To check the congestion on WAN links at the data center and branch site.
A. [WAN Segment] While reports collect data, check whether WAN links at data center site are congested.
1. Go to Monitor > DiffServ > Traffic Stats.
2. Change the data source profile to focus on the SP-A data center WAN link Netflow Data Export
(NDE-DC-WANLinkIn/NDE-DC-WANLinkOut).
3. Check traffic by aggregation class.
B. Check whether the SP-A WAN link at the branch office site is congested.
Either check the router using CLI, use a third-party tool, or configure NetFlow Export to NAM-2 at DC and follow these steps:
1. Go to Monitor > DiffServ > Traffic Stats.
2. Change the data source profile to focus on the branch office WAN link NetFlow Data Export (NDE-DC-WANLinkIn/NDE-DC-WANLinkOut).
3. Check traffic by aggregation class.
For further information click this link.
http://www.cisco.com/en/US/docs/nsite/enterprise/wan/wan_optimization/chap09.html#wp1055944