Re: [mpls] draft-fang-mpls-label-forwarding-no-swap - how much does it really save?
"Adrian Farrel" <adrian@olddog.co.uk> Thu, 23 July 2015 14:08 UTC
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From: Adrian Farrel <adrian@olddog.co.uk>
To: 'Andrew Qu' <andrew.qu@mediatek.com>
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Date: Thu, 23 Jul 2015 15:08:33 +0100
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Cc: mpls@ietf.org
Subject: Re: [mpls] draft-fang-mpls-label-forwarding-no-swap - how much does it really save?
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Andrew, Are you mixing "no swap" with "bump in the wire"? If you are going to not consider TTL then you are doing some far more "interesting" things: like not decrementing the TTL so not being counted as a hop; not appearing in OAM; not checking incoming packets for TTL going to zero. The discussion of "no swap" as applied *solely* to the label is a black box optimisation. There is no difference at the external interfaces when "no swap" is done or when "pop'n'push" or "swap-inline" is done. The packet coming out has the same features in all cases. But, if you are doing other special things to the label stack entry (e.g. not looking at it, or not changing it) then IMHO you are not a router, you are a wire. Adrian From: mpls [mailto:mpls-bounces@ietf.org] On Behalf Of Andrew Qu Sent: 23 July 2015 15:01 To: Alexander Vainshtein; Stewart Bryant; Andrew G. Malis; S. Davari Cc: mpls@ietf.org Subject: Re: [mpls] draft-fang-mpls-label-forwarding-no-swap - how much does it really save? I don’t agree no-swap is the same as “swap with same value”. I think if standard adds a no-swap operation, that would be great for people to implement Either SW or HW. Once the label is defined as swap, I need to consider 1) TTL Copy payload TTL ? or using const_value 2) QoS (pipe mode or not) If pipe mode => then I need to do something If not=> then I need to do something else. However if it is really a “no-swap”, then it is very clear for HW/SW to implement such operation. I don’t need to consider any part of above cases. I don’t think swaping a same value label is NOT the same as “no-swap” at all. >From Standard point of view, we should NOT leave ambiguity here at all. Thanks, Andrew From: mpls [mailto:mpls-bounces@ietf.org] On Behalf Of Alexander Vainshtein Sent: Tuesday, July 21, 2015 5:05 PM To: Stewart Bryant; Andrew G. Malis; S. Davari Cc: mpls@ietf.org Subject: Re: [mpls] draft-fang-mpls-label-forwarding-no-swap - how much does it really save? +1. Thumb typed on my LG, Sasha ------ Original message ------ From: Stewart Bryant Date: 21/07/2015 17:58 To: Andrew G. Malis;S. Davari; Cc: mpls@ietf.org; Subject:Re: [mpls] draft-fang-mpls-label-forwarding-no-swap - how much does it really save? This draft proposes architectural changes, and as we can show that these changes are not needed, in my view, this draft should not go forward. - Stewart On 21/07/2015 09:02, Andrew G. Malis wrote: As there are no architectural or protocol changes or IANA considerations, this draft should be informational if it goes forward (it currently says "standards track"). Cheers, Andy On Mon, Jul 20, 2015 at 8:52 PM, S. Davari <davarish@yahoo.com> wrote: Eric I agree no standard change is required since this is a local optimization issue. Regards, Shahram > On Jul 20, 2015, at 11:43 AM, Eric C Rosen <erosen@juniper.net> wrote: > >> On 7/20/2015 2:07 PM, Shahram Davari wrote: >> The new swapped labels (The outgoing label that replaces the >> incoming label) need to be stored in a table. Using this draft >> reduces the number of swapped labels that needs to be stored, >> regardless of implementation. Don't you agree? > > No. If you notice that the incoming label needs to be 'replaced' by an outgoing label of the same value, you could just make the rewrite string shorter, so it won't overwrite the top label on the stack. This seems to be what the draft suggests, but it could be done as an optimization for the particular case where the incoming and outgoing labels have the same value. You could do this today, as a local implementation optimization. There doesn't seem to be any interop issue or any change to the data plane semantics. > >> It also reduces the configuration and management of the new swapped labels. > > We're not discussing whether there are any advantages to the use of domain-wide labels. We're discussing whether the use of domain-wide labels requires a change in the forwarding plane architecture. I just don't see that it does. > > _______________________________________________ > mpls mailing list > mpls@ietf.org > https://www.ietf.org/mailman/listinfo/mpls _______________________________________________ mpls mailing list mpls@ietf.org https://www.ietf.org/mailman/listinfo/mpls _______________________________________________ mpls mailing list mpls@ietf.org https://www.ietf.org/mailman/listinfo/mpls -- For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/index.html ************* Email Confidentiality Notice ******************** The information contained in this e-mail message (including any attachments) may be confidential, proprietary, privileged, or otherwise exempt from disclosure under applicable laws. It is intended to be conveyed only to the designated recipient(s). 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- [mpls] draft-fang-mpls-label-forwarding-no-swap -… Stewart Bryant
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Shahram Davari
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Eric C Rosen
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Shahram Davari
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Shahram Davari
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Eric C Rosen
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… S. Davari
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Andrew G. Malis
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Alexander Vainshtein
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Andrew G. Malis
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Alexander Vainshtein
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Stewart Bryant
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Alexander Vainshtein
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Andrew Qu
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Adrian Farrel
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Alexander Vainshtein
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Stewart Bryant
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Loa Andersson
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Shahram Davari
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Robert Raszuk
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Andrew G. Malis
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Shahram Davari
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Shahram Davari
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Robert Raszuk
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Gregory Mirsky
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Shahram Davari
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Robert Raszuk
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Robert Raszuk
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Eric C Rosen
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Shahram Davari
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Robert Raszuk
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Robert Raszuk
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Gregory Mirsky
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Andrew Qu
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Andrew Qu
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Shahram Davari
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Robert Raszuk
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Andrew Qu
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Gregory Mirsky
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Alexander Vainshtein
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Xuxiaohu
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Andrew Qu
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Andrew Qu
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Alexander Vainshtein
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Alexander Vainshtein
- [mpls] 答复: draft-fang-mpls-label-forwarding-no-sw… Lizhenbin
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Xuxiaohu
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Robert Raszuk
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Andrew Qu
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Andrew Qu
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Robert Raszuk
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Eric C Rosen
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Uma Chunduri
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Jeff Tantsura
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Andrew Qu
- Re: [mpls] 答复: draft-fang-mpls-label-forwarding-n… Eric C Rosen
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Andrew Qu
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Robert Raszuk
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Eric C Rosen
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Robert Raszuk
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Adrian Farrel
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Adrian Farrel
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Robert Raszuk
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Andrew G. Malis
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Robert Raszuk
- Re: [mpls] 答复: draft-fang-mpls-label-forwarding-n… Loa Andersson
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Stewart Bryant
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Eric C Rosen
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Robert Raszuk
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Andrew Qu
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Stewart Bryant
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Robert Raszuk
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Andrew G. Malis
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Andrew Qu
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Andrew Qu
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Gregory Mirsky
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Shahram Davari
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Andrew Qu
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Alexander Vainshtein
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Adrian Farrel
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Xuxiaohu
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Stewart Bryant
- Re: [mpls] draft-fang-mpls-label-forwarding-no-sw… Andrew Qu