The MPLS WG Archive

[Shahram Davari <Shahram_Davari@pmc-sierra.com>]

Eric,

The LSP-ping text says:

"  In either case, the MPLS echo request would
   have a label stack of <1001, 23456>.  (Note: in this example, 1001 is
   the "outer" label and 23456 is the "inner" label.)"

-Shahram

> -----Original Message-----
> From: Shahram Davari 
> Sent: Tuesday, December 10, 2002 1:55 PM
> To: 'erosen@cisco.com'; Alia Atlas
> Cc: mpls@UU.NET
> Subject: RE: Last Call on MPLS ping 
> 
> 
> > -----Original Message-----
> > From: Eric Rosen [mailto:erosen@cisco.com]
> > Sent: Monday, December 09, 2002 12:38 PM
> > Alia> So,  my concern  here  is  for the  case  where the  
> > route  is not  an
> > Alia> aggregate  and the label  indicates the  egress 
> > attachment  circuit as
> > Alia> well as the encapsulation header for the packet. 
> > 
> > Alia> In  this case,  LSP ping  would send  an IP  packet 
> > with  the specific
> > Alia> route's label and then the PSN's label. 
> > 
> > That isn't  my interpretation of the  draft.  I think the  
> > intention is that
> > the LSP  ping carries only  the "PSN label".   That is, it 
> > carries  only the
> > label  or labels  needed to  get it  to the  egress PE,  not 
> > the  label that
> > identifies a particular VPN route (or a particular PWE3 
> pseudowire). 
> > 
> > If  you wanted  to  know not  only whether  a  particular LSP 
> >  leads to  the
> > intended PE,  but also whether that PE  is a proper egress  
> > for a particular
> > VPN route (or PWE3  pseudowire), then I think you would need  
> > to use the FEC
> > stack TLV in the body of the message to identify that VPN route.
> > 
> 
> But how do you test that the VPN route is bound to the proper 
> PW label?
> 
> 
> -Shahram
>