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GRE tunnel is getting mirrored and duplicating flows on S-Series or PV-FC-180

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Information

 
TitleGRE tunnel is getting mirrored and duplicating flows on S-Series or PV-FC-180
Symptoms
  • show flow stat shows high port count for tun.0.x ports
  • switch packet processing is running high or max (60 percent)
  • High CPU S-Series
  • Packets show multiple GRE and IP headers (see below picture)
Environment
  • S-Series
  • PV-FC-180
  • GRE
  • Purview Tap
  • Netsight Purview
  • Analytics
  • Extreme Management Center
Cause
Flows are being mirrored again. There is a logical loop in place.
Resolution
drop GRE frames from being mirrored in path. 
 
set policy profile 1 name APPid pvid-status enable pvid 4095 mirror-destination 1
set policy rule admin-profile port ge.1.48 mask 16 port-string ge.1.48 admin-pid 1
set policy rule 1 ipproto 47 mask 8 drop prohibit-mirror
 

 

By prohibiting the mirror of GRE, then we did not try to re-encapsulate it. 

Additional notes
Note: Using "pvid 0" in the policy drops all ingress frames being mirrored, so only do this on dedicated Purview switch at last-hop.

Here is sample of GRE being added into the frame multiple times.
User-added image

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