Mobile NAT Mobility across Heterogeneous Address Spaces q

Mobile. NAT (Mobility across Heterogeneous Address Spaces) q Presented by Kundan Singh q (Columbia University) q q Joint work with Milind Buddhikot, Adiseshu Hari and Scott Miller q Agenda Motivation Architecture Implementation Comparison with current approaches Summary (30 slides, 60 min) 13 -Oct-03 Mobile. NAT/IRT group meeting

Current Trends Explosive growth in connected devices q Heterogeneity q 802. 11 • Access: 802. 11, 3 G, • • Private address 3 G 13 -Oct-03 Mobile. NAT/IRT group meeting Ethernet Provider; billing Address space Ø IPv 4 vs IPv 6 Ø Public vs Private 2

Project IOTO 13 -Oct-03 http: //www. bell-labs. com/~mbuddhikot/IOTAProject/IOTA. htm Mobile. NAT/IRT group meeting 3

The goal NAT (5) Routed IP Network www. cnn. com Preserve session for 1. inter access-point 2. inter sub-net 3. inter-NAT 4. to 3 G network 5. to public network PDSN/3 G Internet (4) NAT Public Addr A NAT Private Address Space (3) 802. 11 (1) Ethernet Access-point (2) Router with NAT 13 -Oct-03 Mobile. NAT/IRT group meeting 4

Mobile. NAT (Mobility across Heterogeneous Address Spaces) q Presented by Kundan Singh q (Columbia University) q q Joint work with Milind Buddhikot, Adiseshu Hari and Scott Miller 13 -Oct-03 q Mobile. NAT/IRT group meeting Agenda Motivation Architecture Implementation Comparison with current approaches Summary

Problem with IP address TCP association q 128. 59. 16. 149 135. 180. 32. 4 80 1733 • Host identification • Routing information CN (corresponding node) q 128. 59. 16. 149 moves MN (mobile node) Change in IP address breaks TCP/socket connection MN 135. 180. 32. 4 135. 180. 54. 7 135. 180. 32. 4 128. 59. 16. 149 1733 80 135. 180. 54. 7 128. 59. 16. 149 1733 80 13 -Oct-03 IP address overloaded Mobile. NAT/IRT group meeting Convention: Source IP Destination IP SP DP 6

Two addresses q 128. 59. 16. 149 135. 180. 32. 4 80 1733 Two IP addresses • Virtual IP (fixed host-id) • Actual IP (routable; changes) CN 128. 59. 16. 149 Application Socket TCP/UDP IP V=135. 180. 32. 4 Anchor node (AN) MN moves 135. 180. 32. 6 A=135. 180. 54. 7 135. 180. 32. 4 128. 59. 16. 149 1733 80 13 -Oct-03 Addr “V” MN Shim Layer Actual IP Virtual IP Mobile. NAT/IRT group meeting Addr “A” Net IF 7

Packet forwarding mechanisms: tunneling or translation CN 128. 59. 16. 149 V=135. 180. 32. 4 CN 128. 59. 16. 149 135. 180. 32. 4 128. 59. 16. 149 135. 180. 54. 7 AN 128. 59. 16. 149 135. 180. 32. 4 moves V=135. 180. 32. 4 128. 59. 16. 149 135. 180. 32. 4 AN 128. 59. 16. 149 135. 180. 54. 7 moves MN A=135. 180. 54. 7 Translation Tunneling • Outer: CN=>A or HA=>A • Inner: CN=>V • Header overhead • More processing overhead • Not an issue if NAT 1 is already present 1 NAT is described later 13 -Oct-03 Mobile. NAT/IRT group meeting 8

Address allocation using DHCP Virtual and actual IP allocated using DHCP q New DHCP options q • MN sends current virtual IP DHCP server • DHCP relay agent 10. 0. 1. x 10. 0. 2. 2 • address (or 0. 0 if none) in the request Server sends the allocated actual and virtual IP addresses in the response Actual IP is allocated based on relay agent IP 10. 0. 1. 5 10. 0. 2. x 10. 0. 2. 9 13 -Oct-03 Mobile. NAT/IRT group meeting 9

Overview of NA(P)T q CN Packet processing rules need to be changed in the event of mobility 128. 59. 16. 149 Packet processing rule 135. 180. 32. 4 Internet Public Addr 135. 180. 32. 1 -7 128. 59. 16. 149 7088 80 out 10. 0. 1. 5 128. 59. 16. 149 1756 80 In-1 NAT Private Address Space (10. 0 -10. 255) 10. 0. 7. x 10. 0. 1. x 10. 0. 2. x 10. 0. 1. 5 13 -Oct-03 Mobile. NAT/IRT group meeting 10

Mobility manager and MIDCOM to control NAT rules Mobility manager IP in DHCP response q q Internet Change of lease DHCP server Mobility manager NAT rules NAT relay 10. 0. 1. x 10. 0. 2. x 10. 0. 1. 5 13 -Oct-03 Mobile. NAT/IRT group meeting 11

Example Address assignment q Packet flow when MN is private and CN is public q MN moves to a new subnet q Packet flow after mobility to a new subnet q Packet flow when MN and CN are in the same NAT domain q Packet flow when MN is private and CN is public and MN moves to new NAT domain q 13 -Oct-03 Mobile. NAT/IRT group meeting 12

Address assignment Mobility manager DHCP request (my virtual IP = 0. 0) (my Mac address) DHCP server NAT DHCP response (your virtual IP = 10. 128. 0. 2) (your actual IP = 10. 0. 1. 5) DHCP server NAT Internet 13 -Oct-03 Mobile. NAT/IRT group meeting 13

Packet flow 10. 128. 0. 2 128. 59. 16. 149 1756 80 128. 59. 16. 149 10. 128. 0. 2 80 1756 Applicatio n Socket TCP/UDP IP Shim 10. 0. 1. 5 128. 59. 16. 149 1756 80 Shim 128. 59. 16. 149 10. 0. 1. 5 80 1756 NAT 135. 180. 32. 4 128. 59. 16. 149 7088 80 NAT 128. 59. 16. 149 135. 180. 32. 4 80 7088 (1) 10. 128. 0. 2: 1756 Addr “V” SHIM Layer 10. 0. 1. 5: 1756 Addr “A” 10. 0. 1. 5: 1756 135. 180. 32. 4: 7088 (2) (3) Net IF NAT q 13 -Oct-03 Mobile. NAT/IRT group meeting Internet CN NAT picks up an external IP and port 14

Inter-subnet mobility Mobility manager change DHCP request (my virtual IP = 10. 128. 0. 2) DHCP server (my Mac address) NAT rules 10. 0. 2. 7 S: 10. 0. 1. 5: 1756 D: 128. 59. 16. 149: 80 S: 135. 180. 32. 4: 7088 D: same DHCP response (your virtual IP = 10. 128. 0. 2) (your actual IP = 10. 0. 2. 7) 10. 0. 2. x DHCP server NAT Internet CN 10. 0. 1. x 13 -Oct-03 Mobile. NAT/IRT group meeting 15

Packet flow after the node moves 10. 128. 0. 2 128. 59. 16. 149 1756 80 128. 59. 16. 149 10. 128. 0. 2 80 1756 Applicatio n Socket Shim 10. 0. 2. 7 128. 59. 16. 149 1756 80 Shim 128. 59. 16. 149 10. 0. 2. 7 80 1756 NAT 135. 180. 32. 4 128. 59. 16. 149 7088 80 NAT 128. 59. 16. 149 135. 180. 32. 4 80 7088 (1) TCP/UDP 10. 0. 2. 7: 1756 135. 180. 32. 4: 7088 IP Addr “V” SHIM Layer (3) Addr “A” Net IF (2) NAT q 13 -Oct-03 Mobile. NAT/IRT group meeting Internet CN MN application or CN do not know about change in actual IP 16

Intra-domain sessions CN A=10. 0. 4. 9 V=10. 128. 0. 2 A=10. 0. 2. 7 NAT MN Moves V=10. 128. 0. 2 A=10. 0. 1. 5 MN q Optimization: new signaling message between two Mobile. NAT clients to route the packets directly 13 -Oct-03 Mobile. NAT/IRT group meeting 17

Inter-domain mobility q q Mobility manager of visited NAT fetches the existing connection mapping from mobility manager of the home NAT If MN moves to public address space, Shim layer acts as visited NAT Dynamic home agent: use visited NAT as home NAT for new session Tunneling between visited and home NAT MN Visited NAT moves Internet MN Home NAT 13 -Oct-03 Mobile. NAT/IRT group meeting CN 18

Mobile. NAT (Mobility across Heterogeneous Address Spaces) q Presented by Kundan Singh q (Columbia University) q q Joint work with Milind Buddhikot, Adiseshu Hari and Scott Miller 13 -Oct-03 q Mobile. NAT/IRT group meeting Agenda Motivation Architecture Implementation Comparison with current approaches Summary

Implementation: client (Win XP/2000) 10. 128. 0. 2 / 255. 0. 0. 0 Application Mobile. NAT Client Server Client Socket TCP/UDP IP Mobile. NAT Client Mobile. IP Client DHCP server - client Network and interface selector Addr “V” Shim Layer 10. 0. 1. 5 / 255. 0 q q q Addr “A” Net IF Unified mobility client (on-going work) Shim-layer driver to capture DHCP packets and translate IP addresses Mobile. NAT client application acting as DHCP client and server Handles ARP for nodes in other sub-nets 13 -Oct-03 Mobile. NAT/IRT group meeting 20

Client architecture Graphical User Interface & Monitoring OS PPP Support User Level MIP State Machine Network Detection Network Selection Mobile NATClient Interface Abstraction Layer/API Ethernet 802. 11 PPP CDMA 2000 Sierra 3 G 1 x. RTT OS Kernel Level Serial Driver AT Command Set TCP/IP Protocol Stack VPN/IPSec Client Driver Multi-interface Mobility Client Driver IS-835 Shim PPP Interface 13 -Oct-03 Ethernet Interface 802. 11 Interface Virtual Mobile. IP Adaptor Mobile. NAT/IRT group meeting VPN/ IPSec Control New code developed, Specifically for 3 G-802. 11 integration VPN/IPSec integration (e. g. Lucent IPSec Client) Interaction with Existing Windows OS modules 21

User interface q Approximately 45, 000 lines of code, 13, 000 of which are Windows NDIS kernel networking code 13 -Oct-03 Mobile. NAT/IRT group meeting 22

Implementation: DHCP server and NAT (Linux) Virtual IP range Actual IP range NAT connection tracking DHCP server PRE-ROUTING Destination NAT POST-ROUTING Source NAT DHCP server to allocate virtual and actual IP q Actual IP is based on subnet of DHCP relay agent q MM is integrated into DHCP server q NAT using netfilter, iptables, ip_conntrack and ip_nat modules q 13 -Oct-03 Mobile. NAT/IRT group meeting 23

Mobile. NAT (Mobility across Heterogeneous Address Spaces) q Presented by Kundan Singh q (Columbia University) q q Joint work with Milind Buddhikot, Adiseshu Hari and Scott Miller 13 -Oct-03 q Mobile. NAT/IRT group meeting Agenda Motivation Architecture Implementation Comparison with current approaches Summary

Similarities/Differences with current proposals q Translation mode vs. tunneling • Packet size vs processing overhead • Two addresses per MN; can afford since private addresses • No external FA needed q Signaling • Using DHCP (new options) and a per-domain Mobility Manager (MM) q Routing path • No change in routers or CN; but change in MN, NAT and DHCP server • Dynamic home agent (I. e. , the NAT) 13 -Oct-03 Mobile. NAT/IRT group meeting 25

Comparison to existing schemes Schemes considered in following chart q Mobile IP • Extensions: Location Register (MIP-LR), Route Optimization (MIP-RO) q Micro-mobility schemes Ø Cellular IP Ø Hawaii Ø Intra-Domain Mobility Protocol (IDMP) Ø Hierarchical Mobile IP (HMIP) IPv 6 q Application level mobility mechanism q • SIP q Virtual NAT • Similar address translation in the client stack • Targeted for connection migration where both end-points implements v. NAT 13 -Oct-03 Mobile. NAT/IRT group meeting 26

Comparison chart MIP Mobile NAT CIP Hawaii HMIP (RR) IDMP Tele. MIP LR MIP RO SIP IPv 6 MIP messaging Y N Y Y Y - - N Y N N Inter-tunnel Y Y Y N O O N Intra-tunnel - N N Y Y - - - O O N Paging O Y Y - - N Y UD N Host ID HA HA Co. A LCo. A - - SIP HA Co. A virtual signaling Y Data Y Y Y Y DHCP/ Y MM CN modify? N N N Y Y - N N Y MN modify? Y Y Y Y - Y Y Y Router modify? FA Y Y FA FA - - - O N N NAT support Y 1 Y Y IN IN Y IN Non-mobile IP nodes Y N Y Y Y - - - Y Y IN Triangular route Y Y Y N N N/Y N Y: yes N: no - : N/A O: optional IN: independent UD: Under Development 1: We assume Mobile IP with UDP tunneling for NAT Mobile. NAT/IRT group meeting 13 -Oct-03 Virtual NAT 27

Mobile NAT Advantages q Problems in existing approaches • • • q Huge infrastructure change (CIP, IPv 6, routers, even deploying FA) Not much discussion on optimizing intra-domain sessions Require tunneling overhead, inter, intra or both Triangular routing Modification in CN Mobile. NAT approach • Addresses rapid growth in end-devices, which most likely will have private • addresses due to slow deployment of IPv 6 Assume the presence of NA(P)T in a domain Ø Roaming and services across heterogeneous address spaces Ø Reduce problem space to only private address space • Choice between tunneling and address translation Ø Addresses bandwidth limitations of wireless links • Use existing protocols (DHCP, ICMP) for signaling • Discourage changing routing infrastructure • Can co-exist with Mobile. IP 13 -Oct-03 Mobile. NAT/IRT group meeting 28

On-going work q q q Scalability: • Subdivide domains into smaller NAT-ed domains • Multiple NATs per domain Security • DHCP authentication and Access-point authentication/encryption • Works with IP-sec (AH mode and UDP tunnel) and SSL Paging: • Re-use of existing IP-multicast based paging Possible deployment issues • Changing every MN driver (similar to Mobile IP) • Mobility to 3 G network • Location information distribution • Allow incremental deployment Other issues • Does not solve NAT problems where application layer message uses IP address • • • 13 -Oct-03 (FTP, SIP, RTSP) Fast hand-off for micro-mobility Intra-domain sessions on inter-domain mobility Combined Mobile. IP and Mobile. NAT client Mobile. NAT/IRT group meeting 29

Summary q Main Ideas • • • q Virtual IP for host identification; actual IP for routing Address translation in client as well as in NAT Existing protocols like DHCP for signaling Mobility manager to handle nodes in a domain NAT acts as a dynamic home agent Inter-NAT packet flow for inter-domain mobility No change in routers or no need for FA • Change In MN, NAT and DHCP server q Demonstrated a simple inter-subnet mobility 13 -Oct-03 Mobile. NAT/IRT group meeting 30

Survey of existing mobility approaches for private/public addresses BACKUP SLIDES 13 -Oct-03 Mobile. NAT/IRT group meeting

Mobile IP for macro mobility (1) q CN HA Internet • Route optimization q (4) (2) Slow handoff • Hierarchical mobility • Tunneling (HMIP) • Mobile specific routing MN FA (1) CN=>HA (2) HA=>FA CN=>HA (3) CN=>HA (4) HA=>CN Triangular routing (CIP, Hawaii) (3) MN q Signaling overhead • Paging (CIP, Hawaii, HMIP) q Firewall, etc. • Reverse tunneling 13 -Oct-03 Mobile. NAT/IRT group meeting 32

Mobile IP with NAT (2) CN=>HA CN Internet Oubound traffic NAT (1) register; establish port mapping UDP port mapping HA created during register q HA finds that FA is behind NAT (3) HA=>NAT (UDP) CN=>HA (IP) q HA uses IP in UDP tunnel q (4) NAT=>FA (UDP) CN=>HA (IP) FA MN 13 -Oct-03 Mobile. NAT/IRT group meeting 33

Micro mobility: Cellular IP HA Internet gateway Intra-domain cellular IP (non-IP) cloud MN MN Id = HA 13 -Oct-03 Co. A is of gateway (FA) q No change in Co. A within domain q Gateway converts cellular IP to IP q Network elements snoop on data packets from MN to GW; set the reverse route from GW to MN q Paging to discover idle MN q NAT can be at gateway q CN Mobile. NAT/IRT group meeting 34

Micro mobility: Hawaii CN=>HA Co. A is of root router (FA) q Host specific route in IP q Path setup tradeoff q CN HA Internet HA=>Co. A CN=>HA • Explicit signal from MN to root router IP cloud HA=>Co. A CN=>HA Paging (IP multicast) to discover idle MN if no routing information q NAT can be at root router q MN MN Id=Co. A 13 -Oct-03 • update route Packet loss, reorder, handoff latency Mobile. NAT/IRT group meeting 35

Micro mobility: Hierarchical mobile IP CN=>HA HA Internet HA=>GFA CN=>HA GFA=>FA CN=>HA FA MN 13 -Oct-03 Two levels q Works with non-mobile (but) IP traffic in domain q Paging q Two IP addresses (GFA and FA) per MN q NAT can be at GFA q High level network of FA (preferably tree) above IP; registration updates at optimal point in the tree q CN Mobile. NAT/IRT group meeting 36

Micro mobility: IDMP/Tele. MIP CN=>HA CN Internet MA FA MN 13 -Oct-03 MA acts as gateway to HA internet q Subnet agent (e. g. , HA=>MA (GCo. A) DHCP or FA) sends CN=>HA domain info q MN registers MA=>FA (LCo. A) GCo. A=MA @ HA; CN=>HA LCo. A=FA @ MA; two level addressing q Similar to HMIP except multiple MA allowed for load balancing q MA does NAT q Mobile. NAT/IRT group meeting 37

MIP Location Registers CN Get and cache Co. A of MN for given TTL HLR Internet (4) VLR (3) MN 13 -Oct-03 Avoids encapsulation q Modify CN q New VLR deregisters old VLR q If VLR runs out of address inform HLR; which informs CN to use tunnel from CN to VLR q If MN moves before TTL, (1) inform VLR, HLR that informs CN (2) inform CN directly (3) old VLR relays to new q Mobile. NAT/IRT group meeting 38

SIP application level mobility Initial INVITE CN Home SIP server Internet Re-INVITE Re-REGISTER MN 13 -Oct-03 Only for Vo. IP/multimedia calls q No change in existing infrastructure q NAT traversal (next slide) q Initial INVITE MN Mobile. NAT/IRT group meeting 39

Middle box communication (midcom) Internet signaling NAT midcom server signaling media host 13 -Oct-03 Application specific proxy server controls NAT/firewall port binding/hole q Separate NAT/ALG functionality q Proxy snoops or modifies signaling q Signaling traffic allowed on fixed port; media on dynamic port q Works with SIP q No incentive to install q CN Mobile. NAT/IRT group meeting 40

Simple Traversal of UDP through NAT (STUN) stun server CN q (2) q Internet (6) (3) q NAT q (5) (1) (4) q q host Host sends a packet to stun server NAT converts internal IP to external IP Responds with source IP of packet (i. e. , external) Host knows that its external IP is not same as internal It uses external IP/port when advertising in SDP Does not work for symmetric NAT • external IP for same host different for connection to different external host 13 -Oct-03 Mobile. NAT/IRT group meeting 41

Realm Specific IP (RSIP) q CN Internet CN NAT NAT host <CN NAT> q q q Get an external address from NAT for this private host Tunnel packets between NAT and private host Works for various combinations of multiple RSIP gateway, NAT with RSIP, and RSIP hosts. Need RSIP aware host 13 -Oct-03 Mobile. NAT/IRT group meeting 42

Mobility in IPv 6 CN (1) First IPv 6 packet CN=>HA (3) IPv 6 (4) destination subsequent option packets q HA • Always obtain a Co. A in FN • Net part+local part • No FA needed Internet (2) Tunneled HA=>Co. A CN=>HA Address autoconfiguration q Route optimization • IPv 6 Destination option to • MN q CN and HA CN caches Co. A of MN and sends directly Hierarchical MIPv 6 • Global address = mobile • 13 -Oct-03 Mobile. NAT/IRT group meeting server’s network; allow change in MS Local address known to mobile server 43

Mobile NAT: motivation q Problems in existing approaches • • • q Not much discussion on optimizing intra-domain sessions Require tunneling overhead, inter, intra or both Triangular routing or modification in CN Huge infrastructure change (CIP, IPv 6, even deploying FA). . . What Mobile. NAT does? • • 13 -Oct-03 Reduce problem space to only private address space MN Assume the presence of NA(P)T in a domain Choice between tunneling and address translation Use existing protocols (DHCP, ICMP) for signaling mobility Discourage changing routing infrastructure Can co-exist with Mobile. IP, Hawaii and IPv 6 (? ) Provide roaming and services across heterogeneous address spaces demarked by address translation devices Mobile. NAT/IRT group meeting 44

Mobile NAT: intra-domain q CN • HA is in NAT (MN is private) • FA is in MN (driver, kernel) Internet CN<=>A q A=a Virtual vs routable address • Virtual: fixed private address “a” NAT • IP cloud CN<=>b a/b No explicit HA or FA MN • q exposed to application on MN Routable: dynamic private address “a” or “b” using DHCP Transport sessions between CN A (external), CN a (internal) Address translation • NAT (A a b), MN (b a) a/a MN Id=Private 13 -Oct-03 q Tunneling • NAT MN Mobile. NAT/IRT group meeting 45

Mobile NAT: inter-domain Inter-NAT tunnel or relay q MN moves a/a=>a/c q NAT 1 and NAT informed q Translation q CN Internet B=a CN<=>A NAT 2 A=a NAT 1 CN<=>b a/c • NAT 1: A a B • NAT 2: B a c • MN: c a MN q Issues • Multiple “a” in NAT 2 Ø But unique map B a • Does IP security work (? ) q a/a 13 -Oct-03 MN Like Mobile IP • FA=NAT 2, HA=NAT 1 • At most two level of NATs Mobile. NAT/IRT group meeting 46

Mobile NAT: intra-domain sessions CN q • MN 2 sends to NAT; destination “a” • NAT responds router redirect “b” (? ) • MN 2 now sends to MN 1 Internet A=a q NAT MN 2 MN 1 a/b MN 1 active session MN 1 moves a/b=>a/c • • • d/e a/c MN 1 MN 2 active session q MN 1 gets “c” DHCP server (or MN 1) informs NAT MN 2 gets ICMP host unreachable Starts sending to NAT responds router redirect “c” MN 1 moves out of domain • Path MN 1 visited NAT home NAT MN 2 (? ) ICMP Redirect message is expected from router in the same sub-net to which packet is being sent. It is vulnerable to attacks (confirm? ) Cisco routers don’t forward ICMP redirect from another network. We may use proprietary IP options if allowed. 13 -Oct-03 Mobile. NAT/IRT group meeting 47

TODO q Can Mobile. NAT co-exist with MIP, Hawaii and non-mobile but IP clients? • • 13 -Oct-03 If MIP MN discovers no FA, switches to Mobile. NAT If Mobile. NAT MN discovers FA, enables both MIP and Mobile. NAT If Mobile. NAT MN goes out of domain and gets a public address If a public MN moves within the domain and gets private address For intra-domain session between MN and fixed IP host, route optimization does not work Does route optimization work if both MN move at the same time? Does Mobile. NAT work with multicast? Write a simulation program for Mobile. NAT, Mobile. IP and Hawaii network Mobile. NAT/IRT group meeting 48

TODO q Can part of it be implemented using existing protocols like Mobile IPv 6 (destination option for route optimization), IDMP (for public/private addresses), RSIP)? • Intra-domain Route optimization is similar to IPv 6 destination option; can • • • 13 -Oct-03 we use IPv 6 within domain – need to change all routers (? ) Assuming IPv 6 domain with NAT as IPv 4 IPv 6 converter. What changes we need in NAT/IOTA so that it works with Mobile IP? For IPv 6 do we need private address domain? How do we minimize changes in IPv 6 MN? IDMP supports multiple MA. Can we install multiple NAT/IOTA for load balancing? Does tunnel mode Mobile. NAT reduce to IDMP, when HA is outside of NAT and FA is in MN? (yes) Why can’t Mobile. NAT be proposed as an extension to IDMP? IDMP does not describe intra-domain session optimization. Mobile. NAT/IRT group meeting 49

TODO q Windows related issues • Check if TCP connections are dropped when ipconfig /release is done • Check what happens when CONNECTED status is indicated on already • q connected state Check if TCP connections are dropped even if DISCONNECTED status is not propagated to higher layer Possible deployment hindrances • • 13 -Oct-03 Changing every MN driver (similar to Mobile IP) Should allow incremental deployment Processing overhead on NAT/IOTA What happens to domain/sub-net specific options that are not indicated to the higher layer when domain/sub-net change? Need to write a controlling application also that does Dhcp. Ip. Renew. Address when driver finds a different options field. Mobile. NAT/IRT group meeting 50

TODO q Basic design issues • • • Does DHCP security/authentication work? Can we use ICMP router redirect from NAT to private host? Can IP security work in all scenarios? Fast handoff applicability Since anyway we are modifying MN driver, can it be made more extensible or more auto-configurable. Ø E. g. , if IOTA/NAT is moved to sub-net routers then can modification in MN be avoided? What if multiple hierarchical IOTA/NAT in a domain? 13 -Oct-03 Mobile. NAT/IRT group meeting 51