[c-nsp] Ethernet Preamble and FCS on EoMPLS

Reinhold Fischer Reinhold.Fischer at gmx.net
Fri Sep 25 13:50:23 EDT 2009


On Fri, Sep 25, 2009 at 01:33:09PM -0300, Ruter Guike wrote:
> Hi List.
> 
> Is Cisco able to include Ethernet "preamble" and "FCS" within the mpls
> packet, on EoMPLS? Is it configurable?
> 
> AFAIK, these fields are removed, by default, before encapsulating...
> 

RFC4448 (Encapsulation Methods for Transport of Ethernet
over MPLS Networks) specifies that preamble and FCS is not
transported. There is RFC4720 (Pseudowire Emulation
Edge-to-Edge (PWE3) Frame Check Sequence Retention) but to
my knowledge it is not implemented in IOS yet.  

What would be the benefit of transporting the Ethernet preamble?

hth

Reinhold


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