Packets can have a max size as well based on the path MTU, such as 1500 bytes in an Ethernet (10/100) link. I think there are a lot of other variables here such as are you billed per data unit, bandwidth and control factors on the links, and what type of data is being sent. If your data can always fit in a smaller N-byte cell, that can be quite efficient since you have minimal overhead or wasted space and all the benefits of the fixed length data unit from a processing standpoint. If you are constantly fragmenting and then having to reassemble data due to the small cell size, you would be better off with a variable length packet, especially when bandwidth is less in demand than processing power. -Scott -----Original Message----- From: Murphy, Jay, DOH [mailto:Jay.Murphy@state.nm.us] Sent: Wednesday, January 14, 2009 3:56 PM To: nanog@nanog.org Subject: Which is more efficient? All, In your humble opinion, which transmission method is more efficient, packet or cell? Granted a cell is a fixed length packet and an IP packet is variable length....would this necessarily only relate to a specific protocol, namely, cell in ATM, and IP in Ethernet or other types of domains....feedback highly welcomed. Trying to make a decision on the transport mode for cost, delay, jitter, ROI, etcetera. Jay Murphy IP Network Specialist NM Department of Health ITSD - IP Network Operations Santa Fé, New México 87502 Bus. Ph.: 505.827.2851 "We move the information that moves your world." Confidentiality Notice: This e-mail, including all attachments is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited unless specifically provided under the New Mexico Inspection of Public Records Act. If you are not the intended recipient, please contact the sender and destroy all copies of this message. -- This email has been scanned by the Sybari - Antigen Email System.