In many cases, the examples above will not fit the needs of many users. This
is because they are not government organizations, the company does not
reside in a country which has an NSAP authority, or the company does not
wish to pay the registration fees required to obtain an NSAP space.
In cases like these, a network administrator can create a temporary
Administrative Prefix that their company may use as an interim solution
until a more permanent AP becomes available. The network administrator
must be sure to create a PAP format that can easily be migrated to the
permanent NSAP space, once it becomes available.
The first two methods described create a unique NSAP space, and the NSAP
addresses may be used on open networks (that is, networks connected to a
public network). The last method, Local Format, does not guarantee a
unique NSAP space and should only be used when connectivity to OSI
networks outside the customer's network is not required.
Use an International Telephone Number |
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ISO allows NSAP spaces to be built that have an International Telephone
Number as their IDI value. This is known as the E.163 format. The AFI code
to use is 43. The telephone number is encoded as Binary Coded Decimal
(BCD) into the IDI. Up to 12 digits may be used. Any unused digits should
be set to F (hexadecimal). The DSP portion, and therefore the PAP, may be
up to 13 octets in length.
As an example, suppose Joe's Grommet Shop decides not to obtain an ANSI
Org Id at this time. Instead, they use the E.163 format. The network
administrator decides to use the International Telephone Number of their
customer order department for the IDI value.
Use an X.121 Address |
|
Another option is to use an X.121 address as the IDI value. The AFI for this
format is 37. The IDI is up to 14 BCD encoded digits, with any extras
padded with F. The DSP, and therefore the PAP, may be up to 12 octets in
length. Note that the X.121 address is only used to uniquely identify the
customer's AP. It does not have any routing significance in this example.
For instance, Joe's Grommet shop decides to use one of its public X.121
address for the IDI value.
Use the ISO Local Format |
|
ISO defines a format known as the Local format. HP recommends that you
do not use this format because it can result in non-unique NSAP values.
They should only be used for pilot networks or for diagnostic purposes on
networks that are isolated, that is, not connected to any public networks.
When using Local Format it is especially important to create and manage the
PAP portion in a way that can be easily migrated to another AP in the future.
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