Re: [Lsr] Publication has been requested for draft-ietf-lsr-ip-flexalgo-06

Hi Robert,

On 17/05/2022 12:11, Robert Raszuk wrote:
> 
> Actually I would like to further clarify if workaround 1 is even doable ...
> 
> It seems to me that the IP flexalgo paradigm does not have a way for 
> more granular then destination prefix forwarding.

that is correct. In IP flex-algo the prefix itself is bound to the 
algorithm.

> 
> So if I have http traffic vs streaming vs voice going to the same load 
> balancer (same dst IP address) there seems to be no way to map some 
> traffic (based on say port number) to take specific topology.

no, you can not do that with IP flex-algo.

> 
> That's pretty coarse and frankly very limiting for applicability of IP 
> flex-algo. If I am correct the draft should be very explicit about this 
> before publication.

please look at the latest version of the draft, section 3:

https://datatracker.ietf.org/doc/html/draft-ietf-lsr-ip-flexalgo#section-3

thanks,
Peter

> 
> Kind regards
> R.
> 
> On Tue, May 17, 2022 at 12:01 PM Robert Raszuk <robert@raszuk.net 
> <mailto:robert@raszuk.net>> wrote:
> 
>     Folks,
> 
>     A bit related to Aijun's point but I have question to the text from
>     the draft he quoted:
> 
>         In cases where a prefix advertisement is received in both a IPv4
>         Prefix Reachability TLV and an IPv4 Algorithm Prefix Reachability
>         TLV, the IPv4 Prefix Reachability advertisement MUST be preferred
>         when installing entries in the forwarding plane.
> 
>     Does this really mean that I can not for a given prefix say /24 use
>     default topology for best effort traffic and new flex-algo topology
>     for specific application ?
> 
>     Is the "workaround 1" to always build two new topologies for such
>     /24 prefix (one following base topo and one new) and never advertise
>     it in base topology ?
> 
>     Is the "workaround 2" to forget about native forwarding and use for
>     example SR and mark the packets such that SID pool corresponding to
>     base topology forwarding will be separate from SID pool
>     corresponding to new flex-algo topology ?
> 
>     Many thx,
>     Robert
> 
> 
>     ---------- Forwarded message ---------
>     From: *Acee Lindem via Datatracker* <noreply@ietf.org
>     <mailto:noreply@ietf.org>>
>     Date: Mon, May 16, 2022 at 3:36 PM
>     Subject: [Lsr] Publication has been requested for
>     draft-ietf-lsr-ip-flexalgo-06
>     To: <jgs@juniper.net <mailto:jgs@juniper.net>>
>     Cc: <acee@cisco.com <mailto:acee@cisco.com>>,
>     <iesg-secretary@ietf.org <mailto:iesg-secretary@ietf.org>>,
>     <lsr-chairs@ietf.org <mailto:lsr-chairs@ietf.org>>, <lsr@ietf.org
>     <mailto:lsr@ietf.org>>
> 
> 
>     Acee Lindem has requested publication of
>     draft-ietf-lsr-ip-flexalgo-06 as Proposed Standard on behalf of the
>     LSR working group.
> 
>     Please verify the document's state at
>     https://datatracker.ietf.org/doc/draft-ietf-lsr-ip-flexalgo/
>     <https://datatracker.ietf.org/doc/draft-ietf-lsr-ip-flexalgo/>
> 
> 
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