Re: BFD over VXLAN: Trapping BFD Control packet at VTEP

"Joel M. Halpern" <jmh@joelhalpern.com> Wed, 31 July 2019 18:05 UTC

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Subject: Re: BFD over VXLAN: Trapping BFD Control packet at VTEP
To: Greg Mirsky <gregimirsky@gmail.com>, rtg-bfd WG <rtg-bfd@ietf.org>, "T. Sridhar" <tsridhar@vmware.com>, Dinesh Dutt <didutt@gmail.com>, bfd-chairs@ietf.org, Martin Vigoureux <martin.vigoureux@nokia.com>
Cc: draft-ietf-bfd-vxlan@ietf.org
References: <CA+RyBmW=byLBNfVQSdaEoMf-QnJtj13k788XhbZ9tqH4bcgqNQ@mail.gmail.com>
From: "Joel M. Halpern" <jmh@joelhalpern.com>
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Date: Wed, 31 Jul 2019 14:05:49 -0400
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I made the mistake of assuming we were in agreement.
What Greg has proposed below makes very good sense to me.

Thank you Greg.
Joel

On 7/31/2019 8:48 AM, Greg Mirsky wrote:
> Dear All,
> thank you for your comments, suggestions on this issue, probably the 
> most challenging for this specification. In the course of our 
> discussions, we've agreed to abandon the request to allocate the 
> dedicated MAC address to be used as the destination MAC address in the 
> inner Ethernet frame. Also, earlier using VNI 0 was changed from 
> mandatory to one of the options an implementation may offer to an 
> operator. The most recent discussion was whether VTEP's MAC address 
> might be used as the destination MAC address in the inner Ethernet 
> frame. As I recall it, the comments from VXLAN experts equally split 
> with one for it and one against. Hence I would like to propose a new 
> text to resolve the issue. The idea is to let an operator select 
> Management VNI and use that VNI in VXLAN encapsulation of BFD Control 
> packets:
> NEW TEXT:
> 
>     An operator MUST select a VNI number to be used as Management VNI.
>     VXLAN packet for Management VNI MUST NOT be sent to a tenant. VNI
>     number 1 is RECOMMENDED as the default for Management VNI.
> 
> With that new text, what can be the value of the destination MAC in the 
> inner Ethernet? I tend to believe that it can be anything and ignored by 
> the reciever VTEP. Also, if the trapping is based on VNI number, the 
> destination IP address of the inner IP packet can from the range 127/8 
> for IPv4, and for IPv6 from the range 0:0:0:0:0:FFFF:7F00:0/104. And 
> lastly, the TTL to be set to 1 (no change here).
> 
> Much appreciate your comments, questions, and suggestions.
> 
> Best regards,
> Greg