Configuring Tcp Parameters - HP Cisco MDS 9216 - Fabric Switch Configuration Manual

Chapter 48 Configuring FCIP
S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m

Configuring TCP Parameters

You can control TCP behavior in a switch by configuring the following TCP parameters.
Note When FCIP is sent over a WAN link, the default TCP settings may not be appropriate. In such cases, we
recommend that you tune the FCIP WAN link by modifying the TCP parameters (specifically bandwidth,
round-trip times, and CWM burst size).
This section includes the following topics:
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Minimum Retransmit Timeout
You can control the minimum amount of time TCP waits before retransmitting. By default, this value is
200 milliseconds (msec).
Keepalive Timeout
You can configure the interval that the TCP connection uses to verify that the FCIP link is functioning.
This ensures that an FCIP link failure is detected quickly even when there is no traffic.
If the TCP connection is idle for more than the specified time, then keepalive timeout packets are sent
to ensure that the connection is active. The keepalive timeout feature can be used to tune the time taken
to detect FCIP link failures.
You can configure the first interval during which the connection is idle (the default is 60 seconds). When
the connection is idle for the configured interval, eight keepalive probes are sent at 1-second intervals.
If no response is received for these eight probes and the connection remains idle throughout, that FCIP
link is automatically closed.
Note Only the first interval (during which the connection is idle) can be changed.
Maximum Retransmissions
You can specify the maximum number of times a packet is retransmitted before TCP decides to close the
connection.
OL-16184-01, Cisco MDS SAN-OS Release 3.x
Minimum Retransmit Timeout, page 48-19
Keepalive Timeout, page 48-19
Maximum Retransmissions, page 48-19
Path MTUs, page 48-20
Selective Acknowledgments, page 48-20
Window Management, page 48-20
Monitoring Congestion, page 48-20
Estimating Maximum Jitter, page 48-21
Buffer Size, page 48-21
Cisco MDS 9000 Family CLI Configuration Guide
Using the FCIP Wizard
48-19