Re: OT: Layer 2 over Layer 3 for SPAN (Voice Recording)

Ouch!
This is the kind of thing you never forget in the next design, I guess.

Just an idea that popped in my mind: what about keeping L2 just for
an RSPAN vlan ?
I.e., make your DA (distribution access) links L2 trunks, have your L3
traffic into a dedicated vlan (SVIs) and create the RSPAN vlan.

Appart from the RSPAN, all vlans would be point to point, so no need for
spanning tree in them.
It's not going to be clean configuration wise, but I think is the
cheapest way to separate the SPAN traffic and do so in hardware.

-Carlos

Saud Malik @ 1/11/2009 7:15 -0300 dixit:
> Hi Experts,
>
> I am facing a scenario where i deployed Campus network with Routed Access
> Layer (EIGRP) using 6503s on Distribution Layer and 3750s at Access Layer.
> I configured Point-to-point IPs between the distribution and Access layer.
>
> Now when i deployed the whole solution, customer is facing issue configuring
> RSPAN for voice recording. RSPAN session cannot cross any Layer 3 boundry as
> RSPAN is a LAN (Layer 2) feature. In order to monitor traffic across
> different networks, we may use Encapsulated Remote SwitchPort Analyser
> (ERSPAN). But ERSPAN is only supported on 6500s.
>
> I am looking for a best solution to SPAN vlan across Layer3 boundries. I
> found some solutions like EoL2TPv3, Fancier Ethernet-Over Techniques (VPLS,
> EoMPLSoGRE, etc.)
> Bridge over GRE (not supported anymore, assuming it ever was really
> supported) which i believe are not optimal solutions for this kind of
> scenario. I would like to get feedback if someone faced the same scenario
> and what was the best solution to overcome it.
>
> Your feedback is highly appriciated
>
> thanks.
>
> Saud
>
>
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-- 
Carlos G Mendioroz  <tron_at_huapi.ba.ar>  LW7 EQI  Argentina
Blogs and organic groups at http://www.ccie.net