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Retransmitting LSAs LSAs are retransmitted only along adjacencies, as in OSPF. Thus, retransmitted LSAs are sent only between DR/BDR routers and non-DR/BDR routers. One advantage: DR/BDR routers can group together several retransmitted LSAs into the same LSU packet, thus reducing overhead and avoiding a large number of retransmitted LSAs between non-DR/BDR routers. In addition, a non-DR/BDR router never retransmits an LSA that it did not originally transmit as a broadcast (see draft for details). Link State Acknowledgments are always multicast. An LSA received as a multicast is acknowledged only the first time it is received, and must be processed even if received from a 2-way neighbor that is not adjacent. |