Updates readme with update steps.

test/aws-us-gov/mdr-test-c2/018-interconnect-instances/README.md

@@ -2,23 +2,48 @@
 
 Instances to interconnect govcloud with commercial
 
-# Full Connectivity Update
+## Testing Performance
 
-Untested, but starting to take notes:
+Easiest way to test performance is via iperf. One instance needs to act as a server. The security group should allow inbound port tcp/5001.
+```
+iperf -s
+```
+
+The second server will act as a client.
+```
+# test single connection performance
+iperf -c 10.20.10.8 -w 2m -t 300s -i 1 --parallel 2 --enhanced
+
+# test multithread performance
+iperf -c 10.20.10.8 -w 2m -t 300s -i 1 --parallel 10 --enhanced | grep SUM
+```
+
+Notes:
+* AWS ipsec VPNs have an aggregate throughput limit of 1.25Gbps
+* Initial testing showed that multithread performance far exceeds single thread.
+
+## Full Connectivity Update
+
+There will be a brief (30s-90s) interruption to existing connections. It may be possible to 
 
 1. Verify that nothing would be rebuilt
 ```
 terragrunt plan
 ```
-1. Stop routing daemon on instance? (May not be necessary)
-1. Taint one instance: 
+1. Make changes that would cause a rebuild, or taint one instance if you just want to replace it.
 ```
 terragrunt taint aws_instance.interconnects[0]
 ```
-1. Rebuild
+1. Rebuild just one instance
+```
+terragrunt apply -target=aws_instance.interconnects[0]
+```
+1. Validate routing has come back up. 
 ```
-terragrunt apply
+# On interconnection node
+sudo vtysh
+sh ip bgp summary
+# The Up/Down column should have times in all 5 entries
 ```
-1. Validate routing is back up
-1. Repeat for other servers.
+1. Repeat for other instances.