Hi Joel,
thank you for your review and the pointed questions. Please find my answers, comments in-line and tagged GIM>>.
Regards,
Greg
On Thu, May 23, 2019 at 3:06 PM Joel Halpern via Datatracker <noreply@xxxxxxxx> wrote:
Reviewer: Joel Halpern
Review result: Has Issues
Hello,
I have been selected as the Routing Directorate reviewer for this draft. The
Routing Directorate seeks to review all routing or routing-related drafts as
they pass through IETF last call and IESG review, and sometimes on special
request. The purpose of the review is to provide assistance to the Routing ADs.
For more information about the Routing Directorate, please see
http://trac.tools.ietf.org/area/rtg/trac/wiki/RtgDir
Although these comments are primarily for the use of the Routing ADs, it would
be helpful if you could consider them along with any other IETF Last Call
comments that you receive, and strive to resolve them through discussion or by
updating the draft.
Document: ddraft-ietf-bfd-vxlan-07
Reviewer: your-name
Review Date: date
IETF LC End Date: date-if-known
Intended Status: copy-from-I-D
Summary: This document does not appear to be ready for publication as a
Proposed Standard RFC.
Major issues:
The scoping of the BFD usage is unclear. In places, this looks like it is
intended to be used by the underlay service provider, who will monitor the
connectivity between VTEPs.
GIM>> I think that the DCI provider would not be able to instantiate a BFD session using VXLAN encapsulation and, possibly, monitor that VXLAN part of forwarding operates properly. Such BFD session may monitor the path between the two VTEP but, if there exists ECMP environment in the transport, ensuring that that BFD session follows the same path as VXLAN data may be challenging.
In other places it seems to be aimed at
monitoring individual VNIs.
GIM>> The BFD session between VTEPs is not actually used to monitor the particular VNI but MAY be used to communicate, as concatenated path state signaling, the change of VNI state using the method described in Section 6.8.17 RFC 5880.
This is made worse when the packet format is
laid out. The inner packet is an Ethernet Packet with an IP packet (with
UDP, with BFD). This means that it is a tenant packet.
GIM>> Could you please point to the text which suggests that the BFD control packet is a tenant packet? Meant to be delivered to a tenant?
The IP address is
a tenant IP.
GIM>> The explanation of the format states in regard to the inner IP header:
IP header:
Source IP: IP address of the originating VTEP.
Destination IP: IP address of the terminating VTEP.
But the diagram shows this as being the IP address of the
VTEP. Which is not a tenant entity.
There is further confusion as to whether the processing is driven by the VNI
the packet arrived with, or the VNI is ignored.
GIM>> The use of VNI is implementation specific. Section 6 states:
6. Use of the Specific VNI
In most cases, a single BFD session is sufficient for the given VTEP
to monitor the reachability of a remote VTEP, regardless of the
number of VNIs in common. When the single BFD session is used to
monitor the reachability of the remote VTEP, an implementation SHOULD
choose any of the VNIs but MAY choose VNI = 0.
Minor Issues:
N/A
Nits: N/A
