Subject: [mpls] Alvaro Retana's No Objection on draft-ietf-mpls-lsp-ping-relay-reply-10: (with COMMENT)

From: "Alvaro Retana" <[email-masked]>
Date: Tue, 29 Sep 2015 20:11:11 -0700

Alvaro Retana has entered the following ballot position for
draft-ietf-mpls-lsp-ping-relay-reply-10: No Objection

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COMMENT:
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I have some comments/questions:

1. TBD2 is the Relay Node Address Stack TLV Type.  There seems to be some
confusion in the text: Section 4.2. (Receiving an Echo Request)  says
that the "Type of the Relay Node Address Stack TLV is chosen from the
range 32768 to 49161…” giving the impression that any value can be used,
while 8.2. (New TLV) in the IANA Considerations says that a "suggested
value should be assigned” giving me the impression that the assignment is
just a suggestion (and somehow reinforcing the text in 4.2), but the
original definition in 3.2. (Relay Node Address Stack) simply says that
the "value should be assigned by IANA”.  Assuming that you simply want an
assignment and that it would be what is used, please clean the text up; I
suggest just referring to the value as TBD2 (in 4.2 and 8.2) and
explicitly including the text about the assignment and the range (from
3.2) in 8.2.

2. Section 4.1. (Sending an Echo Request) says that the "Relay Node
Address Stack TLV MUST be carried in the Echo Request message if the
relay functionality is required”.  How does the initiator know that it
needs the functionality?

3. Section 4.2. (Receiving an Echo Request) "A second or more address
entries MAY also be added if necessary, depending on implementation.” 
Isn’t this document defining how the implementation should work?  What
are the cases where these additional entries may be added?

---

From: Loa Andersson <[email-masked]>
Date: Wed, 30 Sep 2015 13:30:45 +0800

Alvaro,

Pleaese see your first comment.

> https://datatracker.ietf.org/doc/draft-ietf-mpls-lsp-ping-relay-reply/

I'm not sure how to read this - it looks like you are removing the range
information. However for LSP Ping the ranges are important. The IANA
section should state which range the code point should come from. Here
are the allocation policies and how TLVs from the different ranges are
reted.

0-16383         Standards Action	
                 This range is for mandatory TLVs or for optional TLVs
                 that require an error message if not recognized.

16384-31743	Specification Required	
                 Experimental RFC needed

32768-49161	Standards Action	
                 This range is for optional TLVs that can be silently
                 dropped if not recognized.

49162-64511	Specification Required	Experimental RFC needed

So asking for a TLV from the 32768-49161 range will give you an optional
TLV that can be silently dropped if not recognized.

/Loa

---

From: "George Swallow (swallow)" <[email-masked]>
Date: Wed, 30 Sep 2015 13:41:42 +0000

Loa, Lizhong -

I suggest:

OLD:

   The Type of the Relay Node Address Stack TLV is chosen from the range
   32768 to 49161 so that (per section 3 of [RFC4379] an LSR that does
   not recognize the TLV knows that the TLV is optional and can safely
   ignore it.

NEW:

   The Type of the Relay Node Address Stack TLV is chosen from the range
   Range defined in [RFC4379] as "optional TLVs that can be silently
   dropped if not recognized².  An LSR that does
   not recognize the TLV SHOULD ignore it.

George

On 9/30/15, 1:30 AM, "Loa Andersson" <[email-masked]> wrote:

>> Please refer to 
>>https://www.ietf.org/iesg/statement/discuss-criteria.html
>> range 32768 to 49161Š² giving the impression that any value can be used,
>> value should be assigned² giving me the impression that the assignment
>>is
>> the "value should be assigned by IANA².  Assuming that you simply want
>>an
>> relay functionality is required².  How does the initiator know that it
>> needs the functionality?
>>
>> entries MAY also be added if necessary, depending on implementation.²
>> Isn¹t this document defining how the implementation should work?  What

---

From: Loa Andersson <[email-masked]>
Date: Wed, 30 Sep 2015 21:56:54 +0800

George,

I don't think that this really addresses Alvaro's point, waiting for
Alvaro to acknowledge my point, after that I was going to suggest.

NEW:

   The Type of the Relay Node Address Stack TLV will be allocated by
   IANA from the range Range defined in [RFC4379] as "optional TLVs
   that can be silently dropped if not recognized².  An LSR that does
   not recognize the TLV SHOULD ignore it.

I think that does addresses the concern that one can use any number
in the range. We also need the range pointed out explicitly in the
IANA section.

/Loa

---

From: Lizhong Jin <[email-masked]>
Date: Wed, 30 Sep 2015 23:46:52 +0800

Hi Alvaro,
Thanks for the review. See inline below.

Regards
Lizhong

> https://datatracker.ietf.org/doc/draft-ietf-mpls-lsp-ping-relay-reply/
[Lizhong] Please refer to Loa and George's reply. It seems your concern is
the word "suggested" in sectin 8.2. Remove this word is OK for me.

> relay functionality is required”.  How does the initiator know that it
[Lizhong] This depends on the implementation. One way is the operator
will explicitly add an option to the ping command, e.g., ping mpls -r
x.x.x.x,
where option "-r" refers to ping with relay reply.

> are the cases where these additional entries may be added?
[Lizhong] we do not make any restriction that only one address entry is
allowed
since the designed mechanism would work with multiple address entries. We
use word "MAY" to describe this. One possible case to use more address
entries is to provide more reliability, where one address becoming
unreachable
could be replaced with the other one.

---

From: "Alvaro Retana (aretana)" <[email-masked]>
Date: Wed, 30 Sep 2015 16:26:41 +0000

On 9/30/15, 12:30 AM, "Loa Andersson" <[email-masked]> wrote:

Hi!

Sorry that I was cryptic..

>>value should be assigned² giving me the impression that the assignment is
>>the "value should be assigned by IANA².  Assuming that you simply want an

In short, the range should only matter in the IANA Considerations so that
the right assignment is made.  In the rest of the text referencing TBD2
should be enough.

Explicitly, this is what I¹m proposing:

Section 3.2:

OLD
      Type: value is TBD2.  The value should be assigned by IANA from
      32768-49161 as suggested by [RFC4379] Section 3.

NEW
      Type: value is TBD2.

Section 4.2:

OLD
   The Type of the Relay Node Address Stack TLV is chosen from the range
   32768 to 49161 so that (per section 3 of [RFC4379]) an LSR that does
   not recognize the TLV knows that the TLV is optional and can safely
   ignore it.

NEW
   The Type of the Relay Node Address Stack TLV is TBD2 so that
   (per section 3 of [RFC4379]) an LSR that does
   not recognize the TLV knows that the TLV is optional and can safely
   ignore it.

Section 8.2:

OLD
   A suggested value should be assigned from "Standards Action" range
   (32768-49161) as suggested by [RFC4379] Section 3, using the first
   free value within this range.

NEW
   A value should be assigned from "Standards Action" range
   (32768-49161) as suggested by [RFC4379] Section 3, using the first
   free value within this range.

BTW, I found a new nit:  In Section 3.3. (MTU Exceeded Return Code)
s/TBD2/TBD3

Thanks!

Alvaro.

---

From: "Alvaro Retana (aretana)" <[email-masked]>
Date: Wed, 30 Sep 2015 16:28:20 +0000

>   not recognize the TLV SHOULD ignore it.

If you want to add some of this text instead of what I suggested (see my
other e-mail), I’m fine too.

Alvaro.

---

From: "Alvaro Retana (aretana)" <[email-masked]>
Date: Wed, 30 Sep 2015 16:30:38 +0000

On 9/30/15, 10:46 AM, "Lizhong Jin" <[email-masked]<mailto:[email-masked]>> wrote:

Lizhong:

Hi!

will explicitly add an option to the ping command, e.g., ping mpls -r x.x.x.x,

3. Section 4.2. (Receiving an Echo Request) "A second or more address
entries MAY also be added if necessary, depending on implementation.”
Isn’t this document defining how the implementation should work?  What
are the cases where these additional entries may be added?
[Lizhong] we do not make any restriction that only one address entry is allowed
since the designed mechanism would work with multiple address entries. We
use word "MAY" to describe this. One possible case to use more address
entries is to provide more reliability, where one address becoming unreachable
could be replaced with the other one.

In both cases a little clarification in the text would be nice.

Thanks!

Alvaro.