Reset Search



Does Oversubscribing Port Mirrors affect Production Traffic?

« Go Back


TitleDoes Oversubscribing Port Mirrors affect Production Traffic?

 S and K-Series products: is there negative impact associated with oversubscription of a destination port with mirrored traffic - ex: mirroring a 1gb source port to a 10mb destination port ?
  • S-Series
  • K-Series
    • All firmware rev's
      • port mirror
Production traffic will not be affected but  the traffic in the mirror may be impacted as follows.  
If mirrored traffic bandwidth should overwhelm the destination port's bandwidth capacity, traffic will be dropped.
No negative impact should be expected from a simple bandwidth unavailable condition - however there is no ability to predict or control which traffic gets clipped.
Unless a random-sample capture is intended oversubscription of the destination port defeats the typical mirror/span purpose.

Additional notes

Note the mirror destination port is a live switch port allowing an admin to mirror traffic to a sniffer/laptop port and also have that laptop active on the network. 
If active communication is desired from/to the analysis tool (remote desktop protocol for example) port oversubscription will interfere with this communication.  

Bear in mind a vlan with egress common to mirror source and destination ports will duplicate broadcast, unknown-unicast and multicast packets not controlled with igmp - the same as any other port with common vlan egress.  Placing the mirror destination port in a vlan of its own will avoid this broadcast path replication.

Hub Thread:



Was this article helpful?



Please tell us how we can make this article more useful.

Characters Remaining: 255