The author is correct. This is why when you do a "monitor session x source vlan" the only option is rx and there is no tx or both option available. If you want to monitor an entire VLAN you need to monitor RECEIVED traffic of that vlan, not transmitted traffic.
On Wed, Jan 13, 2010 at 7:37 AM, Fabio Mendes <[email protected]>wrote: > Hello everybody, this is my first message. :) > > I'd like to clarify something that is confusing me for a while. > > Reading through cisco documentation at: > http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_52_se/configuration/guide/swspan.html > > The author says: > > "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." > > From my understanding, after the traffic is routed to a source VLAN, it > enters the VLAN and becomes part of source VLAN's traffic. In other words, > it is flowing on the source VLAN, so it can be monitored by SPAN/RSPAN, am I > correct ? > > Why the author mentioned that, since the traffic will be monitored anyway ? > > TIA > > -- > CCNA - Cisco Certified Network Associate > CCNP - Cisco Certified Network Professional > > "A bird that you set free may be caught again, but a word that escapes your > lips will not return." Jewish Proverb > > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > > -- Regards, Joe Astorino CCIE #24347 (R&S) Sr. Technical Instructor - IPexpert Mailto: [email protected] Telephone: +1.810.326.1444 Live Assistance, Please visit: www.ipexpert.com/chat eFax: +1.810.454.0130 IPexpert is a premier provider of Classroom and Self-Study Cisco CCNA (R&S, Voice & Security), CCNP, CCVP, CCSP and CCIE (R&S, Voice, Security & Service Provider) Certification Training with locations throughout the United States, Europe and Australia. Be sure to check out our online communities at www.ipexpert.com/communities and our public website at www.ipexpert.com
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