Internet DRAFT - draft-ietf-dmm-pmipv6-dlif
draft-ietf-dmm-pmipv6-dlif
DMM Working Group CJ. Bernardos
Internet-Draft A. de la Oliva
Intended status: Experimental UC3M
Expires: September 9, 2020 F. Giust
Athonet
JC. Zuniga
SIGFOX
A. Mourad
InterDigital
March 8, 2020
Proxy Mobile IPv6 extensions for Distributed Mobility Management
draft-ietf-dmm-pmipv6-dlif-06
Abstract
Distributed Mobility Management solutions allow for setting up
networks so that traffic is distributed in an optimal way and does
not rely on centrally deployed anchors to provide IP mobility
support.
There are many different approaches to address Distributed Mobility
Management, as for example extending network-based mobility protocols
(like Proxy Mobile IPv6), or client-based mobility protocols (like
Mobile IPv6), among others. This document follows the former
approach and proposes a solution based on Proxy Mobile IPv6 in which
mobility sessions are anchored at the last IP hop router (called
mobility anchor and access router). The mobility anchor and access
router is an enhanced access router which is also able to operate as
a local mobility anchor or mobility access gateway, on a per prefix
basis. The document focuses on the required extensions to
effectively support simultaneously anchoring several flows at
different distributed gateways.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on September 9, 2020.
Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. PMIPv6 DMM extensions . . . . . . . . . . . . . . . . . . . . 6
3.1. Initial registration . . . . . . . . . . . . . . . . . . 7
3.2. The CMD as PBU/PBA relay . . . . . . . . . . . . . . . . 8
3.3. The CMD as MAAR locator . . . . . . . . . . . . . . . . . 11
3.4. The CMD as MAAR proxy . . . . . . . . . . . . . . . . . . 12
3.5. De-registration . . . . . . . . . . . . . . . . . . . . . 13
3.6. Retransmissions and Rate Limiting . . . . . . . . . . . . 14
3.7. The Distributed Logical Interface (DLIF) concept . . . . 14
4. Message Format . . . . . . . . . . . . . . . . . . . . . . . 18
4.1. Proxy Binding Update . . . . . . . . . . . . . . . . . . 18
4.2. Proxy Binding Acknowledgment . . . . . . . . . . . . . . 19
4.3. Anchored Prefix Option . . . . . . . . . . . . . . . . . 19
4.4. Local Prefix Option . . . . . . . . . . . . . . . . . . . 21
4.5. Previous MAAR Option . . . . . . . . . . . . . . . . . . 22
4.6. Serving MAAR Option . . . . . . . . . . . . . . . . . . . 23
4.7. DLIF Link-local Address Option . . . . . . . . . . . . . 24
4.8. DLIF Link-layer Address Option . . . . . . . . . . . . . 25
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5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26
6. Security Considerations . . . . . . . . . . . . . . . . . . . 26
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 27
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 27
8.1. Normative References . . . . . . . . . . . . . . . . . . 27
8.2. Informative References . . . . . . . . . . . . . . . . . 28
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 28
1. Introduction
The Distributed Mobility Management (DMM) paradigm aims at minimizing
the impact of currently standardized mobility management solutions
which are centralized (at least to a considerable extent) [RFC7333].
Current IP mobility solutions, standardized with the names of Mobile
IPv6 [RFC6275], or Proxy Mobile IPv6 (PMIPv6) [RFC5213], just to cite
the two most relevant examples, offer mobility support at the cost of
handling operations at a cardinal point, the mobility anchor (i.e.,
the home agent for Mobile IPv6, and the local mobility anchor for
Proxy Mobile IPv6), and burdening it with data forwarding and control
mechanisms for a great amount of users. As stated in [RFC7333],
centralized mobility solutions are prone to several problems and
limitations: longer (sub-optimal) routing paths, scalability
problems, signaling overhead (and most likely a longer associated
handover latency), more complex network deployment, higher
vulnerability due to the existence of a potential single point of
failure, and lack of granularity of the mobility management service
(i.e., mobility is offered on a per-node basis, not being possible to
define finer granularity policies, as for example per-application).
The purpose of Distributed Mobility Management is to overcome the
limitations of the traditional centralized mobility management
[RFC7333] [RFC7429]; the main concept behind DMM solutions is indeed
bringing the mobility anchor closer to the Mobile Node (MN).
Following this idea, the central anchor is moved to the edge of the
network, being deployed in the default gateway of the mobile node.
That is, the first elements that provide IP connectivity to a set of
MNs are also the mobility managers for those MNs. In this document,
we call these entities Mobility Anchors and Access Routers (MAARs).
This document focuses on network-based DMM, hence the starting point
is making PMIPv6 work in a distributed manner [RFC7429]. Mobility is
handled by the network without the MNs involvement, but, differently
from PMIPv6, when the MN moves from one access network to another, it
may also change anchor router, hence requiring signaling between the
anchors to retrieve the MN's previous location(s). Also, a key-
aspect of network-based DMM, is that a prefix pool belongs
exclusively to each MAAR, in the sense that those prefixes are
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assigned by the MAAR to the MNs attached to it, and they are routable
at that MAAR. Prefixes are assigned to MNs attached a MAAR at that
time, but remain with those MNs as mobility occurs, remaining always
routable at that MAAR as well as towards the MN itself.
We consider partially distributed schemes, where only the data plane
is distributed among access routers similar to MAGs, whereas the
control plane is kept centralized towards a cardinal node used as
information store, but relieved from any route management and MN's
data forwarding task.
2. Terminology
The following terms used in this document are defined in the Proxy
Mobile IPv6 specification [RFC5213]:
Local Mobility Anchor (LMA)
Mobile Access Gateway (MAG)
Mobile Node (MN)
Binding Cache Entry (BCE)
Proxy Care-of Address (P-CoA)
Proxy Binding Update (PBU)
Proxy Binding Acknowledgement (PBA)
The following terms are used in this document:
Home Control-Plane Anchor (Home-CPA or H-CPA): The Home-CPA function
hosts the mobile node (MN)'s mobility session. There can be more
than one mobility session for a mobile node and those sessions may
be anchored on the same or different Home-CPA's. The home-CPA
will interface with the home-DPA for managing the forwarding
state.
Home Data Plane Anchor (Home-DPA or H-DPA): The Home-DPA is the
topological anchor for the MN's IP address/ prefix(es). The Home-
DPA is chosen by the Home-CPA on a session- basis. The Home-DPA
is in the forwarding path for all the mobile node's IP traffic.
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Access Control Plane Node (Access-CPN or A-CPN): The Access-CPN is
responsible for interfacing with the mobile node's Home-CPA and
with the Access-DPN. The Access-CPN has a protocol interface to
the Home-CPA.
Access Data Plane Node (Access-DPN or A-DPN): The Access-DPN
function is hosted on the first-hop router where the mobile node
is attached. This function is not hosted on a layer-2 bridging
device such as a eNode(B) or Access Point.
The following terms are defined and used in this document:
MAAR (Mobility Anchor and Access Router). First hop router where the
mobile nodes attach to. It also plays the role of mobility
manager for the IPv6 prefixes it anchors, running the
functionalities of PMIP's MAG and LMA. Depending on the prefix,
it plays the role of Access-DPN, Home-DPA and Access-CPN.
CMD (Central Mobility Database). The node that stores the BCEs
allocated for the MNs in the mobility domain. It plays the role
of Home-CPA.
P-MAAR (Previous MAAR). When a MN moves to a new point of attachment
a new MAAR might be allocated as its anchor point for future IPv6
prefixes. The MAAR that served the MN prior to new attachment
becomes the P-MAAR. It is still the anchor point for the IPv6
prefixes it had allocated to the MN in the past and serves as the
Home-DPA for flows using these prefixes. There might be several
P-MAARs serving a MN when the MN is frequently switching points of
attachment while maintaining long-lasting flows.
S-MAAR (Serving MAAR). The MAAR which the MN is currently attached
to. Depending on the prefix, it plays the role of Access-DPN,
Home-DPA and Access-CPN.
Anchoring MAAR. A MAAR anchoring an IPv6 prefix used by an MN.
DLIF (Distributed Logical Interface). It is a logical interface at
the IP stack of the MAAR. For each active prefix used by the MN,
the S-MAAR has a DLIF configured (associated to each MAAR still
anchoring flows). In this way, an S-MAAR exposes itself towards
each MN as multiple routers, one as itself and one per P-MAAR.
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3. PMIPv6 DMM extensions
The solution consists of de-coupling the entities that participate in
the data and the control planes: the data plane becomes distributed
and managed by the MAARs near the edge of the network, while the
control plane, besides those on the MAARs, relies on a central entity
called Central Mobility Database (CMD). In the proposed
architecture, the hierarchy present in PMIPv6 between LMA and MAG is
preserved, but with the following substantial variations:
o The LMA is relieved from the data forwarding role, only the
Binding Cache and its management operations are maintained. Hence
the LMA is renamed into CMD, which is therefore a Home-CPA. Also,
the CMD is able to send and parse both PBU and PBA messages.
o The MAG is enriched with the LMA functionalities, hence the name
Mobility Anchor and Access Router (MAAR). It maintains a local
Binding Cache for the MNs that are attached to it and it is able
to send and parse PBU and PBA messages.
o The binding cache will be extended to include information
regarding P-MAARs where the mobile node was anchored and still
retains active data sessions.
o Each MAAR has a unique set of global prefixes (which are
configurable), that can be allocated by the MAAR to the MNs, but
must be exclusive to that MAAR, i.e. no other MAAR can allocate
the same prefixes.
The MAARs leverage the CMD to access and update information related
to the MNs, stored as mobility sessions; hence, a centralized node
maintains a global view of the network status. The CMD is queried
whenever a MN is detected to join/leave the mobility domain. It
might be a fresh attachment, a detachment or a handover, but as MAARs
are not aware of past information related to a mobility session, they
contact the CMD to retrieve the data of interest and eventually take
the appropriate action. The procedure adopted for the query and the
message exchange sequence might vary to optimize the update latency
and/or the signaling overhead. Here is presented one method for the
initial registration, and three different approaches for updating the
mobility sessions using PBUs and PBAs. Each approach assigns a
different role to the CMD:
o The CMD is a PBU/PBA relay;
o The CMD is only a MAAR locator;
o The CMD is a PBU/PBA proxy.
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The solution described in this document allows performing per-prefix
anchoring decisions, to support e.g., some flows to be anchored at a
central Home-DPA (like a traditional LMA) or to enable an application
to switch to the locally anchored prefix to gain route optimization,
as indicated in [RFC8563]. This type of per-prefix treatment would
potentially require additional extensions to the MAARs and signaling
between the MAARs and the MNs to convey the per-flow anchor
preference (central, distributed), which are not covered in this
document.
Note that a MN may move across different MAARs, which might result in
several P-MAARs existing at a given moment of time, each of them
anchoring a different prefix used by the MN.
3.1. Initial registration
Initial registration is performed when an MN attaches to a network
for the first time (rather than attaching to a new network after
moving from a previous one).
In this description (shown in Figure 1), it is assumed that:
1. The MN is attaching to MAAR1.
2. The MN is authorized to attach to the network.
Upon MN attachment, the following operations take place:
1. MAAR1 assigns a global IPv6 prefix from its own prefix pool to
the MN (Pref1). It also stores this prefix (Pref1) in the
locally allocated temporary Binding Cache Entry (BCE).
2. MAAR1 sends a PBU [RFC5213] with Pref1 and the MN's MN-ID to the
CMD.
3. Since this is an initial registration, the CMD stores a BCE
containing as primary fields the MN-ID, Pref1 and MAAR1's address
as a Proxy-CoA.
4. The CMD replies with a PBA with the usual options defined in
PMIPv6 [RFC5213], meaning that the MN's registration is fresh and
no past status is available.
5. MAAR1 stores the BCE described in (1) and unicasts a Router
Advertisement (RA) to the MN with Pref1.
6. The MN uses Pref1 to configure an IPv6 address (IP1) (e.g., with
stateless auto-configuration, SLAAC).
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Note that:
1. Alternative IPv6 auto-configuration mechanisms can also be used,
though this document describes the SLAAC-based one.
2. IP1 is routable at MAAR1, in the sense that it is on the path of
packets addressed to the MN.
3. MAAR1 acts as a plain router for packets destined to the MN, as
no encapsulation nor special handling takes place.
In the diagram shown in Figure 1 (and subsequent diagrams), the flow
of packets is presented using '*'.
+-----+ +---+ +--+
|MAAR1| |CMD| |CN|
+-----+ +---+ +*-+
| | *
MN | * +---+
attach. | ***** _|CMD|_
detection | flow1 * / +-+-+ \
| | * / | \
local BCE | * / | \
allocation | * / | \
|--- PBU -->| +---*-+-' +--+--+ `+-----+
| BCE | * | | | | |
| creation |MAAR1+------+MAAR2+-----+MAAR3|
|<-- PBA ---| | * | | | | |
local BCE | +---*-+ +-----+ +-----+
finalized | *
| | Pref1 *
| | +*-+
| | |MN|
| | +--+
Operations sequence Packets flow
Figure 1: First attachment to the network
Note that the registration process does not change regardless of the
CMD's modes (relay, locator or proxy) described next. The procedure
is depicted in Figure 1.
3.2. The CMD as PBU/PBA relay
Upon MN mobility, if the CMD behaves as PBU/PBA relay, the following
operations take place:
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1. When the MN moves from its current point of attachment and
attaches to MAAR2 (now the S-MAAR), MAAR2 reserves an IPv6 prefix
(Pref2), it stores a temporary BCE, and it sends a PBU to the CMD
for registration.
2. Upon PBU reception and BC lookup, the CMD retrieves an already
existing entry for the MN, binding the MN-ID to its former
location; thus, the CMD forwards the PBU to the MAAR indicated as
Proxy CoA (MAAR1), including a new mobility option to communicate
the S-MAAR's global address to MAAR1, defined as Serving MAAR
Option in Section 4.6. The CMD updates the P-CoA field in the
BCE related to the MN with the S-MAAR's address.
3. Upon PBU reception, MAAR1 can install a tunnel on its side
towards MAAR2 and the related routes for Pref1. Then MAAR1
replies to the CMD with a PBA (including the option mentioned
before) to ensure that the new location has successfully changed,
containing the prefix anchored at MAAR1 in the Home Network
Prefix option.
4. The CMD, after receiving the PBA, updates the BCE populating an
instance of the P-MAAR list. The P-MAAR list is an additional
field on the BCE that contains an element for each P-MAAR
involved in the MN's mobility session. The list element contains
the P-MAAR's global address and the prefix it has delegated.
Also, the CMD sends a PBA to the new S-MAAR, containing the
previous Proxy-CoA and the prefix anchored to it embedded into a
new mobility option called Previous MAAR Option (defined in
Section 4.5), so that, upon PBA arrival, a bi-directional tunnel
can be established between the two MAARs and new routes are set
appropriately to recover the IP flow(s) carrying Pref1.
5. Now packets destined to Pref1 are first received by MAAR1,
encapsulated into the tunnel and forwarded to MAAR2, which
finally delivers them to their destination. In uplink, when the
MN transmits packets using Pref1 as source address, they are sent
to MAAR2, as it is MN's new default gateway, then tunneled to
MAAR1 which routes them towards the next hop to destination.
Conversely, packets carrying Pref2 are routed by MAAR2 without
any special packet handling both for uplink and downlink.
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+-----+ +---+ +-----+ +--+ +--+
|MAAR1| |CMD| |MAAR2| |CN| |CN|
+-----+ +---+ +-----+ +*-+ +*-+
| | | * *
| | MN * +---+ *
| | attach. ***** _|CMD|_ *
| | det. flow1 * / +-+-+ \ *flow2
| |<-- PBU ---| * / | \ *
| BCE | * / | *******
| check+ | * / | * \
| update | +---*-+-' +--+-*+ `+-----+
|<-- PBU*---| | | * | | *| | |
route | | |MAAR1|______|MAAR2+-----+MAAR3|
update | | | **(______)** *| | |
|--- PBA*-->| | +-----+ +-*--*+ +-----+
| BCE | * *
| update | Pref1 * *Pref2
| |--- PBA*-->| +*--*+
| | route ---move-->|*MN*|
| | update +----+
Operations sequence Data Packets flow
PBU/PBA Messages with * contain
a new mobility option
Figure 2: Scenario after a handover, CMD as relay
For MN's next movements the process is repeated except the number of
P-MAARs involved increases (accordingly to the number of prefixes
that the MN wishes to maintain). Indeed, once the CMD receives the
first PBU from the new S-MAAR, it forwards copies of the PBU to all
the P-MAARs indicated in the BCE, namely the one registered as
current P-CoA (i.e., the MAAR prior to handover) plus the ones in the
P-MAARs list. They reply with a PBA to the CMD, which aggregates
them into a single one to notify the S-MAAR, that finally can
establish the tunnels with the P-MAARs.
It should be noted that this design separates the mobility management
at the prefix granularity, and it can be tuned in order to erase old
mobility sessions when not required, while the MN is reachable
through the latest prefix acquired. Moreover, the latency associated
to the mobility update is bound to the PBA sent by the furthest
P-MAAR, in terms of RTT, that takes the longest time to reach the
CMD. The drawback can be mitigated introducing a timeout at the CMD,
by which, after its expiration, all the PBAs so far collected are
transmitted, and the remaining are sent later upon their arrival.
Note that in this case the S-MAAR might receive multiple PBAs from
the CMD in response to a PBU. The CMD SHOULD follow the
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retransmissions and rate limiting considerations described in
Section 3.6, especially when aggregating and relaying PBAs.
When there are multiple previous MAARs, e.g., k MAARs, a single PBU
received by the CMD triggers k outgoing packets from a single
incoming packet. This may lead to packet bursts originated from the
CMD, albeit to different targets. Pacing mechanisms MUST be
introduced to avoid bursts on the outgoing link.
3.3. The CMD as MAAR locator
The handover latency experienced in the approach shown before can be
reduced if the P-MAARs are allowed to signal directly their
information to the new S-MAAR. This procedure reflects what was
described in Section 3.2 up to the moment the P-MAAR receives the PBU
with the S-MAAR option. At that point a P-MAAR is aware of the new
MN's location (because of the S-MAAR's address in the S-MAAR option),
and, besides sending a PBA to the CMD, it also sends a PBA to the
S-MAAR including the prefix it is anchoring. This latter PBA does
not need to include new options, as the prefix is embedded in the HNP
option and the P-MAAR's address is taken from the message's source
address. The CMD is relieved from forwarding the PBA to the S-MAAR,
as the latter receives a copy directly from the P-MAAR with the
necessary information to build the tunnels and set the appropriate
routes. Figure 3 illustrates the new message sequence, while the
data forwarding is unaltered.
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+-----+ +---+ +-----+ +--+ +--+
|MAAR1| |CMD| |MAAR2| |CN| |CN|
+-----+ +---+ +-----+ +*-+ +*-+
| | | * *
| | MN * +---+ *
| | attach. ***** _|CMD|_ *
| | det. flow1 * / +-+-+ \ *flow2
| |<-- PBU ---| * / | \ *
| BCE | * / | *******
| check+ | * / | * \
| update | +---*-+-' +--+-*+ `+-----+
|<-- PBU*---| | | * | | *| | |
route | | |MAAR1|______|MAAR2+-----+MAAR3|
update | | | **(______)** *| | |
|--------- PBA -------->| +-----+ +-*--*+ +-----+
|--- PBA*-->| route * *
| BCE update Pref1 * *Pref2
| update | +*--*+
| | | ---move-->|*MN*|
| | | +----+
Operations sequence Data Packets flow
PBU/PBA Messages with * contain
a new mobility option
Figure 3: Scenario after a handover, CMD as locator
3.4. The CMD as MAAR proxy
A further enhancement of previous solutions can be achieved when the
CMD sends the PBA to the new S-MAAR before notifying the P-MAARs of
the location change. Indeed, when the CMD receives the PBU for the
new registration, it is already in possession of all the information
that the new S-MAAR requires to set up the tunnels and the routes.
Thus the PBA is sent to the S-MAAR immediately after a PBU is
received, including also in this case the P-MAAR option. In
parallel, a PBU is sent by the CMD to the P-MAARs containing the
S-MAAR option, to notify them about the new MN's location, so they
receive the information to establish the tunnels and routes on their
side. When P-MAARs complete the update, they send a PBA to the CMD
to indicate that the operation is concluded and the information is
updated in all network nodes. This procedure is obtained from the
first one re-arranging the order of the messages, but the parameters
communicated are the same. This scheme is depicted in Figure 4,
where, again, the data forwarding is kept untouched.
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+-----+ +---+ +-----+ +--+ +--+
|MAAR1| |CMD| |MAAR2| |CN| |CN|
+-----+ +---+ +-----+ +*-+ +*-+
| | | * *
| | MN * +---+ *
| | attach. ***** _|CMD|_ *
| | det. flow1 * / +-+-+ \ *flow2
| |<-- PBU ---| * / | \ *
| BCE | * / | *******
| check+ | * / | * \
| update | +---*-+-' +--+-*+ `+-----+
|<-- PBU*---x--- PBA*-->| | * | | *| | |
route | route |MAAR1|______|MAAR2+-----+MAAR3|
update | update | **(______)** *| | |
|--- PBA*-->| | +-----+ +-*--*+ +-----+
| BCE | * *
| update | Pref1 * *Pref2
| | | +*--*+
| | | ---move-->|*MN*|
| | | +----+
Operations sequence Data Packets flow
PBU/PBA Messages with * contain
a new mobility option
Figure 4: Scenario after a handover, CMD as proxy
3.5. De-registration
The de-registration mechanism devised for PMIPv6 cannot be used as-is
in this solution. The reason for this is that each MAAR handles an
independent mobility session (i.e., a single or a set of prefixes)
for a given MN, whereas the aggregated session is stored at the CMD.
Indeed, if a previous MAAR initiates a de-registration procedure,
because the MN is no longer present on the MAAR's access link, it
removes the routing state for that (those) prefix(es), that would be
deleted by the CMD as well, hence defeating any prefix continuity
attempt. The simplest approach to overcome this limitation is to
deny a P-MAAR to de-register a prefix, that is, allowing only a
serving MAAR to de-register the whole MN session. This can be
achieved by first removing any layer-2 detachment event, so that de-
registration is triggered only when the binding lifetime expires,
hence providing a guard interval for the MN to connect to a new MAAR.
Then, a change in the MAAR operations is required, and at this stage
two possible solutions can be deployed:
o A previous MAAR stops the BCE timer upon receiving a PBU from the
CMD containing a "Serving MAAR" option. In this way only the
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Serving MAAR is allowed to de-register the mobility session,
arguing that the MN definitely left the domain.
o Previous MAARs can, upon BCE expiry, send de-registration messages
to the CMD, which, instead of acknowledging the message with a 0
lifetime, sends back a PBA with a non-zero lifetime, hence re-
newing the session, if the MN is still connected to the domain.
3.6. Retransmissions and Rate Limiting
When sending PBUs, the node sending them (the CMD or S-MAAR) SHOULD
make use of the timeout also to deal with missing PBAs (to retransmit
PBUs). The INITIAL_BINDACK_TIMEOUT [RFC6275] SHOULD be used for
configuring the retransmission timer. The retransmissions by the
node MUST use an exponential backoff process in which the timeout
period is doubled upon each retransmission, until either the node
receives a response or the timeout period reaches the value
MAX_BINDACK_TIMEOUT [RFC6275]. The node MAY continue to send these
messages at this slower rate indefinitely. The node MUST NOT send
PBU messages to a particular node more than MAX_UPDATE_RATE times
within a second [RFC6275].
3.7. The Distributed Logical Interface (DLIF) concept
One of the main challenges of a network-based DMM solution is how to
allow a mobile node to simultaneously send/receive traffic which is
anchored at different MAARs, and how to influence the mobile node's
selection process of its source IPv6 address for a new flow, without
requiring special support from the mobile node's IP stack. This
document defines the Distributed Logical Interface (DLIF), which is a
software construct in the MAAR that allows to easily hide the change
of associated anchors from the mobile node.
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+---------------------------------------------------+
( Operator's )
( core )
+---------------------------------------------------+
| |
+---------------+ tunnel +---------------+
| IP stack |===============| IP stack |
+---------------+ +-------+-------+
| mn1mar1 |--+ (DLIFs) +--|mn1mar1|mn1mar2|--+
+---------------+ | | +-------+-------+ |
| phy interface | | | | phy interface | |
+---------------+ | | +---------------+ |
MAAR1 (o) (o) MAAR2 (o)
x x
x x
prefA::/64 x x prefB::/64
(AdvPrefLft=0) x x
(o)
|
+-----+
prefA::MN1 | MN1 | prefB::MN1
(deprecated) +-----+
Figure 5: DLIF: exposing multiple routers (one per P-MAAR)
The basic idea of the DLIF concept is the following: each serving
MAAR exposes itself towards a given MN as multiple routers, one per
P-MAAR associated to the MN. Let's consider the example shown in
Figure 5, MN1 initially attaches to MAAR1, configuring an IPv6
address (prefA::MN1) from a prefix locally anchored at MAAR1
(prefA::/64). At this stage, MAAR1 plays both the role of anchoring
and serving MAAR, and also behaves as a plain IPv6 access router.
MAAR1 creates a distributed logical interface to communicate (point-
to-point link) with MN1, exposing itself as a (logical) router with a
specific MAC and IPv6 addresses (e.g., prefA::MAAR1/64 and
fe80::MAAR1/64) using the DLIF mn1mar1. As explained below, these
addresses represent the "logical" identity of MAAR1 towards MN1, and
will "follow" the mobile node while roaming within the domain (note
that the place where all this information is maintained and updated
is out-of-scope of this draft; potential examples are to keep it on
the home subscriber server -- HSS -- or the user's profile).
If MN1 moves and attaches to a different MAAR of the domain (MAAR2 in
the example of Figure 5), this MAAR will create a new logical
interface (mn1mar2) to expose itself towards MN1, providing it with a
locally anchored prefix (prefB::/64). In this case, since the MN1
has another active IPv6 address anchored at a MAAR1, MAAR2 also needs
to create an additional logical interface configured to resemble the
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one used by MAAR1 to communicate with MN1. In this example, there is
only one P-MAAR (in addition to MAAR2, which is the serving one):
MAAR1, so only the logical interface mn1mar1 is created, but the same
process would be repeated in case there were more P-MAARs involved.
In order to maintain the prefix anchored at MAAR1 reachable, a tunnel
between MAAR1 and MAAR2 is established and the routing is modified
accordingly. The PBU/PBA signaling is used to set-up the bi-
directional tunnel between MAAR1 and MAAR2, and it might also be used
to convey to MAAR2 the information about the prefix(es) anchored at
MAAR1 and about the addresses of the associated DLIF (i.e., mn1mar1).
+------------------------------------------+ +----------------------+
| MAAR1 | | MAAR2 |
|+----------------------------------------+| |+--------------------+|
||+------------------++------------------+|| ||+------------------+||
|||+-------++-------+||+-------++-------+||| |||+-------++-------+|||
||||mn3mar1||mn3mar2||||mn2mar1||mn2mar2|||| ||||mn1mar1||mn1mar2||||
|||| LMAC1 || LMAC2 |||| LMAC3 || LMAC4 |||| |||| LMAC5 || LMAC6 ||||
|||+-------++-------+||+-------++-------+||| |||+-------++-------+|||
||| LIFs of MN3 || LIFs of MN2 ||| ||| LIFs of MN1 |||
||+------------------++------------------+|| ||+------------------+||
|| MAC1 (phy if MAAR1) || || MAC2 (phy if MAAR2)||
|+----------------------------------------+| |+--------------------+|
+------------------------------------------+ +----------------------+
x x x
x x x
(o) (o) (o)
| | |
+--+--+ +--+--+ +--+--+
| MN3 | | MN2 | | MN1 |
+-----+ +-----+ +-----+
Figure 6: Distributed Logical Interface concept
Figure 6 shows the logical interface concept in more detail. The
figure shows two MAARs and three MNs. MAAR1 is currently serving MN2
and MN3, while MAAR2 is serving MN1. Note that a serving MAAR always
plays the role of anchoring MAAR for the attached (served) MNs. Each
MAAR has one single physical wireless interface as depicted in this
example.
As introduced before, each MN always "sees" multiple logical routers
-- one per anchoring MAAR -- independently of its currently serving
MAAR. From the point of view of the MN, these MAARs are portrayed as
different routers, although the MN is physically attached to one
single interface. The way this is achieved is by the serving MAAR
configuring different logical interfaces. Focusing on MN1, it is
currently attached to MAAR2 (i.e., MAAR2 is its serving MAAR) and,
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therefore, it has configured an IPv6 address from MAAR2's pool (e.g.,
prefB::/64). MAAR2 has set-up a logical interface (mn1mar2) on top
of its wireless physical interface (phy if MAAR2) which is used to
serve MN1. This interface has a logical MAC address (LMAC6),
different from the hardware MAC address (MAC2) of the physical
interface of MAAR2. Over the mn1mar2 interface, MAAR2 advertises its
locally anchored prefix prefB::/64. Before attaching to MAAR2, MN1
was attached to MAAR1, configuring also an address locally anchored
at that MAAR, which is still being used by MN1 in active
communications. MN1 keeps "seeing" an interface connecting to MAAR1,
as if it were directly connected to the two MAARs. This is achieved
by the serving MAAR (MAAR2) configuring an additional distributed
logical interface: mn1mar1, which behaves as the logical interface
configured by MAAR1 when MN1 was attached to it. This means that
both the MAC and IPv6 addresses configured on this logical interface
remain the same regardless of the physical MAAR which is serving the
MN. The information required by a serving MAAR to properly configure
this logical interfaces can be obtained in different ways: as part of
the information conveyed in the PBA, from an external database (e.g.,
the HSS) or by other means. As shown in the figure, each MAAR may
have several logical interfaces associated to each attached MN,
having always at least one (since a serving MAAR is also an anchoring
MAAR for the attached MN).
In order to enforce the use of the prefix locally anchored at the
serving MAAR, the router advertisements sent over those logical
interfaces playing the role of anchoring MAARs (different from the
serving one) include a zero preferred prefix lifetime (and a non-zero
valid prefix lifetime, so the prefix remains valid, while being
deprecated). The goal is to deprecate the prefixes delegated by
these MAARs (so that they will no longer be serving the MN). Note
that on-going communications may keep on using those addresses, even
if they are deprecated, so this only affects the establishment of new
sessions.
The distributed logical interface concept also enables the following
use case: suppose that access to a local IP network is provided by a
given MAAR (e.g., MAAR1 in the example shown in Figure 5) and that
the resources available at that network cannot be reached from
outside the local network (e.g., cannot be accessed by an MN attached
to MAAR2). This is similar to the local IP access scenario
considered by 3GPP, where a local gateway node is selected for
sessions requiring access to services provided locally (instead of
going through a central gateway). The goal is to allow an MN to be
able to roam while still being able to have connectivity to this
local IP network. The solution adopted to support this case makes
use of RFC 4191 [RFC4191] more specific routes when the MN moves to a
MAAR different from the one providing access to the local IP network
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(MAAR1 in the example). These routes are advertised through the
distributed logical interface representing the MAAR providing access
to the local network (MAAR1 in this example). In this way, if MN1
moves from MAAR1 to MAAR2, any active session that MN1 may have with
a node on the local network connected to MAAR1 will survive via the
tunnel between MAAR1 and MAAR2. Also, any potential future
connection attempt towards the local network will be supported, even
though MN1 is no longer attached to MAAR1.
4. Message Format
This section defines extensions to the Proxy Mobile IPv6 [RFC5213]
protocol messages.
4.1. Proxy Binding Update
A new flag (D) is included in the Proxy Binding Update to indicate
that the Proxy Binding Update is coming from a MAAR or a CMD and not
from a mobile access gateway. The rest of the Proxy Binding Update
format remains the same as defined in [RFC5213].
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 # |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A|H|L|K|M|R|P|F|T|B|S|D| Rsrvd | Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. Mobility options .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
DMM Flag (D)
The D Flag is set to indicate to the receiver of the message that
the Proxy Binding Update is from a MAAR or a CMD. When an LMA
that does not support the extensions described in this document
receives a message with the D-Flag set, the PBU in that case MUST
NOT be processed by the LMA and an error MUST be returned.
Mobility Options
Variable-length field of such length that the complete Mobility
Header is an integer multiple of 8 octets long. This field
contains zero or more TLV-encoded mobility options. The encoding
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and format of defined options are described in Section 6.2 of
[RFC6275]. The receiving node MUST ignore and skip any options
that it does not understand.
4.2. Proxy Binding Acknowledgment
A new flag (D) is included in the Proxy Binding Acknowledgment to
indicate that the sender supports operating as a MAAR or CMD. The
rest of the Proxy Binding Acknowledgment format remains the same as
defined in [RFC5213].
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status |K|R|P|T|B|S|D| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence # | Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. Mobility options .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
DMM Flag (D)
The D flag is set to indicate that the sender of the message
supports operating as a MAAR or a CMD. When a MAG that does not
support the extensions described in this document receives a
message with the D-Flag set, it MUST ignore the message and an
error MUST be returned.
Mobility Options
Variable-length field of such length that the complete Mobility
Header is an integer multiple of 8 octets long. This field
contains zero or more TLV-encoded mobility options. The encoding
and format of defined options are described in Section 6.2 of
[RFC6275]. The MAAR MUST ignore and skip any options that it does
not understand.
4.3. Anchored Prefix Option
A new Anchored Prefix option is defined for use with the Proxy
Binding Update and Proxy Binding Acknowledgment messages exchanged
between MAARs and CMDs. Therefore, this option can only appear if
the D bit is set in a PBU/PBA. This option is used for exchanging
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the mobile node's prefix anchored at the anchoring MAAR. There can
be multiple Anchored Prefix options present in the message.
The Anchored Prefix Option has an alignment requirement of 8n+4. Its
format is as follows:
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 | Length | Reserved | Prefix Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Anchored Prefix +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
IANA-1.
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 18.
Reserved
This field is unused for now. The value MUST be initialized to 0
by the sender and MUST be ignored by the receiver.
Prefix Length
8-bit unsigned integer indicating the prefix length in bits of the
IPv6 prefix contained in the option.
Anchored Prefix
A sixteen-octet field containing the mobile node's IPv6 Anchored
Prefix. Only the first Prefix Length bits are valid for the
Anchored Prefix. The rest of the bits MUST be ignored.
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4.4. Local Prefix Option
A new Local Prefix option is defined for use with the Proxy Binding
Update and Proxy Binding Acknowledgment messages exchanged between
MAARs or between a MAAR and a CMD. Therefore, this option can only
appear if the D bit is set in a PBU/PBA. This option is used for
exchanging a prefix of a local network that is only reachable via the
anchoring MAAR. There can be multiple Local Prefix options present
in the message.
The Local Prefix Option has an alignment requirement of 8n+4. Its
format is as follows:
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 | Length | Reserved | Prefix Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Local Prefix +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
IANA-2.
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 18.
Reserved
This field is unused for now. The value MUST be initialized to 0
by the sender and MUST be ignored by the receiver.
Prefix Length
8-bit unsigned integer indicating the prefix length in bits of the
IPv6 prefix contained in the option.
Local Prefix
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A sixteen-octet field containing the IPv6 Local Prefix. Only the
first Prefix Length bits are valid for the IPv6 Local Prefix. The
rest of the bits MUST be ignored.
4.5. Previous MAAR Option
This new option is defined for use with the Proxy Binding
Acknowledgement messages exchanged by the CMD to a MAAR. This option
is used to notify the S-MAAR about the previous MAAR's global address
and the prefix anchored to it. There can be multiple Previous MAAR
options present in the message. Its format is as follows:
The Previous MAAR Option has an alignment requirement of 8n+4. Its
format is as follows:
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 | Length | Reserved | Prefix Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ P-MAAR's address +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Home Network Prefix +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
IANA-3.
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 34.
Reserved
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This field is unused for now. The value MUST be initialized to 0
by the sender and MUST be ignored by the receiver.
Prefix Length
8-bit unsigned integer indicating the prefix length in bits of the
IPv6 prefix contained in the option.
Previous MAAR's address
A sixteen-octet field containing the P-MAAR's IPv6 global address.
Home Network Prefix
A sixteen-octet field containing the mobile node's IPv6 Home
Network Prefix. Only the first Prefix Length bits are valid for
the mobile node's IPv6 Home Network Prefix. The rest of the bits
MUST be ignored.
4.6. Serving MAAR Option
This new option is defined for use with the Proxy Binding Update
message exchanged between the CMD and a Previous MAAR. This option
is used to notify the P-MAAR about the current Serving MAAR's global
address. Its format is as follows:
The Serving MAAR Option has an alignment requirement of 8n+6. Its
format is as follows:
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ S-MAAR's address +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
IANA-4.
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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 16.
Serving MAAR's address
A sixteen-octet field containing the S-MAAR's IPv6 global address.
4.7. DLIF Link-local Address Option
A new DLIF Link-local Address option is defined for use with the
Proxy Binding Acknowledgment message exchanged between MAARs and
between a MAAR and a CMD. This option is used for exchanging the
link-local address of the DLIF to be configured on the serving MAAR
so it resembles the DLIF configured on the P-MAAR.
The DLIF Link-local Address option has an alignment requirement of
8n+6. Its format is as follows:
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ DLIF Link-local Address +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
IANA-5.
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 16.
DLIF Link-local Address
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A sixteen-octet field containing the link-local address of the
logical interface.
4.8. DLIF Link-layer Address Option
A new DLIF Link-layer Address option is defined for use with the
Proxy Binding Acknowledgment message exchanged between MAARs and
betwwe a MAAR and a CMD. This option is used for exchanging the
link-layer address of the DLIF to be configured on the serving MAAR
so it resembles the DLIF configured on the P-MAAR.
The format of the DLIF Link-layer Address option is shown below.
Based on the size of the address, the option MUST be aligned
appropriately, as per mobility option alignment requirements
specified in [RFC6275].
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 | Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ DLIF Link-layer Address +
. ... .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
IANA-6.
Length
8-bit unsigned integer indicating the length of the option in
octets, excluding the type and length fields.
Reserved
This field is unused for now. The value MUST be initialized to 0
by the sender and MUST be ignored by the receiver.
DLIF Link-layer Address
A variable length field containing the link-layer address of the
logical interface to be configured on the S-MAAR.
The content and format of this field (including octet and bit
ordering) is as specified in Section 4.6 of [RFC4861] for carrying
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link-layer addresses. On certain access links, where the link-
layer address is not used or cannot be determined, this option
cannot be used.
5. IANA Considerations
This document defines six new mobility options, the Anchored Prefix
Option, the Local Prefix Option, the Previous MAAR Option, the
Serving MAAR Option, the DLIF Link-local Address Option and the DLIF
Link-layer Address Option. The Type value for these options needs to
be assigned from the same numbering space as allocated for the other
mobility options in the "Mobility Options" registry defined in
http://www.iana.org/assignments/mobility-parameters. The required
IANA actions are marked as IANA-1 to IANA-6.
This document reserves a new flag (D) in the "Binding Update Flags"
and a new flag (D) in the "Binding Acknowledgment Flags" of the
"Mobile IPv6 parameters" registry http://www.iana.org/assignments/
mobility-parameters.
6. Security Considerations
The protocol extensions defined in this document share the same
security concerns of Proxy Mobile IPv6 [RFC5213]. It is recommended
that the signaling messages, Proxy Binding Update and Proxy Binding
Acknowledgment, exchanged between the MAARs are protected using IPsec
using the established security association between them. This
essentially eliminates the threats related to the impersonation of a
MAAR.
When the CMD acts as a PBU/PBA relay, the CMD may act as a relay of a
single PBU to multiple previous MAARs. In situations of many fast
handovers (e.g., with vehicular networks), there may exist multiple
previous (e.g., k) MAARs. In this situation, the CMD creates k
outgoing packets from a single incoming packet. This bears a certain
amplification risk. The CMD MUST use a pacing approach in the
outgoing queue to cap the output traffic (i.e., the rate of PBUs
sent) to limit this amplification risk.
When the CMD acts as MAAR locator, mobility signaling (PBAs) is
exchanged between P-MAARs and current S-MAAR. Hence, security
associations are REQUIRED to exist between the involved MAARs (in
addition to the ones needed with the CMD).
Since deregistration is performed by timeout, measures SHOULD be
implemented to minimize the risks associated to continued resource
consumption (DoS attacks), e.g., imposing a limit of the number of
P-MAARs associated to a given MN.
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The CMD and the participating MAARs MUST be trusted parties,
authorized perform all operations relevant to their role.
There are some privacy considerations to consider. While the
involved parties trust each other, the signalling involves disclosing
information about the previous locations visited by each MN, as well
as the active prefixes they are using at a given point of time.
Therefore, mechanisms MUST be in place to ensure that MAARs and CMD
do not disclose this information to other parties nor use it for
other ends that providing the distributed mobility support specified
in this document.
7. Acknowledgments
The authors would like to thank Dirk von Hugo, John Kaippallimalil,
Ines Robles, Joerg Ott, Carlos Pignataro, Vincent Roca, Mirja
Kuehlewind, Eric Vyncke, Adam Roach, Benjamin Kaduk and Roman Danyliw
for the comments on this document. The authors would also like to
thank Marco Liebsch, Dirk von Hugo, Alex Petrescu, Daniel Corujo,
Akbar Rahman, Danny Moses, Xinpeng Wei and Satoru Matsushima for
their comments and discussion on the documents
[I-D.bernardos-dmm-distributed-anchoring] and
[I-D.bernardos-dmm-pmip] on which the present document is based.
The authors would also like to thank Lyle Bertz and Danny Moses for
their in-deep review of this document and their very valuable
comments and suggestions.
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and
More-Specific Routes", RFC 4191, DOI 10.17487/RFC4191,
November 2005, <https://www.rfc-editor.org/info/rfc4191>.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
DOI 10.17487/RFC4861, September 2007,
<https://www.rfc-editor.org/info/rfc4861>.
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[RFC5213] Gundavelli, S., Ed., Leung, K., Devarapalli, V.,
Chowdhury, K., and B. Patil, "Proxy Mobile IPv6",
RFC 5213, DOI 10.17487/RFC5213, August 2008,
<https://www.rfc-editor.org/info/rfc5213>.
[RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility
Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July
2011, <https://www.rfc-editor.org/info/rfc6275>.
[RFC7333] Chan, H., Ed., Liu, D., Seite, P., Yokota, H., and J.
Korhonen, "Requirements for Distributed Mobility
Management", RFC 7333, DOI 10.17487/RFC7333, August 2014,
<https://www.rfc-editor.org/info/rfc7333>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
8.2. Informative References
[I-D.bernardos-dmm-distributed-anchoring]
Bernardos, C. and J. Zuniga, "PMIPv6-based distributed
anchoring", draft-bernardos-dmm-distributed-anchoring-09
(work in progress), May 2017.
[I-D.bernardos-dmm-pmip]
Bernardos, C., Oliva, A., and F. Giust, "A PMIPv6-based
solution for Distributed Mobility Management", draft-
bernardos-dmm-pmip-09 (work in progress), September 2017.
[RFC7429] Liu, D., Ed., Zuniga, JC., Ed., Seite, P., Chan, H., and
CJ. Bernardos, "Distributed Mobility Management: Current
Practices and Gap Analysis", RFC 7429,
DOI 10.17487/RFC7429, January 2015,
<https://www.rfc-editor.org/info/rfc7429>.
[RFC8563] Katz, D., Ward, D., Pallagatti, S., Ed., and G. Mirsky,
Ed., "Bidirectional Forwarding Detection (BFD) Multipoint
Active Tails", RFC 8563, DOI 10.17487/RFC8563, April 2019,
<https://www.rfc-editor.org/info/rfc8563>.
Authors' Addresses
Bernardos, et al. Expires September 9, 2020 [Page 28]
Internet-Draft PMIPv6 DMM and DLIF March 2020
Carlos J. Bernardos
Universidad Carlos III de Madrid
Av. Universidad, 30
Leganes, Madrid 28911
Spain
Phone: +34 91624 6236
Email: cjbc@it.uc3m.es
URI: http://www.it.uc3m.es/cjbc/
Antonio de la Oliva
Universidad Carlos III de Madrid
Av. Universidad, 30
Leganes, Madrid 28911
Spain
Phone: +34 91624 8803
Email: aoliva@it.uc3m.es
URI: http://www.it.uc3m.es/aoliva/
Fabio Giust
Athonet S.r.l.
Email: fabio.giust.2011@ieee.org
Juan Carlos Zuniga
SIGFOX
425 rue Jean Rostand
Labege 31670
France
Email: j.c.zuniga@ieee.org
URI: http://www.sigfox.com/
Alain Mourad
InterDigital Europe
Email: Alain.Mourad@InterDigital.com
URI: http://www.InterDigital.com/
Bernardos, et al. Expires September 9, 2020 [Page 29]