Hi Ketan,
Thank you for the suggested text, very helpful.
I've just posted a new revision that incorporates all your comments. Link as
below.
https://datatracker.ietf.org/doc/html/draft-ietf-bfd-unaffiliated-echo-09
Please see inline with [XM-2]>>>.
Original
From: KetanTalaulikar <ketant.i...@gmail.com>
To: 肖敏10093570;
Cc: draft-ietf-bfd-unaffiliated-e...@ietf.org
<draft-ietf-bfd-unaffiliated-e...@ietf.org>;rtg-bfd@ietf.org
<rtg-bfd@ietf.org>;jh...@pfrc.org <jh...@pfrc.org>;
Date: 2023年09月25日 15:37
Subject: Re: Comments on draft-ietf-bfd-unaffiliated-echo-08
Hi Xiao Min,
Thanks for your response. Please check inline below for further suggestions.
On Mon, Sep 25, 2023 at 11:41 AM <xiao.m...@zte.com.cn> wrote:
Dear Ketan,
Thanks for your review and thoughtful comments.
Please see inline.
Original
From: KetanTalaulikar <ketant.i...@gmail.com>
To: draft-ietf-bfd-unaffiliated-e...@ietf.org
<draft-ietf-bfd-unaffiliated-e...@ietf.org>;
Cc: rtg-bfd@ietf.org <rtg-bfd@ietf.org>;Jeffrey Haas <jh...@pfrc.org>;
Date: 2023年09月22日 22:55
Subject: Comments on draft-ietf-bfd-unaffiliated-echo-08
Hello Authors,
Looks like I've missed the WGLC on this document, but nevertheless would like
to share the following comments:
Sec 1 of the document says:
Section 5 of [RFC5880] indicates that the payload of an affiliated BFD Echo
packet is a local matter and hence its contents are outside the scope of that
specification. This document, on the other hand, specifies the contents of the
Unaffiliated BFD Echo packet and what to do with them.
However, when I go through the procedures in Section 2, there is no description
of the actual construction of the IP packet that A sends out to B - what is the
source and destination IP - or MAC addresses for that matter? How is it that B
would loop it back? I believe it is important for the document to specify this.
[XM]>>> This document does specify the source and destination IP, through
reference to RFC 5881. In section 2 it says
"Regarding the selection of IP address, the rules stated in Section 4 of
[RFC5881] are applicable to the encapsulation of an Unaffiliated BFD Echo
packet."
In -07 version the rules of RFC 5881 were restated, however in -08 version
they're removed by following the suggestion from Greg.
KT> I missed that conversation. One small suggestion so it covers not just IP
address but also MAC.
OLD: Regarding the selection of IP address, the rules stated in Section 4 of
[RFC5881] are applicable to the encapsulation of an Unaffiliated BFD Echo
packet.
NEW: An Unaffiliated BFD Echo packet follows the same encapsulation rules as
for a BFD Echo packet as specified in Section 4 of [RFC5881].
[XM-2]>>> Accepted.
Another important part is that normally BFD verifies the bidirectional path,
the liveness of the other endpoint, but also validates the presence of a
specific IP at that endpoint. Is that still the case when operating in this
mode? This question arises since the document talks about liveness to servers -
so is it monitoring liveness to the server host or a specific server IP?
[XM]>>> It's monitoring liveness to the server host, not a specific server IP.
Also note that the Unaffiliated BFD Echo can be used for multiple use cases, in
section 1 it says
"Section 6.2.2 of [BBF-TR-146] describes one use case of the Unaffiliated BFD
Echo. Section 2 of [I-D.wang-bfd-one-arm-use-case] describes another use case
of the Unaffiliated BFD Echo."
KT> This is OK. I was looking for some text (perhaps in Section 1) that says
something on the lines of ... "The Unaffiliated BFD Echo functionality only
monitors liveness of the node and does not monitor the availability of a
specific IP address at that node." - I believe this is an important distinction
from normal BFD operations that needs to be called out. Would you agree?
[XM-2]>>> Some text as you want was added to section 1.
Finally, is it normal or natural to expect server hosts to be able to "loop
them back by normal IP forwarding"? Or does it require some additional/special
capabilities to be turned ON those hosts as hosts don't do forwarding by
default.
[XM]>>> As I know of a deployment, there is no need to turn ON those hosts. At
the same time, it's feasible to have such a knob. Propose to add some text as
below.
OLD
The method for provisioning device B to loop back BFD Unaffiliated Echo packets
is outside the scope of this document.
NEW
There may be a knob to turn on/off the loopback of Unaffiliated BFD Echo
packets at device B. The method for provisioning device B to loop back
Unaffiliated BFD Echo packets is outside the scope of this document.
KT> This is not quite where I was going. Perhaps something on the following
lines?
NEW:
BFD Unaffiliated Echo feature depends on device B performing IP forwarding
(actually IP redirect) functionality. While such functionality may normally be
expected to be supported on a router, it may not be enabled on a host by
default. The method for provisioning device B to loop back BFD Unaffiliated
Echo packets is outside the scope of this document.
[XM-2]>>> Accepted.
Best Regards,
Xiao Min
Thanks,
Ketan
Best Regards,
Xiao Min
It would help if these aspects are clarified in the document.
Thanks,
Ketan
On Thu, Jul 6, 2023 at 7:50 AM <internet-dra...@ietf.org> wrote:
A New Internet-Draft is available from the on-line Internet-Drafts
directories. This Internet-Draft is a work item of the Bidirectional
Forwarding Detection (BFD) WG of the IETF.
Title : Unaffiliated BFD Echo
Authors : Weiqiang Cheng
Ruixue Wang
Xiao Min
Reshad Rahman
Raj Chetan Boddireddy
Filename : draft-ietf-bfd-unaffiliated-echo-08.txt
Pages : 12
Date : 2023-07-05
Abstract:
Bidirectional Forwarding Detection (BFD) is a fault detection
protocol that can quickly determine a communication failure between
two forwarding engines. This document proposes a use of the BFD Echo
where the local system supports BFD but the neighboring system does
not support BFD. BFD Control packet and its processing procedures
can be executed over the BFD Echo port where the neighboring system
only loops packets back to the local system.
This document updates RFC 5880.
The IETF datatracker status page for this Internet-Draft is:
https://datatracker.ietf.org/doc/draft-ietf-bfd-unaffiliated-echo/
There is also an htmlized version available at:
https://datatracker.ietf.org/doc/html/draft-ietf-bfd-unaffiliated-echo-08
A diff from the previous version is available at:
https://author-tools.ietf.org/iddiff?url2=draft-ietf-bfd-unaffiliated-echo-08
Internet-Drafts are also available by rsync at rsync.ietf.org::internet-drafts
