| Description | GSN peer table. The SGSN-GGSN peer relationship is established
as following:
o A table in DNS listing the APN and corresponding ip
address of GGSN.
o When Mobile System (MS) wants service, it sends packets to
a SGSN with specific APN.
o SGSN asks DNS for ip address of a GGSN that service this
APN.
o DHCP returns a GGSN.
o SGSN requires a path to the GGSN using GTP protocol.
o The SGSN and GGSN peer maintains path by sending echo
request message to each other. If one side fails in echo
reply for certain times, the other side will send a trap to
NMS.
Note:
o Multiple-Multiple peer relationship, i.e. a SGSN have
multiple GGSN as peers, while a GGSN have multiple SGSN
peers, depending on routing path.
o Path is kept in database. |