H3C S9500 Series Operation Manual page 48

Operation Manual – OSPF
H3C S9500 Series Routing Switches
When a protocol is restarted, the protocol will notify the peer that it will be restarted and
let the peer keep the neighbor relationship through the RS_bit set in the EO_TLV of a
HELLO packet. The R_bit set in a DD packet indicates that this is an OOB process.
The neighbor will keep the neighbor relationship and set the Restartstat-flag after
receiving HELLO packets of the RS_bit set.
When both neighbors exit from the OOB process, the standard OSPF algorithm is
performed.
Note:
The GR method on both OSPF neighbors must be the same. Different GR methods
cannot perform the GR process successfully. A OSPF process can use only one GR
method.
1.2.2 Packet Format of OSPF GR
I. Format of Grace LSA
This LSA is an Opaque-LSA generated by the Restarter. For this LSA, the LS-type is 9,
Opaque type is 3 and Opaque ID is 0.
Figure 1-2 Format of Grace LSA
II. Format of TLV
Figure 1-3 Format of TLV
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Chapter 1 OSPF Configuration