Question

Make a Presentation about the topic"6lowpan on network ". It shouldn't take more than 20 minutes of presentation and should not be copy pasted from Google.

Answer 1

1>Introduction of 6lowpan:

>What it is: 6lowpan is an IoT networking protocol which is open as it is specified by IETF(Internet Engineering Task Force).

>Need: To make network reachable to low power devices, IPV6 is upgraded with low power personal area network. The need for 6lowpan comes when Internet of things is going to implemented. In Internet of things, there are many low power devices like open of window, close of door in IoT. 6lowpan makes able the network to communicate with these low power devices.

>How: For this 6lowpan uses technique of encapsulation and header compression. These techniques make sure IPV6 packets should sent or received IEEE 802.15.4 based network.

>Where to use: 6lowpan is used in variety of applications like wireless sensor network, IoT, home, industry.

2>Overview of IEEE 802.15.4

>IEEE 802.15.4 Is WPAN means wireless personal area network. Here node send packets to other nodes for communication.

>When a node wants to join the network, it makes use of WIFI access point.

>Here 64-bit address is used for nodes with maximum frame size of 127 bytes.

3>6lowpan

>Meaning

• 6 means IPV6
• low means low power wireless
• pan means personal area network

>It uses mesh topology with mesh addressing as intermediate address and mesh broadcast by hop by hop.

>It uses simple addressing with no routing i.e. direct addressing of nodes.

>It has RFC4944. adaptation layer between data link layer and network layer.

>In RFC4944, neighbour discovery is done via autoconfiguration.

>RFC4944, RFC6282 and RFC7400 for header and payload compression.

4>6lowpan adaptation layer:

>Adaptation layer is the layer between data link layer and network layer.

>Adaptation layer means it become the part of network layer and of data link layer.

>In this, for acknowledgement hop by hop feature of WPAN is used by keeping in mind that number of retransmissions should be less.

> See image attached for position of adaptation layer.

5>6lowpan fragmentation

>Need for fragmentation: IPV6 has maximum packet size of 1280 bytes. So, for such large packet’s fragmentation should be done because maximum size handled is 127 bytes.

>For these 11 bits are kept for fragmentation header.

>As fragmentation decreases the performance of network large packet should be avoided.

6>Header size

>Maximum frame size in WPAN is 127 bytes.

25-frame header

21-LLC section

40-IPV6 header

UDP

33-payload

Now see here total size is 127 and 25+21+40 is used for other purpose. So, we left with only 33 bytes for payload.

7>IPV6 header compression

>Header compression is done by two ways:

1.With single hop.

2.With multi hop.

>These ways are updated and deprecated by IPHC and NHC (next header compression).

>GHC (generic header compression) facilitate extension to header.

>There are other schemes also. For example, EAP.

>This compression is specified in RFC4944.

>It supports UDP compression.

>One thing that make compression complicated is address needed the prefix to be carried. It decreases efficiency of compression.  

See the image attached.

8>Stateless address Autoconfiguration

>Based on layer 2 address autoconfiguration is done.

>For this Link local address use the FE80::/64 prefix. So, for autoconfiguration link this.

>For autoconfiguration after linking local neighbour discovery is done as specified if RFC6775.

9>Summary

i)It has 3 new headers:

>Mesh addressing intermediate address.

>Mesh broadcast by hop by hop.

>Fragmentation for destination processing.

ii)127-byte header size..

iii)Adaptation layer.

iv)Header compression by two ways.

v)Autoconfiguration.