[lwip-users] PPP: Change default MRU

[narke]

Hi,

I found in my PPP negotiation, the MRU value is not negotiated.  The
RFC 1661 specified, the default MRU should 1500 octets, but I found
following values in the PPP source:

#define PPP_MTU                         1500     /* Default MTU (size
of Info field) */
#ifndef PPP_MAXMTU
/* #define PPP_MAXMTU  65535 - (PPP_HDRLEN + PPP_FCSLEN) */
#define PPP_MAXMTU                      1500 /* Largest MTU we allow */
#endif
#define PPP_MINMTU                      64
#define PPP_MRU                         1500     /* default MRU = max
length of info field */
#define PPP_MAXMRU                      1500     /* Largest MRU we allow */
#ifndef PPP_DEFMRU
#define PPP_DEFMRU                      296             /* Try for this */
#endif
#define PPP_MINMRU                      128             /* No MRUs below this */

I have following questions:

1. Which any change of these values, what MRU value is being used
actually? Does it count PPP header or only information field?
2. How to enable MRU negotiation?
3. What's the difference between PPP MRU and MTU?

Thanks in advance.


-- 
Life is the only flaw in an otherwise perfect nonexistence
    -- Schopenhauer

narke
public key at http://subkeys.pgp.net:11371 (address@hidden)