Modify the default behavior of the TCP/IP protocol so that your server is more accepting of
inconsistent WAN links.
TCP/IP uses the initial packet round
trip time at the moment when the session is initiated to
determine what is "normal" for that connect
ion. Because of this, it is better to have a consistently
slow WAN connection and worse to have a connection that starts out fast and then becomes
slow. Such an erosion of connection speed is common when connecting through an Internet
Service Provider (ISP
), particularly when the connection is opened in the morning and maintained
into the work day.
To accommodate for this erosion of bandwidth, add a value to the TcpMaxDataRetransmissions
subkey on the Citrix server under the following registry key:
TcpMaxDataRetransmissions = 10
If the value does not exist, highlight PARAMETERS, go to Edit and select add value. Choose
REG_ DWORD format.
TCP starts a retransmission timer when each outb
ound segment is handed down to IP. If no
acknowledgment is received for the data in a given segment before the timer expires, the
segment is retransmitted, up to the TcpMaxDataRetransmissions times. The default value for this
parameter is 5.
ssion timer is initialized to 3 seconds when a TCP connection is established;
however, it is adjusted "on the fly" to match the characteristics of the connection using Smoothed
Round Trip Time (SRTT) calculations as described in RFC793. The timer for a giv
en segment is
doubled after each retransmission of that segment.
Using this algorithm, TCP tunes itself to the "normal" delay of a connection. Because the default
number of retries is five, the round
trip time can double four times (or in other words beco
slower than its initial value) before the session is dropped. By increasing this number to 10, you
are allowing the round
trip time to double nine times instead of four, thereby allowing the
connection quality to erode up to 512X its original value
before being dropped. For example, a
connection that begins with a roundtrip time of 20 milliseconds would have to erode to a round
trip time of 10,240 milliseconds before being dropped by the server.
If possible, make this registry change on the client
machine as well (Windows 95/98/ME does not
support this). More information is available in Microsoft Technet Articles