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Data Service Failure due to the Inconsistent Configurations Between the Local DN

abrahim Diamond Medal

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A roaming subscriber cannot access the network by using the uninet. Figure 1 shows the service procedure.

Figure 1 Service procedure
http://localhost:7904/pages/31185199/02/31185199/02/resources/figure/ch/dns_05en.png

Possible Causes

The root cause of the problem is that the NS records on the root DNS server are different from the NS records on the BJ DNS server.

Figure 2 shows the procedure in which DNS server resolution is performed.

Figure 2
http://localhost:7904/pages/31185199/02/31185199/02/resources/figure/ch/dns_06en.png

When the root DNS server receives an APN resolution request from the GZ DNS server, the following operations are performed:

Upon receipt of a resolution request (from GZ DNS server) that carries an APN such as uniwap.1860000.mnc001.mcc460.gprs, the DNS server searches the cache for the authoritative NS address corresponding to the domain name.
If no, the root DNS server obtains the domain name (bjdns1.mnc001.mcc460.gprs) and IP address based on local configuration. A recursive resolution request is initiated, and the resolution is successfully performed.
After the resolution, the response returned carries the GGSN IP address (corresponding to the number segment) and the authoritative name server (NS) address configured on the BJ DNS server, namely, bjdns1.mnc001.mcc460.gprs. The DNS server caches the addresses.
When the MS requests another APN, such as uninet.1860000.mnc001.mcc460.gprs, the root DNS server attempts to obtain the GGSN IP address by directly resolving the APN because the authoritative NS address already exists in the cache. The authoritative NS address on the GZ DNS server, however, is different from that on the BJ DNS server. Therefore, the APN resolution fails.

After the authoritative name server addresses of 1860000.mnc001.mcc460.gprs in the cache become ineffective, resolution can be performed again according to Steps 1 to 3. Only one APN can be resolved by the root DNS server for each number segment within a short period of time.

Procedure

On the root DNS server, change the domain name from dns1bj.mnc001.mcc460.gprs to bjdns1.mnc001.mcc460.gprs.

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Data Service Failure due to the Inconsistent Configurations Between the Local DN

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