The MPLS WG Archive

[Rahul Aggarwal <rahul@redback.com>]

On Wed, 29 Jan 2003, Xiaoning He wrote:

> Hi all
> 
> Some parts of my research require some knowledge of RSVP-TE and MPLS. I
> have a simple question and I appreciate if you can give me some idea or
> link so that I can read the right draft or RFC.
> 
> My questions is
> 
> If there is an existing LSP established by RSVP-TE. Now, some segments
> of the link have to be changed as shown as follows:
> 
> a---> b--->c to a--->b--->d
> 
> my question is that is there anyway we don't have to tear down the old
> path, I mean the label from a-->b doesn't have to be changed? Is that
> something allowed in RSVP-TE? 

Yes it is. If explicit routes are being used, B will start forwarding
PATH messages to D as the new explicit route willl start pointing in
that direction. D will reply with a RESV message with its label. B will
stasrt using that as the outgoing label and leave the label it sent out to
A the same..



> 
> Thank you very much,
> 
> Xiaoning He, Ph.D
> Research Engineer
>  
> NTT-DoCoMo USA Labs
> 181 Metro Drive, Suite 300
> San Jose, CA 95110
>  
> Email: xiaoning@docomolabs-usa.com
> Phone: +1 (408) 451-4737
> Fax:   +1 (408) 573-1090
>  
> 
> 
> 
>