The MPLS WG Archive

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

Hi James,

When two peer LSRs are not directly connected to each other you should use per-platform label space. Also note that any label that has been drawn from the per-platform label space should not be used any more by the per-interface label spaces. By observing this rule, B can unambiguously interpret the per-platform label even in the presence of PHP.

Regards,
-Shahram

> -----Original Message-----
> From: James_Huang@Mitel.COM [mailto:James_Huang@Mitel.COM]
> Sent: Wednesday, November 22, 2000 3:12 PM
> To: mpls@UU.NET
> Subject: Label space of a label advertised through MPLS-BGP
> 
> 
> Hi  All,
>      Suppose two LSRs A and B are BGP peers and are not 
> directly adjacent.  When
> the egress LSR (B) advertises a FEC and the corresponding 
> lable to the ingree
> LSR (A), in which label space should the advertised label 
> reside?   Should B
> always use its per-platform label space in this situation?  
> When B receives a
> labeled  packet in the FEC routed through A, how can B 
> unambiguously interpret
> the label (assuming PHP is used)?   See figure8.4 of Bruce 
> Davie's book on MPLS
> for example of this scenario.
> 
>      Thanks for your answer.
> 
> -- James Huang
> 
> 
>