What is the difference between ETWS primary notification and secondary notification?

Question

Please give any example with scenario for making it more clear ....

Answer 1

LTE supports functionality to distribute warning messages through its network. Apart from LTE MME and eNodeB, two other nodes like CBE and CBC have been developed/implemented to meet this requirement.
When an warning message information needs to send from emergency services agencies, first they send to CBE.
Once CBC receives this information, it prepares and sends Write-Replace Warning Request to MME and MME responds with confirmation to CBC. Based on the location information presents within the Write-Replace Warning Request message, MME sends Write-Replace Warning Request to relevant eNodeBs.

SIB 10 is used to send ETWS primary notification and SIB 11 is used to send ETWS secondary notifications. Primary notification just tells about warning message type (message identifier + serial number) while secondary notification is used to carry actual warning text message.

References:
1.https://www.nttdocomo.co.jp/english/binary/pdf/corporate/technology/rd/technical_journal/bn/vol11_3/vol11_3_020en.pdf
2. 3GPP TS 36.331

Comments

The last sentence is not quite correct. The standard allows either the primary or secondary notification to stand alone. The purpose of the primary is to make it small enough to be sent with <4 sec latency but have enough information for the receiving device to take pre-programmed action. The alert types that are currently defined are: earthquake, tsunami, earthquake and tsunami, test and other. There are also values reserved for future use.

Reference: 3GPP TS 22.268 v13.0.0  http://www.3gpp.org/ftp/Specs/archive/22_series/22.268/22268-d00.zip

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Thanks to correct me. Can you please share the reference ?