Re: [EAI] The value of simplified downgrade

["Yao Jiankang" <yaojk at cnnic.cn>]

----- Original Message ----- 
From: "Ernie Dainow" <edainow at ca.afilias.info>
To: "EAI" <ima at ietf.org>
Sent: Thursday, September 10, 2009 2:43 AM
Subject: [EAI] The value of simplified downgrade


> There is a question of whether the EAI spec should include simplified 
> downgrade at all. To help answer this, compare what a user has to do in 
> various situations when there is downgrade and when there is not. From the 
> user's point of view, there are not that many cases to consider.
>
> 1. Sending email to an EAI user ("sending" includes compose new mail, 
> forward, reply).
> This case will not have downgrade. If any recipients cannot in fact 
> receive EAI mail, it will bounce. This is being considered a 
> 'configuration' error. Note this is different from the current Downgrade 
> spec which supports downgrade to forward pointing addresses.

If it is ascii user sending message to EAI,  there should have a downgrade.

If the SMTP server or MUA has not been updated to support EAI, the ascii 
user can not send the message to EAI account because the SMTP server or MUA 
can not recognize the EAI and will regard the EAI address as illegal one. 
This has been pointed out in draft-yao-eai-problem-00.txt.

> 2. Sending email to an non-EAI user.
> a. If EAI has downgrade, the user may use his EAI email account. As long 
> as an alternate address has been configured, the mail will be downgraded 
> using the supplied ASCII address as the From address.
> b. If there is no downgrade, the user will have to use his non-EAI email 
> account. This is slightly awkward, but not be a major hindrance. Many 
> people are used to managing more than one email accounts, for example one 
> for work and a second for personal email.
>
> 3. Sending email to a mix of EAI and non-EAI users.
> a. If EAI has downgrade, the user may use his EAI email account and send a 
> single message, freely mixing EAI and non-EAI addresses on To, Cc, etc.
> b. If there is no downgrade, the user will have to send the same email 
> twice; once using the EAI account for the EAI recipients and a second time 
> using the non-EAI account for the non-EAI recipients.
>
> Note that in 3b, EAI users and non-EAI recipients do not know the whole 
> list of recipients, and Reply All will not reach the full list (unless the 
> original sender is very disciplined and copies replies from EAI to non-EAI 
> recipients and vice versa).
>
> By comparison, in 3a, EAI recipients will see all the people that received 
> the email and Reply All will reach everyone. However, non-EAI recipients 
> will not see any of the EAI recipients, and their Reply All will only 
> reach the non-EAI recipients and the sender. This is a consequence of 
> dropping double angle brackets on forward pointing addresses, and was 
> pointed out by Harald as the "triangle" case. As noted in that discussion, 
> even with double angle brackets the triangle case will not consistently 
> work in practice, as it depends on users being sufficiently disciplined to 
> undertake the extra effort of entering alterrnate addresses for all EAI 
> email addresses.

in 3a,
+1, it means that even if the current full downgrade mechanism is used,
we still can not assure 100% downgrade since the alt-address is depending 
on the user.
so in this sense, simple downgrade does not differ from much the full 
downgrade.


> Clearly, the pain is case 3b. To the extent that we wish to improve on 
> this scenario, we should include downgrade.

3b,  is really pain?

it is similar to business card situation.
the chinese business card has two sides, english side and chinese side.
english side is only for those who can not under stand english; chinse side 
is for those who knows chinese.



> A second consideration is the effect on encouraging and speeding the 
> migration to EAI from legacy email systems. Without downgrade, people have 
> to actively maintain two email accounts. Under this circumstance, they may 
> just choose the non-EAI account as the primary. With downgrade, there is 
> an incentive to use the EAI account as the primary account, since it 
> handles mail for all cases 1, 2 and 3.
>
> One of the assumptions in a simplified downgrade is that it is not perfect 
> (does not handle every possible case) and may lose some audit trail 
> information. We need to decide if an imperfect downgrade is still better 
> than no downgrade at all.

+1, yes. the WG should decide it.

Yao Jiankang
CNNIC
>    -Ernie
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