Span Multiple VLANs on 6006

[netlife]

Hi All,

If I span multiple vlans continuously on MSFC,will affect CPU utilisation of MSFC or what would are the possible implications.

Thanks

netlife

 

[hinesjrh]

I just researched this myself recently, and found the following. The bottom line is NO, it doesn't.

"Performance Impact
Whether one or several ports eventually transmit the packet has absolutely no influence on the switch operation. Therefore, considering this architecture, the SPAN feature has no impact on the performance."

http://cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a008015c612.shtml#topic7-3

 

[vipergg]

May not be a restriction but if you are monitoring to a single 100/full port then you run the risk of over sunbscribing the port at which point the switch will start dropping the packets and your data will no then be accurate . If the vlans are lightly used then it probably won't be a problem .

 

[RookThis]

In addition to what viper posted, you have to be aware of the bufferring that the particular line card does as well. You'll have to double check me on this, but if I'm not mistaking a ws-x6348 line card for example groups the ports in banks of 12 ports, each having a set amount of buffer space per port, when that buffer space runs out, it uses the buffer space on the asic that it is connected to. Once this is occurs you could cause performance issues to other devices on that bank of ports. I've seen it happen in my environment, so I try to keep a line card that I strictly use for sniffing. Again, double check me on this, or maybe someone else can comment on this.