Re: [Lsr] WG Adoption Call for "IGP Flexible Algorithms (Flex-Algorithm) In IP Networks" - draft-bonica-lsr-ip-flexalgo-01

Robert Raszuk <> Fri, 04 December 2020 00:24 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id 1DA223A0E55 for <>; Thu, 3 Dec 2020 16:24:59 -0800 (PST)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -2.098
X-Spam-Status: No, score=-2.098 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, HTML_MESSAGE=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: (amavisd-new); dkim=pass (2048-bit key)
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id md2IRah5Kldp for <>; Thu, 3 Dec 2020 16:24:57 -0800 (PST)
Received: from ( [IPv6:2a00:1450:4864:20::12d]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by (Postfix) with ESMTPS id 3F88A3A0AA1 for <>; Thu, 3 Dec 2020 16:24:57 -0800 (PST)
Received: by with SMTP id d20so5334659lfe.11 for <>; Thu, 03 Dec 2020 16:24:57 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=BrYnSErheM+iqJFseYkYRQxgj1LdSaPlRGev/H7vmRQ=; b=dXZfVrA7oqaw7s4v08lDF4PzcDeZ9biMZ6YMezyMoPyj2h1/fA1gxoDJjEuAvJEeO3 dmwhaLIaVCzzDY77eb/4uo9musHqgwzR98DJOX8RFjFvzBcjSbnsT3VqYQQ6o8a2M9Yt yHTk+4Kn/v7PKEjb+8rOtlH6wtrnmJ/dKPjI/c3p/GX8oe+sJkOxKB5Ay1yuGdL6zt2b MaSVqojl4bD6845I5Y9SUe0cCdTYgUy7BXrO2k7joxCmJ8VkhxXR5A1cCYbx9NjjPTkd oZ3KYkBrABeJLlGfl15jKzO+RgHK8sQeyh6XG3fYXpM+NLy0+3bMp20QmUhFamcml98b FduQ==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=BrYnSErheM+iqJFseYkYRQxgj1LdSaPlRGev/H7vmRQ=; b=IwzPEOAjWXG/RT+Aa5kMfKT5/vpStQ4+t6kQhUH3Sd8vkzhedFN32rQBCJBL1uxMzi LORlGWwSaFL4bQ06eykl750nE0+ZyIMvUjAhU/OwYWHei36ZXwTmpr0hzqJR9oBrm5GC SmDTobq+b4RrrExa15T4SkbIGrAi6yHn6SCYHdAtdCyIX3yMfei2/4nmclOVZ2pgrqmJ r1TKREmmkKdGFvx/NXDZc3wFRqstRVEGZuFYfoWnZfHKdiPJud4zGSd7XMc/rPzFWT9x efbZ/dH5C5TuSAcba+5LpuzaOmq1SLa76AkzLaCkp7vqbTQzw1AW7DYjpjraNLOvpaMc O6Lw==
X-Gm-Message-State: AOAM532HN3BRQEzsvNfRCE+N1VQwcdw7KU+RMyMw/H2UP+aWYlYwAUk/ ZTSh7qMmy/RpJLFtP6hQtSh4ZhfE9cAsM8TEXW9pug==
X-Google-Smtp-Source: ABdhPJyvcxTcVaVthoBORfVyOxswget4Gz8F1vJiU9T+i2A3EQC6xjLfNyGQcZWBUIHxcdOMBDQBpK0QfUblmuzAD2w=
X-Received: by 2002:a19:ca57:: with SMTP id h23mr2511535lfj.12.1607041495129; Thu, 03 Dec 2020 16:24:55 -0800 (PST)
MIME-Version: 1.0
References: <> <> <>
In-Reply-To: <>
From: Robert Raszuk <>
Date: Fri, 4 Dec 2020 01:24:44 +0100
Message-ID: <>
To: Tony Li <>
Cc: "Acee Lindem (acee)" <>, lsr <>
Content-Type: multipart/alternative; boundary="00000000000074f98905b5988148"
Archived-At: <>
Subject: Re: [Lsr] WG Adoption Call for "IGP Flexible Algorithms (Flex-Algorithm) In IP Networks" - draft-bonica-lsr-ip-flexalgo-01
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Link State Routing Working Group <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Fri, 04 Dec 2020 00:24:59 -0000

Hi Tony,

The moment I hit "Send" I knew that this response may be coming as it
really depends what is one's definition of TE.

If indeed IGP TE is anything more then SPF - then sure we can call it a TE

However, while a very useful and really cool proposal, my point is to make
sure this is not oversold - that's all.


On Fri, Dec 4, 2020 at 1:13 AM Tony Li <> wrote:

> Hi Robert,
> > However I really do not think that what Flexible Algorithm offers can be
> compared or even called as Traffic Engineering (MPLS or SR).
> >
> > Sure Flex Algo can accomplish in a very elegant way with little cost
> multi topology routing but this is not full TE. It can also direct traffic
> based on static or dynamic network preferences (link colors, rtt drops etc
> ... ),  but again it is not taking into account load of the entire network
> and IMHO has no way of accomplish TE level traffic distribution.
> >
> > Just to make sure the message here is proper.
> It’s absolutely true that FlexAlgo (IP or SR) has limitations. There’s no
> bandwidth reservation. There’s no dynamic load balancing. No, it’s not a
> drop in replacement for RSVP. No, it does not supplant SR-TE and a good
> controller. Etc., etc., etc….
> However I don’t feel that it’s fair to say that FlexAlgo can’t be called
> Traffic Engineering.  After all TE is a very broad topic. Everything that
> we’ve done that’s more sophisticated than simple SPF falls in the area of
> Traffic Engineering.  Link coloring and SRLG alone clearly fall into that
> bucket.
> I’ll grant you that it may not have the right TE features for your
> application, but that doesn’t mean that it’s not sufficient for some.
> Please don’t mislead people by saying that it’s not Traffic Engineering.
> Regards,
> Tony