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Re: [mpls] Concerns about ISD

Tony Li <tony.li@tony.li> Fri, 15 April 2022 18:08 UTC

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From: Tony Li <tony.li@tony.li>
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Date: Fri, 15 Apr 2022 11:08:42 -0700
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Cc: John E Drake <jdrake=40juniper.net@dmarc.ietf.org>, Tianran Zhou <zhoutianran=40huawei.com@dmarc.ietf.org>, "mpls@ietf.org" <mpls@ietf.org>
To: Haoyu Song <haoyu.song@futurewei.com>
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Subject: Re: [mpls] Concerns about ISD
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Hi Haoyu,


> Please take a look at our EH draft if you haven’t yet. The mechanism is there and the essence is that it doesn’t tamper the MPLS label stack and label semantics. That’s why I say PSD is least intrusive.


Thank you, I was unaware of it and have now looked at it.  If I understand it correctly, the EHI is the trigger to look for extension headers, all of which are in PSD.  Again, the parsing performance is a linear read to find the bottom of stack.

While it may be minimally intrusive to the label stack semantics, that doesn’t seem like a good trade-off for the performance penalty.

On a separate point, I have deep concerns about the encoding efficiency of the extension headers.  We can talk about this if and when it becomes relevant.

Tony

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