Issue 1: Use of 1.5 hours in the text

Brett -

>Perhaps another approach might be to simply have some
text that says that when changing the lifetime 
> of a prefix, a router must send at least 3 Router
Advertisements with the new prefix lifetime before removing
the prefix from a link.  Even if a router 
> normally only sends Advertisements very infrequently,
it doesn't seem unreasonable to make 
> it send a few quick ones just during a period of prefix
change.

This sounds ok to me. But, I am not sure how this change
addresses the issue. If the router advertises very
infrequently, the host will start dropping prefixes from the
DNAHostPrefixList if we keep the 1.5 hours restriction.
After sometime, the list could become empty and useless from
DNA point of view.

- Sathya

----- Original Message -----
From: Brett Pentland <brett.pentlandeng.monash.edu.au>
Date: Saturday, November 18, 2006 4:59 am
Subject: Re: [DNA] Issue 1: Use of 1.5 hours in the text

> Sathya Narayanan wrote:
> > Issue: WiMAX is trying to increase the
MaxRtrAdvInterval into 
> hours or 
> > days. Should we change 1.5 hours to 3 *
MaxRtrAdvInterval?
> > Agreement at the meeting: Yes. Lets make the
change. We need to 
> include 
> > the MaxRtrAdvInterval in the RA so that the hosts
can know about 
> the 
> > value. If different routers on the link use
different values for 
> > MaxRtrAdvInterval, host should use the minimum
(Should it be 
> maximum?) 
> > value of MaxRtsAdvtInterval times three as the
lifetime for 
> prefixes in 
> > the DNAHostPrefixList.
> > 
> > If you have any objection to the proposed change,
please post 
> your 
> > objection on the list.
> 
> Hi Sathya,
> 
> JinHyeock is right about the 1.5 coming from the
maximum value of 
> MaxRtrAdvInterval.  If this maximum is to be increased
to "hours 
> or 
> days" then I'd worry about just using 3 * that
value.
> 
> The 1.5 hours is the time used to age out old prefix
information.  
> It 
> was picked because it was supposed to ensure that at
least 3 
> router 
> advertisements from each router would have been sent in
that time. 
> The 
> idea was to ensure that hosts have received an
indication that the 
> lifetime of a prefix has been changed if an operator
wants to move 
> a 
> prefix to another link.
> 
> Section 5.1.11 recommends that operators wait for at
least 1.5 
> hours 
> after removing a prefix from a link before reassigning
it to 
> another 
> link. (I don't know if any operators will read this,
but I guess 
> that's 
> another issue)  I don't think it desirable to increase
this to days.
> 
> Perhaps another approach might be to simply have some
text that 
> says 
> that when changing the lifetime of a prefix, a router
must send at 
> least 
> 3 Router Advertisements with the new prefix lifetime
before 
> removing the 
> prefix from a link.  Even if a router normally only
sends 
> Advertisements 
> very infrequently, it doesn't seem unreasonable to make
it send a 
> few 
> quick ones just during a period of prefix change.
> 
> Cheers,
> Brett.
> 

Ah, ok.  I'd missed that point.  I'm still not keen on the
idea of using 
3 times the maximum value of MaxRtrAdvInterval if that
maximum is to be 
raised much larger than 1800 seconds.  Perhaps the 1.5 hours
can be 
retained where it relates to prefix changes on routers.

For expiry of DNA information, 3 times the actual advertised

MaxRtrAdvInterval for each prefix. Where the same prefix is
advertised 
by more than one router, then the maximum value of
MaxRtrAdvInterval 
could be used.

Cheers,
Brett.

Sathya Narayanan wrote:
> Brett -
> 
>> Perhaps another approach might be to simply have
some text that says that when changing the lifetime 
>> of a prefix, a router must send at least 3 Router
Advertisements with the new prefix lifetime before removing
the prefix from a link.  Even if a router 
>> normally only sends Advertisements very
infrequently, it doesn't seem unreasonable to make 
>> it send a few quick ones just during a period of
prefix change.
> 
> This sounds ok to me. But, I am not sure how this
change addresses the issue. If the router advertises very
infrequently, the host will start dropping prefixes from the
DNAHostPrefixList if we keep the 1.5 hours restriction.
After sometime, the list could become empty and useless from
DNA point of view.
> 
> - Sathya
> 
> ----- Original Message -----
> From: Brett Pentland <brett.pentlandeng.monash.edu.au>
> Date: Saturday, November 18, 2006 4:59 am
> Subject: Re: [DNA] Issue 1: Use of 1.5 hours in the
text
> 
>> Sathya Narayanan wrote:
>>> Issue: WiMAX is trying to increase the
MaxRtrAdvInterval into 
>> hours or 
>>> days. Should we change 1.5 hours to 3 *
MaxRtrAdvInterval?
>>> Agreement at the meeting: Yes. Lets make the
change. We need to 
>> include 
>>> the MaxRtrAdvInterval in the RA so that the
hosts can know about 
>> the 
>>> value. If different routers on the link use
different values for 
>>> MaxRtrAdvInterval, host should use the minimum
(Should it be 
>> maximum?) 
>>> value of MaxRtsAdvtInterval times three as the
lifetime for 
>> prefixes in 
>>> the DNAHostPrefixList.
>>>
>>> If you have any objection to the proposed
change, please post 
>> your 
>>> objection on the list.
>> Hi Sathya,
>>
>> JinHyeock is right about the 1.5 coming from the
maximum value of 
>> MaxRtrAdvInterval.  If this maximum is to be
increased to "hours 
>> or 
>> days" then I'd worry about just using 3 * that
value.
>>
>> The 1.5 hours is the time used to age out old
prefix information.  
>> It 
>> was picked because it was supposed to ensure that
at least 3 
>> router 
>> advertisements from each router would have been
sent in that time. 
>> The 
>> idea was to ensure that hosts have received an
indication that the 
>> lifetime of a prefix has been changed if an
operator wants to move 
>> a 
>> prefix to another link.
>>
>> Section 5.1.11 recommends that operators wait for
at least 1.5 
>> hours 
>> after removing a prefix from a link before
reassigning it to 
>> another 
>> link. (I don't know if any operators will read
this, but I guess 
>> that's 
>> another issue)  I don't think it desirable to
increase this to days.
>>
>> Perhaps another approach might be to simply have
some text that 
>> says 
>> that when changing the lifetime of a prefix, a
router must send at 
>> least 
>> 3 Router Advertisements with the new prefix
lifetime before 
>> removing the 
>> prefix from a link.  Even if a router normally only
sends 
>> Advertisements 
>> very infrequently, it doesn't seem unreasonable to
make it send a 
>> few 
>> quick ones just during a period of prefix change.
>>
>> Cheers,
>> Brett.
>>
> 

> Ah, ok.  I'd missed that point.  I'm still not keen on
the idea of 
> using 
> 3 times the maximum value of MaxRtrAdvInterval if that
maximum is 
> to be 
> raised much larger than 1800 seconds.  Perhaps the 1.5
hours can be 
> retained where it relates to prefix changes on routers.
> 
> For expiry of DNA information, 3 times the actual
advertised 
> MaxRtrAdvInterval for each prefix.

Sorry, my typing didn't match my thinking there  I meant:

For expiry of DNA information, perhaps each prefix could
expire at 3
times the actual advertised MaxRtrAdvInterval after the last
RA received
with the prefix.

Cheers,
Brett.

> Where the same prefix is advertised 
> by more than one router, then the maximum value of 
> MaxRtrAdvInterval 
> could be used.
> 
> Cheers,
> Brett.
> 
> Sathya Narayanan wrote:
> > Brett -
> > 
> >> Perhaps another approach might be to simply
have some text that 
> says that when changing the lifetime 
> >> of a prefix, a router must send at least 3
Router Advertisements 
> with the new prefix lifetime before removing the prefix
from a 
> link.  Even if a router 
> >> normally only sends Advertisements very
infrequently, it doesn't 
> seem unreasonable to make 
> >> it send a few quick ones just during a period
of prefix change.
> > 
> > This sounds ok to me. But, I am not sure how this
change 
> addresses the issue. If the router advertises very
infrequently, 
> the host will start dropping prefixes from the
DNAHostPrefixList if 
> we keep the 1.5 hours restriction. After sometime, the
list could 
> become empty and useless from DNA point of view.
> > 
> > - Sathya
> > 
> > ----- Original Message -----
> > From: Brett Pentland <brett.pentlandeng.monash.edu.au>
> > Date: Saturday, November 18, 2006 4:59 am
> > Subject: Re: [DNA] Issue 1: Use of 1.5 hours in
the text
> > 
> >> Sathya Narayanan wrote:
> >>> Issue: WiMAX is trying to increase the
MaxRtrAdvInterval into 
> >> hours or 
> >>> days. Should we change 1.5 hours to 3 *
MaxRtrAdvInterval?
> >>> Agreement at the meeting: Yes. Lets make
the change. We need to 
> >> include 
> >>> the MaxRtrAdvInterval in the RA so that
the hosts can know 
> about 
> >> the 
> >>> value. If different routers on the link
use different values 
> for 
> >>> MaxRtrAdvInterval, host should use the
minimum (Should it be 
> >> maximum?) 
> >>> value of MaxRtsAdvtInterval times three as
the lifetime for 
> >> prefixes in 
> >>> the DNAHostPrefixList.
> >>>
> >>> If you have any objection to the proposed
change, please post 
> >> your 
> >>> objection on the list.
> >> Hi Sathya,
> >>
> >> JinHyeock is right about the 1.5 coming from
the maximum value 
> of 
> >> MaxRtrAdvInterval.  If this maximum is to be
increased to "hours 
> >> or 
> >> days" then I'd worry about just using 3 *
that value.
> >>
> >> The 1.5 hours is the time used to age out old
prefix 
> information.  
> >> It 
> >> was picked because it was supposed to ensure
that at least 3 
> >> router 
> >> advertisements from each router would have
been sent in that 
> time. 
> >> The 
> >> idea was to ensure that hosts have received an
indication that 
> the 
> >> lifetime of a prefix has been changed if an
operator wants to 
> move 
> >> a 
> >> prefix to another link.
> >>
> >> Section 5.1.11 recommends that operators wait
for at least 1.5 
> >> hours 
> >> after removing a prefix from a link before
reassigning it to 
> >> another 
> >> link. (I don't know if any operators will read
this, but I guess 
> >> that's 
> >> another issue)  I don't think it desirable to
increase this to 
> days.>>
> >> Perhaps another approach might be to simply
have some text that 
> >> says 
> >> that when changing the lifetime of a prefix, a
router must send 
> at 
> >> least 
> >> 3 Router Advertisements with the new prefix
lifetime before 
> >> removing the 
> >> prefix from a link.  Even if a router normally
only sends 
> >> Advertisements 
> >> very infrequently, it doesn't seem
unreasonable to make it send 
> a 
> >> few 
> >> quick ones just during a period of prefix
change.
> >>
> >> Cheers,
> >> Brett.
> >>
> > 
> 
>