Network Mobility Across Private Domains Harish Viswanathan, Sampath Rangarajan, Suman Das April, 2007
Mobile Broadband new usage scenarios Mobile broadband is evolving to provide high data rates New services and usage models of wide area wireless networks are emerging Further increase in data rates and capacities of MBNs are planned for the future 3G Routers appearing in the market Approved by Sprint, Verizon, Vodafone EV-DO INTERNET UMB, LTE, WiMax Wide area mobile broadband wireless enables network mobility DIR 450 EV- DO Router from D-Link WiFi CISCO 3G WWAN Router 3G Digi-Connect Kyocera 2 Network Mobility April 2007
Example Scenario I: Personal Area Networks in Transit Public Address Public Address Private Address Network Movement 3 Network Mobility April 2007
Example Scenario II: Mobile Mesh Rapidly Deployable Network Network deployed where needed Operating network components move as a whole Internet connectivity may not be there initially Public Address INTERNET Private Address Domain Movement Movement 4 Network Mobility April 2007
Motivation Future networks are likely to be mobile themselves Network itself will be portable Example: Rapidly deployable networks for emergency application Personal area networks between multiple devices move together or separately and join other networks Connectivity to backbone network may not be available before network operation How do we provide services and seamless mobility management when network moves? Evolutionary Approach: Achieve this goal with minimum changes to existing core infrastructure and protocols 5 Network Mobility April 2007
Mobility Management Aspects Treated Layer 3 (IP layer) mobility Retain IP address Be able to route to new location with existing IP address Layer 1 and Layer 2 mobility is handled in a network technology dependent manner Seamless connectivity depends on handoff times at Layers 1, 2, and 3 Restarting/handoff at Layer 1 and 2 typically faster with properly designed technology If Layer 1 and 2 handoff causes substantial interruption resulting in loss of service then seamless Layer 3 mobility may be irrelevant 6 Network Mobility April 2007
Typical Scenario Characteristics Local network of access points interconnected by mesh or other point-tomulti-point network One of the nodes, Gateway AP, has connectivity to the Internet through a wide area access network Wide Area Wireless Network Mobility Scenarios Access terminals (AT) moving within the local network Gateway ATs moving out of the local network A portion of the local network (AP+ATs) moves and joins another similar local network 7 Network Mobility April 2007
Mobility Scenario AT moving out of local network Initial Configuration New Configuration Cellular Network Cellular Network NAT/Gateway NAT/Gateway NAT/Gateway NAT/Gateway Network B Network B Network A Network A 8 Network Mobility April 2007
Mobility Scenario AP moving out of the local network Initial Configuration New Configuration Cellular Network Cellular Network Gateway Gateway Network B Gateway Network A Gateway Network B Network A 9 Network Mobility April 2007
Mobility Scenario 3 Entire Private domain moving under another private domain Initial Configuration New Configuration Cellular Network Cellular Network NAT/Gateway NAT/Gateway NAT/Gateway Network B Network A 10 Network Mobility April 2007
Related Work: Network Mobility Solutions IETF NEMO (Network Mobility) working group has proposed a solution for network mobility Assumes IPv6 prefix based global addressing Assumes mobile node connected to the Internet is a mobile router Based on Mobile IPv6 extensions Incorporates suffix binding to reduce signaling Applicable to IPv4 with public addresses only Main Idea MRs registers network segments explicitly with the HA or known implicitly to the HA. Packets to these network segments received at the HA will be forwarded to the MR 11 Network Mobility April 2007
Key Components of the Network Gateway Access Point (AP) Access Point (AP) Access Terminal (AT) Local network Service Provider Network F-HA Wide Area Wireless Network Wide Area Access Provider Network Fixed Network Home Agent (F-HA) Gateway AP Local Network AP AT 12 Network Mobility April 2007
Direct Mobile IP Solution Gateway AP acts as the foreign agent for AT in standard Mobile IP Public home address assigned to AT by F-HA through gateway using Mobile IP Service Provider Network F-HA Wide Area Wireless Network FA is itself mobile; Home address assigned to it by F-HA Disadvantages Does not address mobility for calls that originated before infrastructure connectivity was available Infrastructure needs to be aware of all nodes in local network Tunneling overhead even in the absence of mobility Local traffic has to be routed through Gateway AT even in the absence of mobility Gateway AP AT Local Network AP 13 Network Mobility April 2007
Mobility Solution with private addresses Co-locate Home Agent functionality for local network nodes at the Gateway node together with the NAT When nodes move, because of private addressing packets will continue to have to be address translated for on-going connections to be maintained Directly tunnel packets from an AP to the Gateway AP to hide old private addresses in the new local network Route optimization whenever possible When Gateway AP itself moves under another Gateway AP then it is possible to route packets directly in the new local network 14 Network Mobility April 2007
Gateway AP Functions Router Personality Host Personality HA FA Local Routing NAT Co-located FA LAN Interface WAN Interface 15 Network Mobility April 2007
Example: Initial Configuration Access-Interface Link 192.168.1.1 135.222.104.1 Cellular Network 2 Mesh Interface-Link 3 4 192.168.15.5 192.168.15.1 192.168.1.1 135.222.104.1 Gateway AP A Gateway AP B 3 4 135.22.108.10 Backhaul-Interface Links 135.222.104.1 2 5 5 Mesh Interface-Link 192.168.5.1 192.168.5.10135.22.108.10 192.168.10.1 1 6 6 135.22.108.10 Access-Interface Link 192.168.10.1 16 Network Mobility April 2007
When Gateway AP A moves under Gateway AP B 1 Access-Interface Link Cellular Network 192.168.1.1 135.222.104.1 2 Mesh Interface-Link 192.168.15.5 192.168.15.1 192.168.1.1 135.222.104.1 NAT/Gateway NAT/Gateway 3 2 1 4 5 3 4 5 Mesh-Interface Link to NAT B 192.168.5.3 192.168.5.1 135.222.108.10 192.168.5.1 192.168.5.10135.22.108.10 135.22.108.10 Mesh Interface-Link Access-Interface Link 192.168.10.1 135.222.104.1 192.168.10.1 17 Network Mobility April 2007
When only AP moves Cellular Network 3 HA+NAT Gateway AP B Gateway AP A FA 4 2 1 5 18 Network Mobility April 2007
Summary Network mobility is likely to become increasingly common with advent of mobile broadband wireless Private addressing and NAT may continue to be in use in some scenarios Maintaining calls when networks move can be addressed by locating HA in the local network together with the NAT Signaling optimizations similar to IETF NEMO solution can be incorporated 19 Network Mobility April 2007