comments and more

draft-ietf-quic-recovery.md

@@ -248,23 +248,24 @@ An acknowledgement SHOULD be sent immediately upon receipt of a second
 ack-eliciting packet. QUIC recovery algorithms do not assume the peer sends
 an ACK immediately when receiving a second ack-eliciting packet.
 
-In order to accelerate loss recovery and reduce timeouts, a receiver SHOULD
+In order to accelerate loss recovery and reduce timeouts, an endpoint SHOULD
 immediately send an ACK frame when it receives an out-of-order packet that is
-ACK-eliciting. The receiver MAY continue sending ACK frames immediately on each
-subsequently received packet, but the receiver SHOULD return to acknowledging
+ACK-eliciting. The endpoint MAY continue sending ACK frames immediately on each
+subsequently received packet, but the endpoint SHOULD return to acknowledging
 every other packet after a period of 1/8 x RTT, unless more ACK-eliciting
 packets are received out of order.  If every subsequent ACK-eliciting packet
 arrives out of order, then an ACK frame SHOULD be sent immediately for every
 received ACK-eliciting packet.
 
-Similarly, packets marked with the ECN Congestion Experienced (CE) codepoint in
-the IP header SHOULD be acknowledged immediately, to reduce the peer's response
-time to congestion events.
+If a packet is received with the ECN Congestion Experienced (CE) codepoint in
+the IP header, the endpoint SHOULD respond with an ACK frame immediately, even
+if the packet is received in order.  Doing so reduces the peer's response time
+to congestion events.
 
-As an optimization, a receiver MAY process multiple packets before sending any
-ACK frames in response.  In this case the receiver can determine whether an
-immediate or delayed acknowledgement should be generated after processing
-incoming packets.
+If multiple packets are already available at an endpoint, the endpoint MAY
+process them all before sending an ACK frame in response.  The endpoint can
+determine whether an acknowledgement should be sent immediately or delayed after
+processing the batch.
 
 ## Crypto Handshake Data