Commit d75b0bc3 authored by Mike Hibler's avatar Mike Hibler

Add some stuff I just learned about "span".

We can have multiple span sessions per switch!
parent 30ee73a7
......@@ -191,7 +191,8 @@ ID Name Members of VLAN
To forward the traffic from an entire VLAN:
Console> (enable) set span <vlan #> <monitor>
NOTE: You might want to append 'rx' or 'tx' to the VLAN command line, or
you'll get doubles of everything (incoming and outgoing both)
you'll get doubles of everything (incoming and outgoing both).
<rx> means into the switch on <port>, <tx> means out of the switch.
NOTE2: If you want to be able to send traffic from the monitor port,
you'll need to append 'inpkts enable' ala:
Console> (enable) set span 18 3/9 rx inpkts enable
......@@ -207,7 +208,32 @@ ID Name Members of VLAN
ifconfig fxp1 down
when I am done.
10. Good reference for making nodes boot quickly (ensuring that port spanning,
10. Multiple span sessions
You can setup multiple span sessions on a switch. Just add 'create'
to the end of your setup line:
Console> (enable) set span <port> <monitor> create
To tear down a specific span session, name it by the <monitor> port
as above:
Console> (enable) set span disable <monitor>
11. Span on trunk ports
You can also span traffic on a trunk port or even a set of bonded
trunk ports. For example, on our experimental switches we have four
bonded Gb ports, 2/1-4, as an inter switch link, so you could see all
traffic coming in from the trunk with:
Console> (enable) set span 2/1-4 5/5 rx create
You can even pick out a specific VLAN or VLANs from the trunk. So
if you only care about VLAN 300 and 400:
Console> (enable) set span 2/1-4 5/5 rx filter 300,400 create
I haven't tried this, but according to the document cited below (#12),
you can preserve the VLAN tagging when spanning a trunk by putting the
monitor port into trunk mode first.
12. Good reference for span:
http://www.netplusinc.com/misc/CiscoSPAN.pdf
13. Good reference for making nodes boot quickly (ensuring that port spanning,
trunking, etc. are off on the switch port):
http://www.cisco.com/warp/public/473/12.html
......
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