F.3 PDUs and parameters specific to the present annex

24.3023GPPAccess to the 3GPP Evolved Packet Core (EPC) via non-3GPP access networksRelease 17Stage 3TS

F.3.1 Void

F.3.2 Message types of FTT messages

F.3.2.1 Generic FTT envelope

Generic FTT envelope is coded according to figure F.3.2.1-1 and table F.3.2.1-1.

7

6

5

4

3

2

1

0

Length

octet 1

octet 2

Payload

octet 3

octet n

Figure F.3.2.1-1: Generic FTT envelope

Table F.3.2.1-1: Generic FTT envelope

Length field is in the octet 1 and the octet 2. The Length field indicates the length of the generic FTT envelope in octets.

Payload field is in octets starting from octet 3 and its value depends on the message type.

F.3.2.2 IKEv2 envelope

IKEv2 envelope is coded according to figure F.3.2.2-1 and table F.3.2.2-1.

7

6

5

4

3

2

1

0

Length

octet 1

octet 2

Non-ESP marker

octet 3

octet 6

IKEv2 message

octet 7

octet n

Figure F.3.2.2-1: IKEv2 envelope

Table F.3.2.2-1: IKEv2 envelope

Length field is described in clause F.3.2.1. The Length field value is bigger than 6.

Non-ESP marker field is in the octet 3, the octet 4, the octet 5 and the octet 6. The Non-ESP marker field value is zero.

IKEv2 message field is in octets starting from octet 7. The IKEv2 message contains the IKEv2 message as defined in IETF RFC 7296 [28], section 3.1 in format as for transmission from UDP port 500.

F.3.2.3 ESP envelope

ESP envelope is coded according to figure F.3.2.3-1 and table F.3.2.3-1.

7

6

5

4

3

2

1

0

Length

octet 1

octet 2

ESP message

octet 3

octet n

Figure F.3.2.3-1: ESP envelope

Table F.3.2.3-1: ESP envelope

Length field is described in clause F.3.2.1. The Length field value is bigger than 6.

ESP message field is in octets starting from octet 3. The ESP message contains the encapsulating security payload as defined in IETF RFC 4303 [32], section 2. The SPI field in the ESP header is not a zero value.

F.3.2.4 Keep-alive envelope

Keep-alive envelope is coded according to figure F.3.2.4-1 and table F.3.2.4-1.

7

6

5

4

3

2

1

0

Length

octet 1

octet 2

Keep-alive payload

octet 3

Figure F.3.2.4-1: keep-alive envelope

Table F.3.2.4-1: keep-alive envelope

Length field is described in clause F.3.2.1. The Length field value is 3.

Keep-alive payload field is in octet 3. The Keep-alive payload field value is 255.

F.3.3 IKEv2 configuration attributes

F.3.3.1 FTT_KAT configuration attribute

The FTT_KAT configuration attribute is coded according to figure F.3.3.1-1 and table F.3.3.1-1.

Bits

7

6

5

4

3

2

1

0

Octets

R

Attribute type

1

Attribute type

2

Length

3 – 4

Keep alive time

5 – 6

Figure F.3.3.1-1: FTT_KAT configuration attribute

Table F.3.3.1-1: FTT_KAT configuration attribute

R field is defined in IETF RFC 7296 [28].

Attribute type field has value 22.

Length field is defined in IETF RFC 7296 [28].

When FTT_KAT configuration attribute is included in the CFG_REQUEST configuration payload of IKEv2 security association, packets of which are transported via FTT, the Keep-alive time field indicates preferred maximum time in seconds between two envelopes (any of those described in clause F.3.2) sent via FTT. When FTT_KAT configuration attribute is included in the CFG_REPLY configuration payload of IKEv2 security association, packets of which are transported via FTT, the Keep-alive time field indicates actual maximum time in seconds between two envelopes (any of those described in clause F.3.2) sent via FTT.

Annex G (Informative):
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