When I run the show service-policy I can find info about dropped connectios, but What is the cause of a "dropped connection" ?
Server? LAN? LoadBalancer?
What is understood for a "dropped connection"?
Dropped connection is not the same tha a timeout seesion. Isn´t it?
Status : ACTIVE
-----------------------------------------
Interface: vlan 1 16 21
service-policy: int16-n2-1
class: Virtual_WEB02-app_http
loadbalance:
L7 loadbalance policy: Virtual_WEB02-app_http-l7slb
VIP ICMP Reply : ENABLED-WHEN-ACTIVE
VIP State: INSERVICE
VIP DWS state: DWS_DISABLED
Persistence Rebalance: DISABLED
curr conns : 1361 , hit count : 265760
dropped conns : 9582
conns per second : 0
client pkt count : 1576014 , client byte count: 195873255
server pkt count : 1472400 , server byte count: 630313128
conn-rate-limit : 0 , drop-count : 0
bandwidth-rate-limit : 0 , drop-count : 0
compression:
bytes_in : 0 bytes_out : 0
Compression ratio : 0.00%
Gzip: 0 Deflate: 0
compression errors:
User-Agent : 0 Accept-Encoding : 0
Content size: 0 Content type : 0
Not HTTP 1.1: 0 HTTP response error: 0
I found useful info about it in
http://docwiki.cisco.com/wiki/Cisco_Application_Control_Engine_(ACE)_Troubleshooting_Guide_--_Troubleshooting_Layer_4_Load_Balancing
The dropped conns counter under a VIP in the output of the show service policy detail command is incremented whenever the ACE discards a connection request destined to that VIP. There are several reasons why the ACE discards such connection requests. For example:
- If all the real servers in the server farm associated with the VIP go down, then the VIP will go down. So, all the incoming connections to that VIP are discarded.
- If the URL in a connection request to the VIP is unknown, then the connection request is discarded.
- If the server to which the ACE load balances the connection does not respond to the request, then, after the maximum number of retries, the ACE discards the connection.
About the second point (URL unknown). Is this a 404 error?
The reason for the drop is usually the server did not respond or server responded with a RST or no server were active.
It might not be detectable, because a browser will usually retry immediately if it does not get a response.
