nanog mailing list archives
RE: ATM vs. DS3
From: "Murray, Steve" <murray.steve () MFSDatanet COM>
Date: Fri, 11 Jul 97 11:41:00 PDT
Peter Kline wrote
Another way of looking at this is that we know an ATM PVC over a DS3
using
PLCP is configurable for a maximum of 96000 cells per second. 96000
cells
per second * 48 payload octets per cell * 8 bits per octet = 36864000
bps,
or 36.864 Mbps, not too far from what I observed above. With PLCP
turned
off, the maximum PVC config was ~105000 cells per second, yielding ~40.3
Mpbs. The SAR function will add eight bytes to the payload. The eight bytes contain the CPCS-UU(1 bytes), CPI (1 byte), length of payload (two bytes) and a CRC (4 bytes). This additional overhead needs to be taken into account if you are segmenting small frames. The last cell after segmentation will have these eight bytes at the end of the cell plus any padding needed to fill out the cell. If you are segmenting a 96 byte payload for example you would think this would actually fit into two cells (using the 48 byte payload), but it really take three cells. The last cell would only contain padding and this overhead. Steve Murray Worldcom
Current thread:
- Re: ATM vs. DS3, (continued)
- Re: ATM vs. DS3 Eric D. Madison (Jul 10)
- Re: ATM vs. DS3 Alex.Bligh (Jul 11)
- Re: ATM vs. DS3 Dorian R. Kim (Jul 11)
- Re: ATM vs. DS3 Vadim Antonov (Jul 10)
- Re: ATM vs. DS3 William Allen Simpson (Jul 10)
- Re: ATM vs. DS3 Avitosh Pal (Jul 10)
- RE: ATM vs. DS3 Chris A. Icide (Jul 10)
- RE: ATM vs. DS3 Stephen Balbach (Jul 10)
- RE: ATM vs. DS3 Eric D. Madison (Jul 10)
- RE: ATM vs. DS3 Stephen Balbach (Jul 10)
- RE: ATM vs. DS3 Chris A. Icide (Jul 10)
- RE: ATM vs. DS3 Murray, Steve (Jul 11)