[manet] AB#1 Review for draft-ietf-manet-olsrv2-dat-metric (DAT metric for RFC7181)

[Abdussalam Baryun <[e-mail]>]

Reviewed draft name: draft-ietf-manet-olsrv2-dat-metric-02.
Date: 14.09.2014.

Dear WG editors, and All WG participants,

I thank you very much for this interesting work. I read the draft and don't
think the draft is ready for WGLC as Thomas proposed previously in July [1]
(no action/reply by WG yet for the proposal). Furthermore, I agree with the
comment of Thomas regarding IANA section, specially for
olsrv2 multitopology's consideration. However, IMHO the draft should be
clear who the RFC5444 packets belong to (from other discussions with WG,
they think it only belongs to the multiplexer), while measuring
link packets loss.

 The terminology section should clarify what are packets for this protocol,
is a packet: the link packet, control packet, data packet, IP packet, or
mixed, but because not clear about that it may taken more reading time. I
understand it is only link packets because this metric-protocol measures
only link packets. The WG draft in section 9 defines value for RFC5444
packet, but does not describe how it is implemented or does not mention the
unified multiplexer function. I suggest adding one section for multiplexing
considerations. I remember in one conversation [2], you suggested a code
line into right place. For this experimental protocol where will be the
right place to instruct RFC5444 to input value for packet sequence numbers.

[1]. http://www.ietf.org/mail-archive/web/manet/current/msg16741.html

[2]. http://www.ietf.org/mail-archive/web/manet/current/msg16987.html


AB> the draft needs to be clear what is the "packet loss". IMO it should
always say "link packet loss". Please amend.

In section 3:
Some links may have more than one routing protocol using it as RFC5498/5444
shares the number/port for all MANET protocols' control traffic.

--- OLD ---
If [RFC5444] control traffic is used to determine the link packet loss, the
administrator should take care that link layer multicast transmission do
not not have a higher reception probability than the slowest unicast
transmission.

--- NEW ---
If [RFC5444] control traffic is used to determine the average packet loss,
the administrator should take care the following: 1) that the control
traffic is owned by the routing protocol determining the metric, 2) that
link layer multicast transmission do not not have a higher reception
probability than the slowest unicast transmission.

In section 5:
The ratio is not average because it should be less than 1. The draft has to
determine that the ratio is per protocol not per multiplexer. IMHO The
draft is now calculating the ratio per multiplexer.

--- OLD ---
The average packet loss ratio is calculated as the sum of the ’total
packets’ counters divided by the sum of the ’packets received’ counters.
 This value is then divided through the current link-speed and then scaled
into the range of metrics allowed for OLSRv2.

--- NEW ---
The link packet loss value is calculated as the sum of the ’total packets’
counters routing protocol links divided by the sum of the ’packets
received’ counters for same links.  This average value is then divided
through the current link-speed and then scaled into the range of metrics
allowed for OLSRv2.

In section 6:

It says defines two constants that are defined but then refers to four
constants. I expect you mean the first two are MUST and the others are
mandatory per case. If that is case please clarify in the section.

In section 8.1:

Repeated packet sequence number initial ( please delete one).

--- OLD ---
L_DAT_lost_hello_messages := 0 (no HELLO interval without packets).

--- NEW ---
L_DAT_lost_hello_messages := 0 (no HELLO interval without a hello message).

In Section 9.3

---OLD---
While this metric was designed for measuring the packet loss based on the
[RFC5444] packet sequence number, some implementations might not be able to
add the packet sequence number to their output. Because of this the
following section contains multiple alternatives to calculate the packet
loss.

--- NEW ---
While this metric was designed for measuring the packet loss and link
speed based on the Link packet sequence number and the multiplexer
policy, some implementations might not be able to add the packet sequence
number to their output. Because of this the following section contains
multiple alternatives to calculate the packet loss.

In section 10:

You mention RFC5444 processing, what do you mean, I understand you
mean the unified multiplexing of RFC5444, is that what you mean?

Overall, looking into our WG drafts and RFCs, is the WG avoiding
mentioning the multiplexer function in its drafts for an unknown
reason? Is that an official editing procedure plan? Even the RFC5444
puts it in the appendix, which I think is the wrong place, if the WG
is considering interoperability.

Best Regards,

AB

This is the first review of AB for this WG draft.


On Friday, August 8, 2014, wrote:

>
> A New Internet-Draft is available from the on-line Internet-Drafts
> directories.
>  This draft is a work item of the Mobile Ad-hoc Networks Working Group of
> the IETF.
>
>         Title           : Packet Sequence Number based directional airtime
> metric for OLSRv2
>         Authors         : Henning Rogge
>                           Emmanuel Baccelli
>         Filename        : draft-ietf-manet-olsrv2-dat-metric-02.txt
>         Pages           : 17
>         Date            : 2014-08-08
>
> Abstract:
>    This document specifies an directional airtime link metric for usage
>    in OLSRv2.
>
>
> The IETF datatracker status page for this draft is:
> https://datatracker.ietf.org/doc/draft-ietf-manet-olsrv2-dat-metric/
>
> There's also a htmlized version available at:
> http://tools.ietf.org/html/draft-ietf-manet-olsrv2-dat-metric-02
>
> A diff from the previous version is available at:
> http://www.ietf.org/rfcdiff?url2=draft-ietf-manet-olsrv2-dat-metric-02
>
>
> Please note that it may take a couple of minutes from the time of
> submission
> until the htmlized version and diff are available at tools.ietf.org.
>
> Internet-Drafts are also available by anonymous FTP at:
> ftp://ftp.ietf.org/internet-drafts/
>
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