Re: Setting MTU (fwd)

MegaZone (megazone@livingston.com)
Sat, 28 Dec 1996 17:11:14 -0800 (PST)

Once upon a time Joe Portman shaped the electrons to say...
>No, that's just the way it works on a portmaster. On other terminal
>servers, you can globally set the MTU, or set it on a per port basis, and
>the PPP service will only negotiate a connection up to that MTU size.

Let me clarify - you cannot set MTU *BY USER* for PPP when users use PAP
or CHAP. Why? Because MTU is negotiated BEFORE PAP/CHAP so that it is
set before the userid is known. Therefore it is too late to set it by
the userid.

>1500, BTW is just an arbitrary number the PM chooses.

This is not true. 1500 is the default MRU as specified by the RFC. It
is NOT arbitrary.
---cut---
The maximum length for the Information field, including Padding,
but not including the Protocol field, is termed the Maximum
Receive Unit (MRU), which defaults to 1500 octets. By
negotiation, consenting PPP implementations may use other values
for the MRU.
---cut---

>choose what they would like their maximum negotiated MTU to be, you just
>have chosen not to.

We could allow it to be set on the port, yes. And we chose not to, yes.

-MZ

--
Livingston Enterprises - Chair, Department of Interstitial Affairs
Phone: 800-458-9966 510-426-0770 FAX: 510-426-8951 megazone@livingston.com
For support requests: support@livingston.com  <http://www.livingston.com/> 
Snail mail: 4464 Willow Road, Pleasanton, CA 94588