Re: [mpls] Secdir last call review of draft-ietf-mpls-flow-ident-06

Stewart Bryant <> Thu, 01 March 2018 20:07 UTC

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To: Daniel Franke <>,
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From: Stewart Bryant <>
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Date: Thu, 1 Mar 2018 20:06:54 +0000
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Subject: Re: [mpls] Secdir last call review of draft-ietf-mpls-flow-ident-06
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Hi Daniel

Thank you for the review.

On 10/01/2018 21:36, Daniel Franke wrote:
> Reviewer: Daniel Franke
> Review result: Has Nits
> I have reviewed this document as part of the security directorate's ongoing
> effort to review all IETF documents being processed by the IESG. These comments
> were written primarily for the benefit of the security area directors. Document
> editors and WG chairs should treat these comments just like any other last call
> comments.
> I know next to nothing about MPLS. The proposed functionality seems reasonable
> and persuasively justified, but it is possible that there are significant
> issues I'm overlooking. I have a couple nitpicks about the Security
> Considerations section.
> The lowercased (i.e., non-RFC-2119) "must"s and "should"s are weasel words when
> not connected with a statement of what objective is achieved by following those
> recommendations. For example, the sentence "Propagation of identification
> information outside the MPLS network imposing it must be disabled by default"
> ought to be prefaced or suffixed with something along the lines of "In order to
> preserve present assumptions about MPLS privacy properties".
This is a useful point and I have included it in the security section.
> I see a lot of discussion about confidentiality concerns when flow information
> is propagated across trust boundaries, but no discussion about the dual
> integrity concerns.
I am not sure what a dual integrity concern is. Do you mean data integrity?
> I suggest including some word of warning that flow
> information received from an untrusted LSR cannot be assumed correct, so
> caution is advised before relying on it, e.g., to determine for billing
> purposes whether SLAs are being met.
In an MPLS network we would not have any exchange with an untrusted LSR.
It is a fundamental assumption that routers within the same domain are 
If a router was untrustworthy it could cause immense damage to the whole
network, for example, by sending false reachability information that 
would bring the
whole network down.  So within an MPLS network we tend to trust that the
routers tell the truth.

- Stewart