The MPLS WG Archive

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

Correct. This label is used to enable PHP.

-Shahram

>-----Original Message-----
>From: Abhijit [mailto:gabhijit@ee.iitb.ernet.in]
>Sent: Wednesday, June 07, 2000 9:35 AM
>To: mpls@UU.NET
>Subject: doubts in ENCAPS draft. 
>
>
>
>Hi all
>
>I have a doubt abt the implicit NULL label. 
>
>The draft says 
>
>===============================================================
>=========
> value of 3 represents the "Implicit NULL Label".
>                 This is a label that an LSR may assign and distribute,
>                 but which never actually appears in the encapsulation.
>                 When an LSR would otherwise replace the label at the
>                 top of the stack with a new label, but the 
>new label is
>                 "Implicit NULL", the LSR will pop the stack instead of
>                 doing the replacement.  Although this value may never
>                 appear in the encapsulation, it needs to be 
>specified          
>		 in the Label Distribution Protocol, so a value is
>                 reserved.                          
>
>=======================================================================
>
>I didn't get the exact use of the Implicit Null Label. 
>
>1. What I can infer is that this binding could be given by 
>Egress LSR to
>its Upstream so that when the outgoing label value is 3 as 
>specified here,
>the Penultimate LSR will Pop the Label entry. 
>
>Is this correct? 
>
>Thanks and Regards 
>
>-abhijit
>