A couple of points not brought up (or didn't see in my quick scan).
Use of the telephone network for data is on a permissive basis, it is
designed for analog voice traffic, no guarantee by the telco that you can
obtain any specific rate out of a given phone line.
Frame Relay services is a shared system. You can purchase a 56kbps access
line and port, but the important parameter is the committed information rate
you purchase from the carrier. Most of Sprint's frame relay business may
have a 56kbps access line with ZERO committed information rate. Welcome to
use it and can peak to 56kbps, but your actual performance may vary anywhere
from 0-56kbps. Can purchase 56kbps CIR, but it costs extra, would need to
then look at the economics of using a dedicated line instead. Unles your
app is to mesh several locations together, then frame relay could be used to
set up virtual connections to multiple locations usning one access line, an
important economic point.
Daniel T. Scott
Chief Engineer
NASA Integrated Services Network (http://www.nisn.nasa.gov)
MSFC Information Systems Services Office
******NOTE NEW AREA CODE FOR MSFC ******
256.544.0131 voice
256.544.2554 fax dan.scott@msfc.nasa.gov
line and port, but the important parameter is the committed information rate
you purchase from the carrier. Most of Sprint's frame relay business may
[snip]
from 0-56kbps. Can purchase 56kbps CIR, but it costs extra, would need
[snip]
CIR is guaranteed only under "normal" conditions. You won't get it under
heavy congestion. Find out the MIR configured for your PVC. I don't know
if they will tell you though...
I'm curious. Is your assertion that "CIR is guaranteed only under
"normal" conditions" based on the Frame Relay spec or a paticular vendor(s)
implementation? I ask because I have been in that very debate for some
time (usually with a FR vendor justifying lousey performance).
My tendancy is to take the "Comitted" in CIR literally. It's my
understanding that the FR congestion management routines (at least the
Stratacom one - Foresight?) will only back off bursty PVC to the point
where it's <= CIR. The implication then is that you'll always get at least
CIR - which makes sense since that's what you're paying for.
Dan
[snip]
line and port, but the important parameter is the committed information
I was speaking from a specific vendor's implementation point of view and,
as such, I should not have responded on the NANOG list. Let's take this
to a private conversation as it's most likely not appropiate here. I'll
respond to you privately.
In a parting shot for the rest of the crew, though, past experiences did
not give me that "touchy feely" sensation of getting all that was paid
for... Oversubscription is guesswork at best!