Used to discover a path to a specified Network Number
The NPDU packet optionally contains a 2 octet Network Number.
If this is missing, addressed router responds with it's Routing Table, except for the entries already accessible on the port that the Who-Is-Router-To-Network arrived on. ( See Section 22.214.171.124 pg 60 )
Who-Is-RouterTo-Network is generally be broadcast but may be directed to a specific router to learn the contents of its router table. (126.96.36.199)
If the receiving router has the desired Network Number in it's routing table, it responds with I-Am-Router-To-Network. (Unless the Network Number is already accessible elsewhere on the network that the request originated from)
It shall broadcast this response to allow other devices to take advantage of this information
If it does not contain the desired Network Number, it shall broadcast Who-Is-Router-To-Network further down the line as appropriate. SNET and SADR of the originating device to be included in the new broadcasts so return messages make it back to the originating device, unless the originating device is a router, in which case SNET and SADR are already constructed.
|2||Desired DNET||Optional - specifies desired DNET|
|APDU BBMD BVLC BVLL DADR DNET Encoding I-Am LSAP MAC NPCI NPDU NSAP NSDU SA SADR SNET|
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