[18369] in North American Network Operators' Group
Re: T1 Circuit actual throughput 1290Kbp
daemon@ATHENA.MIT.EDU (Vaananen Pasi NTC/Boston)
Mon Jul 13 13:15:35 1998
From: vaananen@NASBPD01BS.ntc.nokia.com (Vaananen Pasi NTC/Boston)
To: carlson@ironbridgenetworks.com (James Carlson), nanog@merit.edu (nanog)
Date: Fri, 10 Jul 1998 16:17:39 -0400
>(!) The cell tax is about 10% -- the SAR expands user data from 48
>bytes to 53 bytes, plus an additional amount of overhead for internal
>fragmentation on the final cell (AAL-5), plus overhead for whatever
>encapsulation mode is being used.
The cell tax is actually about 20%, based on the traces of the backbone IP
traffic. Reason for this is the additional overhead imposed of partially filled cells.
Fixwest 960926:
total packets seen = 15315121, total payload bytes seen = 4276560002
ATM framing bytes = 5155881287 ATM efficiency = 82.95%
ATM w/snap framing bytes = 5387212772 ATM w/snap efficiency = 79.38%
Funet 970608:
total packets seen = 6699991, total payload bytes seen = 2336213700
ATM framing bytes = 2783454053 ATM efficiency = 83.93%
ATM w/snap framing bytes = 2919019891 ATM w/snap efficiency = 80.03%
Pasi
