Internet DRAFT - draft-wei-dmm-ro-consideration
draft-wei-dmm-ro-consideration
Distributed Mobility Management (DMM) X. Wei
Internet-Draft Huawei Technologies
Intended status: Informational February 13, 2014
Expires: August 17, 2014
Consideration of Routing Optimization for DMM network
draft-wei-dmm-ro-consideration-00
Abstract
Distributed Mobility Management (DMM) is designed to be a distributed
and scalable mobility management solution, and providing optimal
route for traffics is one of DMM's aims. There have been several
proposals on DMM framework, and this document provides discussion on
how to optimize traffic routes, and aims to provide suggestioins on
how to avoid long route in DMM network.
Status of this Memo
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This Internet-Draft will expire on August 17, 2014.
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology and Abbreviation . . . . . . . . . . . . . . . . . 4
2.1. Conventions Used in This Document . . . . . . . . . . . . 4
3. Impacts of routing optimization . . . . . . . . . . . . . . . 5
3.1. Tunneling . . . . . . . . . . . . . . . . . . . . . . . . 5
3.2. IP changing . . . . . . . . . . . . . . . . . . . . . . . 6
3.3. Local Routing . . . . . . . . . . . . . . . . . . . . . . 7
4. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . 9
5. Security Considerations . . . . . . . . . . . . . . . . . . . 10
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
7.1. Normative References . . . . . . . . . . . . . . . . . . . 12
7.2. Informative References . . . . . . . . . . . . . . . . . . 12
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 13
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1. Introduction
The new network service scenarios such as network traffic offloading
and mobility service in local Content Delivery Networks (CDNs) impose
new requirements on network mobility management, and a more flat
mobility management system with fewer levels of routing hierarchy
introduced into the data path is more preferred. So Distributed
Mobility Management (DMM) is proposed to satisfy these new network
mobility management requirements, and DMM aims to solve the problems
such as non-optimal routes, poor network scalability, and single
point of failure and attack which are widely faced by existing
centralized mobility management protocols [4].
Currently several solutions on DMM framework are being discussed,
some of the solutions are based on existing IP mobility management
protocols [5] [6], and others provide new solutions [7] [8]. These
solutions provide their own DMM frameworks, and in order to transport
traffic through an optimal path the basic idea of these solutions is
placing mobility anchors in a distributed way.
Routing redundancy is a common problem in mobile IP network. In
mobile IP network, Mobility Anchor (MA) acts as topological anchor of
IP address, and due to the existing of mobility anchors, the packets
sent from MN's Correspondent Node (CN) are always firstly routed to
MN's mobility anchor and then forwarded to MN. In order to reduce
routing redundancy problem existing in mobile IP network, some
routing optimization methods could be implemented. Because mobility
anchor will be existed in DMM network, so routing optimization
method(s) would also be taken into consideration in the design of DMM
network.
This document provides some considerations of routing optimization
related issues for the design of DMM network, several routing
optimization methods and their impacts on traffic will be discussed.
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2. Terminology and Abbreviation
2.1. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
NOT","SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in
thisdocument are to be interpreted as described in [1].
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3. Impacts of routing optimization
This section analyzes the impacts of routing optimization on network
traffic. Several routing optimization methods, including tunneling,
changing the IP address and local routing, are discussed here.
3.1. Tunneling
In IP network, tunnel could be used to hide the network topology, and
it is a method of changing the route of traffic. Because tunnel can
let traffic travel in network without constrain of network topology,
so it is often used as a tool for changing the route of network
traffics.
In DMM network, MAs are distributed deployed and towards to access
network, it is likely for MN to attach to different MAs when MN moves
in the network. In order to keep service continuity, DMM network
would keep MN's IP address for IP session, and routes the packets
through the anchor of IP address. The change of MA would bring about
routing redundancy, so tunnel based routing optimization could be
used to reduce the routing redundancy.
For DMM network, When MN moves to a new MA, the tunnel for routing
optimization could be set up between MN's MA and CN's MA (Figure 1),
or between MN and CN (Figure 2).
+--+
|CN|
+-|+
|
|
+-|-+
|MA3|=========||
.'+---+ ||
,' || RO tunnel
/ ||
/ ||
+-`-+ +---+
|MA1|--------------|MA2|
+-|-+ +-|-+
| |
| |
| |
+|-+ +|-+
|MN| ----------> |MN|
+--+ move +--+
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Figure1: tunnel based routing optimization 1
+--+
+--------+|CN|=========||
| +--+ ||
| ||
| || RO tunnel
| ||
| ||
| ||
+---------+------------+ +-----||-------------+
| ++--+ | | || |
| |MA1| | | || |
| +-+-+ | | || |
| | + | | || |
| ++-+ | | +--+ |
| |MN| -------------> |MN| |
| +--+ move | +--+ |
| | | |
+----------------------+ +--------------------+
network of MA1 network of MA2
Figure2: tunnel based routing optimization 2
3.2. IP changing
In mobile IP network, the reason of non-optimal route is that in
order to provide service continuity for MN, network always guarantees
the consistency of MN's IP address when MN moves in network. But in
today's network there are a lot of applications that don't need
service continuity, e.g. web service, DNS; and for the applications
which though need service continuity, but they deal with service
continuity in other layers, e.g. application layer, transport layer
etc, and not depends on network layer. So for these applications,
the consistency of IP address will cause unnecessary non-optimal
route for them.
But for some other applications, they need mobility support from
network layer, and in order to keep service continuity the IP address
of MN must not be changed during the whole service session.
So in order to provide optimal path for service traffics from
applications that don't require IP address consistency, when MN moves
to a new MA, DMM network could assign new IP address for MN, and then
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MN could use current MA's IP address for these applications; for the
applications that require IP address consistency, when MN moves to a
new MA, DMM network should allow MN to use the IP address assigned by
previous MA to make sure the address for these applications not
change.
For the traffic that requires the consistency of IP address, other
routing optimization methods such as tunneling and local routing
could be implemented.
3.3. Local Routing
Local routing is another routing optimization method that could be
used in the situation that MN and CN are in the same network region.
In the same region means MN and CN are under control of the same
mobility management entity, e.g. mobility anchor.
When MN and CN are in the same region, their traffic path might be
shortened significantly by local routing. For example, there is a
local routing function in PMIPv6 [2] protocol as shown in Figure 3.
When MN and CN are under the control of the same MAG, the local
routing path could be set up between MN and CN through the MAG, and
then packets will transported along the path of MN--MAG--CN without
passing through LMA.
+----------+
| LMA |
+----------+
+---------+
|------->| MAG |<-----|
| +---------+ |
| |
| |
| |
| |
+--V------+ +----V----+
| MN | | CN |
+---------+ +---------+
Figure3: Local Routing in PMIPv6
Because in DMM network, MA would be deployed towards to the access
network, so when MN and CN are under the same MA, local routing
method would provide a optimal path for packets between MN and CN.
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An example of local routing for DMM network is shown in Figure 4.
+---------+
|------->| MA |<-----|
| +---------+ |
| |
| |
| |
| |
+--V------+ +----V----+
| MN | | CN |
+---------+ +---------+
Figure4: Local Routing for DMM
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4. Conclusions
This document discusses three kinds of method for routing
optimization in DMM network, these methods aims to provide optimal
traffic route in DMM network, and they would be suitable for
different situations and different traffics.
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5. Security Considerations
Security related issues are not considered in current document.
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6. IANA Considerations
There have been no IANA considerations so far in this document.
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7. References
7.1. Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[2] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K., and
B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.
[3] Perkins, C., Johnson, D., and J. Arkko, "Mobility Support in
IPv6", RFC 6275, July 2011.
7.2. Informative References
[4] Chan (Ed.) et al., "Requirements for Distributed Mobility
Management", draft-ietf-dmm-requirements-12 (work in progress),
Dec 2013.
[5] CJ. Bernardos et al,, "PMIPv6-based distributed anchoring",
draft-bernardos-dmm-distributed-anchoring-03 (work in progress),
Oct 2013.
[6] W. Luo, J. Liu,, "PMIP Based DMM Approaches",
draft-luo-dmm-pmip-based-dmm-approach-02 (work in progress),
July 2013.
[7] H. Chan, P. Seite, K. Pentikousis, A. Dutta,, "Distributed
Mobility Management Framework", draft-chan-dmm-framework-03
(work in progress), Oct 2013.
[8] M. Liebsch, P. Seite, G. Karagiannis,, "Distributed Mobility
Management - Framework & Analysis",
draft-liebsch-dmm-framework-analysis-02 (work in progress),
Oct 2013.
[9] D. Liu et al,, "Distributed Mobility Management: Current
practices and gap analysis",
draft-ietf-dmm-best-practices-gap-analysis-02 (work in progress)
(work in progress), Oct 2013.
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Author's Address
Xinpeng Wei
Huawei Technologies
Email: weixinpeng@huawei.com
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