Hello Greg,
   Thanks for your comments. Please see my reply inline tagged[ SPK].

Thanks
Santosh P K

On Tue, Jul 4, 2017 at 1:02 AM, Greg Mirsky <[email protected]> wrote:

> Dear Authors, WG chairs, et. al,
> please kindly consider my comments to the latest version of the draft as
> part of WGLC:
>
>    - Very general
>       - I suggest to add note clarifying that all terms that include
>       "connectivity" in the document are being used as alternative to
>       "continuity", i.e. existence of a path between the sender and the 
> receiver,
>       and should not be interpreted as "connectivity verification in terms of
>       transport network".
>    - Introduction
>       - I find that characterization of BFD and unidirectional continuity
>       verification as "natural fit" bit of stretching. Perhaps "capable of
>       supporting this use case" is acceptable;
>
> [SPK] Will take care.

>
>    - Goals
>       - the last statement of non-goal seems little unclear. In fact, if
>       there's only one tail, the BFD for multipoint network does verify
>       connectivity, though unidirectional, between the head and the tail. I 
> think
>       that the intention is to stress that p2p bi-directional connectivity
>       verification is not supported by this document.
>
> [SPK] It only says that this document does not support verification of
unicast path between head and tail. I can clarify a bit on this. Please let
me know if you have a suggestion for this.


>
>    - Section 4.7
>       - the last paragraph notes that the discriminator value MUST NOT be
>       changed. Since Your Discriminator MUST be set to 0 this refers to My
>       Discriminator only. I think that explicit reference will make the 
> statement
>       more clear. Thus suggest s/the discriminator values/the My Discriminator
>       value/
>
> [SPK] Will take care of this.

>
>    - Section 4.8
>       - I believe that requiring use of IP/UDP encapsulation for BFD in
>       multipoint networks over MPSL LSP is too restrictive. I suggest changing
>       text as following:
>
> OLD:
>
> For multipoint LSP, MultipointTail MUST use destination UDP port "3784" and 
> IP "127.0.0.0/8" range.
>
>
> NEW
>
> If IP/UDP encapsulation used by MultipointHead for multipoint LSP, 
> MultipointTail MUST use IP/UDP encapsulation of BFD destination UDP port 
> "3784" and IP "127.0.0.0/8" range.
>
> Use of other types of encapsulation for multipoint LSP is outside the scope 
> of this document.
>
>
[SPK] Thanks. I think this make sense for non MPLS tunnels.

>
>    - Section 4.10
>       - I cannot say what bfd.DetectMult packet is. It has not been defined 
> in RFC 5880, nor in this document. What is the scenario described in the 
> second paragraph? Is it when MultipointHead reduces Desired Min TX  Interval 
> thus making defect detection more aggressive?
>    -
>
> [SPK] This section talks about how to handle Poll sequence. In case of
Multipoint head we cant afford to send POLL and expect all tail to reply
with F bit set. Keeping track and building state at headend will be costly.


>
>    - Section 7
>       - I think it should be plural in the first paragraph, i.e. 
> s/MultipointTail session/MultipointTail sessions/
>       - I think that we can add another consideration to improve, strengthen 
> security of BFD for multipoint network by suggesting that MultipointTail 
> sessions created only for known combination of MultipointHead and My 
> Discriminator. Such information MAY be learned from out-of-band and 
> mechanisms are outside the scope of this document.
>
>
> Regards,
>
> Greg
>
>
>
> On Mon, Jun 19, 2017 at 12:39 PM, Jeffrey Haas <[email protected]> wrote:
>
>> Working Group,
>>
>> https://tools.ietf.org/html/draft-ietf-bfd-multipoint-10
>> https://tools.ietf.org/html/draft-ietf-bfd-multipoint-active-tail-04
>>
>>
>> The BFD Multipoint documents have been stable for some time.  Prior
>> discussion at meetings has suggested we have an implementation for the
>> main
>> protocol component.  Also per prior discussions, we split the active-tail
>> component of the original multipoint document to permit implementors to
>> not
>> have to worry about implementing active-tail procedures if they weren't
>> interested in that feature.
>>
>> We are starting an extended last call on these documents.  The WGLC will
>> conclude on July 14.  This provides ample time for list discussion.  If
>> necessary, the IETF-99 meeting may provide for opportunities to close any
>> contentious technical points.  (BFD is not currently scheduled to meet.)
>>
>> One item I would like to kick off is the document status of the
>> active-tail
>> mechanism.  At this time, no one has implemented it that I am aware of.
>> Discussion with our AD suggests that publishing the document with
>> Experimental status may be reasonable to preserve the work that went into
>> the proposal.
>>
>> -- Jeff
>>
>>
>

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