Calculating L2 encap overload

Hello,

Is there any way to discover l2 overhead just by sitting on the router and
try some debug commands?
If we send ip packet and we know its size, if we receive it on the second
side on the link and see its size with l2 overhead, it would be more than
simple to calculate how much does it take.

For example, i've been trying to ping one router from another through the
HDLC connection:

#ping 1.1.1.2 size 100 repeat 1
(so we know, that we want to send 100 bytes of data, one packet)

on the other side i just did debug ip packet on according acl, but what i
saw was:

*Nov 22 20:43:49.292: IP: s=1.1.1.1 (Serial0/1/0), d=1.1.1.2, len 100, input
feature, MCI Check(63), rtype 0, forus FALSE, sendself FALSE, mtu 0
*Nov 22 20:43:49.292: IP: tableid=0, s=1.1.1.1 (Serial0/1/0), d=1.1.1.2
(Serial0/1/0), routed via RIB
*Nov 22 20:43:49.292: IP: s=1.1.1.1 (Serial0/1/0), d=1.1.1.2 (Serial0/1/0),
len 100, rcvd 3
*Nov 22 20:43:49.292: IP: s=1.1.1.1 (Serial0/1/0), d=1.1.1.2, len 100, stop
process pak for forus packet

But it also shows length of 100. :/
Is there any way to see it?

regards,

-- 
Jakub Drwal
Blogs and organic groups at http://www.ccie.net