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Asymmetric Broadband Roaming over DVB

• Workshop on Broadband Wireless Ad-Hoc Networks
  and Services 12th - 13th September 2002 ETSI,
  Sophia Antipolis, France
• UNCLASSIFIED
• R. Segura, NATO C3 Agency, ACT/CISD
• ramon.segura_at_nc3a.nato.int

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The NATO C3 Agency Role

• Perform central planning, systems integration,
  design, systems engineering, technical support
  and configuration control for NATO C3 systems and
  installations
• Provide scientific and technical advice and
  support to the Strategic Commands and other
  customers on matters pertaining to
• operations research,
• surveillance, air command and control including
  theatre missile defence,
• electronic warfare and airborne early warning
• communications and information systems
• Provide technical support for exercises and for
  unforeseen operations assigned to the NATO
  Military Authorities (NMA) by the North Atlantic
  Council (NAC)/Defence Planning Committee (DPC)

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The NATO C3 Agency Role (cont.)

• Perform technical policy and standardization work
  in support of the NATO C3 Board (NATO
  Standardization Agreements, a.k.a. STANAGs)
• Procurement and project implementations

The NATO C3 Agency became Member of Project MESA
in April 2002
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IP Roaming over DVB Motivation

• Supporting the wideband communications
  requirements of multi-national forces engaged in
  rapid coalition deployments, e.g.
• Humanitarian relief
• Peacekeeping, Peace Enforcement, Collective
  defence
• Nomadic networks provided by participating
  nations are integrated into mobile Virtual
  Network (VN) overlays, subtended by a fixed
  backbone established by the nation leading the
  deployment
• VNs shall support broadband content delivery from
  fixed data repositories to hosts in the Mobile
  Networks through symmetric or asymmetric data
  transactions
• VNs shall support communications between mobile
  networks
• Satellite and Terrestrial DVB bearers, carrying
  IP over MPEG2 are proposed to transport the
  forward traffic from fixed to mobile hosts

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Mobile Networks, Mobile Routers

• Mobile Network a stub LAN connected to an access
  router that supports IP mobility as per RFC 2002
  (Mobile Router)
• A Mobile Router can have multiple roaming
  interfaces, which can dock into the fixed IP
  network over different wireless media and access
  points
• The Mobile Routers counterpart in the fixed
  network is the Home Agent Router
• The Home Agent has WAN access to a number of
  Foreign Agent routers, which cover the area where
  Mobile Routers will be roaming during the mission
• The Home Agent is the single gateway for all
  traffic addressed to the Mobile Networks,
  effectively acting as a registration and routing
  broker

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Mobile Router Principle

• The Mobile IP model (RFC 2002) is extended from
  the classic Mobile Host to the Mobile Router
  implementation (e.g. Cisco IOS 12.2)
• Mobile Routers listen to routing service
  advertisements from Foreign Agents after entering
  their coverage area, and can register with the
  Home Agent through the Foreign Agent of their
  choice
• Following registration, all traffic from fixed
  and mobile hosts addressed to the Mobile Networks
  is routed to the Home Agent, and then
  double-tunnelled (using IP-IP encapsulation)
• Outer Tunnel from Home Agent to Foreign Agent
• Inner Tunnel from Home Agent to Mobile Router
• All traffic from the Mobile Networks is by
  default sent to the Foreign Agent, and passed to
  the destination host using standard routing
  mechanisms (or mobile IP if the destination host
  is in a Mobile Network)

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Virtual Networks

• Objective is to build Virtual Networks in which
  all nodes are mobile over a wire area of
  operations
• Mobile Routers are access routers in motion
  around a wide area wireless access infrastructure
• Mobile Networks hooked to the Mobile Router need
  not be Mobile-IP aware, and can maintain their
  home IP configuration
• All traffic is tunnelled through a virtual Home
  Agent down to the Foreign Agent covering the area
  visited by the Mobile Network
• The Home Agent is virtual in the sense that it is
  not attached to the actual (domestic) home
  network of any of the mobile networks
• The Home Agent advertises IP routes for all
  registered mobile networks

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Virtual Networks
at the docking site
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Virtual Networks
on the move
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Tunnel Overlays

• Mobile Routers are logically meshed over a
  star-shaped overlay of IP-IP tunnels
• Hub spoke topology spokes are established
  on-demand, between the Home Agent (hub) and the
  edge Foreign Agents
• IP encryption devices can be used for securing
  all mobile network traffic, either
• as an IPSEC tunnel overlay, i.e. the crypto is
  placed between the Mobile Router and the Mobile
  Network(s) mobile IP protocol goes in the
  clear
• - or -
• at the air interface edge (), i.e. the crypto
  is placed as a bump-in-the-wire between the
  Foreign Agent and the wireless/broadcast
  front-end (and between the wireless front-end and
  the Mobile Router)

() this configuration requires the IP crypto to
support broadcast/multicast
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Implementation Constraints

• Time, budget and technology constrained military
  deployment scenarios
• establishing a cellular network of several
  access points with omni directional antennas,
  full-duplex, wide area coverage and broadband
  capabilities may not be feasible
• Yet traffic flows between fixed and mobile
  networks are expected to be highly asymmetric in
  bandwidth, therefore
• broadband unidirectional bearers (e.g. DVB-S /
  T) could carry forward traffic downstream into
  the mobile nodes
• narrowband channels of opportunity could carry
  return traffic upstream (mobile IP registration
  and user traffic)
• take advantage of users in mobile networks
  already carrying legacy narrowband and personal
  communications systems, which can be used to
  hook into the fixed network

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Cellular Broadcast Solution

• Combine asymmetric split-path network
  configurations with mobile routing protocols
• Connect transmit-only Foreign Agent routers to a
  star network of broadcast stations blanketing the
  missions target area
• Broadcasts from a Foreign Agent can go over a
  satellite spot beam (DVB-S) or a terrestrial cell
  (DVB-T)
• Mobile Routers will receive the broadcast over
  one or more wideband roaming interfaces (receive
  only)
• Mobile Routers return traffic will be diverted
  over narrowband transmit media, and reach the
  Foreign Agent over one or multiple hops across
  the fixed network (first hop being wireless)

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DVB-S Scenario

• Macro-cellular infrastructure intent is to
  provide broadband roaming services to very
  high-speed moving platforms, e.g. aircrafts,
  equipped with steerable antennas (phased arrays
  or reflectors)
• Continuous coverage can be provided by multiple
  downlink spot beams (e.g. at Ka-band), or by
  multiple satellites
• Each footprint is fed by a different Foreign
  Agent and uplink hub
• Mobile units are equipped with satellite tracking
  antennas, and DVB-S Integrated-Receive-Decoders
  (IRD) with multiple tuners (one per beam)
• Changing beams involves re-registering with the
  Home Agent through a different Foreign Agent
• Registration and return traffic goes over a
  different medium (e.g. Inmarsat phone, VHF radio,
  etc.)

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DVB-T Scenario

• Micro-cellular infrastructure intent is to
  provide roaming services to fast moving land
  platforms equipped with omni-directional antennas
• Target area covered by cells of a DVB-T
  Multi-Frequency Network (MFN)
• Each cell is fed by a different Foreign Agent and
  transmit front-end, and operates at a different
  channel frequency
• Mobile units are equipped with light UHF
  omni-antennas (GSM-like), and DVB-T IRD, fitted
  with multiple tuners (one per MFN channel)
• Handovers between cells involve re-registering
  with the Home Agent through a different Foreign
  Agent
• Registration and return traffic goes over a
  different medium (e.g. GSM/GPRS, TETRA, 802.11b,
  UMTS, etc.)

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IP over DVB Bearers

• Multi-Protocol Encapsulation (MPE, ISO/IEC 13818)
  to carry unicast and multicast IP packets
  encapsulated into MPEG2 transport streams
• IP/MPEG2 Encapsulator (IPE) placed between the
  Foreign Agent Router and the DVB modulator
  (satellite or terrestrial), over Fast Ethernet
  and MPEG-2 ASI interfaces

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The DVB-T Advantage

• COFDM over Band IV/V UHF channels (470872 MHz
  6, 7, and 8 MHz)
• NATO can use channels 61 to 69 (790 MHz 862
  MHz), which are part of the military radio relay
  band (Chester Multinational Coordination
  Agreement, 25 July 1997)
• Can also use VHF (46-250 MHz) or L-band
• COFDM provides
• unprecedented performance against fast and
  selective multipath fading
• resilience against narrowband interferers
• support of fast moving platforms at data rates up
  to 10-15 Mbps
• DVB-T IRDs are small, compact and inexpensive
  (e.g. PCMCIA)
• DVB-T cells can be very large in open field
  propagation environments
• Use of civilian broadcast infrastructure can
  significantly shorten the deployment times (i.e.
  transmitters and bandwidth of opportunity )

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Mobile IP - Asymmetric Link support

• Asymmetric link support is provided by the latest
  implementation of RFC 2002 in Cisco IOS (12.2)
  ()
• Foreign Agent interface can now be a
  transmit-only Fast Ethernet port
• Mobile Router roaming interface is receive-only,
  return traffic is redirected to a different
  interface (e.g. a dial-up GSM/GPRS)
• One single IP/DVB broadcast bearer can serve
  multiple Mobile Routers in the cell, each
  attached to multiple Mobile Networks (stub LANs)
• Each Mobile Router roaming interface address is
  assigned an MPEG2 Program ID (PID). Multicast
  advertisements PID is defined in all receivers
• One single Home Agent can manage multiple VN in
  the area, each with a variable number of hosts
  (Mobile Routers)

() NC3A tested experimental version in March 2002
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Mobile Router split-path registration over a
DVB-T broadcast bearer
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Mobile Node a sample PC-104 stack
PC-104 ruggedized enclosure
Western Datacom Type-2 IP Crypto (PC-104
form-factor)
PCMCIA DVB-T IRD
PC-104 embedded PC w. PCMCIA slot
Ciscos Mobile Router prototype, now Cisco 3200
(PC-104 form factor)
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Satellite-Terrestrial Augmentation

• Motivation need to receive broadband content
  from strategic data repositories, as well as from
  theatre-deployed sources (sensors)
• The former is of global interest, and can be
  transmitted as multicast to all theatres over
  satellite DVB
• The latter is of local interest, and can be
  transmitted as roaming unicast to a limited area
  (cell) over terrestrial DVB
• Target mobile units receiving both global and
  local products aggregated over the same DVB-T
  broadcast carrier, eliminating the need for a
  motion-stabilized satellite dish
• Means satellite-terrestrial MPEG2 relay
  stations, IP/MPEG2 inserters (using opportunistic
  bandwidth on the received MPEG2 transport stream)
• Mobile IP tunnels are combined at MPEG2 level
  with IP multicast flows received over the
  satellite channel

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Satellite-Terrestrial Relays
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with Mobile Routers
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Conclusions

• Combining DVB broadcast with mobile routing under
  very asymmetric networking configurations can
  speed up deployments involving mobile networks
  from multiple coalition partners
• Virtual-network topology enables communications
  among mobile networks through a virtual Home
  Agent acting as a hub
• Proposed architecture is fully based on open
  standards (ETSI, ISO/IEC, IETF) mainstream,
  multi-vendor components
• COTS technology is combined with MOTS/GOTS Type-1
  IP encryption devices to meet military COMSEC
  requirements
• Tradeoff space symmetric vs. asymmetric
  broadband access alternatives, in terms of
  deployment costs, channel capacity, mobility
  support and coverage range

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• Questions?