Transcript Mobile Routers in IPv6

Mobile Routers in IPv6
Thierry Ernst - MOTOROLA Labs & INRIA (Planete)
Claude Castelluccia - INRIA (Planete)
Hong-Yon Lach - Motorola Labs
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Presentation overview
 Foreword
 Mobile Networks:
What applications need mobile routers and networks ?
Definition and terminology
Requirements (What do we need to support mobile routers)
 Current status at the IETF:
Mobile IPv6 and Mobile Networks
Prefix Scope Binding Updates in Mobile IPv6
Extended mode in Hierarchical Mobile IPv6
 Ongoing research:
Innovative trends: Multicast delivery of Binding Updates
 Conclusion
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Foreword
 Most IP devices will be mobile
always connected to the Internet by some means
 Networks will themselves be mobile
mobile networks may be of any size, ranging:
• from a few IP devices (e.g. PAN)
• to thousands of IP devices (e.g. a train)
 There is no explicit support of mobile networks in today’s
IP specifications
 However, Mobile Networks have:
specific characteristics,
specific requirements
specific problems
 Thus, IP needs explicit support for mobile networks
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Mobile Networks: What applications ?
 Network of sensors deployed in aircrafts, boats, cars,
trains, …
air-traffic signaling data exchanged with the Internet whereas
passengers are given access to the Internet (web surfing, remote
connection to office, …)
= Mobile Router
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Mobile Networks: What applications ?
 Personal Area Networks (PANs) connected to the Internet
The mobile network is composed by all IP devices carried by
humans: cellular phone, notebook, digital camera, …
Devices in the PAN may be connected using Bluetooth
The device connecting the PAN to the Internet is a Mobile Router
= Mobile Router
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Mobile Networks: the Mobile Network vision
 devices and networks are:
always connected by heterogeneous networks
unified by IP
Wireless WAN (IEEE 802.11b, GPRS, Bluetooth, ...)
Picocellular MAN
Wired or Wireless LAN
(WaveLAN, HiperLAN,..)
john@mylovelycar
john@street
john@work
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Mobile Networks: The Mobile Network vision
 mobile networks formed by smaller ones:
A set of mobile devices which compose...
a PAN which enters ...
a car which enters in ...
a queue of cars
• on the motorway, or
• in the Eurostar Shuttle
INTERNET
john@mylovelycar
queuecar@motorway
mylovelycar@queuecar
= Mobile Router
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Mobile Networks: Internet Definition
 Mobile Node = a single node that changes its point of attachment
by means of Mobile IPv6
 Mobile Network = an entire network that changes its point of
attachment
Mobile Router (MR) + its attached Nodes and Routers.
IP subnet or a collection of IP subnets
MR
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Mobile Networks: Terminology
Mobile Router (MR) = Border router of the mobile network
nodes in the mobile networks are:
• SNs = all Stationary Nodes permanently located in mobile network (
SNs are not Mobile Nodes !)
• MNs = all Mobile Nodes temporarily visiting the mobile network
CNs = all nodes communicating with MR, SNs and MNs
MR
MN
SN
SN
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Mobile Network: Characteristics
 As we have seen, mobile networks:
are always connected to the Internet through a mobile router
mobile networks may be composed by a set of subnets and a set
of routers
size may range for a few (PAN) to hundreds or even thousands of
nodes and routers (train, etc …)
part of a mobile networks may be a sub-mobile network
MR
SN
MN
SN
MR
SN
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Mobile Networks: Aim of Mobility Support
 to provide continuous Internet connectivity to nodes
located in the mobile network
 to offer optimal routing between CNs and nodes located
in the mobile network (both SNs and MNs)
end-system
SN
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IETF Status
 Mobile IP Working Group:
Mobile Networks are not currently supported by Mobile IPv6
Current work:
• Prefix Scope Binding Update: draft-ernst-mobileip-v6-network-01.txt
• HMIPv6 draft-ietf-mobileip-hmipv6-03.txt
 Seamoby Working Group (Context Transfer and Micromobility routing):
support of mobile routers and networks is listed by the micromobility design team
• draft-ietf-seamoby-mm-problem-01.txt
 IPNG Working Group (IP Next Generation or IPv6)
• some discussions in the mailing list
 MANET Working group (Ad-hoc routing)
• No discussion about this subject
• But ad-hoc network that changes its AR is a mobile network according to
our definition
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IETF Status: Mobile IPv6 for mobile nodes (review)
 Working Group Mobile IP at the IETF.
 Allow mobility of end-systems without communication
disruption […]:
mobile node MN is identified by its home address IP1 (address on the
home link)
a new temporary address IP2 (care-of address or CoA) is allocated to
MN on each visited foreign link and is used for routing.
Binding between the home address and the CoA
MN is associated with a Home Agent HA (a router on the home link )
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IETF Status: Mobile IPv6 for mobiles nodes (review)
 First packets
MN obtains CoA IP2 from a router on
the foreign link
MN registers its current CoA IP2 with its
home agent HA.
CN sends packets to the CoA IP1
HA intercepts, encapsulates, and
redirects packets to CoA IP2
MN decapsulates packets
 Following packets
MN sends its CoA to CN.
 CN sends packets directly to CoA IP2
using a IPv6 Routing Extension
Header.
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IETF Status: Mobile IPv6 for mobile networks ?
 IETF Mobile IPv6 is a natural candidate to support
mobile routers and networks
 Specification says that mobile nodes may either be
Mobile Hosts or Mobile Routers.
However, no explicitly mention of mobile networks
Could Mobile IPv6 support mobile networks anyway ?
 If we follow the specification, MR:
is a mobile node and operates Mobile IPv6
has a home address in its home network
gets a new CoA on each visited link
registers its new CoA address:
• with its HA and its own CNs
• by means of BUs containing current CoA
=> Packets intended to the MR itself are optimally routed from
the CN to the MR
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IETF Status: Mobile IPv6 for mobile networks ?
 What about packets intended to the SNs ?
 CNs do not have a CoA for SNs:
No optimal routing between CNs and SNs
Packets intended to SNs are routed to the home network
MR’s HA has a binding between MR’s home address and MR’s
CoA
Packets are intercepted by MR’s HA (proxy ARP)
HA does not know that packets intended to SNs have to be
encapsulated to the MR’s CoA
packets enter a routing loop and get finally discarded
• Experiments conducted on FreeBSD has demonstrated this
• see draft-ernst-mobileip-network-01.txt
• in some implementations, it may work, but the specification does not say
what to do for a mobile router
=> communication is not possible at all if the implementation strictly
follows the specification
• If we want to use Mobile IPv6, it needs clarification and extensions
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IETF Status: Prefix Scope BU extensions to MIPv6
 Draft-ernst-mobileip-v6.01.txt
developed by INRIA and MOTOROLA Labs
Presented at 48th IETF 8/00 and 49th IETF 12/00
under revision - new version will come before next IETF
 Draft addresses 2 issues:
Redirection of packets intended to SNs by the HA to the MR
Optimal Routing between CNs and SNs
 Proposes Mobile IPv6 extensions:
Key idea: MR is solely responsible for the mobility management of
the entire network
• MR acts as any other MN and operates Mobile IPv6
• all interfaces in the mobile network are identified by a common network
prefix => the Mobile Network Prefix
• Binding between the Mobile Network Prefix and the MR’s CoA
• Record in Binding Cache = network route vs host route
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IETF Status: Prefix Scope BU extensions to MIPv6
 How:
The Mobile Network Prefix is carried in BUs in addition to the CoA
A BU worth for an entire network, not for a single node
BUs are sent by the MR to the
• MR’s HA,
• all CNs of the MR
• all CNs of SNs behind the MR
We define
• a new sub-Option to record the Mobile Network Prefix
• A bit “Prefix Scope Registration” in the Binding Update option that tells BU
contains a care-of address valid for a mobile network
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IETF Status: Prefix Scope BU extensions to MIPv6
 Both CNs and HA are then able to redirect packets sent to
any node in the mobile network
all packets with a destination address corresponding to mobile
network prefix are re-routed to the MR’s CoA
• using a routing extension header or encapsulation
CN’s BINDING CACHE
MR home address => MR’s CoA
Mobile Network prefix /48 => MR’s CoA
= Standard Mobile IPv6
= our extension
 Security issues:
The sender of the BU is easily authenticated
Remaining open issue:
• Authorization for the MR to manage mobility of the entire network
• But same problem as for MNs:
– a MN needs to be authorized to send a BU for a home address
– a MR needs to be authorized to send a BU for a network prefix
– this is presently discussed at the IETF and we are waiting for the outcome
of this discussion
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IETF Status: Extended mode in HMIPv6
 Draft-ietf-mobileip-hmipv6-03.txt
•
•
•
•
First version around 10/00
Presented at 49th IETF 12/00
Developed by INRIA (Planete) and Ericsson Research
Based on original work designed at INRIA (Planete) in 1998
 Hierarchical Mobility Management
separate local mobility management from global mobility
management
2 modes of operation: Basic Mode and Extended Mode
Extended Mode:
• could be used to support mobile networks
• MR has 2 CoAs:
– RCoA is kept as long it remains in the same administrative region
– LCoA is topologically correct and changes at each new access point
– MR broadcast the RCoA in the mobile network
• MNs (and SNs ?) in the mobile network:
– use the RCoA as their CoA
– register RCoA with MAP, their HA, their CNs
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IETF Status: Extended mode in HMIPv6
RCoA / LCoA1
MR
MR has 2 CoAs:
• RCoA is permanent in the site
• LCoA changes at each new Access Router
MN uses MR’s RCoA as its CoA
MN registers RCoA with MAP, its HA and CNs
MR ’s Home Agent
MR H@ => RCoA
LCoA1, RCoA
MAP
RCoA
MN
RCoA
MN H@ => RCoA
MN ’s Correspondent
MN H@ => RCoA
MN ’s Home Agent
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IETF Status: Extended mode in HMIPv6
MN does not need to change its CoA as long as MR remains in
the same administrative domain
(but it still needs to send periodic Binding Updates !)
MR ’s Home Agent
MR H@ => RCoA
LCoA1, RCoA
LCoA2, RCoA
MAP
RCoA
RCoA / LCoA2
MR
MN H@ => RCoA
MN ’s Correspondent
MN H@ => RCoA
RCoA
MN
MN ’s Home Agent
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IETF Status:
 HMIPv6
is more appropriate to support MNs visiting the mobile network
mobility management of the MR is not transparent to the MNs
 Prefix Scope Binding Updates
is more appropriate to support SNs permanently located in the
mobile network
mobility management of the MR is transparent to the SNs
 Both solution may not scale to large mobile networks
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Ongoing work: How to minimise signalling ?
Each SN / MN communicate with several CNs
We want to perform optimal routing:
• Current CoA must be sent periodically to each CN
• MR’s CoA if we use Prefix Scope Binding Updates
• MR’s RCoA if we use HMIPv6 Extended Mode
Binding Update explosion
• Periodic burst due to Binding
Updates on the first link
– about 6744 bits every 10
seconds if only one CN
– about 198408 bits every 10
seconds if 100 CNs
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Ongoing work: Multicast delivery of BUs
If MR sends Prefix Scope Binding Updates, we note that all CNs
get an identical copy of the BU
Multicast delivery of Binding Updates for large mobile networks
• an innovative trend
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Ongoing work: Multicast delivery of BUs
• Examples on a 1000 nodes topology - CNs are selected randomly
• For each number of CN, MR visits the same list of ARs
• Graphs show the total number of links and bandwidth consumed by
Binding Updates during 400 seconds for each number of CNs
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Conclusion: Open issues
 Mobile routers and networks have very specific problems and
requirements
They deserve their own solutions
Many open issues to address:
• Mobile Router moving without its attached nodes
• Nested mobility:
– Mobile Nodes visiting the mobile network
– the car which enters in the Eurostar Shuttle is a MN (phone) in a mobile network
(PAN) in a mobile network (car) in a mobile network (train)
• impact on routing protocols
 What about:
Router advertisements sent by MR ?
Multihomed MR
Network Renumbering
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Conclusion: Requirements
 Requirements usually associated with mobility of end-systems
+:
Scalability:
• a very large number of mobile networks
• mobile network comprising one or more IP subnets
• very large mobile networks (hundred of SNs or MNs)
Optimal use of network resources:
• Optimal Routing between CNs and nodes behind the MR (both SNs and MNs)
• Minimal signalling load
• Minimise bandwidth use between MR and access router
Mobility transparency for nodes behind the MR
As good security as for mobile nodes (Authentication, Authorisation,…)
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Conclusion: In summary
 Mobile IPv6 can not support mobile networks as is:
redirection by the HA of packets intended to the SNs is not clear
no optimal routing between CNs and SNs
 Solutions:
Prefix Scope Binding Updates (MOTOROLA / INRIA)
• for SNs permanently in the mobile network
HMIPv6 Extended Mode (ERICSSON / INRIA)
• for MNs temporarily in the mobile network
Multicast delivery of Binding Updates (MOTOROLA / INRIA)
• for large mobile network
• still a research item
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Thank you
 Fore more information:
http://www.inrialpes.fr/planete/
• Draft, presentation made at the IETF and other documents
 IETF web site: http://www.ietf.org (MobileIP / Seamoby)
Prefix Scope Binding Update:
draft-ernst-mobileip-v6-network-01.txt
HMIPv6 Extended Mode
draft-ietf-mobileip-hmipv6-03.txt
Seamoby Working Group - micro-mobility design team
draft-ietf-seamoby-mm-problem-01.txt
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