Multi-homing APNs in GPRS/UMTS

[phn at icke-reklam.ipsec.nu]

wcbasquin <wcbasquin at yahoo.com> wrote:
> Regarding APNs that exist on many GGSNs: When a SGSN resolves an APN
> name into a GGSN IP address is it normal for the DNS server to return
> multiple IP addresses?  Can SGSNs maintain a list of several IP
> addresses for a specific APN?

There is a mix-up of knowledge and beleif in the phoneindustry. One such area
is TCP/IP another DNS. 
The capabilyties and config of "GGSN" and "APNs" is, contrary to common
beleif, not used outside the phone industry. 

> Or does the DNS server maintain the list of IP addresses for the APN
> and just return a single IP address using round-robin selection?

A DNS server returns whatever it has been configured to answer.

> If APNs are mulithomed then some sort of redundancy or load balancing
> can be implemented.  Should the TTL for the APN be set to 0?

DNS TTL should never be zero. ( neither should TTL in a IP-header)



-- 
Peter Håkanson         
        IPSec  Sverige      ( At Gothenburg Riverside )
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