The MPLS WG Archive

[Curtis Villamizar <curtis@fictitious.org>]

In message <20030221030857.GJ18082@gblx.net>, Matthew Meyer writes:
> Comments in line.
> 
> Thus spake Markus Jork (mjork@avici.com):
> 
>  |I like the original soft preemption idea in the draft as it stands now.
> 
> I think there have been some strong arguments to leave it as is.
> 
>  |But I have my doubts about the extensions discussed in this e-mail thread.
>  |When planning an admin link or node shutdown, it is probably a better
>  |idea to indicate that via the IGP (through a metric change or announcing
>  |the available bandwidth as 0).
> 
> While I agree with you that it is perhaps more appropriately 
> accomplished in the IGP, I don't believe the IGP has all 
> the needed mechanisms. 
> 
> Cranking the metric & setting/flooding available reserveable BW 
> at 0 is not enough.  Even if you soft preempt as well, you still
> have 0BW LSPs or explicitly routed LSPs or disparate backups that
> need to be forced to forget this link.  Currently SPs are forced
> to remove configuration parameters if we want to drive some types
> of tunnels off a link.  

Keeping a admin-color (aka admin-group) and naming it "maintenance"
and always configuring exclude-admin-color maintenance to your LSPs
does solve this problem easily.  Just advertise the link with
"admin-color maintenance" and the LSPs should go away rather quickly.

This is just a good operations trick/practice to have handy.
Increasing the IGP cost keeps the non-MPLS packets away.

Curtis