High latency when connecting to AWS Console through ProxySG/ASG
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High latency when connecting to AWS Console through ProxySG/ASG


Article ID: 249380


Updated On:


Advanced Secure Gateway Software - ASG ProxySG Software - SGOS


General slowness or high latency is observed when connecting to AWS Console through ProxySG.


Packet capture taken on ProxySG shows that AWS Console(Destination) is advertising small TCP Window sizes:


It's due to the fact that ProxySG is not configured to use TCP Windows Scaling(RFC1323).


To enable Windows Scaling on ProxySG:

  • RFC-1323 has to be Enabled in configuration and TCP window size is set higher than the default of 65535 bytes:

Enable Password:
ProxySG#config t
Enter configuration commands, one per line.  End with CTRL-Z.
ProxySG#(config)show tcp-ip
  RFC-1323 support:             enabled
  TCP Newreno support:          enabled
  IP forwarding:                enabled
  ICMP bcast echo response:     disabled
  ICMP timestamp echo response: disabled
  Path MTU Discovery:           disabled
  TCP silly-window avoidance:   enabled
  Routing algorithm:            weighted-round-robin
  TCP 2MSL timeout:             120 seconds
  TCP window size:              2031585 bytes
  TCP Loss Recovery Mode:       normal
  Bypass connection keep-alive: disabled
  Fast retransmit:              enabled
  Fast TCP FIN_WAIT_2 recycle:  disabled
  SCPS link bandwidth:          (not configured)
  SCPS interface:               (not configured)
  SCPS link rtt:                (not configured)
  SCPS processing:              Disabled



Additional Information