Tear Down indication in
Gtpv1 (Teardown Ind)
As you have seen a parameter
named teardown Ind in Delete PDPContext GTP message from SGSN to GGSN. This parameter
has a great significance in Deleting already existed PDP Contexts.
Teardown Indication IE has only two possible values 0 and 1.
For deleting existing PDP Context , there are 4 different
scenarios where tear down indicator IE plays its role :
1.
If 1, then all the PDP Context that share same
PDP address ( UE is allocated an IP/PDP address, say 70.70.70.1 for primary PDP
context and secondary PDP context linked
with this primary PDP context has same IP/PDP address) is deleted.
Example:
If secondary PDP context is deleted with tear down set to 1 then with
secondary PDP context as well as primary PDP context gets deleted and vice versa.
2.
If 0, then only PDP context identified by NSAPI
(bearer-ID) in Delete PDP Context gets deleted not all PDP context linked with
the same UE/PDP address.
Note: If primary context is deleted with tear
down indication to zero then primary PDP context gets deleted and secondary context linked if
any, with this primary PDP context gets the
primary PDP context role.
3.
If not mentioned any value for tear down
indication then PDP context identified by NSAPI (bearer-ID) in Delete PDP
Context gets deleted not all PDP context linked with the same UE/PDP address.
4.
If 0 or no value, and only primary PDP Context
is activated/available, then GGSN ignore the Delete PDP Context message and
discard.
Hi Amit,
ReplyDeleteI am very interesting in this topic. In the poin 2, you say the secondary will change its role to primary, but where can I find related TS descripting this?
Thanks,
Adrian