Subject: [MMUSIC] ICE-10 Issue #3: Component limits

From: Jonathan Rosenberg <[email-masked]>
Date: Tue, 05 Sep 2006 16:49:25 -0400

The priority formula in ICE-10 introduces a limit of 10 media streams 
and 10 components per stream when used with ICE. With my proposed 
resolution to issue #1, the limit of 10 streams goes away. That still 
leaves a limit of 10 components per stream. Is this an issue?

Right now, the only case of more than one component that we have is RTP, 
which has just two components.

There are three options as I see it:

1. keep current limit
2. make the limit dynamic, so that its a function of the type of stream. 
In particular, it would be set to 10 for RTP, and if there was some new 
type of stream that had 12 components, it would jump to 100.
3. raise the limit to 100

We can still raise it to 100 without requiring more than 32 bits of 
storage for the pair priority.

By the way, the reason I like powers of 10 for these limits, is that you 
can readily extract the component values from the combined priorities. 
For example, if agent A has a priority of 1234 for a candidate, and 
agent B hasa  priority of 4567, the candidate pair itself has a priority 
of 123445671 based on the formula in my previous post.

I think #2 is too complicated. I can't think of any particular reason 
not to make the limit 100 given it can be represented in a 32 bit integer...

Comments?

-Jonathan R.
-- 
Jonathan D. Rosenberg, Ph.D.                   600 Lanidex Plaza
Cisco Fellow                                   Parsippany, NJ 07054-2711
Cisco Systems
[email-masked]                              FAX:   (973) 952-5050
http://www.jdrosen.net                         PHONE: (973) 952-5000
http://www.cisco.com

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From: Philip Matthews <[email-masked]>
Date: Thu, 7 Sep 2006 07:52:11 -0400

On 5-Sep-06, at 16:49 , Jonathan Rosenberg wrote:

> The priority formula in ICE-10 introduces a limit of 10 media  
> streams and 10 components per stream when used with ICE. With my  
> proposed resolution to issue #1, the limit of 10 streams goes away.  
> That still leaves a limit of 10 components per stream. Is this an  
> issue?
>

Yes, I feel this is a concern. I am even more concerned about the
equivalent limit for local preference component of the priority formula,
since the priority formula now limits the combination of
  (# interfaces) * (# STUN servers) <= 10.

I see two solutions.

The most obvious fix is to two decimal digits for each of these  
values in the priority formula,
as you suggested.

The other is to rework the priority formula completely.
It seems wrong that all these limits are being introduced simply because
of the formula used to compute the priority.
Overall, the priority formula is a small part of ICE, and it seems  
wrong that this
one little part is introducing some very arbitrary limits on the  
numbers of components,
streams, interfaces, and STUN servers.

- Philip