One document matched: draft-wu-netext-local-ro-03.txt
Differences from draft-wu-netext-local-ro-02.txt
Network Working Group Q.Wu
B.Sarikaya
Internet Draft Huawei
Intended status: Standard Track July 13, 2009
Expires: January 2010
Proxy MIP extension for local routing optimization
draft-wu-netext-local-ro-03.txt
Status of this Memo
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Abstract
This document extends local routing in proxy Mobile IPv6 and defines
a simplified localized routing optimization protocol within one
PMIPv6 domain. The protocol supports IPv4 transport network
operation, IPv4 home address mobility and handover. The Local
mobility anchor/mobile access gateway initiates local routing for
the mobile and correspondent node by sending messages to each mobile
access gateway/local mobility anchor. In case the correspondent node
is connected to another local mobility anchor, the local mobility
anchors connected by the correspondent node needs to be discovered
firstly so that it can notify its mobile access gateways to the
mobile access gateway attached by the mobile node afterwards. Mobile
access gateways create and refresh bindings using proxy binding
update and acknowledgement messages.
Table of Contents
1. Introduction.................................................3
2. Conventions used in this document............................4
3. Scenarios analysis for PMIP6 local routing...................5
4. Local routing optimization protocol overview.................6
4.1. MAG initiated local routing optimization................6
4.1.1. Handover Consideration.............................8
4.2. LMA initiated local routing optimization................9
4.2.1. Handover Consideration............................11
5. Process consideration.......................................11
5.1. Mobile Access Gateway Consideration....................11
5.2. Local Mobility Anchor Consideration....................13
6. IPv4 support................................................13
6.1. IPv4 HoA support.......................................14
6.2. IPv4 transport support.................................14
7. Inter-LMA Local routing Consideration.......................15
7.1. MAG Initiated Inter-LMA local routing..................15
7.2. LMA Initiated Inter-LMA local routing..................16
7.2.1. IPv4 Support Consideration........................17
8. Conceptual Data Structure Extension.........................18
8.1. Binding Update List Extension..........................18
8.2. Binding Cache Entry Extension..........................18
9. Local routing optimization message format...................19
9.1. Local Routing optimization mobility option.............19
9.2. Local Routing optimization Request message(LROREQ).....19
9.3. Local Routing optimization Response Message(LRORSP)....20
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9.4. Context Request Option................................21
9.5. MN-CNs pair mobility option...........................22
9.6. LMA Route Optimization Start Request Message..........23
9.7. LMA Route Optimization Start Response Message.........24
10. Security Considerations...................................25
11. IANA Considerations.......................................25
12. Acknowledgement...........................................25
13. References................................................25
13.1. Normative References.................................25
13.2. Informative References...............................26
1. Introduction
Proxy Mobile IPv6 [RFC5213] can allow the Mobility Access Gateway
(MAG) to optimize the media delivery by locally routing the packets
within one MAG and by not reverse tunneling them to the mobile node's
local mobility anchor (LMA). However it does not address the case of
routing optimization between two MAGs sharing the same LMA or
registering to the different LMA. The capability for local routing
optimization provided in [RFC5213] requires the MAG to support the
EnableMAGLocalRouting flag and allow the MAG to control local routing
optimization behavior. However, [RFC5213] does not define how local
routing optimization capability is detected, who initiates local
routing optimization and how to negotiate between the MAG and the LMA
to determine whether the local routing optimization is allowed.
This document defines a local routing optimization mobility messages
or options for proxy mobile ipv6 that is intended to assist the MAGs
to negotiate and setup local routing path between each other. The new
local routing optimization mobility options included in each binding
update or local routing optimization messages exchange is used to
negotiate between the LMA and the MAG whether and what local routing
is allowed. Different from the local forwarding control message
described in the [I-D.LocalFwd], the local routing optimization
messages can be initiated by either of pmip6 managed node and provide
flexible negotiation mechanism for local routing. As [RFC5213] warns,
use of local routing may affect accounting and traffic policies
relating to the mobile node, LMA routing policies, and security
policies. The general aim of the proposals in this document is to
provide better manageability of mobility services and mobility
service provisioning from the point of view of both operators and
service providers within one PMIPv6 domain.
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2. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC-2119
The document uses the terminology specified in [RFC5213] and in
[RFC3775]. In addition, this document defines the following:
Local routing: Traffic between MN and CN does not pass through LMA
and is locally routed in the same PMIPv6 domain.
Local Routing Optimization Request (LROREQ): A message initiated by
the MAG or LMA requesting the MAG to establish local routing
optimization for a pair of MNs who communicate with each other.
Local Routing Optimization Response (LRORSP): A reply message from
the MAG or LMA to confirm local routing optimization results.
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3. Scenarios analysis for PMIP6 local routing
Figure 1 shows the reference architecture for PMIP6 local routing. In
this architecture, the local communication between PMIPv6 managed
nodes is constrained within a single PMIPv6 domain. LMA1 and LMA2
which MN and CN are respectively anchored to may be the same LMA or
different LMAs in the same PMIPv6 domain. With IPv4 transport support,
+---------+
============|LMA1/LMA2|============
// +---------+ \\
|| ||
+-----+ ||
| NAT | +-----------+
+--+-----+--+ | IPv4/IPv6 |
| IPv4 | | Network |
| Network | +-----------+
+-----------+ ||
|| ||
|| +-----------+ ||
+------+ |IPv4/IPv6 +---+ +------+
| MAG1 |===================|NAT|=====| MAG2 |
+------+ | Network +---+ +------+
| | +-----------+ | |
+-----+ +-----+ +-----+ +-----+
| | | |
+----+ +-----+ +-----+ +-----+
| MN | | CN1 | | CN2 | | CN3 |
+----+ +-----+ +-----+ +-----+
{IPv4-MN-HoA1} {IPv4-CN1-HoA2} {IPv4-CN2-HoA3} {IPv6-CN3-HoA4}
{IPv6-MN-HoA1} {IPv6-CN2-HoA3}
Figure 1: Reference architecture for PMIP6 local routing
the NAT may exist between MAG1 and MAG2 or between the LMA1 and LMA2.
Depending on how MN and CN are distributed into one PMIP6 domain,
three typical scenarios need to be considered as follows:
Scenario 1: Intra-MAG local routing
In this scenario, MN and CN attach to the same MAG and are anchored
with the same LMA or different LMAs.
Scenario 2: Intra-LMA local routing
In this scenario, MN and CN attach to the different MAGs and are
anchored with the same LMA.
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Scenario 3: Inter-LMA local routing
In this scenario, MN and CN attach to the different MAGs and are
anchored with the different LMAs.
In all the above scenarios, although all the PMIP6 managed node are
constrained in the same PMIP6 domain, however MN and CN may be
roaming user and their subscription may belong to the different
operators described in [I-D.wu-netext-pmipv6-ipv4-ro-ps], e.g.,
roaming user MN moves to the visited network owned by the operator
using IPv4 transport where no-roaming CN is located. Another example
is roaming user MN and CN move to the same visited network and use
the different LMAs within the same PMIP6 domain.
4. Local routing optimization protocol overview
The protocol specified here assumes that the MAG and the LMA are
situated in one PMIP domain and MN and CN attach to the same MAG or
MN and CN are anchored with the same LMA.(i.e., intra-MAG local
routing or intra-LMA local routing occurs). The MAG has the
capability to perceive intra-MAG local routing (i.e., in the intra-
MAG local routing scenario, the MAG can detect whether the mobile
node and correspondent node attach to the same MAG by checking
binding update list). The LMA has the capability to perceive intra-
LMA local routing (i.e., in the intra-LMA local routing scenario, the
LMA can detect whether the MAGs to which MN and CN are attach belong
to the same or different LMAs by checking its binding cache list).
The flag EnableDetectLocalRouting on the MAG and LMA may be used to
control this behavior. The decision to enable/disable detection of
local routing should be based on the policy configured on the MAG or
LMA. The specific details on how this is achieved are beyond of the
scope of this document. Subsequently there are two modes in which the
local routing optimization protocol operates.
4.1. MAG initiated local routing optimization
When the EnableDetectLocalRouting is enabled in the MAG, the MAG can
start to detect whether the MN and CN attach to the same MAG by
checking binding List of MN and CN.
Upon the MAG intercept the packet from the MN and perceives MN and CN
attach to the same MAG, it can initiate local routing optimization to
determine the value of the intra-MAG localrouting flag (defined in
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section 5) by message exchange between the MAG and LMA (If the MAG
attached by the MN and CN register to the different LMAs, it needs to
initiate local routing optimization to the different LMAs
respectively). When the MAG perceives intra-MAG local routing is not
possible but want to check whether intra-LMA routing is allowed, it
also can initiate the local routing optimization by message exchange
between the MAG and LMA. The message may be an binding update message
which contains the local routing optimization mobility option and
home network prefix option for the correspondent node or a newly
defined local routing optimization message. It will be used to
negotiate with LMA to determine whether or what the local routing
optimization between the mobile node and correspondent node is
supported. The AAA server can be used to authorize the use of
localized routing serice for MN. If the AAA sever does not authorize
the use of localized routing service or the LMA does not allow the
MAG bypass traffic from itself, it will respond to the MAG that the
local routing optimization is not available. Otherwise it will set
the intra-MAG locarouting or intra-LMA localrouting flag on the MAG
into value one in the successful response message.
After successful local routing optimization process, if MN and CN
attach to the different MAGs, i.e., MAG1, MAG2, the MAG1 to which the
MN attaches may send PBU message to the MAG2 which the CN attaches to.
The PBU/PBA signaling is protected using IPsec Encapsulation security
payload [RFC4303]in transport mode with mandatory integrity
protection. This PBU message sets the lifetime of the binding of MN
at MAG2. Similarly the MAG2 sends PBU message to the MAG1. This PBU
message sets the lifetime of the binding of CN at MAG1. Each PBU MUST
be acknowledged with PBAs. With PBU/PBA exchange, the local data path
between MAGs is established. Also PBU-PBA exchange is repeated to
extend the lifetime of the binding.
For the data traffic, either of the MAGs can lookup local routing
flag and process traffic in terms of the value of Localrouting flag.
If the Intra-MAG Localrouting flag is set to value one, the traffic
from MN will go directly to CN via MAG. If the Intra-LMA localrouting
flag is set to value one, the traffic from MN will be forwarded
directly to the MAG associated with the CN.
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+--+ +------+ +-----+ +------+ +--+
|MN| | MAG1 | | LMA | | MAG2 | |CN|
++-+ +--+---+ +--+--+ +--+---+ +-++
Attach to MAG1 | |Attach to MAG2
|---------->| | <------------+
| Datagram | PBU'/LROREQ | | |
|==========>|(MN-CN Pair) | | |
| |------------->| | |
| | +---+-----+ | |
| | |BCE Check| | |
| PBA'/LRORSP|---------+ | |
| | [MAG2] | | |
| |<------------ | | |
| +-------+---------+ | | |
| |Enable Intra-LMA/| | | |
| |intra-MAG Routing| | | |
| +-------+---------+ | | |
| Bidirectional PBU/PBA between MAGs |
| |<--------------------------->| |
| +-------------+ | +-------------+ |
| |Setup Binding| | |Setup Binding| |
| |and Tunnel | | | and Tunnel | |
| +-------------+ | +-------------+ |
| Datagram | Datagram | Datagram |
|==========>|============================>|===========>|
| Datagram | Datagram | Datagram |
|<==========|<=============|==============|<===========|
| | | | |
| | | | |
Figure 2: MAG Initiated Local routing optimization
4.1.1. Handover Consideration
In case of handover when the MN moves from the old MAG (e.g., pMAG1)
in the previous access network to the new MAG(e.g., nMAG1) in the new
access network, registration entry for MN in pMAG1's Binding update
list should be transferred to the nMAG1. The context request option
defined in the [I-D.ietf-mipshop-pfmipv6] can be reused here to carry
the context information on MAG1. And the new MAG(i.e., nMAG1) sends
PBUs to each MAG with which MN was in communication via local route
optimization path established. This PBU/PBA exchange updates the
binding in each MAG with which MN was in communication and re-
establishes optimal local route path between MN and its CNs.
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+-----+ +---------+ +---------+
|pMAG1| |nMAG1(MN)| | MAG2(CN)|
+--+--+ +---+-----+ +---+-----+
| | |
| HI/HACK | |
|<--------------->| |
|Predictive/Reactive |
| |Bidirectional PBU/PBA|
| |<------------------> |
| | |
| +------+------+ +-----+-------+
| |UpdateBinding| |UpdateBinding|
| | and Tunnel | | and Tunnel |
| +------+------+ +-----+-------+
| | Datagram |
| |<===================>|
Figure 3: MAG initiated Local routing during handover
4.2. LMA initiated local routing optimization
When the EnableDetectLocalRouting is enabled in the LMA, the LMA can
start to detect whether the MN and CN register to the same LMA by
checking binding List of MN and CN. Upon receiving the packet from
the CN and perceiving MN and CN register to the same LMA, it can
initiate local routing optimization to determine the value of Intra-
LMA localrouting flag (defined in section 5) and notify it to the MAG
by message exchange between the MAG and LMA. The message could be
proxy binding update message which contain local routing optimization
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mobility option or a newly defined routing optimization message. It
will be used to help LMA to determine whether or not the local
routing optimization is allowed and enforce the local optimization
on the MAG. The AAA server serving LMA can be used to authorize the
use of localized routing serice for MN. If the AAA sever does not
authorize the use of localized routing service or If the LMA verifies
there exists binding cache list of correspondent node and mobile node
and allow the MAG bypass traffic between mobile node and
correspondent node
from itself, it will notify the MAG to set the intra-LMA Localrouting
flag into value one, otherwise, it will respond to MAG with failure
information which indicate the intra-LMA routing optimization is not
supported. The other procedures are same as that of section 4.1.
+--+ +------+ +-----+ +------+ +--+
|MN| | MAG1 | | LMA | | MAG2 | |CN|
++-+ +--+---+ +--+--+ +--+---+ +-++
Attach to MAG1 | |Attach to MAG2
|---------->| +-------+----------+ <------------+
| | | BCE Check | | |
| | |Perceive MAG1 and | | |
| | |MAG2 register to | | |
| | |the same LMA | | |
| | +-------+----------+ | |
| | LROREQ | | |
| | (MAG2) | | |
| |<------------ | | |
| +-------+---------+ | | |
| |Enable Intra-LMA/| | | |
| | Routing | | | |
| +-------+---------+ | | |
| LRORSP | | |
| |------------->| | |
| Bidirectional PBU/PBA between MAGs |
| |<--------------------------->| |
| +-------------+ | +-------------+ |
| |Setup Binding| | |Setup Binding| |
| | and Tunnel | | | and Tunnel | |
| +-----+-------+ | +-----+-------+ |
| Datagram | Datagram | Datagram |
|==========>|============================>|===========>|
| Datagram | Datagram | Datagram |
|<==========|<============================|<===========|
Figure 4: LMA Initiated Local routing optimization
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4.2.1. Handover Consideration
In case of handover when the MN moves from the old MAG (e.g., MAG1)
in the previous access network to the new MAG(e.g., MAG3) in the new
access network, MAG1 may request LMA by sending PBU or LROREQ to
update binding of each MAG with which MN was in communication via
local route optimization path established. Also MAG1 can use the
similar procedure described in the section 4.1.1 to transfer MN's
registration entry on MAG1 to the new MAG (i.e., MAG3).
+-----+ +---------+ +----------+ +---------+
|pMAG1| |nMAG1(MN)| |LMA(MN,CN)| | MAG2(CN)|
+--+--+ +---+-----+ +----+-----+ +---+-----+
| | Normal PBU | |
| |-------------->| |
| | | |
| | Normal PBA | |
| |<------------- | LRQREQ |
| | |-------------->|
| | | |
| | | LRORSP |
| | |<------------- |
| Bidirectional PBU/PBA between MAGs
| |<----------------------------->|
| +------+------+ | +-----+-------+
| |UpdateBinding| | |UpdateBinding|
| | and Tunnel | | | and Tunnel |
| +------+------+ Datagram +-----+-------+
| |<=============================>|
| | | |
Figure 5: LMA initiated Local routing optimization during handover
5. Process consideration
5.1. Mobile Access Gateway Consideration
The MAG may include the routing optimization mobility option and the
correspondent node's home network prefix option into binding update
message or create a new routing optimization request message in which
the above two options are contained. The routing optimization
mobility option is used to negotiate which kind of local routing
optimization is available. The correspondent node's home network
prefix option is used for the LMA to verify the validity of local
routing optimization path end points (in the intra-MAG local routing
scenario) or to request the LMA to determine proxy CoA-Address of
correspondent node for local routing optimization (in the intra-LMA
local routing scenario). In the intra-MAG local routing case, LRI
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field in routing optimization mobility option is set into value 1
while in the intra-LMA local routing case, LRI field in routing
optimization mobility option is set into value 0 for mobile node's
MAG does not know whether traffic between MN and CN can be locally
routed within one LMA.
If the MAG receives binding acknowledge message with routing
optimization mobility option or routing optimization response message,
it will extract the LRI field from the routing optimization mobility
option or routing optimization response message and check the value
of it. If LRI field is 0, it indicates the LMA does not support this
local routing optimization and the MAG should set intra-MAG
LocalRouting flag to value 0 in the binding update list extension; if
LRI field is 1, it indicates the LMA allow local routing in one MAG
and bypass the LMA and MAG should set intra-MAG LocalRouting flag to
value 1 in the binding update list extension, if LRI field is 2, it
indicates LMA has find correspondent node's MAG address in terms of
home network prefix of CN and MAG should extract correspondent node's
MAG address from initial binding acknowledge message or routing
optimization response message and store it in binding update list
extension with correspondent node's home network prefix.
Upon the intra-MAG Localrouting flag or intra-LMA Localrouting flag
setup at the MAGs, one MAG may send the proxy binding update message
to another MAG to establish corresponding binding cache associated
with the MN and CN. Upon receiving Proxy Binding Update message, the
MAG checks if the LocalRouting flag is set to one. If the
LocalRouting flag is not set to one, the MAG MUST reject the request
and send a Proxy Binding Acknowledgement message with the status
field set to 129 (administratively prohibited).
Upon accepting Proxy Binding Update request, the MAG MUST create a
Binding Cache entry. The Source address of Proxy Binding Update is
copied to Proxy CoA field of the binding cache entry. The Mobile
node data (MN- Identifier, link-layer identifier, link-local address,
home network prefixes, etc.) are copied from the corresponding
fields of the proxy binding update.
Upon accepting Proxy Binding Update request for the first time from
another MAG, the MAG MUST establish a bi-directional tunnel between
the two MAGs. The tunnel endpoints are the Proxy-CoA of this mobile
access gateway and the Proxy-CoA of the mobile access gateway that
sent Proxy Binding Update as can be obtained from the source address
of Proxy Binding Update. This tunnel should be deleted when there
are no mobile nodes sharing it or when mobile access gateway receives
RORQ message from local mobility anchor with lifetime set to zero.
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When using IPv4 transport, the endpoints of the bi-directional tunnel
are IPv4-Proxy-CoA of the mobile access gateway that sent Proxy
Binding Update as can be obtained from the source address of Proxy
Binding Update and IPv4-Proxy-CoA of this mobile access gateway with
the encapsulation mode as specified in [I-D.ietf-netlmm-pmip6-ipv4-
support].
For the data traffic between the MN and CN, on receiving a packet
from a mobile node connected to its access link, to a destination
that is directly connected or not directly connected, the MAG will
lookup local routing flag and process traffic in terms of intra-MAG
Localrouting flag or intra-LMA Localrouting flag. If the Intra-LMA
LocalRouting flag is set to one and the destination address matches
one of the home network prefixes in the binding cache, the packet
must be forwarded to the Proxy CoA field in the binding cache entry
as a tunneled packet. For the packet from a mobile node connected to
its access link,to a destination that is also directly connected to
the same access link, if the intra-MAG Localrouting flag is set to
one, the packet must go directly via the MAG.
5.2. Local Mobility Anchor Consideration
For the case where the MAG initiates local routing, upon receiving
binding update message or routing optimization request message, the
LMA will check LRI field in the routing optimization mobility option
or routing optimization message. If LRI field is 1, the LMA will
check whether there exists binding cache list for CN and whether MN's
proxy CoA address is same as CN's proxy CoA address. If LRI field is
0 and correspondent node's home network prefix included, the LMA will
check whether there exists binding cache list for CN in terms of the
correspondent node's home network prefix. If does, the LMA will
respond to the MAG with LRI field set to value 2. Otherwise, the LMA
will respond to the MAG with LRI field set to 0 in the routing
optimization mobility option to indicate the MAG that the local
routing optimization is not available. For the case where the LMA
initiates local routing, upon perceiving intra-LMA routing, the LMA
sends routing optimization request message with the LRI field set to
value 2. And then the LMA receives routing optimization reply message
from the corresponding MAG.
6. IPv4 support
IPv4 support is needed in two cases:
MN is IPv4 enabled and receives IPv4 home address and
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The transport network between the LMA and the MAG is an IPv4
network.
In both two cases, the encapsulation mode as described in [I-
D.draft-netlmm-pmip6-ipv4-support] and NAT existing between the MAGs
attached by the MN and CN respectively are transparent to the MAG
concerned before setting up the localized routing path. This may
result in data packets are dropped by the NAT between the concerned
MAGs or the egress tunnel end point, i.e., the MAG.
So local route optimization can be supported only if the
encapsulated mode is aware and NAT Box is detected during setting up
the localized routing path.
6.1. IPv4 HoA support
In case MN is IPv4 enabled and receives IPv4 home address, both the
MN and the CN configure global IPv4 home addresses by exchanging
PBU/PBA as explained in [I-D.ietf-netlmm-pmip6-ipv4-support] with
the LMA.
The LMA MUST include IPv4 IPv4-MN-HoA in local routing optimization
messages for both MN and CN. The LMA MAY include Home Network Prefix
in PBA if the MN or CN is assigned Home Network Prefix. Both local
routing optimization request and local routing optimization response
messages are IPv6 messages and are transported over LMA-MAG tunnel
as PBU and PBA are transported.
The PBU and PBA exchanged between the MAGs are IPv6 messages and are
transported as unencapsulated IPv6 messages between MAGs. Various
encapsulation modes described in the [I-D.ietf-netlmm-pmip6-ipv4-
support] can be used in PBU and PBA and encapsulation mode
negotiation between the MAGs is required If the MAGs in
communication support different encapsulation mode. For
simplification, we can assume the MAGs in communication are using
the default encapsulation mode. Data traffic between the MAGs after
local routing is established are transported in IPv6 inner packet as
IPv4 payload.
6.2. IPv4 transport support
In case IPv4 transport is used between the MAG and the LMA, LROREQ,
LRORSP, PBU and PBA messages are transported as IPv6 messages using
IPv4 or IPv4-UDP or IPv4-UDP-TLV encapsulation [I-D.ietf-netlmm-
pmip6-ipv4-support].
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IPv4 data packets are transported in an IPv4 packet or encapsulated
in IPv4-UDP/IPv4-UDP-TLV encapsulation. The NAT Detection option
defined in [I-D.ietf-mext-nemo-v4traversal] can be used in the PBU
and PBA between the MAGs to detect the on-path NAT device.
7. Inter-LMA Local routing Consideration
In this section we concentrate on the local routing case where MN
and CN are served by two different LMAs, in the same PMIPv6 domain
which is not covered by the section 4 i.e.,Inter-LMA local routing.
Two different cases is discussed below depending on who initiates
Localrouting.
7.1. MAG Initiated Inter-LMA local routing
The message exchange for the protocol is shown in Figure 6.
Local routing case is triggered at one of the MAGs, e.g. MAG1 when a
datagram is received on its upstream interface whose destination
address is a CN for which LMA2 has a binding cache entry. MAG1
request LMA2 address from LMA1 by sending LROREQ message contain CN
HNP or HoA to LMA1. LMA1 processes LROREQ message and lookup LMA2
address based on CN HNP or HoA. There are one possible ways to
achieve this goal.
a. MAG1 can exchange with AAA server to retrieve LMA2 address. MAG1
sends CN address and asks the address of LMA2 which CN is anchored
to. The AAA server responds LMA2 address to MAG1.
Upon retrieving LMA2 address, MAG1 then sends LROREQ message
containing MN-CN pairs defined in the section 9.5 to LMA2. LMA2
process LROREQ message and looks up MAG2 address based on CN HNP or
HoA extracted from the corresponding message.
In successful case, LMA2 responds to the MAG1 with MAG2 address
corresponding to CN.
MAG1 and MAG2 exchange PBU/PBA to establish binding cache list
between each other and direct path between MAG1 and MAG2 is setup.
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+------+ +----------+ +---------+ +------+
| MAG1 | | LMA1(MN) | | LMA2(CN)| | MAG2 |
+---+--+ +----+-----+ +----+----+ +---+--+
| | | |
+----+----+ | | |
| LMA2 | | | |
|Discovery| | | |
+----+----+ | | |
| LROREQ(MN,MAG1,CN) | |
|------------------------------->| |
| LRORSP(CN,MAG2) | |
|<-------------------------------| |
| | | |
|<------------MAGs Exchange PBU/PBA-------------->|
| | | |
Figure 6: MAG Initiated Inter-LMA Local routing
7.2. LMA Initiated Inter-LMA local routing
The message exchange for the protocol is shown in Figure 7.
Inter-LMA Local routing is triggered at one of the
LMAs, e.g. LMA1 when a datagram is received on its upstream
interface whose destination address is a MN, e.g. MN1 for which LMA1
has a binding cache entry. From the binding cache entry, LMA1
determines the MAG address, e.g. MAG1 (Proxy-CoA1). LMA1 checks the
source address to find out if the datagram is coming from a MN
located in the same PMIPv6 domain and if yes, its MAG address, e.g.
MAG2 (Proxy-CoA2). There are several ways for doing this and the
exact means is out of scope with the document. Below we will mention
two different ways.
a. LMAs in the same PMIPv6 domain are configured with a table
containing a list of /48, /32, etc. prefixes and the corresponding
LMA address for all the LMAs in the domain. LMA1 searches this
table doing a longest prefix match based on the prefix part of the
source address of MN2 and finds the corresponding LMA2 address.
b. LMA1 can exchange with the AAA server to retrieve LMA2 address.
LMA1 sends MN2 address and asks LMA address this MN is attached to.
LMA1 receives LMA2 address and MAG address (Proxy-CoA2) from AAA
server, e.g.DIAMETER server.
LMA1 sends LMAROStartRequest message to LMA2. LMAROStartRequest
message contains MN1 and MN2 address and MAG1 address (Proxy-CoA1).
MAG2 address is set to zero. LMA2 searches its BCE for MN2 and
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determines MAG2 address (Proxy-CoA2). LMA2 sends LMAROStartResponse
message to LMA1. LMAROStartResponse message contains MN1 and MN2
address and MAG1 address (Proxy-CoA1) and MAG2 address (Proxy-CoA2).
LMA1 sends LROREQ message to MAG1 at Proxy-CoA1.
LROREQ message contains MN address and Proxy- CoA1 and CN
address, e.g. MN2 and Proxy-CoA2. LMA2 sends LROREQ message
to MAG2 at Proxy-CoA2. LROREQ message contains CN address,
e.g. MN2 and Proxy-CoA2 and MN address, e.g. MN1 and Proxy-CoA1.
LROREQ messages enable both MAGs to modify their Binding
Update Lists. The two MAGs respond LROREQ with LRORSP
messages.
The two MAGs, MAG1 and MAG2 exchange PBU/PBAs as described in
Section 4.
+------+ +----------+ +---------+ +------+
| MAG1 | |LMA1(MN1) | |LMA2(MN2)| | MAG2 |
+---+--+ +----+-----+ +----+----+ +---+--+
| | | |
| | LMAROStartReq | |
| |-------------->| |
| | | |
| | LMARoStartRsp | |
| |<------------- | |
| LROREQ | | LROREQ |
|<---------------| |--------------->|
| | | |
| LRORSP | | LRORSP |
|--------------->| |<-------------- |
| | | |
|<--------------MAGs exchange PBU/PBA------------>|
| | | |
| | | |
Figure 7: Local routing with Two LMAs involvement
7.2.1. IPv4 Support Consideration
IPv4 support presented in Section 8 also applies here. In addition,
we discuss IPv4 support issues related to LMAROStartRequest and
LMAStartResponse messages. LMAROStartRequest and LMAStartResponse
messages are IPv6 messages. These messages are transported in IPv6
because LMAs support IPv6 and there is IPv6 transport established
among LMAs in the same PMIPv6 domain.
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8. Conceptual Data Structure Extension
8.1. Binding Update List Extension
Every mobile access gateway maintains a Binding Update List. Each
Entry in the Binding Update List represents a mobile node's mobility
binding with its local mobility anchor, as described in Section 6.1
of the PMIPv6 specification [RFC5213]. This specification extends the
Binding Update List Entry data structure with the following
additional fields:
Intra-MAG LocalRouting Flag indicating whether the media delivery
optimization is allowed by locally routing the packets within one MAG.
The flag is set to value 1 for local media delivery optimization is
allowed and vice versa.
Intra-LMA LocalRouting Flag indicating whether the media delivery
optimization is allowed by locally routing the packets from one MAG
to another within one LMA. The flag is set to value 1 for local media
delivery optimization is allowed and vice versa.
Inter-LMA LocalRouting Flag indicating whether the media delivery
optimization is allowed by locally routing the packets from one MAG
served by one LMA to another MAG served by the different LMA. The
flag is set to value 1 for local media delivery optimization is
allowed and vice versa.
Home network prefix assigned to Correspondent Node
Proxy Care-of Address assigned to Correspondent Node
8.2. Binding Cache Entry Extension
Every local mobility anchor MUST maintain a Binding Cache entry for
each currently registered mobile node. For supporting this
specification, the Binding Cache Entry data structure needs to be
extended with the following additional field:
Inra-LMA LocalRouting Flag indicating whether the media delivery
optimization is allowed by locally routing the packets from one MAG
to another within one LMA. The flag is set to value 1 for local media
delivery optimization is allowed and vice versa.
Inter-LMA LocalRouting Flag indicating whether the media delivery
optimization is allowed by locally routing the packets from one MAG
served by one LMA to another MAG served by the different LMA. The
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flag is set to value 1 for local media delivery optimization is
allowed and vice versa.
9. Local routing optimization message format
9.1. Local Routing optimization mobility option
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = TBD | Length | Reserved |LRI~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8. Local Routing Optimization Mobility Option
Type TBD
Length
8-bit unsigned integer indicating the length of the option in octets,
excluding the type and length fields. This field MUST be set to 2.
Reserved (R)
This 8-bit field is unused for now. The value MUST be initialized to
0 by the sender and MUST be ignored by the receiver.
Local Routing Optimization Indication (LRI)
00: Routing optimization state is unknown or routing optimization is
not available.
01: The value of Intra-MAG LocalRouting
10: The value of Intra-LMA LocalRouting
11: The value of Inter-LMA LocalRouting
9.2. Local Routing optimization Request message(LROREQ)
The Local Routing optimization Request message is used by one PMIP6
managed node (e.g., LMA or MAG) to negotiate with another PMIP6
managed node(e.g., MAG or LMA) whether and what local routing is
allowed.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence # |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R|LRI| Reserved | Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. Mobility options .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 9. Local Routing Optimization Request Message
Sequence Number: A monotonically increasing integer. Set by a sending
node in a request message, and used to match a reply to the request.
'R' flag: Set to 0, indicates it is an routing optimization request
message.
Local Routing Optimization Indication (LRI)
00: Routing optimization state is unknown or routing optimization is
not available
01: The value of Intra-MAG LocalRouting
10: The value of Intra-LMA LocalRouting
11: The value of Inter-LMA local routing
Lifetime: The requested time in seconds for which the sender wishes
to have local routing.
9.3. Local Routing optimization Response Message(LRORSP)
The Local Routing optimization Response message is used to
acknowledge the receipt of a Local Routing optimization Request
message described in Section 9.2.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence # |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R|LRI| Reserved | Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. Mobility options .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 10. Local Routing Optimization Response Message
Sequence Number: A monotonically increasing integer. Set by a sending
node in a request message, and used to match a reply to the request.
'R' flag: Set to 0, indicates it is an routing optimization request
message. Set to 1, indicates it is an routing optimization response
message.
Local Routing Optimization Indication (LRI)
00: Routing optimization state is unknown or routing optimization is
not available.
01: The value of Intra-MAG LocalRouting
10: The value of Intra-LMA LocalRouting
11: The value of Inter-LMA Localrouting
Lifetime: The requested time in seconds for which the sender wishes
to have local routing.
Mobility options: local Routing optimization mobility option
described in section 9.1 and MN-CN pair mobility option described in
section 9.4 can be included.
9.4. Context Request Option
The details is defined in the section 6.2.1 of [I-D.ietf-mipshop-
pfmipv6].
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9.5. MN-CNs pair mobility option
A new option, MN-CNs pair mobility option is defined for use with the
local Route Optimization Request and local Response messages exchanged
between LMA and MAGs. This option is used by the PMIP6 managed node to
enable local routing for MN to CNs path from the destination MAG that
receives the request message towards CNs connected a different MAG
whose addresses are given in option. The option MUST be used in pairs
including one MN, one or many CNs in communication with MN. The order
is important. The LMA places the data for MN to which the destination
MAG is connected first.
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |P| Reserved |Prefix Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Home Network Prefix +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Proxy CoA +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 HoA |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Proxy CoA |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 11. MN-CN pair mobility option
P Flag
P flag is set for IPv4 support. When set IPv4 HoA and IPv4 Proxy CoA
fields must be included for MN or CN.
Reserved
This 7-bit field is unused for now. The value MUST be initialized
to 0 by the sender and MUST be ignored by the receiver.
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Prefix Length
8-bit unsigned integer indicating the prefix length of the IPv6
prefix contained in the option.
Home Network Prefix
A sixteen-byte field containing the mobile or corresponding node's
IPv6 Home Network Prefix.
Proxy CoA
A sixteen-byte field containing the global address configured on the
egress interface of the mobile access gateway to which the mobile
or corresponding node is connected.
IPv4 HoA
Optional 32-bit field containing IPv4 home address of the mobile or
corresponding node.
IPv4 Proxy CoA
Optional 32-bit field containing IPv4 address that is configured on
the egress-interface of the mobile access gateway.
9.6. LMA Route Optimization Start Request Message
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number | Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. Mobility Options .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 12. LMA Route Optimization Start Request Message
A new MH type should be assigned by IANA.
Sequence Number
16-bit unsigned integer. The LMA uses this field to match a
returned LMAROStartRsp message. The LMA also uses this field to
identify each new pairs of MN-CN to start local routing if the LMA
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received LMAStartRORsp message.
Reserved
This field is unused. It should be initialized to zero by the
sender and MUST be ignored by the receiver.
Lifetime
16-bit unsigned integer. If non zero, this fields indicates
initial lifetime of MN to CN route optimization binding. If there
are several MN-CN pairs, the same lifetime applies to each pair.
Mobility Options
As defined in section 6.1.7 in [RFC3775].
This document defines a new mobility option: MN-CN RO option in
Section 6.4. The sending LMA sends a pair of MN-RO Options. LMA sets
Home Network Prefix value of the first MN-RO Option to HNP for MN and
Proxy-CoA value to Proxy-CoA1. The LMA sets Home Network Prefix
value of the second MN-RO Option to HNP of CN and Proxy-CoA value to
zero.
9.7. LMA Route Optimization Start Response Message
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. Mobility options .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 13. LMA Route Optimization Start Response Message
A new MH type should be assigned by IANA.
Status
An 8-bit unsigned integer indicating the disposition of
LMAROStartReq message by the receiving LMA. Values less than 128
indicate that ROStartReq message was accepted by the LMA. Values
greater than 128 indicate that LMAROStartReq message was rejected
by LMA.
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Sequence number and Lifetime fields are as defined above for
LMAROStartReq message.
Mobility Options contain pairs of MN-CN RO Option as defined in
Section 6.4. The LMA must copy this field from LMAROStartReq message
when status field contains a value indicating success. The LMA MUST
search its binding cache for the Home Network Prefix value of CN and
find the corresponding MAG address, e.g. Proxy-CoA2. Th LMA MUST
replace MAG address field set to zero by the sending LMA with Proxy-
CoA2.
10. Security Considerations
The protocol specified in this document can use the security
association between the LMA and the MAG to create security
association between MAGs to which MN and CN attach in the intra-LMA
local routing scenario. As regarding intra-MAG local routing
scenario, integrity protection can be considered and confidentiality
using IPsec is not necessary.
11. IANA Considerations
This document has no actions for IANA.
12. Acknowledgement
The authors would like to thank Tom Taylor, Kent Leung, Sri
Gundavelli, Jouni Korhonen for their review and comments of this
draft and all colleagues who have supported the advancement of this
draft effort.
13. References
13.1. Normative References
[RFC3775] Johnson, D. and al. et, "Mobility Support in IPv6", RFC3775,
June 2004
[RFC5213] Gundavelli, S. and al. et, "Proxy Mobile IPv6", RFC5213,
May 2008.
[RFC4303] Kent,S.,"IP Encapsulation Security Payload(ESP)",RFC4303,
December 2005.
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[I-D.ietf-netlmm-pmip6-ipv4-support]
Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy
Mobile IPv6", draft-ietf-netlmm-pmip6-ipv4-support-09 (work
in progress), January 2009.
[I-D.ietf-mipshop-pfmipv6]
Yokota,H.,Chowdhury,K.,Koodli,R.,Patil,B.,Xia,F.,"Fast
handover for Proxy Mobile IPv6",draft-ietf-mipshop-pfmipv6-
05(work in progress),June,2009
13.2. Informative References
[I-D.LocalFwd]
Koodli,R., Chowdhury,K. "Local Forwarding in Proxy Mobile
IPv6", draft-koodli-netlmm-local-forwarding-00, July 2008
[I-D.liebsch-netext-pmip6-ro-ps]
Liebsch, M., "PMIPv6 Localized Routing Problem Statement",
draft-liebsch-netext-pmip6-ro-ps-00 (work in
progress),February 2009.
[I-D.wu-netext-pmipv6-ipv4-ro-ps]
Wu,Q., Korhonen, J.," Problem Statement of IPv4 Support for
PMIPv6 Localized Routing", draft-wu-netext-pmipv6-ipv4-ro-
ps-01 (work in progress),June 2009.
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Authors' Addresses
Qin Wu
Huawei Technologies Co.,Ltd
Site B,Floor 12F,Huihong Mansion,No.91,Baixia Rd.
Nanjing 210001
China
Email: Sunseawq@huawei.com
Behcet Sarikaya
Huawei Technologies Co.,Ltd
1700 Alma Dr.Suite 500
Plano, TX 75075
USA
Email: sarikaya@ieee.org
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