The graceful-restart suppress-sa command suppresses the suppress-advertisement (SA) bit of the restart TLV.
The undo graceful-restart suppress-sa command restores the default setting.
By default, the SA bit of the restart TLV is not suppressed.
Usage Scenario
The switch that starts for the first time (not including GR) does not maintain the forwarding status. If the switch does not start for the first time, the LSPs generated when the switch run last time may exist in the LSP database of other switches in the network.
The sequence number of the LSP fragment is reinitialized when the switch starts, so the LSPs stored in the LSP database of other switches seem to be newer than the LSPs generated after the switch starts. This leads to the black hole in the network, and the black hole lasts until the switch regenerates its LSPs and advertises the LSPs with the highest sequence number.
If the neighbor suppresses the advertisement of the adjacency relationship to this switch during the switch starting until the switch advertises the updated LSPs, the preceding case can be avoided.
Prerequisites
GR has been enabled for the IS-IS process using the graceful-restart command.