Header Compression for Communication exceed 6LoWPAN

outline Problem statement and analysis Solution 1-the existing technical Solution 2-Header Compression base on binding table

Problem statement and analysis(1/2) packet transportation within 6LoWPAN –Source and destination IPv6 addresses in adaptation layer header use MAC addresses, e.g. 7 octet. Reference to RFC4994 6LoWPAN nodes communicate to nodes outside –The source IPv6 address prefix, the prefix and interface identifier of destination IPv6 address would not be omitted, for a total 24 octet.

Problem statement and analysis(2/2) In the 6LoWPAN applications, more scenarios is the communication among nodes within and out of 6lowpan. The cost reduction is to be further addressed, in case a 6LoWPAN node sends a IPv6 package to an IP address outside.

Solution 1 twice-NAT FE80::1:1:1:1 FE80::2:2:2:2 FE80::3:3:3:3 402::0/ ::234: Send a DNS request Q= NAT table FE80::A:A:A:A=202::23 4:89 2.Gateway DNS request Q= R=202::234:89 3.Router reply R=FE80::A:A:A:A 4.Connection request source IP: FE80::3:3:3:3 Dest IP: FE80::A:A:A:A FE80::1:1:1:1=402::1 FE80::2:2:2:2=402::2 FE80::3:3:3:3=402::3 5.Translation request source IP: 402::3 dest IP: 202::234:89 7.Translation reply source IP: FE80::A:A:A:A Dest IP: FE80::3:3:3:3 6.Connection reply source IP: 202::234:89 Dest IP: 402::3 Save 16 byte prefix when use 64-bit extended address The allocation of internal address to external equipment of 6loWPAN and management will be Complex. FE80::7:7:7:7 Reference to: IPv6 Global to Link-layer ADdress Translation for 6LoWPAN Overhead Reducing Zimmermann, A.; Sa Silva, J.; Sobral, J.B.M.; Boavida, F.;

Solution 2 The mechanism to use 16bits short address to identify 6LoWPAN nodes; A binding table with scheme of 16bit short address, PAN id, binding id, identifier of external node and binding expiration, maintained by edge router NOTE: information already stored in edge router. Edge gateway converts inner identifiers and outer identifiers when communication.

Solution 2 1. When a node A within the PAN communicate to nodes outside PAN ， the packet is sent to the edge router with 16bits short address and identifier of destination (IP address or host name).  6LoWPAN edge router uses above binding table to maintain the connections with nodes out of 6LoWPAN.  A static mapping or DNS query mechanism are used to establish the binding table FE80::1:1:1:1 FE80::2:2:2:2 FE80::3:3:3:3 402::0/ ::234:89 FE80::7:7:7:7 64bit MAC address 16bit short address PAN ID binding ID external device binding expiration

IPHC Encoding Extension 2. Node A uses16-bit short address and sends a request extension to DAM fields of LOWPAN_IPHC Encoding | 0 | 1 | 1 | TF |NH | HLIM |CID|SAC| SAM | M |DAC| DAM | LOWPAN_IPHC Encoding DAM=10 no use of binding ID DAM=11 use of binding ID, In accordance with the indication to use binding ID, following 1 octet is to indicate binding ID 3. When node A using binding identifier, edge router fetches the binding table with 16-bit short address and binding ID, and encapsulates data packets sending to the corresponding node out of 6lowpan. If M=1 and DAC=1 00: 48 bits. 01: reserved. 10: reserved 11: reserved From Ietf-6lowpan-hc

binding table scheme(4/4) the maintenance of binding table as node move In the same subnet prefix within the different PAN FE80::1:1:1:1 FE80::2:2:2:2 FE80::3:3:3:3 402::0/ ::234: ::1:0/128 FE80::9:9:9:9 FE80::f:f:f:f FE80::3:3:3:3 64bit MAC address 16bit short address PAN ID Binding ID external device binding period 3:3:3: ::234: bit MAC address 16bit short address PAN ID Binding ID external device binding period 3:3:3: ::234:89100

Compare of two solution headerMAC headeradaptation header fieldSource addrDest addrsource IPdest IP Twice-NAT3:3:3:3(64bi t) 7:7:7:7(64 bit) 0bitA:A:A:A(64bit) Binding- table 3(16bit)0(16bit)0bit FE80::1:1:1:1FE80::2:2:2:2 FE80::3:3:3:3 402::0/ ::234:89 FE80::7:7:7:7  Compare to solution 1,the Binding-table solution can reduce 160 bits. Phy headerMAC headerAdaptation headerIP payload

Consideration next steps Extension to LOWPAN_IPHC Encoding in page 8 is possible to define alternative methods.

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