Re: [Lsr] Request WG adoption of TTZ

Christian, 

The SDWAN use case  is about grouping a set of nodes in geographically different locations to be one TTZ zone being treated as one Virtual Node. 

Linda

-----Original Message-----
From: Christian Hopps <chopps@chopps.org> 
Sent: Saturday, July 11, 2020 6:42 AM
To: Linda Dunbar <linda.dunbar@futurewei.com>
Cc: Christian Hopps <chopps@chopps.org>; LEI LIU <liulei@ieee.org>; Huaimo Chen <huaimo.chen@futurewei.com>; lsr@ietf.org; lsr-chairs@ietf.org
Subject: Re: [Lsr] Request WG adoption of TTZ

> On Jul 10, 2020, at 4:39 PM, Linda Dunbar <linda.dunbar@futurewei.com> wrote:
> 
> I also support the adoption of TTZ draft.
> 
> The Virtual Zone concept would be very useful for the Overlay networks. The proposed TTZ can group a set of nodes not geographically together into one virtual area to scale virtual overlay networks with lots of nodes. Those kind overlay networks are getting more momentum in SDWAN and CDN environment.

I'm not sure I follow this use-case. The intent of TTZ is to treat a bunch of nodes as a single node (or subset of nodes in early work) to reduce the link-state DB size and flooding requirements, AFAICT.

Thanks,
Chris.
[As WG member]

> 
> Linda Dunbar
> 
> From: Lsr <lsr-bounces@ietf.org> On Behalf Of LEI LIU
> Sent: Friday, July 10, 2020 12:42 PM
> To: Huaimo Chen <huaimo.chen@futurewei.com>
> Cc: lsr@ietf.org; lsr-chairs@ietf.org
> Subject: Re: [Lsr] Request WG adoption of TTZ
> 
> I support the adoption of the TTZ draft.
> 
> The operation on TTZ is simple. Smooth transferring between a zone and a single node will improve customer experience. The work on TTZ should be moved forward.
> 
> Thanks,
> Best regards,
> 
> Lei
> 
> On Thu, Jun 18, 2020 at 8:38 PM Huaimo Chen <huaimo.chen@futurewei.com> wrote:
> Hi Chris and Acee, and everyone,
> 
> 
> 
>     I would like to request working group adoption of "Topology-Transparent Zone"
> 
> (TTZ for short) https://datatracker.ietf.org/doc/draft-chen-isis-ttz/ .
> 
> 
> 
>     This draft comprises the following solutions for helping to improve scalability:
> 
>         1) abstracting a zone to a single pseudo node in IS-IS,
> 
>         2) abstracting a zone to a single pseudo node in OSPF,
> 
>         3) abstracting a zone to zone edges' full mess in IS-IS, and
> 
>         4) transferring smoothly between a zone and a single pseudo node.
> 
>     A zone is a block of an area (IS-IS L2 or L1 area, OSPF backbone or
> 
> non-backbone area).
> 
> 
> 
>     When a network area becomes (too) big, we can reduce its size in the sense
> 
> of its LSDB size through abstracting a zone to a single pseudo node or
> 
> abstracting a few zones to a few pseudo nodes.
> 
> 
> 
>     While a zone is being abstracted (or transferred) to a single pseudo node,
> 
> the network is stable. There is no or minimum service interruption.
> 
> 
> 
>     After abstracting a few zones to a few pseudo nodes, if we want to reconstruct
> 
> them, we can transfer (or roll) any of the pseudo nodes back to its zone smoothly
> 
> with no or minimum service interruption.
> 
> 
> 
>     We had a prototype implementation of abstracting a zone to zone edges' full
> 
> mess in OSPF. The procedures and related protocol extensions for transferring
> 
> smoothly from a zone to zone edges' full mess are implemented and tested.
> 
> A zone (block of an OSPF area) is smoothly transferred to its edges’ full mess
> 
> without any routing disruptions. The routes on every router are stable while
> 
> the zone is being transferred to its edges' mess. It is very easy to operate
> 
> the transferring.
> 
> 
> 
>     There are two other drafts for improving scalability: "Area Proxy for IS-IS"
> 
> (Area Proxy for short) and "IS-IS Flood Reflection" (Flood Reflection for short).
> 
> 
> 
>     "Area Proxy" https://tools.ietf.org/html/draft-li-lsr-isis-area-proxy-03
> 
> abstracts an existing IS-IS L1 area to a single pseudo node.
> 
> 
> 
>     "Flood Reflection" https://tools.ietf.org/html/draft-przygienda-lsr-flood-reflection-01
> 
> abstracts an existing IS-IS L1 area to its edges' connections via one or more
> 
> flood reflectors.
> 
> 
> 
>     We believe that TTZ has some special advantages even though
> 
> Area Proxy and Flood Reflection are very worthy. We would like
> 
> to ask for working group adoption of TTZ.
> 
> 
> 
> Best Regards,
> 
> Huaimo
> 
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