How does SSH Window Size affect in paramiko - python-2.7

Question

I am building an application where it SSHs to Cisco devices to collect output of show commands. I am using paramiko module in python to get this done.
While comparing the command output with that of plink, got to know that the output from paramiko is truncated. Tried with unbuffering and increased buffer size and it didn't help. Later, just tried with window_size parameter and it seems to work.
Below is my code:
import paramiko
sshclient = None
try:
sshclient = paramiko.SSHClient()
sshclient.set_missing_host_key_policy(paramiko.AutoAddPolicy())
sshclient.connect('mydevice', username='admin', password='admin12345')
chan = sshclient.get_transport().open_session(window_size=500000)
chan.settimeout(10800)
chan.exec_command('show tech-support fcip')
value = chan.recv(1024)
while value:
print(value)
value = chan.recv(1024)
finally:
if sshclient:
sshclient.close()
As per paramiko document for Transport, default_window_size=2097152; 1597152 lesser than the default_value.
Also the partial log output with default_window_size=2097152 is:
Authentication (password) successful!
[chan 0] Max packet in: 32768 bytes
[chan 0] Max packet out: 32768 bytes
Secsh channel 0 opened.
[chan 0] Sesch channel 0 request ok
EOF in transport thread
Where as with window_size=500000 is:
Authentication (password) successful!
[chan 0] Max packet in: 32768 bytes
[chan 0] Max packet out: 32768 bytes
Secsh channel 0 opened.
[chan 0] Sesch channel 0 request ok
[chan 0] EOF received (0)
EOF in transport thread
Here it looks like, when the window_size is default value, the channel is being closed even before the termination signal from the server.
Experts, please advise me the consequences of reduced window_size in SSH and how will it affect my application?

Answer 1

By modifying the window_size, you effect the maximum length a line can be before a return character is entered. If your application requires you to perform some parsing, and you want to call something like
value.split('\n')
You may find that the strings are being split more/less frequently than you predicted.