Small TCP Window on WAN between 2 Locations
- by Brent
Site A: Denver datacenter. 60MBPS.
Site B: Chicago. 100MBPS.
ICMP pings:
Packets: Sent = 176, Received = 176, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 74ms, Maximum = 94ms, Average = 75ms
File transfer between sites that never goes past ~7MBPS:
Windows Update download at 60MBPS+:
Site to site: IPSec VPN using two Cisco 5520's. CPU at 3-4% and lots of memory to spare.
The latency between to two sites is very acceptable so I can't see an issue why it is performing so slow when transferring between the two sites.
I have found that any type of transfer (FTP, HTTP, Windows file shares) will never go above ~7MBPS.
When the WAN was first setup, I was able to get transfers at 50-60MBPS, which is what is expected due to the WAN connection at the Site A at 60MBPS. Then a few days later, I was not able to get anything going faster than ~7MBPS.
Is there a upstream router between Denver and Chicago causing this? I want to take the blame away from our setup as downloads from Windows Update go blazing fast and for the first few days after the site to site VPN came up, I was transferring VM images at 50-60MBPS.
Our stack:
HP P2000 MSA - HP C7000 Chassis - HP Flex-10 - Cisco Gigabit switch - Cisco ASA - WAN
