Introducing Mobile IPv6 in 2G and 3G mobile networks

Introducing Mobile IPv6 in 2G and 3G mobile networks
White Paper
Introducing Mobile IPv6
in 2G and 3G mobile networks
White Paper
Contents
Executive summary
4
Mobile IP
Mobile IPv4
Mobile IPv6
5
6
6
Link layer mobility
Link layer mobility in 2G and 3G mobile networks
9
10
Mobile IPv6 as a service in GPRS
and WCDMA mobile networks
Mobile IPv6 for Inter-PLMN mobility
Roaming between different access technologies
Mobile IPv6 providing static IPv6 addresses
for mobile terminals
Implementation of Mobile IPv6
in 2G and 3G mobile networks
Application layer Mobile IPv6 main benefits
13
13
Conclusions
13
Abbreviations and Definitions
14
11
11
12
12
3
White Paper
Executive summary
The goal of cellular mobility
standards in GPRS (General Packet
Radio Service) and WCDMA
(Wideband Code Division Multiple
Access) networks has been to
provide global connectivity, where
the IP (Internet Protocol) layer is
not involved in the mobility
management. This makes it
possible to continue using existing
IP enabled access devices when
moving in the network, e.g. laptop
computers connected to GPRS
terminals. This is called link layer
or layer 2 mobility.
In link layer mobility, access to
IP networks is through one specific
IP router (home GGSN). If the
terminal is roaming in a visited
network that is located far away
from the home network and local
services are used, the routing can
be inefficient. Another case is when
a multi-mode mobile terminal is
roaming between different access
networks. If a multi-mode terminal
moves from WCDMA coverage to
a Bluetooth or WLAN (Wireless
Local Area Network) coverage
area, it is given a new IP address.
When the IP address changes,
existing application connections are
lost, and need to be restarted.
A natural solution is to use IP layer
mobility. IP mobility allows
packets sent to the home address to
be delivered to the mobile node.
In addition, mobile IP can hide
any address changes from the
transport and application layers,
enabling the mobile terminal to
roam seamlessly between different
access networks.
4
IP mobility is a standardised part of
Internet Protocol version 6 (IPv6).
In Mobile IPv6, each mobile node
is identified with a static home
address, independent of its current
point of attachment to the Internet.
The home address is stored by the
Home Agent (HA) router in the
home network. When the mobile
node is attached to a foreign link,
it is addressable by a ‘care-of
address’, in addition to its home
address. There may be several care-of
addresses defined for the mobile node,
but only one, the primary care-of
address, is bound to a specific home
address at any one time. The care-of
address provides information about
the mobile node’s current location.
The mapping or association between
the current care-of address and the
home address is called ‘binding’.
IP mobility is also specified for IPv4,
but IPv6 provides more enhanced
support for it. Mobile IPv4 is not
deployed widely enough to satisfy
current mobility needs – a shortage
of globally routable IPv4 addresses
and the use of private IPv4
addresses with Network Address
Translators (NATs) hampers Mobile
IPv4 deployment in many cases.
The benefits of Mobile IPv6
compared to Mobile IPv4 include:
• The huge address space of IPv6
makes Mobile IPv6 deployment
more straightforward.
• IPv6 address autoconfiguration
simplifies the care-of address
assignment for the mobile node.
It also eases the address
management in a large network
infrastructure.
• Optimised routing: Mobile IPv6
avoids so-called triangular routing
of packets from a correspondent
node to the mobile node via the
Home Agent. This reduces transport
delay and saves network capacity.
• No need for Foreign Agents in
Mobile IPv6.
• Using IP Security for all security
requirements.
Mobile IPv6 is a highly feasible
mechanism for implementing static
IPv6 addressing for mobile terminals.
In this case, the Mobile IPv6 home
address is the static address. The
mobile node can always be reached
using the same globally unique IPv6
address, independent of its current
location. Many applications and
services, such as push services
(for example WAP push), need static
IP addresses / static user identity.
Implementing application layer
Mobile IPv6 in 2G and 3G mobile
networks primarily requires
application layer IPv6 support from
the network, the installation of a
Home Agent (HA) router in the home
network, the use of mobile terminals
supporting Mobile IPv6 and the
implementation of IP Security (IPsec).
Mobile IPv6 is a promising technology
that complements the link layer
(layer 2) mobility in GPRS and
WCDMA mobile networks. Mobile
IPv6 can handle the mobility
management in multi-access networks
(e.g. a network with WCDMA and
WLAN coverage using multi-mode
mobile terminals supporting both
technologies). Additionally, Mobile
IPv6 is a feasible method of
providing static IPv6 addresses for
the mobile terminals. Nokia sees
Mobile IPv6 as the enabling platform
for creating IP layer mobility in
the evolution path towards next
generation service offerings.
White Paper
Mobile IP
Mobile IP is the IETF proposed
standard solution for handling
terminal mobility among IP subnets
and was designed to allow a host to
change its point of attachment
transparently to an IP network.
Mobile IP works at the network
layer (layer 3), influencing the routing
of datagrams, and can easily
handle mobility among different
media (LAN, WLAN, dial-up links,
wireless channels, etc.).
Home
network
HA
Home Agent
IPv4
Internet
Foreign Agent
Correspondent Node
FA
Visited
network
178.24.9.36
Figure 1. General scenario of Mobile IPv4
The generic problem with IP
mobility is that when an IP node
moves to a new subnet, it either has
to change its IP address to reflect
the new point of attachment,
or the routers must have host
specific routes for the mobile node.
Both these alternatives have their
drawbacks. Host-specific routes in
general cannot be scaled up for
Internet-wide use. Changing the
IP address seen by the transport
and the application layers every
time a MN (Mobile Node) moves
to a new network may be a solution
to infrequent roaming, but not to
mobility in general. This is because
the transport layer (e.g. TCP) uses
the IP address as an identifier,
correlating IP packets to transport
sessions. If this IP address is changed,
then the correlation is lost and the
sessions need to be restarted.
Mobile IP solves the mobility
problem by managing the
correlation between a changing
IP address (care-of address) and the
static home address. The transport
and application layers keep using
the home address, allowing them to
remain ignorant of any mobility
taking place.
The home address is naturally
routed to the Home Agent (HA),
which maintains the mapping
(“binding”) from the home address
to the current (primary) care-of
address (CoA). The HA will tunnel
packets to the MN at its current
point of attachment via the CoA.
In Mobile IPv4 the care-of address
can be either hosted by a Foreign
Agent (FA in Figure 1) or co-located
with the mobile node itself.
The CoA is always assigned by the
visited network, so that the routing
of the packets to the mobile node
will remain transparent to the
routers in transit. The packets from
the MN to the correspondent
node (CN) will be routed naturally
without going through the home
agent. As the MN moves from one
subnet to another, and its CoA
changes, it will inform the HA of
the new binding.
majority of IPv4 nodes do not
support Mobile IP. For IPv6,
the mobility support has been on
the list of required features from
the beginning. The Mobile IPv6
specification is on its way to
becoming a standard, so it is
expected that virtually all IPv6
deployments will include at least the
minimal mobile IP support (i.e. the
correspondent node functions).
Mobile IP was originally defined
for IPv4 (IETF RFC 2002).
This definition has suffered from
the fact that mobility support for
IPv4 is an add-on, and the vast
5
White Paper
Mobile IPv4
Mobile IP was originally defined for
IP version 4, before IPv6 existed.
The base protocol is defined in RFC
2002. Many enhancements have
been proposed to Mobile IPv4 to
counter some of the identified
problems, which include:
• Triangular routing as shown in
Figure 1. All packets sent to the
mobile node are routed through
its home agent, causing increased
load on the home network and
higher latency. This problem could
be solved with route optimisation
extension, but the required
update may not be practical.
• Deployment problem: Mobile IPv4
typically requires each potential
foreign network to have foreign
agent(s). If foreign agents were
not used, every mobile node would
need a globally routable IPv4
address from the foreign network.
• Ingress filtering: In an ISP (Internet
Service Provider), any border router
may discard packets that contain
a source IP address that is not
topologically correct. In Mobile
IPv4, the Mobile nodes that are
away from home, i.e., in a foreign
ISP, use their home address as the
source IP address, resulting in the
likelihood of dropping of packets
by ingress filtering.
• Authentication and Authorisation:
Mechanisms specific to Mobile
IPv4 are used for authentication
of Mobile IPv4 registrations.
Mobile IPv4 has only a small
percentage (a few million nodes) of
the overall IPv4 deployment.
A shortage of globally routable
IPv4 addresses and use of private
IPv4 addresses with Network
Address Translators hampers its
deployment in many cases.
6
Home
network
HA
Home Agent
in the home network
(the mobile node’s home
address is associated
with the home agent)
IPv6
Internet
Correspondent Node
that is communicating
with the mobile node
Mobile Node
(mobile terminal)
with a
care-of address
Visited
network
Figure 2. General scenario of Mobile IPv6
Mobile IPv6
Mobile IPv4 and Mobile IPv6
protocols share similar ideas,
but their implementations are
somewhat different. Figure 2 shows
the basic elements of Mobile IPv6.
Mobility signalling and security
features (IPsec) are integrated in the
IPv6 protocol as header extensions,
whereas Mobile IPv4 uses a separate
UDP (User Datagram Protocol)
based protocol for registrations.
These registrations apply special
mobility security associations.
In IPv6 stateless address
autoconfiguration, addresses can
be generated easily by combining
the network prefix of a visited
network and an interface identifier
of the MN. In addition, address
exhaustion is not a problem.
Therefore, an IPv6 Care-of Address
(CoA) is always co-located at the
MN, and the concept of the foreign
agent has been eliminated. Also,
route optimisation is built into
Mobile IPv6. If route optimisation
is used, user privacy may be
violated, because it will reveal the
true location of the mobile node.
If the MN needs to discover its HA
dynamically, it can make the
enquiry using IPv6 anycast. This is
more efficient and reliable than
IPv4 directed multicast, which may
return several replies.
Several ICMPv6 (Internet Control
Message Protocol for IPv6)
mechanisms provide support for
mobility management. These include:
• Router Advertisement
• Router Solicitation
• Address Auto-configuration
(stateful and stateless)
• Neighbour Discovery
Some of these have been extended
in Mobile IPv6 to better support
its needs. These changes include a
new home agent bit to the router
advertisement, a new bit to the
prefix information option format,
allowing the router to efficiently
advertise its global IPv6 address
instead of the link local address.
Also, the timing rules for router
advertisements and solicitations
White Paper
have been refined and a new
Advertisement Interval Option
has been defined for Router
Advertisements.
Foreign link
The following subsections detail
the major functional elements of
Mobile IPv6 that make use of these
IPv6 features.
Movement detection
A mobile node can determine its
current location by listening to the
Router Advertisements and storing
the included network prefix
information (as do the normal,
stationary IPv6 nodes). If one of
the network prefixes equals the
network prefix of the home address
of the MN, then the MN is on its
home link. Otherwise the MN is
on a foreign link.
The MN selects one of the
advertised routers as its default
router. Movement from one link to
another is initiated when the
currently selected default router
becomes unreachable.
If the MN does not want to wait for
a periodic Router Advertisement,
it can send a Router Solicitation
asking all the routers on the link to
send Router Advertisements.
To obtain a care-of address, the MN
can use either stateful or stateless
address auto-configuration.
In the first situation the MN
obtains a care-of address from
e.g. a DHCPv6 (Dynamic Host
Configuration Protocol for IPv6)
server. In the latter situation,
the MN extracts the network prefixes
from the Router Advertisements
and adds a unique interface
identifier to form a care-of address.
Binding U
pdate
Mobile Node
IPv6
network
Home link
HA
Bind
ing A
cknowle
dgement
Home Agent
Figure 3a. Mobile Node at a foreign link informing the Home Agent
Home Agent
HA
B i n di n
IPv6
network
g Up
dat
e
Home link
Bi
nd
ing
A ck
no w
le dg e
me n t
Mobile Node
Figure 3b. Mobile Node at its home link informing the Home Agent
Correspondent Node
i
Bin d
ng Up
date
Home Agent
Mobile Node
HA
Bi ndin g Ac k now
Foreign link
le d
e
ge m
nt
IPv6
network
Home link
Figure 3c. Mobile Node at a foreign link informing a correspondent node
7
White Paper
When the MN is not on its home
link, the home agent must intercept
packets destined for the MN
home address, causing them to be
delivered to the HA.
Binding management in
Mobile IPv6
Three destination options are
introduced in Mobile IPv6 for
binding management:
• Binding Update
• Binding Acknowledgement
• Binding Request
All these are implemented as IPv6
Destination Options, allowing
them to be either piggybacked with
any IPv6 packet being destined to
a desired destination, or sent
separately with no upper layer
payload.
IP Security is applied to Binding
Update and Binding
Acknowledgement: IPsec
Authentication Header (AH) is
required for authentication and
Encapsulating Security Payload
(ESP) can also be used together
with AH, if encryption is desired.
No authentication is required for
the Binding Request option.
A Binding Update is used to
inform the HA and any active
correspondent node (CN) of the
current (new) binding, consisting of
the new care-of address, the home
address and a binding lifetime
(Figures 3a and 3c). Each IPv6
node (either mobile or stationary)
is recommended to understand
the Binding Update message,
enabling the packets destined to
the MN to be efficiently routed
without going through the HA.
Initially a new CN knows only the
Home address, but when the MN
8
receives packets routed via the HA,
it can send a Binding Update to the
new CN.
When the MN moves back to its home
link, it will notify the home agent
to delete the binding (Figure 3b).
The Binding Acknowledgement is
sent as a response to the Binding
Update, if so requested by the MN.
The Binding Acknowledgement is
also sent to reject the Binding
Update (e.g. for authentication
failure).
If a CN wants to know the care-of
address of a mobile node, it can
send a Binding Request to the MN,
which does not necessarily have to
respond to the request by sending
a Binding Update. The Binding
Request is mainly used to refresh
binding when nearing the end of
the current binding lifetime.
Mobile node moving in
the network
Whenever the mobile node moves
from one subnet or network to
another it acquires a new care-of
address, which needs to be
registered with the HA serving the
mobile host. This process involves
the following events, each of which
takes some time:
1. Movement detection: The mobile
host determines that it has
moved and needs to acquire a
new care-of address. In IPv6 this
is facilitated in general by the
Router Advertisements being
sent periodically by the subnet
routers. In cellular networks,
the movement detection can be
co-ordinated with link layer
movement detection mechanisms.
2. Acquisition of a co-located
care-of address by some
mechanism (for example
stateless autoconfiguration).
3. Registration of the new care-of
address with the home agent.
Moving to a new subnet can cause
a short break in the IP layer
reachability of the mobile node,
causing packet loss during the
handoff. Such breaks are not
inevitable, depending upon layer 2
effects, range overlap and policy.
White Paper
Link layer mobility
In 2G and 3G mobile networks,
mobility is managed below the user
plane network layer i.e. on the layer
2 (the link layer). Layer 2 mobility
management is also used in other
systems, such as Wireless LANs,
for inter access point handovers.
UMTS (Universal Mobile
Telecommunications System) is a
more general term for the 3G (third
generation) telecommunications
system based on the WCDMA high
capacity radio interface. The goal
of UMTS Packet Switched (PS)
Domain is to provide global layer 2
connectivity that can support any
layer 3 protocol. GPRS Tunneling
Protocol (GTP) handles the global
(macro) mobility. The MT (Mobile
Terminal) is attached to the same
GGSN AP all the time, and keeps
its layer 3 (e.g. IPv6) address.
In this case there is no vital need
for Mobile IP. Figure 4 shows a
simplified transport protocol
structure in the UMTS PS Domain,
where user level IPv6 is tunnelled
across the internal GPRS elements.
In the figure, a laptop computer
is connected to the network using
a WCDMA terminal as a modem
(so-called dial-up emulation).
implements the forwarding of IP
packets from the GTP tunnel to
a PDN over the Gi interface and
vice versa.
within a PLMN only, and the
inter-PLMN backbone is used for
roaming from one PLMN to
another (via the Gp interface and
the Border Gateways). SGSN and
GGSN use the intra-PLMN
backbone to exchange PS Domain
data and signalling. When roaming,
both the intra-PLMN backbone
of the home and visited networks
are used, in addition to the interPLMN backbone.
There are two kinds of PLMN
backbone networks: Intra-PLMN
backbone and Inter-PLMN
backbone (Figure 5). Every intraPLMN backbone network is a
private IP network intended for
packet domain data and signalling
R
Uu
Laptop
computer
Iu-PS
Mobile terminal
Gn
RNC
Gi
SGSN
GGSN
TCP
End user IPv6 connectivity
IPv6
PPP
PPP
PDCP
PDCP
Backbone
layers
IPv6
GTP
GTP
GTP
GTP
UDP
UDP
UDP
UDP
IPv4
IPv4
IPv4
IPv4
L2
L2
L2
L2
L2
Figure 4. Simplified protocol architecture in a 3G network
Figure 5. Intra- and Inter-PLMN backbone networks
Packet Data Network
A GPRS attached MT can be
assigned either a static or dynamic
IP address. The static address is
assigned by the Home Public Land
Mobile Network (HPLMN)
operator at the time of subscription.
The dynamic IP address can be
allocated by the GGSN of either
HPLMN or the visited PLMN
(VPLMN) operator at the PDP
context activation time. In addition
to address allocation, a GGSN
Inter-PLMN Backbone
Gi
Gp
GGSN
BG
Intra-PLMN Backbone
SGSN
SGSN
PLMN A
Gi
BG
GGSN
Intra-PLMN Backbone
SGSN
PLMN B
9
White Paper
Link layer mobility
in 2G and 3G
mobile networks
2. Use a visited domain GGSN,
routing the packets from the
VPLMN to their destination
directly though a Packet Data
Network, such as the public
Internet using the Gi interface.
PLMN (HPLMN) and finished the
location update procedure.
The inter-PLMN backbone network
interconnects SGSNs and GGSNs
and intra-PLMN backbone
networks in different PLMNs.
When a subscriber is roaming to
another PLMN, known as the
visited PLMN (VPLMN), the user
needs to first attach to the network.
In GPRS Attach, the MT informs
the SGSN of its intention to
connect to the network by giving
information about its identity,
capability and location. The SGSN
then checks the MT’s identity and
performs the authentication
procedure in order to secure the
transmission path. The attachment
is completed after the SGSN has
received the roaming subscriber data
from HLR of the subscriber’s Home
After GPRS Attach, the MT sends
an ‘Activate PDP context’ Request,
in which the Access Point Name
(APN) is a reference to the GGSN
AP to be used in either the Home or
Visited PLMN backbone or in an
external network. The SGSN
selects the GGSN based on the PDP
context subscription record and
sends the context data to a selected
GGSN. The GGSN routes the
packets to the appropriate Packet
Data Networks (PDN).
The first case allows the mobile
terminal to have a network layer
identity from the home network.
But it might not be the most
effective way especially in the case
local services (topologically near
the visited network) are used.
When a subscriber is roaming in the
VPLMN, there are two possibilities
for GGSN selection:
1. Use the home network GGSN
via the inter-PLMN backbone,
BGs, and GTP tunnel over the Gp
interface (see Figures 5 and 6).
The home GGSN then routes the
packets to their destination.
In the second case, the mobile
terminal is assigned an IPv6 address
from the address pool of the visited
GGSN. In that case it is impossible
for the mobile terminal to be
reachable via an address from the
home domain. A solution to that
based on Mobile IPv6 is described
in the following chapter.
Figure 6. Link layer (layer 2) mobility in the 2G and 3G mobile network.
Home network
SGSN
GPRS
core
GGSN
Operator
network
Edge Router
FW
BG
Inter-PLMN
backbone
network
IPv6
Internet
GTP tunnel
BG
Visited network
SGSN
MT
10
GPRS
core
GGSN
Operator
network
Edge Router
FW
IPv6
Intranet
Host
White Paper
Mobile IPv6 as a service in GPRS
and WCDMA mobile networks
This section describes the benefits
of the introduction of Mobile IPv6
as a service in GPRS and WCDMA
mobile networks. The use of
Mobile IPv6 as a complementing
mobility method and a method for
multi-access mobility is discussed.
The following section shows how
Mobile IPv6 can be used to provide
static IPv6 addresses for GPRS/
WCDMA terminals. Finally,
the benefits of Mobile IPv6 are
summarised.
Mobile IPv6
for Inter-PLMN
mobility
Consider the situation that a GPRS
subscriber of an operator in
Finland is roaming in the U.S. and
accessing a local service there.
If the link layer mobility is used,
the user’s IP packets would first be
tunnelled to Finland, and then
routed back to the U.S. In this
scenario a round trip time from the
mobile terminal to a server and
back could be unacceptable to
many services.
As a solution to this problem,
the roaming GPRS subscriber
should use the services of a local
GGSN in the visited network,
allowing IP packets to be routed as
soon as possible, without crossing
over to the home network. As the
IP address is now being assigned
from the visited network, the mobile
node would not be accessible via a
network layer identity of the home
network. For some applications this
may not be a problem, but in
general it would be desirable if the
mobile node could be reached with
an IP address being assigned from
the home network as well.
A natural solution to this problem
is to use Mobile IP to register
the visited network address with
the home network, allowing
packets sent to the home address to
be delivered to the mobile node.
The basic operation of Mobile
IPv6 in GPRS/WCDMA network
When the mobile terminal is
roaming in a foreign network, it is
addressable by a care-of address,
in addition to its home address.
The IPv6 address prefix in the
mobile terminal’s care-of address
is the prefix of the foreign link.
The care-of address is acquired by
the addressing mechanism provided
by the visited network. While
roaming in the foreign network,
the mobile terminal registers one
of its care-of addresses with the
home agent and sends a “Binding
Update” to the home agent.
The home agent replies with
“Binding Acknowledgement.”
Any IPv6 packets containing
Binding Update or Binding
Acknowledgement destination
options must be authenticated using
IP Security AH (Authentication
Header). After the binding, this
care-of address becomes the mobile
terminal’s primary care-of address.
(for example a WWW server that is
communicating with the mobile
terminal) addressed to the mobile
terminal’s home address. The home
agent encapsulates each intercepted
packet using IPv6 encapsulation,
with the outer header addressed to
the mobile terminal’s primary
care-of address. After the mobile
terminal has received the first
encapsulated packet from the
home agent, it sends a Binding
Update to the correspondent node
informing it of its care-of address:
the correspondent node then replies
with a Binding Acknowledgement.
After this, sending IP packets
between the correspondent node
and the mobile terminal is
straightforward and routing via a
home agent is not needed.
For packets sent by a mobile
terminal while away from home,
the mobile terminal’s care-of
address is typically used as the
source address in the packet’s
IPv6 header. The Home Address
option can be used to inform the
packet recipient of the mobile
node’s home address.
The correspondent node can then
substitute the mobile node’s home
address for this care-of address
making the use of the care-of
address transparent to the
correspondent node. The upper
protocol layers (e.g. TCP) thus only
see the home address. (Figure 7.)
The home agent intercepts all IPv6
packets from a correspondent node
11
White Paper
Roaming between
different access
technologies
enabling the mobile terminal to
roam seamlessly between different
access networks.
The need for multi-access mobility
raises, when a multi-mode mobile
terminal roams between different
access networks. For example,
when a multi-mode terminal moves
from WCDMA coverage to
Bluetooth or WLAN (Wireless
Local Area Network) coverage
area, it is given a new IP address.
When the IP address changes,
existing application connections are
lost, and need to be restarted.
Mobile IPv6
providing static
IPv6 addresses for
mobile terminals
A solution to this problem also is to
use IP layer mobility (Mobile IPv6).
This allows packets sent to the
home address to be delivered to the
mobile node’s current care-of
address. In addition, mobile IP can
hide any address changes from the
transport and application layers,
The basic addressing method in
GPRS and WCDMA mobile
networks is dynamic addressing
(stateless address autoconfiguration).
This means that GGSN allocates
IPv6 addresses dynamically to
mobile terminals. These addresses
do not typically have registered
DNS (Domain Name System)
names, making it difficult to use,
for example, peer-to-peer services
without explicit support from a
network server that could keep
track of the dynamic addresses.
There are services that benefit from
static IPv6 addressing. For example,
push services (e.g. WAP push) need
static customer identities. It can be
noted that the use of static IPv6
addresses and using Mobile IPv6 to
provide those is a generic solution
for the static identity requirements.
Two-player games implemented in
mobile terminals are an example of
peer-to-peer services. If there is no
static addressing (at the user layer),
the users who want to play a game
together would need to meet via a
network resident server. This could
mean that new games could not
be introduced into new mobile
terminals, before making sure that
the deployed servers (if any) meet
the specific requirements of the
game in question.
Mobile IPv6 can be used as a solution
to this problem. The dynamic
address being assigned by the
Figure 7. IPv6 mobility in the 2G and 3G mobile network
Home network
HA
SGSN
GPRS
core
GGSN
Operator
network
Edge
Router
FW
BG
Inter-PLMN
backbone
network
IPv6
Internet
BG
MT
12
SGSN
GPRS
core
Visited network
GGSN
Operator
network
Edge
Router
FW
IPv6 Intranet
Correspondent
Node
White Paper
GGSN is used as the Mobile IPv6
co-located care-of address.
By registering this address with a
home agent, a mapping of the
dynamic address to a more static
home address is created. This allows
the mobile node to be reached with
the home address, and also via a
DNS name, since the home address
can be registered with the DNS.
Implementation
of Mobile IPv6
in 2G and 3G
mobile networks
Implementation of Mobile IPv6 in
2G and 3G mobile networks
primarily requires user plane
(application layer) IPv6 support
from the network, installing a home
agent (HA) router in the home
network, using mobile terminals
supporting Mobile IPv6 and
implementing IP Security
infrastructure, because Mobile
IPv6 uses IPsec for all its security
requirements.
The home agent can be located in
the network operator’s network or
some other network (e.g. company
intranet, home network, etc.).
In both cases, the GGSN elements
do not necessarily need to be
involved with the Mobile IPv6
protocol. A feasible place to install
the home agent could be near the
operator’s network edge router.
Application layer
Mobile IPv6 main
benefits
The main benefits of Mobile IPv6
in the application layer include:
• efficient roaming from the visited
network to local network services
• seamless roaming between
different access technologies,
i.e. reachability via the same
address also from other types of
access networks (WLAN,
Bluetooth, etc.)
• providing a feasible static IPv6
addressing method for mobile
terminals
• reachability via the home address
also when using services of a
visited GGSN
• peer-to-peer services to be
used by the mobile node;
allowing services to be run on
the terminals with no explicit
support by the operator’s
network.
Conclusions
The two mobility mechanisms in
GPRS and WCDMA mobile
networks are link layer (layer 2)
and IP layer mobility. GPRS and
WCDMA networks provide link
layer mobility using GTP tunnels
to connect to the home network
GGSN. Mobile IPv6 is the
technology to support the IP layer
mobility – it is a very suitable
technology for complementing the
link layer mobility.
Mobile IPv6 can handle the mobility
management in multi-access
networks (e.g. a network with
WCDMA and WLAN coverage
using multi-mode mobile
terminals). Additionally, Mobile
IPv6 is a feasible method of
providing static IPv6 addresses for
the mobile terminals. The home
address is the static IP address and
care-of addresses are taken in use
dynamically when roaming in
foreign networks. The association
between the current care-of address
and the home address is called
‘binding.’ With Mobile IPv6,
routing between the correspondent
node (for example a WWW server
communicating with the mobile
node) and the mobile node’s care-of
address is optimised. Providing
static IPv6 addresses to customers is
a business case for operators –
Mobile IPv6 is an efficient way to
implement that.
Implementation of application
layer Mobile IPv6 in 2G and 3G
mobile networks basically requires
user plane IPv6 support from
the network, installing a home
agent (HA), using mobile terminals
supporting Mobile IPv6 and
implementing IP Security.
Nokia sees that the Mobile IPv6
protocol will have an essential
role in future mobile networks.
The time is ripe to consider
implementing Mobile IPv6 support
in the network.
13
White Paper
Abbreviations and Definitions
2G
Second Generation Mobile
Telecommunications,
including GSM and GPRS technologies
3G
Third Generation Mobile
Telecommunications,
including WCDMA/UMTS technology
AH
IPsec Authentication Header
AP
Access Point
BG
Border Gateway
CN
Correspondent Node
CoA
Care-of Address
DHCPv6 Dynamic Host Configuration Protocol
for IPv6
DNS
Domain Name System
ESP
IPsec Encapsulating Security Payload
FA
Foreign Agent
FW
Firewall
GGSN
Gateway GPRS Support Node
GPRS
General Packet Radio Service
GTP
GPRS Tunneling Protocol
HA
Home Agent
HLR
Home Location Register
ICMP(v6) Internet Control Message Protocol
IETF
Internet Engineering Task Force
IP
Internet Protocol
IPsec
IP security
IPv4
Internet Protocol, version 4
IPv6
Internet Protocol, version 6
ISP
Internet Service Provider
LAN
Local Area Network
MN
Mobile Node
MT
Mobile Terminal
PDCP
Packet Data Convergence Protocol
PDN
Packet Data Network
PDP
Packet Data Protocol
PLMN
Public Land Mobile Network
RFC
Request For Comments
(a specification by IETF)
SGSN
Serving GPRS Support Node
TCP
Transmission Control Protocol
TE
Terminal Equipment
14
UDP
UMTS
User Datagram Protocol
Universal Mobile Telecommunications
System
VoIP
Voice over IP
WAP
Wireless Application Protocol
WCDMA Wideband Code Division Multiple Access
WLAN
Wireless LAN
WWW
World Wide Web
Binding
The association/mapping between the mobile node’s
home address and a care-of address
Care-of Address
A temporary IP address associated with a mobile node
while visiting a foreign link
Correspondent Node
A node that is communicating with the mobile node
(for example a WWW server)
Home Address
A static IP address assigned to the mobile node in
the home network
Home Agent
A router on the mobile node’s home network with
which the mobile node has registered its current
care-of address. The mobile node’s home address is
associated with the home agent
Mobile Node
A node that can change its point of attachment in
the IP network. A mobile node can be reached via its
static home address
Primary Care-of Address
The care-of address of a mobile node most recently
registered with its home agent
White Paper
Copyright © Nokia Networks Oy 2001. All rights reserved.
No part of this publication may be copied, distributed, transmitted, transcribed, stored in a retrieval system, or translated into any human or computer language
without the prior written permission of Nokia Networks Oy.
The manufacturer has made every effort to ensure that the instructions contained in the documents are adequate and free of errors and omissions.
The manufacturer will, if necessary, explain issues which may not be covered by the documents. The manufacturer’s liability for any errors in the documents is limited
to the correction of errors and the aforementioned advisory services.
The documents have been prepared to be used by professional and properly trained personnel, and the customer assumes full responsibility when using them.
The manufacturer welcomes customer comments as part of the process of continual development and improvement of the documentation in the best way possible
from the user’s viewpoint. Please submit your comments to the nearest Nokia sales representative.
NOKIA is a registered trademark of Nokia Corporation. Any other trademarks mentioned in this document are the properties of their respective owners.
15
Nokia code: 10889
0101 Libris
© Nokia Networks 2001. All rights reserved.
Nokia and Nokia Connecting People are registered trademarks of Nokia Corporation.
Other product and company names mentioned herein may be trademarks or trade names of their respective owners.
Products are subject to change without notice.
Nokia Networks
P.O. Box 300
FIN-00045 NOKIA GROUP, Finland
Phone: +358 (0) 7180 08000
www.nokia.com
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertising