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CHN
New Member

SPAN problem,is it my understanding right?

"Only traffic that enters or leaves source ports or traffic that enters or leaves source VLANs can be monitored by using SPAN; traffic routed to a source VLAN cannot be monitored. For example, if

incoming traffic is being monitored, traffic that gets routed from another VLAN to the source VLAN cannot be monitored; however, traffic that is received on the source VLAN and routed to another VLAN can be monitored."

1.Receive SPAN:

Packets will be forworded to destinations before modification (routing(modified TTL ,MAC-address) or QoS) or doping (ACLs , ingress QoS policing ,VLAN ACLs or egress Qos policing).

2.Transit SPAN:

the packets sent by the source interface after all modification(TTL,MAC-address,QoS values) and processing(ACLs and egresss QoS) is performed by the switch.

3.packes like ping the sourece interfaces,will not be monitored.

reference link:

http://www.cisco.com/en/US/products/hw/switches/ps5528/products_configuration_guide_chapter09186a00802b7c55.html#wp1210541

1 REPLY
New Member

Re: SPAN problem,is it my understanding right?

Your understanding about SPAN is correct. To overcome this disadvantage you can go for VLAN ACL Capture port.

http://www.cisco.com/en/US/products/hw/switches/ps708/products_configuration_guide_chapter09186a0080160a7e.html

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