Subject: Re: [spring] Fwd: [mpls] I-D Action: draft-kini-mpls-spring-entropy-label-01.txt

From: "Nobo Akiya (nobo)" <[email-masked]>
Date: Thu, 6 Nov 2014 01:15:36 +0000

Hi Sri, et al,

The update (00 to 02) looks great, many thanks for progressing this!

I've followed the algorithm described in the Figure 2 (Section 4) of the document. If I understood the algorithm correctly, I think it has logic errors.
- Loop condition is incorrect.
- Top of the stack being reached but still needing to insert ELI/EL since we are outside of RLD, is not taken care of.

Additionally:
- we should clarity that the logic must not be followed if (RLD <= 2).
- clarify that insertion of ELI/EL is after the label pointed by the current insertion point.
- "can push more labels" should be clarified as "can push 2 or more labels".

Below is a suggested algorithm update that addresses the points above.

[OLD]
     Initialize the current EL insertion point to the
       bottommost label in the stack that is EL-capable
     while local-node can push more labels OR
       top of stack has been reached {
         insert an ELI+EL at current insertion point
         move insertion point up until current EL is out of RLD
                                              AND
                                     insertion point is EL-capable
         set current insertion point to new insertion point
     }

[NEW]
     if (RLD > 2) {
       initialize the current insertion point to the
         bottommost label in the stack that is EL-capable
       do {
         insert an ELI+EL after the label pointed by the current
           insertion point
         move insertion point up until inserted EL is out of RLD
                                              AND
                                     insertion point is EL-capable
         if insertion point was not updated due to reaching top of
           the stack, break out from the loop
         else set current insertion point to new insertion point
       } while local-node can push 2 or more labels
     } else {
       insert an ELI+EL after the bottommost label in the stack
         that is EL-capable
     }

Thanks!

-Nobo

> -----Original Message-----
> From: spring [mailto:[email-masked]] On Behalf Of Sriganesh Kini
> Sent: Tuesday, September 30, 2014 1:48 PM
> To: [email-masked]; [email-masked]
> Cc: [email-masked]
> Subject: [spring] Fwd: [mpls] I-D Action: draft-kini-mpls-spring-entropy-
> label-01.txt
> 
> FYI
> 
> Comments welcome.
> 
> Sri
> 
> ---------- Forwarded message ----------
> From: <[email-masked]>
> Date: Mon, Sep 29, 2014 at 5:05 PM
> Subject: [mpls] I-D Action: draft-kini-mpls-spring-entropy-label-01.txt
> To: [email-masked]
> Cc: [email-masked]
> 
> 
> 
> A New Internet-Draft is available from the on-line Internet-Drafts
> directories.
>  This draft is a work item of the Multiprotocol Label Switching Working
> Group of the IETF.
> 
>         Title           : Entropy labels for source routed stacked tunnels
>         Authors         : Sriganesh Kini
>                           Kireeti Kompella
>                           Siva Sivabalan
>                           Stephane Litkowski
>                           Rob Shakir
>                           Xiaohu Xu
>                           Wim Hendrickx
>                           Jeff Tantsura
>         Filename        : draft-kini-mpls-spring-entropy-label-01.txt
>         Pages           : 10
>         Date            : 2014-09-29
> 
> Abstract:
>    Source routed tunnel stacking is a technique that can be leveraged to
>    provide a method to steer a packet through a controlled set of
>    segments.  This can be applied to the Multi Protocol Label Switching
>    (MPLS) data plane.  Entropy label (EL) is a technique used in MPLS to
>    improve load balancing.  This document examines and describes how ELs
>    are to be applied to source routed stacked tunnels.
> 
> 
> The IETF datatracker status page for this draft is:
> https://datatracker.ietf.org/doc/draft-kini-mpls-spring-entropy-label/
> 
> There's also a htmlized version available at:
> http://tools.ietf.org/html/draft-kini-mpls-spring-entropy-label-01
> 
> A diff from the previous version is available at:
> http://www.ietf.org/rfcdiff?url2=draft-kini-mpls-spring-entropy-label-01
> 
> 
> Please note that it may take a couple of minutes from the time of
> submission until the htmlized version and diff are available at tools.ietf.org.
> 
> Internet-Drafts are also available by anonymous FTP at:
> ftp://ftp.ietf.org/internet-drafts/
> 
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