, a binding
is checked using of Duplicate Address Detection on the Home Link, and
Home Agents discover each other by means of Neighbor Discovery
extensions over that link.
One simple approach is to reserve one or several subnets from an The Home Prefix, that is advertized on the Home Link, is a final
aggregation for the Home Link, and to use the other subnets as MNPs. prefix, as opposed to an aggregation, and it may be used by hosts on
In that case, the Home Network and the Mobile Networks do not the Home Link for autoconfiguration purposes.
overlap. The aggregation is called an Extended Home Network and
depicted in Figure 1. As we see, the concept of a Home Network for Mobile IPv6 is really a
prefix on a link, served by one or more Home Agents as opposed to a
routed mesh. We will see in the next sections that NEMO needs
additional prefixes for use by the Mobile Networks. For that reason,
NEMO extends the concept of Home Network into a more complex,
aggregated structure.
5. NEMO Extended Home Network
5.1 Configuration
One simple way of extending the MIP Home Network is to use additional
prefixes, contiguous to the Home Link Prefix inherited from MIPv6, as
Mobile Network Prefixes. As this model trivially extends the MIP
Home Network, the resulting aggregation is called a NEMO Extended
Home Network. It is depicted in Figure 1.
| |
route v /48 A:B:C::/48 route v /48 A:B:C::/48
HA HA
| /64 A:B:C:0::/64 | /64 Home Link: A:B:C:0::/64
--+-----+--+- . -+- . -+-- --+-----+--+- . -+- . -+--
| | | | | | | |
MR1 MR2 MRi MRN MR1 MR2 MRi MRN
/64 /64 /64 /64 A:B:C:i::/64 0 < i <= N | | | |
------ ------ ------ ------
/64 /64 /64 /64 MNP: A:B:C:i::/64
Extended Home Network Extended Home Network
<-----------------------------------------------------------> <----------------------------------------------------------->
Home Net Mobile Net Mobile Net ... Mobile Net Home Net Mobile Net Mobile Net ... Mobile Net
<------------><------------><------------> ... <------------> <------------><------------><------------> ... <------------>
Figure 1: Extended Home Network Figure 1: Extended Home Network
In that configuration: In that configuration:
skipping to change at page 6, line 45 skipping to change at page 8, line 47
o There is one physical Home Network and multiple Mobile Networks o There is one physical Home Network and multiple Mobile Networks
o The Home and the MNPs are tailored to allow for IPv6 Stateless o The Home and the MNPs are tailored to allow for IPv6 Stateless
Address Autoconfiguration with typical interface identifier length Address Autoconfiguration with typical interface identifier length
for the type of interface (can be for example /64). for the type of interface (can be for example /64).
o The prefix length of the Extended Home Network is shorter than o The prefix length of the Extended Home Network is shorter than
that of the Home Network and the MNPs, since it is an aggregation that of the Home Network and the MNPs, since it is an aggregation
(can be for example /48). (can be for example /48).
o The Mobile Routers are assigned individually a Home Address from o Since the Extended Home Network operations inherit trivially from
the Home Network and use is to register their MNP(es). In that MIPv6, it can be seen as natural that the Mobile Routers be
case, the Home Agent performs DAD in the Home Network as assigned their Home Addresses from the prefix on the Home Link, as
prescribed by Mobile IPv6 for the Home Addresses. opposed to their own MNP, which is allowed by the NEMO
specification. In that case, a Home Agent can perform DAD on the
o Alternatively, a Mobile Router could also form a Home Address from Home Link as prescribed by Mobile IPv6 for the Mobile Router Home
one of its prefixes and use it to register, performing its own DAD Addresses.
on its ingress network.
4.2 Returning Home 5.2 Returning Home
In the Extended Home Network model, the Home Network is configured on In the Extended Home Network model, the Home Network is configured on
a physical interface of the Home Agent, the Home Link. a physical interface of the Home Agent, the Home Link.
A Mobile Router returns Home by connecting directly to the Home Link, A Mobile Router returns Home by connecting directly to the Home Link,
and dropping the MRHA tunnel. and dropping the MRHA tunnel.
If the Home Address of the Mobile Router is derived from one of its
Mobile Network Prefixes, then the MR may connect to the Home Link
using an egress interface and autoconfigure an address on the Home
Link. The MR recognizes the prefix of its Home Agent in order to
decide that it is Home. Note that in that case the Home Address does
not match the Home Prefix.
When at home, the Mobile Router ensures the connectivity of the When at home, the Mobile Router ensures the connectivity of the
Mobile Network using standard router operations. Mobile Network using standard router operations.
In particular, if the HA has the necessary information to continue In implicit mode, the HA has the necessary information to continue
routing to the MNPs in the absence of registration, for instance if routing to the MNPs in the absence of registration, and the
the Home Address of the Mobile Router is derived from the Home participation of the MR to the Home IGP is not required.
Network, and if the HA uses a static route to the MNP(es) via that
address, then the participation of the MR to the Home IGP is not
required.
But in the general case, when the MR is at Home, it resumes IGP But in explicit mode, or if the MR uses an IGP over the MRHA tunnel,
operations on the Home Link in order to advertise its Mobile then it must resume its IGP operations on the Home Link in order to
Networks. advertise its Mobile Networks.
Alternate procedures for ensuring the connectivity of the Mobile Alternate procedures for ensuring the connectivity of the Mobile
Networks when at home are described in Section 6. Networks when at home are described in Section 7.
4.3 Applicability 5.3 Home Address from MNP
We saw that a natural extension of the MIP procedure is to derive the
Home Address of a Mobile Router from the prefix on the Home Link.
Alternatively, NEMO basic support allows that a Mobile Router forms
its Home Address from one of its Mobile Network Prefixes.
In that case, the Home Address does not match the Home Link Prefix,
and there is a need to configure the HA in a specific mode with the
support for the extended Home Network and the range of the Mobile
Network Prefixes. Based on that new configuration, the HA can accept
a Home Address that is not from the Home Link, and it will know that
it should not perform any DAD.
Also, if the MR uses a Home Address that is derived from its MNP,
some specific support is required on the MR as well. In order to
determine that it is at Home, the MR recognizes the well-known prefix
of its Home Agent as opposed to matching the prefix on the Home Link
with that of its Home Address.
When connecting to the Home Link, the MR also need to autoconfigure
an address on the egress interface as opposed to assigning its Home
Address to the interface.
For all these reasons, this submode of extended is no more a trivial
extension to the MIPv6 Home Model, and it might not be compatible
with all implementations.
5.4 Deployment Caveats
5.4.1 MR side
In explicit mode, the routing to the MNP via the MR must be restored
when the MR is at Home. This is normally performed by the MR by
means of the existing IGP. In that case, a specific support is
required on the MR to control the routing protocol operation,
enabling the participation to the IGP if and only if the MR is at
home. This support might not be present in all implementations.
5.5 Applicability
The extended Home Network keeps the MIP6 concept of a Home Network The extended Home Network keeps the MIP6 concept of a Home Network
for both Mobile Nodes and Mobile Routers to take their Home Address for both Mobile Nodes and Mobile Routers to take their Home Address
from. Since there is no overlap between the prefixes that are from. Since there is no overlap between the prefixes that are
affected to MNPs and prefix(es) that are dedicated to the Home Link, affected to MNPs and prefix(es) that are dedicated to the Home Link,
it is possible for MNs and MRs to coexist with that model. it is possible for MNs and MRs to coexist with that model.
5. Aggregated Home Also, when the Home Address is derived from the prefix on the Home
Link, the HA behavior on the link trivially extends that of MIP and
the support should for that configuration should be available with
all implementations.
5.1 Configuration 6. NEMO Aggregated Home Network
6.1 Configuration
One other approach is to consider that the Aggregation of all the One other approach is to consider that the Aggregation of all the
MNPs is used plainly as the Home Network, referred to as the MNPs is used plainly as the Home Link Prefix. In this model, the
Aggregated Home Network. This means that the Mobile Aggregated Home Network is referred to as a NEMO Aggregated Home Network. This
Prefix is configured on the Home Link and advertised by the Home means that the Mobile Aggregated Prefix is configured on the Home
Agent as a subnet, as depicted in Figure 2. Link and advertised by the Home Agent as a subnet, as depicted in
Figure 2.
HA HA
| /56 Aggreg /56 | /56 Aggreg /56
--+-----+--+- . -+- . -+-- --+-----+--+- . -+- . -+--
| | | | | | | |
MR1 MR2 MRi MRN MR1 MR2 MRi MRN
| | | |
------ ------ ------ ------ ------ ------ ------ ------
/64 /64 /64 /64 Aggreg|i /64 0 < i <= N /64 /64 /64 /64 Aggreg|i /64 0 < i <= N
Aggregated Home Aggregated Home
== Home Net == Home Net
<-----------------------------------------------------------> <----------------------------------------------------------->
Mobile Net Mobile Net Mobile Net ... Mobile Net Mobile Net Mobile Net Mobile Net ... Mobile Net
<------------><------------><------------> ... <------------> <------------><------------><------------> ... <------------>
Figure 2: Aggregated Home Figure 2: Aggregated Home
A node on the Home Link computes that the Aggregated Home Network is In that model, it seems natural to subnet the whole range of
actually a subnet on the Home Link and may use it for addresses into Mobile Network prefixes, as opposed to reserving one
autoconfiguration purposes. Such a node may also install a connected prefix for the Home Link, which would boil down to the Extended Home
route to the Aggregated Home Network over the Home Link. Network model. If the prefix on the Home Link is really an
aggregation and not a final prefix, it should not be allowed for
As a result, unless the node has a better (longest match) route to a autoconfiguration or Home Address allocation.
given MNP, it will lookup all MNNs using Neighbor Discovery over the
Home Link.
Thus, the Home Agent MUST intercept all the packets to the MNNs on
the registered prefixes. In order to do so, the Home Agent might
perform ND proxying for all addresses in all registered Mobile
Network Prefixes, and protect the MNP space from autoconfiguration by
uncontrolled visitors on the Home Link.
Alternatives based on a routing protocol or ICMP redirect may apply Note that in that case, it makes sense for a Mobile Router to
in some cases. register using a Home Address from one of its own MNPs. Taking the
Home Address from its own range guarantees the uniqueness of the
suffix. That uniqueness can be checked by the MR on its ingress
network using DAD.
5.2 Returning Home 6.2 Returning Home
The Aggregated Home Prefix is configured on a physical interface of The Aggregated Home Prefix is configured on a physical interface of
the Home Agent, the Home Link. As a consequence, the Home Agent has the Home Agent, the Home Link. As a consequence, the Home Agent has
a connected route to the Aggregated Home Network over the Home Link. a connected route to the Aggregated Home Network over the Home Link.
A Mobile Router returns Home by connecting directly to the Home Link, A Mobile Router returns Home by connecting directly to the Home Link,
and dropping the MRHA tunnel. The Mobile Router recognizes its Home and dropping the MRHA tunnel. The Mobile Router recognizes its Home
Link by a prefix match with its Home Agent. Link by a prefix match with its Home Agent.
Note that it must expect a shorter prefix than that of its Mobile Note that it must expect a shorter prefix than that of its Mobile
Networks, even if its Home Address is formed out of one of its MNPs, Networks, even if its Home Address is formed out of one of its MNPs,
but that the Home Address matches the Home Network Prefix. but that the Home Address still matches the Home Network Prefix.
Also, Note that in that case, it makes sense for a Mobile Router to
register using a Home Address from one of its own MNPs. Taking the
Home Address from its own range guarantees the unicity of the suffix.
That unicity can be checked by the MR on its ingress network using
DAD.
5.2.1 Returning Home by egress 6.2.1 Returning Home by egress
A Mobile Router coming Home via its egress interface sees overlapping A Mobile Router coming Home via its egress interface sees overlapping
prefixes between the ingress and the egress interface and some prefixes between the ingress and the egress interface and some
specific support may be needed: specific support may be needed:
When a Mobile Router connects to the Home Link using its egress When a Mobile Router connects to the Home Link using its egress
interface, it might set up a bridge between its ingress interface(s) interface, it might set up a bridge between its ingress interface(s)
and the Home Link. and the Home Link.
Alternatively, the Mobile Router might perform ND proxying for all Alternatively, the Mobile Router might perform ND proxying for all
addresses in its MNPs, between the egress and the related ingress addresses in its MNPs, between the egress and the related ingress
interface. Since the prefixes on the egress and ingress interfaces interface. Since the prefixes on the egress and ingress interfaces
are overlapping, routing is disallowed. are overlapping, routing is disallowed.
On the positive side, the MR does not need to join the local IGP when
returning Home, even if it is using the explicit Prefix Mode. When
the MR is not registered, the HA simply expects that all MNNs will be
reachable over the Home Link.
HA HA
| /56 Aggreg /56 | /56 Aggreg /56
--+-----+--+- . -+- . -+-- --+-----+--+- . -+- . -+--
| | | | | | | |
MR1 MR2 MRi MRN MR1 MR2 MRi MRN
------ ------ ------ ------ ------ ------ ------ ------
/64 /64 /64 /64 Aggreg|i /64 0 < i <= N /64 /64 /64 /64 Aggreg|i /64 0 < i <= N
Figure 3: Bridging between egress and ingress Figure 3: Bridging between egress and ingress
5.2.2 Returning Home by ingress 6.2.2 Returning Home by ingress
Alternatively, if the MR has a single ingress Interface, the Mobile Alternatively, if the MR has a single ingress Interface, the Mobile
Router may use the NEMO-Link to connect to the Home Link, merging the Router may use the NEMO-Link to connect to the Home Link, merging the
two links in a single consistent network. two links in a single consistent network.
HA HA
| /56 Aggreg /56 | /56 Aggreg /56
--+-----+--+- . -+- . -+-- --+-----+--+- . -+- . -+--
/64 /64 /64 /64 Aggreg|i /64 0 < i <= N /64 /64 /64 /64 Aggreg|i /64 0 < i <= N
------ ------ ------ ------ ------ ------ ------ ------
MR1 MR2 MRi MRN MR1 MR2 MRi MRN
| | | | | | | |
Figure 4: Merging the Home and the Mobile Networks Figure 4: Merging the Home and the Mobile Networks
This fits the connected route model, since the Aggregated Home is This fits the connected route model, since the Aggregated Home is
truly located on that network. Note that in that case, it makes truly located on that network. Note that in that case, it makes
sense for a Mobile Router to register using a Home Address from one sense for a Mobile Router to register using a Home Address from one
of its own MNPs. . of its own MNPs. .
5.3 Applicability 6.3 Applicability
With this model, there is no specific space for independent nodes as With this model, there is no specific space for independent nodes as
any address in the aggregation belongs to a MNP, and thus to a Mobile any address in the aggregation belongs to a MNP, and thus to a Mobile
Router. This configuration excludes the cohabitation with MIP6 MNs Router. This configuration excludes the cohabitation with MIP6 MNs
on the Home Link. on the Home Link.
A MR that is at Home must own an address from the aggregation on its A MR that is at Home must own an address from the aggregation on its
egress interface and an address from its MNP -a subnet of that egress interface and an address from its MNP -a subnet of that
aggregation- on its ingress interface. A pure router will reject aggregation- on its ingress interface. A pure router will reject
that configuration, and the MR needs to act as a bridge to enable it. that configuration, and the MR needs to act as a bridge to enable it.
In order to deploy the aggregated Home Network model, one must check In order to deploy the aggregated Home Network model, one must check
whether that support is available in the MRs if returning Home is whether that support is available in the MRs if returning Home is
required. required.
6. Virtual Home Network 6.4 Deployment Caveats
6.1 Configuration 6.4.1 HA Side
A node on the Home Link discovers that the Aggregated Home Network is
actually a subnet on the Home Link and may use the prefix on the Home
Link to autoconfigure a Home Address. Such a node may also install a
connected route to the Aggregated Home Network over the Home Link.
As a result, unless the node has a better (longest match) route to a
given Mobile Network Prefix, it will lookup all MNNs on that MNP
using Neighbor Discovery over the Home Link.
Thus, on the Home Link, the Home Agent MUST intercept all the packets
to ALL the Mobile Network Nodes on the registered prefixes. In order
to do so, the Home Agent might perform some form of ND proxying for
all addresses in all registered Mobile Network Prefixes. The HA must
also protect the MNP space from autoconfiguration by uncontrolled
visitors at Neighbor Discovery level.
Alternatives based on a routing protocol or ICMP redirect may apply
in some cases.
In any case, there is a need to provide a specific configuration on
the HA to specify that it operates in Aggregated Mode. If a HA
implementation is simply derived from that of MIP, then the
capability to perform the required proxying might not exist, and the
Aggregated Mode will not operate properly for nodes on the Home Link.
6.4.2 MR side
If the MR returns Home by egress, a specific support is required to
control the bridging operation depending on whether a MR is at Home
or not. This support might not be present in all implementations.
Also, note that NEMO authorizes multiple registrations for a same MNP
by different Mobile Routers. This is a case of multihoming, and it
normally means that the MRs are interconnected by the ingress network
that bears the common MNP. But there is no provision in NEMO basic
support to test that this condition is met at binding time and
maintained overtime.
It is thus possible for 2 different MRs to register a same prefix
with different Home Addresses, and this will cause an undetected
problem if the corresponding ingress links are not connected.
When the Home Address of a Mobile Router is derived from its MNP,
there is thus an additional risk of an undetected misconfiguration if
the Home Address is autoconfigured from the ingress link as opposed
to statically assigned with the MNP itself.
7. Virtual Home Network
7.1 Configuration
The Home Link can be configured on the Home Agent on a virtual link, The Home Link can be configured on the Home Agent on a virtual link,
in which case there's no physical Home Link for Mobile Routers to in which case there's no physical Home Link for Mobile Routers to
return Home or for Home Agents to discover each others and perform return Home or for Home Agents to discover each others and perform
the ND level interactions as described in Mobile IPv6. [7] the ND level interactions as described in Mobile IPv6. [7]
/48 eg: A:B:C::/48 /48 eg: A:B:C::/48
HA HA
| /64 A:C:C:E::/64 | /64 A:C:C:E::/64
--+-----+--+- . -+- . -+-- --+-----+--+- . -+- . -+--
skipping to change at page 12, line 32 skipping to change at page 16, line 32
Mobile Router is directly connected to it. All traffic to and Mobile Router is directly connected to it. All traffic to and
from the Mobile Network is sent through the bi-directional tunnel from the Mobile Network is sent through the bi-directional tunnel
regardless of the Mobile Router location. This results in a regardless of the Mobile Router location. This results in a
tunneling overhead even though the Mobile Router is connected to tunneling overhead even though the Mobile Router is connected to
the Home Network. the Home Network.
Some solutions can be proposed in order to perform an equivalent of Some solutions can be proposed in order to perform an equivalent of
returning Home on a virtual Home Network. One such approach is returning Home on a virtual Home Network. One such approach is
sketched in appendix as an illustration. sketched in appendix as an illustration.
6.2 Applicability 7.2 Applicability
At some point in the future, NEMO basic support may be extended to At some point in the future, NEMO basic support may be extended to
operate fully at L3 for instance if the HAHA protocol [11] gets operate fully at L3 for instance if the HAHA protocol [11] gets
standardized and deployed. Until then, NEMO operations still inherit standardized and deployed. Until then, NEMO operations still inherit
from mobile IPv6 [7] for the HA to HA communication, which is from mobile IPv6 [7] for the HA to HA communication, which is
basically based on Neighbor Discovery extensions over the Home Link. basically based on Neighbor Discovery extensions over the Home Link.
Making that link virtual bars the deployment of multiple Home Agents, Making that link virtual bars the deployment of multiple Home Agents,
which may be desirable for reasons of load balancing. Please refer which may be desirable for reasons of load balancing. Please refer
to the NEMO multihoming issues [12] draft for more on this. to the NEMO multihoming issues [12] draft for more on this.
Yet, for a deployment where a single HA is enough, making the Home Yet, for a deployment where a single HA is enough, making the Home
Link virtual reduces the vulnerability to some attacks and to some Link virtual reduces the vulnerability to some attacks and to some
hardware failures, while making the HA operation faster. hardware failures, while making the HA operation faster.
One should check with the product specifications of an HA to see One should check with the product specifications of an HA to see
whether the implementation actually supports a Virtual Home Network, whether the implementation actually supports a Virtual Home Network,
and if so, whether in that cases, it is optimized for faster DAD-less and if so, whether in that cases, it is optimized for faster DAD-less
bindings. bindings.
7. Mobile Home 8. Mobile Home
7.1 Configuration 8.1 Configuration
In this disposition, there is a bitwise hierarchy of Home Networks. In this disposition, there is a bitwise hierarchy of Home Networks.
A global Home Network is advertised to the infrastructure by a head A global Home Network is advertised to the infrastructure by a head
Home Agent(s) and further subnetted into Mobile Networks. As a Home Agent(s) and further subnetted into Mobile Networks. As a
result, only the Home Agent(s) responsible for the most global result, only the Home Agent(s) responsible for the most global
(shortest prefix) aggregation receive all the packets for all the (shortest prefix) aggregation receive all the packets for all the
MNPs, which are leaves in the hierarchy tree. MNPs, which are leaves in the hierarchy tree.
Each subnet is owned by a Mobile Router that registers it in a NEMO Each subnet is owned by a Mobile Router that registers it in a NEMO
fashion while acting as a Home Agent for that network. This Mobile fashion while acting as a Home Agent for that network. This Mobile
skipping to change at page 14, line 47 skipping to change at page 18, line 47
join the infrastructure, and that the cabs are Mobile Routers join the infrastructure, and that the cabs are Mobile Routers
installed on smaller ships, equipped with low range radios. installed on smaller ships, equipped with low range radios.
If SFO is also the root-MR of a nested structure of cabs, the If SFO is also the root-MR of a nested structure of cabs, the
communication between cabs is relayed by SFO and does not require the communication between cabs is relayed by SFO and does not require the
satellite link. SFO recursively terminates the nested tunnels to the satellite link. SFO recursively terminates the nested tunnels to the
cabs and reencapsulates all the packets between the nested cloud and cabs and reencapsulates all the packets between the nested cloud and
correspondents in the infrastructure in a single tunnel to CA5A, this correspondents in the infrastructure in a single tunnel to CA5A, this
providing for nested NEMO Route Optimization. providing for nested NEMO Route Optimization.
7.2 Applicability 8.2 Applicability
This complex topology applies to large distributed fleet, mostly if This complex topology applies to large distributed fleet, mostly if
there is a single interchange point with the internet (e.g. a NAT or there is a single interchange point with the internet (e.g. a NAT or
a socks farm) where the super HA could be located. a socks farm) where the super HA could be located.
One specific benefit is that when 2 MRs travel together with a common One specific benefit is that when 2 MRs travel together with a common
HA, the traffic between the 2 is not necessarily routed via the HA, the traffic between the 2 is not necessarily routed via the
infrastructure, but can stay confined within the mobile cloud, the infrastructure, but can stay confined within the mobile cloud, the
Mobile Home Agent acting as a rendez-vous point between the MRs. Mobile Home Agent acting as a rendez-vous point between the MRs.
This applies particularly well for a fleet at sea when the long haul This applies particularly well for a fleet at sea when the long haul
access may be as expensive as a satellite link. access may be as expensive as a satellite link.
8. Changes 9. Changes
8.1 Changes from version 00 to 01 9.1 Changes from version 00 to 01
Removed terminology (moved to the Nemo terminology draft). Removed terminology (moved to the Nemo terminology draft).
Added an applicability statement for all documented cases Added an applicability statement for all documented cases
9. Acknowledgements 9.2 Changes from version 01 to 02
Issue 1: Editorial
Issue 2: Added a caveat part in extended and aggregated sections.
Also added a MIP Home Network section prior to those.
Issue 4: Added a subsection to the extended case for the case when
the mr takes a home address from its MNP
10. Acknowledgements
The authors wish to thank: The authors wish to thank:
Erik Nordmark, Kent Leung, Thierry Ernst, TJ Kniveton, Patrick Erik Nordmark, Kent Leung, Thierry Ernst, TJ Kniveton, Patrick
Wetterwald and Alexandru Petrescu for their contributions. Wetterwald, Alexandru Petrescu and David Binet. for their
contributions.
10 References 11 References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997. Levels", BCP 14, RFC 2119, March 1997.
[2] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) [2] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6)
Specification", RFC 2460, December 1998. Specification", RFC 2460, December 1998.
[3] Narten, T., Nordmark, E. and W. Simpson, "Neighbor Discovery [3] Narten, T., Nordmark, E. and W. Simpson, "Neighbor Discovery
for IP Version 6 (IPv6)", RFC 2461, December 1998. for IP Version 6 (IPv6)", RFC 2461, December 1998.
skipping to change at page 17, line 35 skipping to change at page 21, line 36
[5] Hinden, R. and S. Deering, "Internet Protocol Version 6 (IPv6) [5] Hinden, R. and S. Deering, "Internet Protocol Version 6 (IPv6)
Addressing Architecture", RFC 3513, April 2003. Addressing Architecture", RFC 3513, April 2003.
[6] Manner, J. and M. Kojo, "Mobility Related Terminology", RFC [6] Manner, J. and M. Kojo, "Mobility Related Terminology", RFC
3753, June 2004. 3753, June 2004.
[7] Johnson, D., Perkins, C. and J. Arkko, "Mobility Support in [7] Johnson, D., Perkins, C. and J. Arkko, "Mobility Support in
IPv6", RFC 3775, June 2004. IPv6", RFC 3775, June 2004.
[8] Devarapalli, V., "Network Mobility (NEMO) Basic Support [8] Devarapalli, V., Wakikawa, R., Petrescu, A. and P. Thubert,
Protocol", draft-ietf-nemo-basic-support-03 (work in progress), "Network Mobility (NEMO) Basic Support Protocol", RFC 3963,
June 2004. January 2005.
[9] Ernst, T., "Network Mobility Support Goals and Requirements", [9] Ernst, T. and H. Lach, "Network Mobility Support Terminology",
draft-ietf-nemo-requirements-02 (work in progress), February draft-ietf-nemo-terminology-02 (work in progress), October
2004. 2004.
[10] Ernst, T. and H. Lach, "Network Mobility Support Terminology", [10] Ernst, T., "Network Mobility Support Goals and Requirements",
draft-ietf-nemo-terminology-01 (work in progress), February draft-ietf-nemo-requirements-03 (work in progress), October
2004. 2004.
[11] Wakikawa, R., Devarapalli, V. and P. Thubert, "Inter Home [11] Thubert, P., "Global HA to HA protocol",
Agents Protocol (HAHA)", draft-wakikawa-mip6-nemo-haha-01 (work draft-thubert-nemo-global-haha-00 (work in progress), October
in progress), February 2004. 2004.
[12] Ernst, T., "Analysis of Multihoming in Network Mobility [12] Ernst, T., "Analysis of Multihoming in Network Mobility
Support", draft-ietf-nemo-multihoming-issues-00 (work in Support", draft-ietf-nemo-multihoming-issues-01 (work in
progress), July 2004. progress), October 2004.
Authors' Addresses Authors' Addresses
Pascal Thubert Pascal Thubert
Cisco Systems Cisco Systems
Village d'Entreprises Green Side Village d'Entreprises Green Side
400, Avenue de Roumanille 400, Avenue de Roumanille
Batiment T3 Batiment T3
Biot - Sophia Antipolis 06410 Biot - Sophia Antipolis 06410
FRANCE FRANCE
skipping to change at page 20, line 41 skipping to change at page 24, line 41
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Copyright Statement Copyright Statement
Copyright (C) The Internet Society (2004). This document is subject Copyright (C) The Internet Society (2005). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights. except as set forth therein, the authors retain all their rights.
Acknowledgment Acknowledgment
Funding for the RFC Editor function is currently provided by the Funding for the RFC Editor function is currently provided by the
Internet Society. Internet Society.
 End of changes. 

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