Re: WGLC for draft-ietf-bfd-unaffiliated-echo (ending 7 April, 2023)

[[e-mail]]

Jeff,






Thank you for the comments.


Please see inline...




Original



From: JeffreyHaas <[e-mail]>
To: 肖敏10093570;
Cc: [e-mail] <[e-mail]>;[e-mail] <[e-mail]>;
Date: 2023年04月06日 22:28
Subject: Re: WGLC for draft-ietf-bfd-unaffiliated-echo (ending 7 April, 2023)


Xiao Min,
Thanks for addressing Greg's comments.  I some additional comment on Greg's points:


On Apr 6, 2023, at 3:35 AM, <[e-mail]> <[e-mail]> wrote:
One of the considerations may be whether a IPv6 link local address is preferable to a global address.  
The only consideration for the draft as it is written is that the address used as the destination may be looped back by the unaffiliated device.  Link local helps address the security considerations that impact this feature, and it might be worth noting that when link local can be used for the use case that it assists in this point.
[XM]>>> I checked this with the implementer of this feature, and I'm told setting the DA to a IPv6 link local address doesn't work, because the link local address can't be looped back by the neighboring device.




Since the feature is intended to be used for single-hop, the source address SHOULD be an address on the shared subnet with the interface of the device that is looping the packets back.  Perhaps it might even be reasonable to require that the source and destination addresses are identical when possible?

Where this may complicate procedure is the initial demultiplexing step when the session is Down.  Once the session is Up, the Discriminators can be used for this purpose.

[XM]>>> I propose the text change as below.


OLD

Device A would send BFD Unaffiliated Echo packets with IP destination
 address destined for itself, such as the IP address of interface 1 of
 device A.
NEW

Device A would send BFD Unaffiliated Echo packets with IP destination
 address destined for itself, such as the IP address of interface 1 of
 device A. The IP source address of the BFD Unaffiliated Echo packets
 could be identical to the IP destination address or other address provisioned
 on device A.


Regards,

Xiao Min




-- Jeff












The draft describes how the destination IP address of the Echo packet is set. Are there any special considerations for selecting IPv6 destination address?


[XM]>>> The draft currently says "Device A would send BFD Unaffiliated Echo packets with IP destination address destined for itself, such as the IP address of interface 1 of device A". No any special considerations.