Re: [tsvwg] Warren Kumari's Discuss on draft-ietf-tsvwg-le-phb-09: (with DISCUSS and COMMENT)

["Bless, Roland (TM)" <[e-mail]>]

Hi Warren,

Am 20.02.19 um 18:16 schrieb Warren Kumari:
> ----------------------------------------------------------------------
> DISCUSS:
> ----------------------------------------------------------------------
> 
> I believe that this should be trivial DISCUSS to address, but I thought it
> important enough to warrant it. I'm OK with basically whatever you answer, I
> just wanted to make sure this had been seen and considered.
> 
> "An LE PHB SHOULD NOT be used for a customer’s "normal Internet"
>    traffic nor should packets be "downgraded" to the LE PHB instead of
>    being dropped, particularly when the packets are unauthorized
>    traffic.  "

This was actually directly copied from RFC 3662.

> Great, sounds good to me -- but in the USA at least, there is are many cell
> phone plans which are "unlimited", but after some amount of traffic (e.g 22GB)
> your connection gets throttled to a lower data rate. Is this traffic still 'a
> customer's "normal Internet" traffic"? Is it appropriate (whatever that means)
> to downgrade this traffic to the LE PHB? I understand not wanting to touch this
> issue with  a 10 foot pole (and I don't know what the right answer is!), but
> you *did* open this can of worms by talking about what classification user
> traffic should have.
> 
> Note: I'm happy to clear my DISCUSS no matter what the answer is, I just want
> to make sure it has been considered / discussed.

The main idea is that applications/users decide what traffic should go
to the "background", i.e., which packet are marked as LE (end-to-end
argument as hint: the network lacks usually the application knowledge).
Operators must have good reasons to deliberately downgrade users' normal
traffic. In case of throttled traffic, this would still be considered as
being normal BE traffic. One case for downgrading BE traffic could be
non-admitted multicast replication traffic as described in RFC 3754.

> ----------------------------------------------------------------------
> COMMENT:
> ----------------------------------------------------------------------
> 
> Major:
> "Some network providers keep link utilization below 50% to ensure that all
> traffic is forwarded without loss after rerouting caused by a link failure
> (cf.Section 6 of [RFC3439]).  LE marked traffic can utilize the normally unused
> capacity and will be preempted automatically in case of link failure when 100%
> of the link capacity is required for all other traffic. " Yup - very true. But
> I think it needs to be mentioned that the provider will need to upgrade their
> monitoring / management system so that they can see the traffic lass. If they
> monitoring circuit utilization using e.g interface counters (and not by traffic
> class), a link may have 1% "real" traffic and 90% LE traffic, and it will look
> like it it 91% "full". I don't have any suggested text to address this (and
> this is just a comment, so "well, duh, they should know that anyway!" is a fine
> answer.)

Thanks for the hint, valid point, but indeed: if they use Diffserv, they
should also monitor the resource shares for each PHB individually.

> Nits:
> "A main problem is that multicast" -- I'm not sure you can say "A main" - main
> implies singular.; I'd suggest "The main" or "A major".

Right.

> "However,using the Lower Effort PHB for multicast requires to pay special" --
> "requires paying"...

Done.

Regards
 Roland