Respect special cases and bounds

Apply each exception only when its stated condition holds; an optional ceiling is not a universal timeout.

• If a timer expires awaiting a SYN ACK while the implementation is using an RTO below 3 seconds, RTO MUST be re-initialized to 3 seconds when data transmission begins after the handshake (§5.7). A successful handshake without that timeout does not make every data RTO 3 seconds.
• The timestamp option can remove retransmission ambiguity and permit an RTT sample (§3). The diagram uses symbolic transmission tags 10 and 20 and a returned 20; it illustrates correlation, not the full option encoding, timestamp clock or wraparound rules. Tags are not an authentication credential.
• Clock granularity G has no prescribed value (§4). If variation is zero, the max(G,4×RTTVAR) term still uses G; this is required. The separate example SRTT 2000 ms/RTTVAR 0/G 10 ms gives RTO 2010 ms, not 2000 ms.
• A maximum RTO MAY be configured, but it must be at least 60 seconds (§2.5). Choosing no maximum is permitted. A proposed 55 second maximum is invalid under this rule; an illustrative 60 second maximum caps 40000×2=80000 ms at 60000 ms when backing off (§5.5).
• The recommended one-second computed minimum remains SHOULD; the optional maximum’s at-least 60 second condition must not be mistaken for a mandatory 60 second timeout for every connection.
• §6 discusses manipulated delay and forged ACKs. This arithmetic does not authenticate feedback or replace TCP’s other validation/congestion rules. RFC 6298 is a timer specification, not a guarantee that any missing ACK proves a dead peer or that every retransmission represents network loss.