Use Ping utility tool between Routers RTA and RTB  to record the Round Trip Time at different clock Rates.
		Clock Rate (bps)	9600	19200	56000	64000	128000	252000
		RTT (ms)	184	95	32	28	14	8
		Relative Value	23.00	11.88	4.00	3.50	1.75	1.00