Q-Logic ISR6142 manual Performance Tuning, T1 / DS-1 1.554 Mbits/Sec

3 – Planning Performance Tuning

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Distance

Consider the physical distance between routers. This is usually measured in round-trip delay. Round-trip delay ranges anywhere from less than 1 ms to as great as 250 ms.

Performance Tuning

Properly configuring the router maximizes its performance. Knowing the round-trip delay (distance) between routers and the WAN effective data rate (connection type) allows you to tune the routers for optimal performance. The following tables provide TCP Window Scaling Factor and Window Size settings for specific WAN environments.

NOTE:

For high loss networks, QLogic recommends decreasing the TCP Window Size from the initial recommended setting until the network achieves optimal performance.

Table 3-1. T1 / DS-1 – 1.554 Mbits/Sec

Round Trip delay	Total Window Size	Scaling Factor
(ms)	(bytes)
250	64 K	1
100	32 K	0
50	32 K	0
25	32 K	0
20	32 K	0
15	32 K	0
10	32 K	0
5	32 K	0
2.5	32 K	0
1 or less	32 K	0

3-4 SN0051102-00 A