And please give a motivation to why each statement is correct or not correct.

Consider the following statements about the network layer in general and IP routers in particular. Which of the statements are correct? Before an IP packet can be sent, a connection must be established between sender and receiver. If an overloaded router can't accept more packets it will send an ICMP message back to the sender. Fragmentation means that a router which detects bit errors drops packets with errors. Information in an IP header is examined by every router the packet passes through, for example to decide how a packet is to be forwarded. Routers use the identifier field of the IP header to make sure that packets arrive in correct order. A router does not change any information in an IP header. Routers have a buffer memory for temporary storage of IP packets that are passing through the router