Wednesday, 11 December 2013

TFO Troubleshooting(Cisco WAE)

TFO-Transport Flow Optimization; a set of optimizations applied to intercepted traffic by the WAAS devices  
The number of TCP connections, their status, and disposition can give an indication of the health of the WAAS system in a specific location.

The show statistics tfo detailcommand provides an indication of the volume, status, and disposition of connections between a particular WAAS device and other devices in the network.

#sh statistics tfo detail(On Cisco WAE)
  Total number of connections                          : 81350884
  No. of active connections                            : 578
  No. of pending (to be accepted) connections          : 0
  No. of bypass connections                            : 292144
  No. of normal closed conns                           : 78445114
  No. of reset connections                             : 2905192
     Socket write failure                              : 1704
     Socket read failure                               : 2
     WAN socket close while waiting to write           : 967
     AO socket close while waiting to write            : 147326
     WAN socket error close while waiting to read      : 0
     AO socket error close while waiting to read       : 1249665
WAN socket unexpected close while waiting to read : 77254
     Exceeded maximum number of supported connections  : 0
     Buffer allocation or manipulation failed          : 0
     Peer received reset from end host                 : 1427862
     DRE connection state out of sync                  : 0
     Memory allocation failed for buffer heads         : 0
     Unoptimized packet received on optimized side     : 412
   Policy Engine Statistics       
   Session timeouts: 0,  Total timeouts: 0
   Last keepalive received 00.7 Secs ago
   Last registration occurred 84:09:23:33.0 Days:Hours:Mins:Secs ago
   Hits:                424524224, Update Released:              305682847
   Active Connections:        687, Completed Connections:        161054837
   Drops:                       0, Pre-Resource Counter:        347
   Rejected Connection Counts Due To: (Total: 0)
      Not Registered      :          0,  Keepalive Timeout   :          0
      No License          :          0,  Load Level          :          0
      Connection Limit    :          0,  Rate Limit          :          0
      Minimum TFO         :          0,  Resource Manager    :          0
      Global Config       :          0,  TFO Overload        :          0
      Server-Side         :          0,  DM Deny             :          0
      No DM Accept        :          0
   Auto-Discovery Statistics      
   Total Connections queued for accept:  81350826
   Connections queuing failures:         0
   Socket pairs queued for accept:       81350826
   Socket pairs queuing failures:        0
   AO discovery successful:              0
   AO discovery failure:                 0

The No. of active connections field reports the number of connections that are currently being optimized.
No. of pending (to be accepted) connections-Number of TCP connections that will be optimized but are currently in the setup stage.
No. of connections closed normally-Number of optimized connections closed without any issues using TCP FIN.
No. of connections closed with error-Number of optimized connection closed with some issues or using TCP RST.
DRE decode failure-DRE internal error while decoding data. (Should not happen.)
DRE encode failure-DRE internal error while encoding data. (Should not happen.)
Connection init failure-Failed to setup the connection although auto-discovery finished successfully..
Peer received reset from end host-TCP RST sent by the server or client. (Can be normal behavior and does not necessarily indicate a problem.)
In the Policy Engine Statistics section of the output, the Rejected Connection Counts section show various reasons why connections have been rejected. The Connection Limit counter reports the number of times that a connection has been rejected because the maximum number of optimized connections has been exceeded. If you see a high number here, you should look into overload conditions.

#sh statistics connection(On Cisco WAE)
Current Active Optimized Flows:                      660
   Current Active Optimized TCP Plus Flows:          647
   Current Active Optimized TCP Only Flows:          14
   Current Active Optimized TCP Preposition Flows:   0
Current Active Auto-Discovery Flows:                 320
Current Reserved Flows:                              80
Current Active Pass-Through Flows:                   4659
Historical Flows:                                    687
D:DRE,L:LZ,T:TCP Optimization RR:Total Reduction Ratio
ConnID        Source IP:Port          Dest IP:Port            PeerID Accel RR  
983071 00:21:5e:76:8b:88 TDL   00.0%
983196 00:21:5e:76:8b:88 TDL   00.0%
327923               N/A E     00.0%

Current Active Optimized TCP Plus Flows-they are all being handled with TFO/DRE/LZ optimization
Current Active Optimized TCP Only Flows:-flows that are optimized by TFO only.
Current Active Auto-Discovery Flows:-displays flows that have not been fully set up to become optimized flows or pass-through flows.
The Current Active Pass-Through Flows counter shows connections that the device has determined to be pass-through or where the device did not see the SYN, SYN ACK, ACK setup. These flows will not be counted as optimized flows. For pass-through flows, a device should be able to handle up to 10 times the number of optimized flows for which it is rated.
The sum of the following three counters tells you how close the WAE device is to its connection limit:
Current Active Optimized Flows
Current Active Auto-Discovery Flows
Current Reserved Flows (available only in 4.1.5 and later)
If this sum is equal to or greater than the connection limit, the device is in an overload condition.

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