Takes an offset group
of digits from the MSISDN and appends the digits to the DNS query
string to create a new APN intended to assist roaming subscribers
to use the local GGSN.
Privilege
Security Administrator,
Administrator
Mode
Exec > Global Configuration
> APN Profile Configuration
configure > apn-profile profile_name
Entering the above
command sequence results in the following prompt:
[local]host_name(apn-profile-profile_name)#
Syntax
dns-extn { charg-id { binary | decimal | hexadecimal } | lac-rac [ fallback ] | msisdn start-offset start_digits end-offset end-digits | rnc-id [ charg-id { binary | decimal | hexadecimal } ] }
remove dns-extn { charg-id | lac-rac [ fallback ] | msisdn | rnc-id [ charg-id ] }
charg-id { binary | decimal | hexadecimal }
Instructs the SGSN
to take the profile index value of the charging characteristics,
from the PDP subscription record (selected during APN selection)
and include the profile index value in the APN name prior to sending
out DNS queries. The operator can also specify the format (binary, decimal
or hexadecimal) for the CC information to be included.
lac-rac [ fallback ]
Enables the SGSN to append geographical information to the APN string that is being sent in the DNS query. This information
is used during the DNS query process to select the geographically closest GGSN.
The fallback keyword is configured to enable fallback to DNS-query only with APN-name and without lac-rac extension for Gn-SGSN activations.
msisdn start-offset start_digits end-offset end-digits
Defines an offset group
of digits from the MSISDN and appends the digits to create a new APN
DNS query string that is intended to assist roaming subscribers
to use the local GGSN.
-
start_digits is
an integer from 1 through 14 that identifies the position of the
first digit in the MSISDN to start the offset.
-
end-digits is
an integer from 2 through 15 that identifies the position of the
last digit in the MSISDN to be part of the offset.
rnc-id [ charg-id { binary | decimal | hexadecimal } ]
Instructs the SGSN
to include the ID of the calling RNC in the APN DNS query string. Optionally,
the profile index value of the charging characteristics can be inserted
into the APN name prior to sending out DNS queries. As well, the
operator can specify the format (binary, decimal or hexadecimal)
for the CC information to be included.
Usage Guidelines
With this command, the
APN in the DNS query string, used for querying the GGSN address,
can be appended with additional information, such as
This additional information
allows some customization of the DNS query string to facilitate
selecting a specific (usually local or nearest) GGSN.
For example, roaming
subscribers using a specific APN may want to be directed to a specific
GGSN. This can be achieved by having an operator policy for roaming
subscribers associated with an APN profile that includes a configuration
specifying certain digits, from the MSISDN or geographical information
from the LAC/RAC, be appended to the APN. This is then
used as the DNS query string.
In addition, the operator
must configure appropriate DNS entries to enforce the selection of
the required GGSN. After appending the MSISDN digits to the DNS
query string, the string will have the form:
ni.<digits>.mnc*.mcc*.gprs
After appending the
LAC/RAC information to the DNS query string, the string
will have the form:
<apn_network_id>.racAAAA.lacBBBB.<apn_operator_id>
where the AAAA and
BBBB are Hex-coded digits (less than 4 significant digits and one
or more zero ("0") digits will be inserted to
the left side of the Hex to fill the 4-digit coding).
After appending the
charging characteristic (SCHAR) information, the DNS string will take
the following form:
<apn_network_id>.<profile_index>.<apn_operator_id>
The profile index in
the following example has an integer value 10:
quicknet.com.uk.1010.mnc234.mcc027.gprs
If the RNC-ID information
is configured to be a part of the APN name, and if inclusion of the
profile index of the charging characteristics information is also
enabled before the DNS query is sent, the profile index is included
after the included RNC-ID and the DNS APN name will appear in the
following form:
<apn_network_id>.<rnc_id>.<profile_index>.<apn_operator_id>
Once the DNS extension
is defined, the selected extension is applicable when either the wildcard
APN feature or the default APN feature are configured and used.
The information is appended
to the DNS query and the actual APN string sent to the GGSN will
not be modified in any way.
Example
A sample MSISDN is '112233445566778' and
a sample APN NI (network identifier) is 'wap98.testnetz.ca'.
The following command instructs the SGSN to create a new APN with
digits pulled from the MSISDN and appended to the APN:
msisdn start-offset 3 end-offset 9
The resulting APN DNS
query string would have appended 7 digits (2233445)to the APN NI
so that it would appear something like wap98.testnetz.ca.2233445.MNC009.MCC262.GPRS
Enable inclusion of geographical
information in the APN string used for the DNS query to locate the
closest GGSN:
In the following example,
the DNS query for a subscriber using RNC 0321 with the profile index
of value 8 would appear as:
quicknet.com.uk.0321.1000.mnc234.mcc027.gprs
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