Route Record Indicator - 0xA1
Description
This frame type contains the routing information for a remote device on the network. This route information should be stored in external memory and used in a Create Source Route - 0x21 frame to provide a return route for subsequent data transmissions; this eliminates the need to perform a route discovery.
This frame type is emitted when a network concentrator receives a route record from a remote device. The type of concentrator determines how often this frame type is emitted: a high RAM concentrator (the default) will emit this frame type when a unicast data transmission is received for the first time. If a previously established route fails, a new 0xA1 Route Record Indicator will be generated. A low RAM concentrator will emit this frame for every received transmission. Concentrator type is determined by DO (Miscellaneous Device Options) bit 6.
Format
The following table provides the contents of the frame. For details on frame structure, see API frame format.
| Offset | Size | Frame Field | Description |
|---|---|---|---|
| 0 | 8-bit | Start Delimiter | Indicates the start of an API frame. |
| 1 | 16-bit | Length | Number of bytes between the length and checksum. |
| 3 | 8-bit | Frame type |
Route Record Indicator - 0xA1 |
| 5 | 64-bit |
64-bit source address |
The 64-bit IEEE address of the device that initiated the route record. |
| 13 | 16-bit | 16-bit source address | The 16-bit network address of the device that initiated the route record. |
| 15 | 8-bit |
Receive Options |
Bit field of options that apply to the received message:
|
| 16 | 8-bit | Number of addresses |
The number of addresses in the source route—excluding source and destination. |
| 17-n | 16-bit variable | Address |
The 16-bit network address(es) of the devices along the source route, excluding the source and destination. The addresses are in order from destination to source and match the order to be entered into the Create Source Route - 0x21 frame. |
| EOF | 8-bit | Checksum | 0xFF minus the 8-bit sum of bytes from offset 3 to this byte (between length and checksum). |
Examples
Each example is written without escapes (AP = 1) and all bytes are represented in hex format. For brevity, the start delimiter, length, and checksum fields have been excluded.
4-hop route
A remote device sends a unicast transmission to a concentrator that is 4-hops away. The concentrator emits a route record that can be stored for use in a subsequent Create Source Route - 0x21 frame prior to sending data back to the remote.
The route looks like this:
Destination (concentrator) <> Router A <> Router B <> Router C <> Source (remote)
7E 00 13 A1 00 13 A2 00 12 34 56 78 DD DD 01 03 CC CC BB BB AA AA 75
| Frame type | 64-bit source | 16-bit source | Options | Num of addresses | Address 1 | Address 2 | Address 3 |
|---|---|---|---|---|---|---|---|
| 0xA1 |
0x0013A200 |
0xDDDD | 0x01 | 0x03 | 0xCCCC | 0xBBBB | 0xAAAA |
| Route | Source IEEE address | Source NWK address |
|
3 | Neighbor of source | Intermediate hop | Neighbor of destination |
PDF
