ipcn - thierry ernst - may 2001 1 mobile routers in ipv6 thierry ernst - motorola labs & inria...

IPCN - Thierry Ernst - May 2001

1

Mobile Routers in IPv6

Thierry Ernst - MOTOROLA Labs & INRIA (Planete)

Claude Castelluccia - INRIA (Planete)

Hong-Yon Lach - Motorola Labs

PLANETE TEAMPLANETE TEAMIPCN - Thierry Ernst - May 2001 - 2

Presentation overviewForewordMobile 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


ForewordMost 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


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


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


devices and networks are: always connected by heterogeneous networks unified by IP

Wireless WAN (IEEE 802.11b, GPRS, Bluetooth, ...)

Wired or Wireless LAN(WaveLAN, HiperLAN,..)

john@work

john@mylovelycar

Picocellular MAN

john@street

Mobile Networks: the Mobile Network vision


mylovelycar@queuecar

john@mylovelycar

Mobile Networks: The Mobile Network visionmobile 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

= Mobile Router

INTERNETINTERNET

queuecar@motorway


Mobile Networks: Internet Definition

MR

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


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

SN

MR MN

SN


Mobile Network: CharacteristicsAs 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

SN

MR

MN

SN

MR

SN


Mobile Networks: Aim of Mobility Supportto provide continuous Internet connectivity to nodes

located in the mobile networkto offer optimal routing between CNs and nodes located

in the mobile network (both SNs and MNs)

end-system

SN


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 Micro-mobility routing): support of mobile routers and networks is listed by the micro-

mobility 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


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 )

IETF Status: Mobile IPv6 for mobile nodes (review)


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.


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

IETF Status: Mobile IPv6 for mobile networks ?


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


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

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



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

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


CN’s BINDING CACHECN’s BINDING CACHEMR home address => MR’s CoA = Standard Mobile IPv6 Mobile Network prefix /48 => MR’s CoA = our extension


IETF Status: Extended mode in HMIPv6Draft-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


MR ’s Home AgentMR ’s Home Agent

MN ’s CorrespondentMN ’s Correspondent

RCoA / LCoA1RCoA / LCoA1

RCoARCoA

MR H@ => RCoAMR H@ => RCoA

MN H@ => RCoAMN H@ => RCoA

LCoA1, RCoALCoA1, RCoA MAPMAPRCoARCoA

MN ’s Home AgentMN ’s Home Agent

MNMN

MRMR


IETF Status: Extended mode in HMIPv6MR has 2 CoAs:

• RCoA is permanent in the site• LCoA changes at each new Access Router

MN uses MR’s RCoA as its CoAMN registers RCoA with MAP, its HA and CNs


RCoA / LCoA2RCoA / LCoA2

RCoARCoA

MR H@ => RCoAMR H@ => RCoA


LCoA1, RCoALCoA1, RCoA

LCoA2, RCoALCoA2, RCoAMAPMAP

RCoARCoA

MR ’s Home AgentMR ’s Home Agent

MN ’s CorrespondentMN ’s Correspondent

MN ’s Home AgentMN ’s Home Agent


MRMR

MNMN

IETF Status: Extended mode in HMIPv6MN 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 !)


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

IETF Status:


Ongoing work: How to minimise signalling ?

Binding Update explosion

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

• 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


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


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


Conclusion: Open issuesMobile 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


Conclusion: RequirementsRequirements 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,…)


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


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

ipcn - thierry ernst - may 2001 1 mobile routers in ipv6 thierry ernst - motorola labs & inria...

Documents

mobile ipv6 mobile network

mobile umobile networks

mylovelycar mobile networks

street mobile networks

mobile ualways

mobile router slide

mobile network unodes

set of mobile devices