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New Member

ACE4710 info about dropped connections

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.

Everyone's tags (3)
3 REPLIES
Bronze

ACE4710 info about dropped connections

HI

Secind point of unknown URL could be a condition of L7 poilcy map where our L4 VIP class has hit and connection is accepeted, 3 way TCP handshake completeted by ACE with client but then client send L7 payload which doesn't match to any L7 class map and thats why ACE drop the connection.

Hope this help.

New Member

ACE4710 info about dropped connections

But is URL unknown a 404 error?

Bronze

ACE4710 info about dropped connections

No, the situatuion which i have explained, ACE will send a RST to close the connection. Also i guess 404 is legitmate reply from server and should not be considered as a drop, unless server is sending a RST to close the same.

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