draft-ietf-nemo-home-network-models-00.txt   draft-ietf-nemo-home-network-models-01.txt 
Network Mobility P. Thubert Network Mobility P. Thubert
Internet-Draft Cisco Systems Internet-Draft Cisco
Expires: September 30, 2004 R. Wakikawa Expires: April 5, 2005 R. Wakikawa
Keio University Keio University
V. Devarapalli V. Devarapalli
Nokia Nokia
April 1, 2004 October 5, 2004
NEMO Home Network models NEMO Home Network models
draft-ietf-nemo-home-network-models-00 draft-ietf-nemo-home-network-models-01
Status of this Memo Status of this Memo
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and any of which I become aware will be disclosed, in accordance with
RFC 3668.
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Copyright Notice Copyright Notice
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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 [7]. conforming the NEMO Basic Support draft [8]. The aim here is
specifically to provide some examples of organization of the Home
The aim here is specifically to provide some examples of organization Network, as they were discussed in NEMO related mailing lists.
of the Home Network, as they were discussed in the NEMO and NEMO
Design mailing lists.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology and concepts . . . . . . . . . . . . . . . . . . . 4 2. Terminology and concepts . . . . . . . . . . . . . . . . . . . 4
3. General Expectations . . . . . . . . . . . . . . . . . . . . . 6 3. General Expectations . . . . . . . . . . . . . . . . . . . . . 5
4. Extended Home Network . . . . . . . . . . . . . . . . . . . . 7 4. Extended Home Network . . . . . . . . . . . . . . . . . . . . 6
4.1 Returning Home . . . . . . . . . . . . . . . . . . . . . . . . 8 4.1 Configuration . . . . . . . . . . . . . . . . . . . . . . 6
5. Aggregated Home . . . . . . . . . . . . . . . . . . . . . . . 9 4.2 Returning Home . . . . . . . . . . . . . . . . . . . . . . 7
5.1 Returning Home . . . . . . . . . . . . . . . . . . . . . . . . 10 4.3 Applicability . . . . . . . . . . . . . . . . . . . . . . 7
5. Aggregated Home . . . . . . . . . . . . . . . . . . . . . . . 8
5.1 Configuration . . . . . . . . . . . . . . . . . . . . . . 8
5.2 Returning Home . . . . . . . . . . . . . . . . . . . . . . 9
5.2.1 Returning Home by egress . . . . . . . . . . . . . . . 9
5.2.2 Returning Home by ingress . . . . . . . . . . . . . . 10
5.3 Applicability . . . . . . . . . . . . . . . . . . . . . . 10
6. Virtual Home Network . . . . . . . . . . . . . . . . . . . . . 11 6. Virtual Home Network . . . . . . . . . . . . . . . . . . . . . 11
6.1 Configuration . . . . . . . . . . . . . . . . . . . . . . 11
6.2 Applicability . . . . . . . . . . . . . . . . . . . . . . 12
7. Mobile Home . . . . . . . . . . . . . . . . . . . . . . . . . 13 7. Mobile Home . . . . . . . . . . . . . . . . . . . . . . . . . 13
8. Changes from version 00 to 01 . . . . . . . . . . . . . . . . 15 7.1 Configuration . . . . . . . . . . . . . . . . . . . . . . 13
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 16 7.2 Applicability . . . . . . . . . . . . . . . . . . . . . . 14
References . . . . . . . . . . . . . . . . . . . . . . . . . . 16 8. Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 17 8.1 Changes from version 00 to 01 . . . . . . . . . . . . . . 16
A. Returning Home emulation in the virtual case . . . . . . . . . 18 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 17
Intellectual Property and Copyright Statements . . . . . . . . 19 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 18
A. Returning Home emulation in the virtual case . . . . . . . . . 19
Intellectual Property and Copyright Statements . . . . . . . . 20
1. Introduction 1. Introduction
This document assumes that the reader is familiar with Mobile IPv6 as This document assumes that the reader is familiar with IPv6 Mobility
defined in [6], and with the concept of Mobile Router defined in the as defined in [7], with the NEMO Basic Support [8] and with the NEMO
NEMO terminology document [9]. terminology document [10].
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
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
result, the Home Network is not necessarily contained on a Home Link.
In fact, the Mobile Network Prefixes are subnets of the Home Network.
How the two concepts relate in a given deployment depend on the
organization of the Home Network, as described below.
Four different organizations of the Home Network including a Four different organizations of the Home Network including a
hierachical construction are documented: hierarchical construction are documented:
Extended Home Network: In this disposition, the Home Network is but Extended Home Network: In this disposition, the Home Network is only
one subnet of a larger aggregation that encompasses the Mobile one subnet of a larger aggregation that encompasses the Mobile
Networks, called extended Home Network. When at Home, a Mobile Networks, called extended Home Network. When at Home, a Mobile
Router performs normal routing between the Home Link and the Router performs normal routing between the Home Link and the
Mobile Networks. Mobile Networks. More in Section 4.
Aggregated Home Network: In this disposition, the Home Network Aggregated Home Network: In this disposition, the Home Network
actually overlaps with the Mobile Networks. When at Home, a Mobile actually overlaps with the Mobile Networks. When at Home, a
Router acts as a bridge between the Home Link and the Mobile Mobile Router acts as a bridge between the Home Link and the
Networks. Mobile Networks. More in Section 5.
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. Link at all for the Mobile Routers to come back Home to. More in
Section 6.
Mobile Home Network: In this disposition, there is a bitwise Mobile Home Network: In this disposition, there is a bitwise
hierarchy of Home Networks. A global Home Network is advertised to hierarchy of Home Networks. A global Home Network is advertised
the infrastructure by a head Home Agent and further subnetted into to the infrastructure by a head Home Agent and further subnetted
Mobile Networks. Each subnet is owned by a Mobile Router that into Mobile Networks. Each subnet is owned by a Mobile Router
registers it in a NEMO fashion while acting as a Home Agent for that registers it in a NEMO fashion while acting as a Home Agent
that network. for that network. More in Section 7.
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.
Also, it is valid for a Mobile Router to register using an address
from one of its own NEMO-Prefixes in all three cases.
The examples provided here aim at illustrating the NEMO Basic Support The examples provided here aim at illustrating the NEMO Basic Support
draft [7] but are by no mean at limiting its scope of application. draft [8] but do not aim at limiting its scope of application, and
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 [5]. 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 [4]: Addressing Architecture document [5]:
link-local unicast address link-local unicast address
link-local scope multicast address link-local scope multicast address
The following terms used in this document are defined in the mobile Most of the mobility related terms used in this document are defined
IPv6 specification [6]: in the Mobility Related Terminology document [6] and in the Mobile
IPv6 (MIP6) specification [7].
home agent (HA)
The following terms used in this document are defined in the mobile
network terminology document [9]:
mobile router (MR)
mobile network
mobile host (MH) Additionally, some terms were created or extended for NEMO. These
specific terms are defined in the Mobile Network Terminology document
[10]:
This draft uses the following additional or modified terminology: Home Link
Home Link: The link attached to the interface at the Home Agent on Home Network
which the Home Prefix is configured. The interface can be a
virtual interface, in which case the Home Link is a virtual Home
Link.
Home Network: The Network formed by the application of the Home Home Address
Prefix on the Home Link. With NEMO, the concept of Home Network is
extended as explained below.
Home Address: With Mobile IPv6, a Home Address is derived from the MRHA Tunnel
Home Network prefix. This is generalized in NEMO, with some
limitations: A Home Address can be either derived from the Home
Network or from one of the Mobile Router's NEMO-prefixes.
MRHA Tunnel: The bi-directional tunnel between a Mobile Router and Mobile Aggregated Prefix
its Home Agent
Mobile Aggregated Prefix: An aggregation of NEMO-Prefixes.
Aggregated Home Network: The Home Network associated with a Mobile Aggregated Home Network
Aggregated Prefix. This Aggregation is advertised as a subnet on
the Home Link, and thus used as Home Network for NEMO purposes.
Extended Home Network: The network associated with the aggregation of Extended Home Network
one or more Home Network(s) and Mobile Network(s). As opposed to
the Mobile IPv6 Home Network that is a subnet, the extended Home
Network is an aggregation and is further subnetted.
Virtual Home Network: The Home Network associated with a Virtual Virtual Home Network
Network. The Extended Home Network and the Aggregated Home Network
can be configured as Virtual Home Network.
Mobile Home Network: A Mobile Network that is also a Home Network. Mobile Home Network
The MR that own the NEMO-Prefix acts as a Home Agent for it.
3. General Expectations 3. General Expectations
With Mobile IPv6, the Home Network is generally a physical network With Mobile IPv6, the Home Network is generally a physical network
interconnecting the Home Agents, and the Mobile Nodes that are at interconnecting the Home Agents, and the Mobile Nodes that are at
Home. NEMO extends the concept of Home so that it is not only a flat Home. NEMO extends the concept of Home so that it is not only a flat
subnet composed of Home Addresses but an aggregation that is itself subnet composed of Home Addresses but an aggregation that is itself
subnetted in mobile and Home Networks. This aggregation is still subnetted in mobile and Home Networks. This aggregation is still
referred to as Home. referred to as Home.
As an example, say that the aggregation has a global routing prefix As an example, say that the aggregation has a global routing prefix
of m = 48 bits (A:B:C::/48), with subnet ID size of n = 16 bits ( n + of m = 48 bits (A:B:C::/48), with subnet ID size of n = 16 bits ( n +
m = 64). m = 64).
Say that a Mobile Router, MR1, owns the NEMO-Prefix A:B:C:1::/64: Say that a Mobile Router, MR1, owns the MNP A:B:C:1::/64: With NEMO
With basic NEMO, and depending on the deployment, MR1 may register Basic Support, and depending on the deployment, MR1 may register
using a Home Address from the Home network, A:B:C:0::1, say, or a using a Home Address from the Home network, A:B:C:0::1, say, or a
Home Address, A:B:C:1::1, say, from one of its NEMO-Prefixes. Home Address, A:B:C:1::1, say, from one of its MNPs.
In a given deployment, one subnet may be reserved for the Home Link In a given deployment, one subnet may be reserved for the Home Link
(say A:B:C:0::/64) while the others are attributed to Mobile Routers (say A:B:C:0::/64) while the others are attributed to Mobile Routers
as Mobile Networks (as A:B:C:1::/64 for MR1). Another approach could as Mobile Networks (as A:B:C:1::/64 for MR1). Another approach could
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. Extended Home Network
One simple approach can be to reserve one or several subnets from an 4.1 Configuration
aggregation for the Home Link, and to use the other subnets as
NEMO-Prefixes. In that case, the Home Network and the Mobile Networks One simple approach is to reserve one or several subnets from an
do not overlap. The aggregation is called an extended Home Network. aggregation for the Home Link, and to use the other subnets as MNPs.
In that case, the Home Network and the Mobile Networks do not
overlap. The aggregation is called an Extended Home Network and
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 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 A:B:C:i::/64 0 < i <= N
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
In that configuration: In that configuration:
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 NEMO-prefixes are tailored to allow for IPv6 o The Home and the MNPs are tailored to allow for IPv6 Stateless
Stateless Address Autoconfiguration with typical interface Address Autoconfiguration with typical interface identifier length
identifier length for the type of interface (can be for example / for the type of interface (can be for example /64).
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 NEMO-prefixes, since it is an that of the Home Network and the MNPs, since it is an aggregation
aggregation (can be for example /48). (can be for example /48).
o The Mobile Routers are assigned individually a Home Address from o The Mobile Routers are assigned individually a Home Address from
the Home Network and use is to register their NEMO-Prefix(es). In the Home Network and use is to register their MNP(es). In that
that case, the Home Agent performs DAD in the Home Network as case, the Home Agent performs DAD in the Home Network as
prescribed by Mobile IPv6 for the Home Addresses. prescribed by Mobile IPv6 for the Home Addresses.
o Alternatively, a Mobile Router could also form a Home Address from o Alternatively, a Mobile Router could also form a Home Address from
one of its prefixes and use it to register, performing its own DAD one of its prefixes and use it to register, performing its own DAD
on its ingress network. on its ingress network.
4.1 Returning Home 4.2 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 If the Home Address of the Mobile Router is derived from one of its
Mobile Networks, then the MR may connect to the Home Link using an Mobile Network Prefixes, then the MR may connect to the Home Link
egress interface and autoconfigure an address on the Home Link. The using an egress interface and autoconfigure an address on the Home
MR recognizes the prefix of its Home Agent in order to decide that it Link. The MR recognizes the prefix of its Home Agent in order to
is Home. Note that in that case the Home Address does not match the decide that it is Home. Note that in that case the Home Address does
Home Prefix. 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 particular, if the HA has the necessary information to continue
routing to the NEMO-Prefixes in the absence of registration, for routing to the MNPs in the absence of registration, for instance if
instance if the Home Address of the Mobile Router is derived from the the Home Address of the Mobile Router is derived from the Home
Home Network, and if the HA uses a static route to the Network, and if the HA uses a static route to the MNP(es) via that
NEMO-Prefix(es) via that address, then the participation of the MR to address, then the participation of the MR to the Home IGP is not
the Home IGP is not required. required.
But in the general case, when the MR is at Home, it resumes IGP But in the general case, when the MR is at Home, it resumes IGP
operations on the Home Link in order to advertise its Mobile operations on the Home Link in order to advertise its Mobile
Networks. 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. In Particular, it Networks when at home are described in Section 6.
is
4.3 Applicability
The extended Home Network keeps the MIP6 concept of a Home Network
for both Mobile Nodes and Mobile Routers to take their Home Address
from. Since there is no overlap between the prefixes that are
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.
5. Aggregated Home 5. Aggregated Home
5.1 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
NEMO-prefixes is used plainly as the Home Network, refered to as the MNPs is used plainly as the Home Network, referred to as the
Aggregated Home Network. This means that the Mobile Aggregated Prefix Aggregated Home Network. This means that the Mobile Aggregated
is configured on the Home Link and advertised by the Home Agent as a Prefix is configured on the Home Link and advertised by the Home
subnet. 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
<-----------------------------------------------------------> <----------------------------------------------------------->
Mobile Net Mobile Net Mobile Net ... Mobile Net Mobile Net Mobile Net Mobile Net ... Mobile Net
<------------><------------><------------> ... <------------> <------------><------------><------------> ... <------------>
Note: a Mobile Router coming Home sees overlapping prefixes between Figure 2: Aggregated Home
the ingress and the egress interface and some specific support may be
needed.
A node on the Home Link will compute that the Aggregated Home Network A node on the Home Link computes that the Aggregated Home Network is
is actually a subnet on the Home Link and may use it for actually a subnet on the Home Link and may use it for
autoconfiguration purposes. Such a node may also install a connected autoconfiguration purposes. Such a node may also install a connected
route to the Aggregated Home Network over the Home Link. route to the Aggregated Home Network over the Home Link.
As a result, unless the node has a better (longest match) route to a As a result, unless the node has a better (longest match) route to a
given NEMO-Prefix, it will lookup all MNNs using Neighbor Discovery given MNP, it will lookup all MNNs using Neighbor Discovery over the
over the Home Link. Home Link.
Thus, the Home Agent MUST intercept all the packets to the MNNs on Thus, the Home Agent MUST intercept all the packets to the MNNs on
the registered prefixes. In order to do so, the Home Agent MAY the registered prefixes. In order to do so, the Home Agent might
perform ND proxying for all addresses in all registered Mobile perform ND proxying for all addresses in all registered Mobile
Network Prefixes, and protect the NEMO-Prefix space from Network Prefixes, and protect the MNP space from autoconfiguration by
autoconfiguration by uncontrolled visitors on the Home Link. uncontrolled visitors on the Home Link.
Alternatives based on a routing protocol or ICMP redirect may apply Alternatives based on a routing protocol or ICMP redirect may apply
in some cases. in some cases.
5.1 Returning Home 5.2 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 a the Home Agent, the Home Link. As a consequence, the Home Agent has
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. Note that it must expect Link by a prefix match with its Home Agent.
a shorter prefix than that of its Mobile Networks, even if its Home
Address is formed out of one of its NEMO-Prefixes, but that the Home Note that it must expect a shorter prefix than that of its Mobile
Address matches the Home Network Prefix. Networks, even if its Home Address is formed out of one of its MNPs,
but that the Home Address 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
A Mobile Router coming Home via its egress interface sees overlapping
prefixes between the ingress and the egress interface and some
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 MAY 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. Alternatively, the Mobile Router MAY perform ND and the Home Link.
proxying for all addresses in its NEMO-Prefixes, between the egress
and the related ingress interface. Since the prefixes on the egress Alternatively, the Mobile Router might perform ND proxying for all
and ingress interfaces are overlapping, routing is disallowed. addresses in its MNPs, between the egress and the related ingress
interface. Since the prefixes on the egress and ingress interfaces
are overlapping, routing is disallowed.
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
Bridging between egress and ingress Figure 3: Bridging between egress and ingress
5.2.2 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 Mobile Link to connect to the Home Link, merging Router may use the NEMO-Link to connect to the Home Link, merging the
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
| | | | | | | |
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. 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
of its own MNPs. .
5.3 Applicability
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
Router. This configuration excludes the cohabitation with MIP6 MNs
on the Home Link.
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
aggregation- on its ingress interface. A pure router will reject
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
whether that support is available in the MRs if returning Home is
required.
6. Virtual Home Network 6. Virtual Home Network
6.1 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. [6] 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
--+-----+--+- . -+- . -+-- --+-----+--+- . -+- . -+--
| | | | | | | |
MR1 MR2 MRi MRN MR1 MR2 MRi MRN
/64 /64 /64 /64 A:B:C:i::/64 0 < i <= N /64 /64 /64 /64 A:B:C:i::/64 0 < i <= N
Virtual Home Network Figure 5: Virtual Home Network
The Extended Home network and the Aggregated Home network models can The Extended Home Network and the Aggregated Home Network models can
be adapted for virtual links. There is no change in the way Home be adapted for virtual links.
Addresses are allocated. As in the case of a physical link, the Home
Address of a Mobile router is constructed based on the Home Prefix or As in the case of a physical link, the Home Address of a Mobile
one of the prefixes of its Mobile Network(s). router can be constructed based on a dedicated subnet of the Home
Prefix or one of the MR MNPs.
Note that since the Home Address is never checked for DAD, it makes
the configuration easier to take it from the MNP as opposed to a
specific subnet.
There are certain advantages to making the Home Link a virtual link: There are certain advantages to making the Home Link a virtual link:
A virtual link may not experience any disruption related to A virtual link may not experience any disruption related to
physical maintenance or to hardware problems, so it is more physical maintenance or to hardware problems, so it is more
available than a physical link. The high availability of the Home available than a physical link. The high availability of the Home
Link is critical for the mobility service. Link is critical for the mobility service.
The Home Agent does not have to defend the Mobile Router's Home The Home Agent does not have to defend the Mobile Router's Home
Address through Proxy Neighbor Discovery. The Home Agent does not Address through Proxy Neighbor Discovery. The Home Agent does not
also have to perform Duplicate Address Detection (DAD) for the also have to perform Duplicate Address Detection (DAD) for the
Mobile Router's Home Address when it receives a Binding Update Mobile Router's Home Address when it receives a Binding Update
from the Mobile Router. from the Mobile Router.
The Mobile Router does not have to implement the Returning Home The Mobile Router does not have to implement the Returning Home
procedure (section 11.5.4 of Mobile IPv6. [6]). procedure (section 11.5.4 of Mobile IPv6. [7]).
In order for a Mobile Router to emulate returning Home, it can In order for a Mobile Router to emulate returning Home, it can
connect to one or more access link(s) configured for that purpose on connect to one or more access link(s) configured for that purpose on
the Home Agent. The Mobile Router, after connecting to the access the Home Agent. The Mobile Router, after connecting to the access
link, SHOULD not send any routing protocol updates on the egress link, SHOULD not send any routing protocol updates on the egress
interface because the routing information from the Mobile Router interface because the routing information from the Mobile Router
might adversely affect IPv6 route aggregation on the Home Network. might adversely affect IPv6 route aggregation on the Home Network.
However, the Mobile Router must register its binding as if it was However, the Mobile Router must register its binding as if it was
accessing a foreign link. accessing a foreign link.
There are also some drawbacks to the virtual Home Link approach: There are also some drawbacks to the virtual Home Link approach:
There can be only one Home Agent since Mobile IPv6 relies on There can be only one Home Agent since Mobile IPv6 relies on
Neighbor Discovery on the Home Link for other HA discovery and for Neighbor Discovery on the Home Link for other HA discovery and for
Duplicate Address Detection. Duplicate Address Detection.
The Home Agent must maintain a Binding Cache entry for a Mobile The Home Agent must maintain a Binding Cache entry for a Mobile
Router and forwarding state for its Mobile Network even when the Router and forwarding state for its Mobile Network even when the
Mobile Router is directly connected to it. All traffic to and from Mobile Router is directly connected to it. All traffic to and
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
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
standardized and deployed. Until then, NEMO operations still inherit
from mobile IPv6 [7] for the HA to HA communication, which is
basically based on Neighbor Discovery extensions over the Home Link.
Making that link virtual bars the deployment of multiple Home Agents,
which may be desirable for reasons of load balancing. Please refer
to the NEMO multihoming issues [12] draft for more on this.
Yet, for a deployment where a single HA is enough, making the Home
Link virtual reduces the vulnerability to some attacks and to some
hardware failures, while making the HA operation faster.
One should check with the product specifications of an HA to see
whether the implementation actually supports a Virtual Home Network,
and if so, whether in that cases, it is optimized for faster DAD-less
bindings.
7. Mobile Home 7. Mobile Home
In this disposition, there is a bitwise hierarchy of Home Networks. A 7.1 Configuration
global Home Network is advertised to the infrastructure by a head
In this disposition, there is a bitwise hierarchy of Home Networks.
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
NEMO-prefixes, 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
Router is at Home at the upper level of hierarchy. This configuration Router is at Home at the upper level of hierarchy. This
is referred to as Mobile Home. configuration is referred to as Mobile Home.
An example of that is the Cab Co configuration. Say a Taxi Company An example of that is the Cab Co configuration. Say a Taxi Company
owns a /32 prefix. This prefix is advertised at a fixed point, the owns a /32 prefix. This prefix is advertised at a fixed point, the
Headquarters say. Regional offices are deployed around the world. Headquarters say. Regional offices are deployed around the world.
Even though these regional offices are relatively stable in terms of Even though these regional offices are relatively stable in terms of
location and prefix requirement -say this changes every few years- location and prefix requirement -say this changes every few years-
making them mobile allows a simpler management when a move has to making them mobile allows a simpler management when a move has to
take place, or should the ISP service change. Finally, each regional take place, or should the ISP service change.
office owns a number of taxis, each one equipped with a mobile router
and an associated /64 prefix.
To illustrate this, here is a possible addressing scheme:
global Home Network CAB:C0::/32 owned by HQ global Home Network CAB:C0::/32 owned by HQ
<-------------------------------------------------------------------> <------------------------------------------------------------------->
HQ extended Home Net Mobile Home for SFO office HQ extended Home Net Mobile Home for SFO office
(casa) (casa)
CAB:C0:CA5A::/48 CAB:C0:5F0::/48 CAB:C0:CA5A::/48 CAB:C0:5F0::/48
<----------------------------> ... <--------------------------------> <----------------------------> ... <-------------------------------->
| |
Home for offices HQ | Home for offices HQ |
CAB:C0:CA5A:CA5A::/64 MN | CAB:C0:CA5A:CA5A::/64 MN |
<----------------------><----> | <----------------------><----> |
CAB:C0:CA5A:CA5A::CA5A | CAB:C0:CA5A:CA5A::CA5A |
CAB:C0:CA5A:CA5A::CA5B | CAB:C0:CA5A:CA5A::CA5B |
are HAs on link with for each office a route like | are HAs on link with for each office a route like |
| |
CAB:C0:CA5A:CA5A::5F0 <---------------------- via CAB:C0:CA5A:CA5A::5F0 <---------------------- via
is the Home addr is the Home addr
of SFO office of SFO office
and recursively for each Office, say San Francisco (SFO) as example:
Mobile Home Network CAB:C0:5f0::/48 owned by SFO office Figure 6: CAB Company HQ configuration
Finally, each regional office owns a number of taxis, each one
equipped with a mobile router and an associated /64 prefix.
For each Office, say San Francisco (SFO) as an example:
Mobile Home Network CAB:C0:5F0::/48 owned by SFO office
<------------------------------------------------------------------> <------------------------------------------------------------------>
HQ Home Network Mobile Networks for taxis SFO Home Network Mobile Networks for taxis
for offices for taxis <---------------------...--------------------->
CAB:C0:5F0:5F0::/64 CAB:C0:5F0:CAB1::/64 CAB:C0:5F0:....::/6 CAB:C0:5F0:5F0::/64 CAB:C0:5F0:CAB1::/64 CAB:C0:5F0:....::/6
<-------------------><-------------------> ... <-------------------> <-------------------><-------------------> ... <------------------->
CAB:C0:5F0:5F0::5F0 | CAB:C0:5F0:5F0::5F0 |
is HA on link with for | is HA on link with for |
each taxi a route like | each taxi a route like |
| |
CAB:C0:5F0:5F0::CAB1 <------ via CAB:C0:5F0:5F0::CAB1 <------ via
is the Home addrSsync is the Home addrSsync
of CAB 1 of CAB 1
Figure 7: CAB Company regional configuration
Note that the hierarchy occurs at a configuration level and may not Note that the hierarchy occurs at a configuration level and may not
be reflected in the actual connection between nodes. For instance in be reflected in the actual connection between nodes. For instance in
the Cab Co case, cabs are roaming within the city, each one attaching the Cab Co case, cabs are roaming within the city, each one attaching
to a different hot spot, while the regional office is connected to to a different hot spot, while the regional office is connected to
the infrastructure using some ISP connection. the infrastructure using some ISP connection.
But it is also possible to reflect the organizational hierarchy in a But it is also possible to reflect the organizational hierarchy in a
moving cloud of Mobile Router. If a Mobile Home Agent acts as root-MR moving cloud of Mobile Router. If a Mobile Home Agent acts as
for a nested configuration of its own MRs, then the communication root-MR for a nested configuration of its own MRs, then the
between MRs is confined within the nested structure. communication between MRs is confined within the nested structure.
This can be illustrated in the case of a fleet at sea. Say that now This can be illustrated in the case of a fleet at sea. Say that now
SFO is a communication ship of a fleet, using a satellite link to SFO is a communication ship of a fleet, using a satellite link to
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.
8. Changes from version 00 to 01 7.2 Applicability
Added Mobile Home Section This complex topology applies to large distributed fleet, mostly if
there is a single interchange point with the internet (e.g. a NAT or
a socks farm) where the super HA could be located.
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
infrastructure, but can stay confined within the mobile cloud, the
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
access may be as expensive as a satellite link.
8. Changes
8.1 Changes from version 00 to 01
Removed terminology (moved to the Nemo terminology draft).
Added an applicability statement for all documented cases
9. Acknowledgements 9. 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 and Alexandru Petrescu for their contributions.
References 10 References
[1] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[2] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6)
Specification", RFC 2460, December 1998. Specification", RFC 2460, December 1998.
[2] 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.
[3] Thomson, S. and T. Narten, "IPv6 Stateless Address [4] Thomson, S. and T. Narten, "IPv6 Stateless Address
Autoconfiguration", RFC 2462, December 1998. Autoconfiguration", RFC 2462, December 1998.
[4] 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.
[5] Bradner, S., "Key words for use in RFCs to Indicate Requirement [6] Manner, J. and M. Kojo, "Mobility Related Terminology", RFC
Levels", BCP 14, RFC 2119, March 1997. 3753, June 2004.
[6] Johnson, D., Perkins, C. and J. Arkko, "Mobility Support in [7] Johnson, D., Perkins, C. and J. Arkko, "Mobility Support in
IPv6", draft-ietf-mobileip-ipv6-24 (work in progress), July IPv6", RFC 3775, June 2004.
2003.
[7] Devarapalli, V., "Nemo Basic Support Protocol", [8] Devarapalli, V., "Network Mobility (NEMO) Basic Support
draft-ietf-nemo-basic-support-02 (work in progress), December Protocol", draft-ietf-nemo-basic-support-03 (work in progress),
2003. June 2004.
[8] Ernst, T., "Network Mobility Support Goals and Requirements", [9] Ernst, T., "Network Mobility Support Goals and Requirements",
draft-ietf-nemo-requirements-02 (work in progress), February draft-ietf-nemo-requirements-02 (work in progress), February
2004. 2004.
[9] Ernst, T. and H. Lach, "Network Mobility Support Terminology", [10] Ernst, T. and H. Lach, "Network Mobility Support Terminology",
draft-ietf-nemo-terminology-01 (work in progress), February draft-ietf-nemo-terminology-01 (work in progress), February
2004. 2004.
[10] Wakikawa, R., Devarapalli, V. and P. Thubert, "Inter Home [11] Wakikawa, R., Devarapalli, V. and P. Thubert, "Inter Home
Agents Protocol (HAHA)", draft-wakikawa-mip6-nemo-haha-01 (work Agents Protocol (HAHA)", draft-wakikawa-mip6-nemo-haha-01 (work
in progress), February 2004. in progress), February 2004.
[12] Ernst, T., "Analysis of Multihoming in Network Mobility
Support", draft-ietf-nemo-multihoming-issues-00 (work in
progress), July 2004.
Authors' Addresses Authors' Addresses
Pascal Thubert Pascal Thubert
Cisco Systems Technology Center Cisco Systems
Village d'Entreprises Green Side Village d'Entreprises Green Side
400, Avenue Roumanille 400, Avenue de Roumanille
Batiment T3
Biot - Sophia Antipolis 06410 Biot - Sophia Antipolis 06410
FRANCE FRANCE
Phone: +33 4 97 23 26 34
EMail: pthubert@cisco.com EMail: pthubert@cisco.com
Ryuji Wakikawa Ryuji Wakikawa
Keio University and WIDE Keio University and WIDE
5322 Endo Fujisawa Kanagawa 5322 Endo Fujisawa Kanagawa
252-8520 252-8520
JAPAN JAPAN
EMail: ryuji@sfc.wide.ad.jp EMail: ryuji@sfc.wide.ad.jp
skipping to change at page 18, line 10 skipping to change at page 19, line 10
Mountain View, CA 94043 Mountain View, CA 94043
USA USA
EMail: vijay.devarapalli@nokia.com EMail: vijay.devarapalli@nokia.com
Appendix A. Returning Home emulation in the virtual case Appendix A. Returning Home emulation in the virtual case
When a Home Link is virtual, all traffic to and from the Mobile When a Home Link is virtual, all traffic to and from the Mobile
Network is sent through the bi-directional tunnel even at the Home Network is sent through the bi-directional tunnel even at the Home
Link. This section describes one possible mechanism that extends Link. This section describes one possible mechanism that extends
basic NEMO to eliminate this tunneling overhead. NEMO Basic Support to eliminate this tunneling overhead.
Although the Home Link is virtual, the Home Agent has at least one Although the Home Link is virtual, the Home Agent has at least one
physical link to communicate with the external world. One or several physical link to communicate with the external world. One or several
of such links, called the virtual Home Access Links, are conceptually of such links, called the virtual Home Access Links, are conceptually
associated with the virtual Home Link and considered as part of Home. associated with the virtual Home Link and considered as part of Home.
When accessing one of its virtual Home Access Links, a Mobile Router When accessing one of its virtual Home Access Links, a Mobile Router
autoconfigures a Care-of Address from a Router Advertisement as it autoconfigures a Care-of Address from a Router Advertisement as it
would do on any visited link, in order to perform the next binding would do on any visited link, in order to perform the next binding
flow. flow.
skipping to change at page 18, line 37 skipping to change at page 19, line 37
status code implies that Home Agent successsful de-register the status code implies that Home Agent successsful de-register the
binding at the virtual Home Access Link. Detection of the virtual binding at the virtual Home Access Link. Detection of the virtual
Home Access Links is achieved by a prefix comparison(s) between the Home Access Links is achieved by a prefix comparison(s) between the
care-of address and the prefix(es) on the virtual Home Access care-of address and the prefix(es) on the virtual Home Access
Link(s). Link(s).
With both approaches, the result of the binding flow is a With both approaches, the result of the binding flow is a
deregistration. Consequently, both the Mobile Router and the Home deregistration. Consequently, both the Mobile Router and the Home
Agent disable the bi-directional tunnel. At that point, the Home Agent disable the bi-directional tunnel. At that point, the Home
Agent configures its forwarding in order to reach the Mobile Router Agent configures its forwarding in order to reach the Mobile Router
and its mobile networks at Home. For instance, this may take the form and its mobile networks at Home. For instance, this may take the
of a route to the Mobile Network prefixes via the MR Home Address, form of a route to the Mobile Network prefixes via the MR Home
and a connected host route to the MR Home Address via the virtual Address, and a connected host route to the MR Home Address via the
Home Access link. virtual Home Access link.
After successful binding de-registration, the Mobile Router MUST After successful binding de-registration, the Mobile Router MUST
receive packets meant to the Mobile Router's Home Address at the receive packets meant to the Mobile Router's Home Address at the
Virtual Home Link. How to intercept packets addressed to the Home Virtual Home Link. How to intercept packets addressed to the Home
Address depends on implementations of the Mobile Router. If the Home Address depends on implementations of the Mobile Router. If the Home
Address is not configured at the egress interface, the Mobile Router Address is not configured at the egress interface, the Mobile Router
MUST use proxy Neighbor Discovery to intercept all packets addressed MUST use proxy Neighbor Discovery to intercept all packets addressed
to the Home Address on the virtual Home Link. Otherwise, the Mobile to the Home Address on the virtual Home Link. Otherwise, the Mobile
Router does not have to perform any special operation at the virtual Router does not have to perform any special operation at the virtual
Home Link. Home Link.
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