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DEFINITY ECS Release 8.2 ATM Installation,
Upgrades, and Administration
555-233-124
Issue 1
April 2000
Preparing for Installation and Upgrades
1-9Determine ATM Switch Suitability
1
Determine ATM Switch Suitability
To fully support DEFINITY ATM-PNC and provide nonblocking ATM access
between all port networks, ATM switches must support at least 400
point-to-multipoint switched virtual connection (SVC) roots or leaves per
OC-3/STM-1 interface. Because different switches have different limits—some
limit roots, some leaves, and some the total, we have developed the Meiners’
Algorithm to determine whether a switch can support a proposed set of port
networks in a proposed switch. This algorithm is available to Lucent engineers as
a calculator within a Microsoft Excel spreadsheet. You may access the MS Excel
file at http://info.dr.lucent.com/~meiners/atm.html
. Check periodically for
updates.
For best results, use the calculator for one ATM switch at a time. Use trial and
error to set the values in the user-defined values section until the feasibility
indicator reports
YES
or
PROBABLY
.
NOTE:
Use of this spreadsheet is no substitute for thinking. Please apply basic
sanity checks to the outcome. ATM switches may have limitations that the
calculator does not consider.
To use the calculator, type the network layout and resource limits for the ATM
switch you are using. Refer to the following caveats as you input your information:
1. Not all ATM switches have limits on all of the values. If a limit does not
apply, enter any very large number (1000000 is good).
2. Some ATM switches (for example, access concentrators) allow a limited
ability to configure the limits. Other switches have fixed limits. If you do not
know the limits, ask the ATM switch vendor.
3. If your ATM switch is handling non-DEFINITY traffic, enter the resource
limits after subtracting the resources used by the non-DEFINITY traffic.
4. If you are using an ATM switch with different limits on different modules or
ports (for example, Lucent Cajun M770):
a. compute the average limits per port to which a DEFINITY port
network is attached.
b. select the port with the most restrictive limitations.
c. enter the system limit as these limits times the number of DEFINITY
port networks attached to that ATM switch.
NOTE:
The more partitioned the limits are, the less accurate are the
results of the spreadsheet.
5. If you answer "yes" to transit traffic, the calculator may or may not be able
to determine feasibility. If it cannot, the feasibility displays as
UNKNOWN
.