3GPP 24.501 v20.0.0 — the document's own text
9.11.4.24 IP header compression configuration
Taught in 4. Inside TS 24.501, the document at the centre (CT1 — the group that writes what your phone says, overview).
The purpose of the IP header compression configuration information element is to negotiate ROHC channel setup parameters specified in IETF RFC 5795 [39B] and, optionally, provide additional header compression context setup parameters.
The IP header compression configuration information element is coded as shown in figure 9.11.4.24.1 and table 9.11.4.24.1.
The IP header compression configuration is a type 4 information element with a minimum length of 5 octets and a maximum length of 257 octets.
The optional Additional IP header compression parameters container field conveys the additional header compression context setup parameters as specified in 3GPP TS 23.501 [8] in a generic container. This field corresponds to the profile-specific information in the header of the ROHC IR packet type in IETF RFC 5795 [39B].
| 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | |
|---|---|---|---|---|---|---|---|---|
| IP header compression configuration IEI | octet 1 | |||||||
| Length of IP header compression configuration contents | octet 2 | |||||||
| Spare | P0x0104 | P0x0103 | P0x0102 | P0x0006 | P0x0004 | P0x0003 | P0x0002 | octet 3 |
| MAX_CID | octet 4 | |||||||
| octet 5 | ||||||||
| Additional IP header compression context setup parameters type | octet 6* | |||||||
| Additional IP header compression context setup parameters container | octet 7* | |||||||
| octet n* |
Figure 9.11.4.24.1: IP header compression configuration information element
Table 9.11.4.24.1: IP header compression configuration information element
| ROHC Profiles (octet 3)The ROHC Profiles shall indicate which of the ROHC profiles is supported. When a particular bit is set to 1, this indicates that the corresponding profile is supported. The No Compression profile 0x0000 (see IETF RFC 5795 [39B]) shall always be supported. When all the bits are set to 0, this indicates that only the No Compression profile 0x0000 is supported.Profile 0x0002 support indicator (see IETF RFC 3095 [33A] and IETF RFC 4815 [38A]) (octet 3 bit 1)0 RoHC profile 0x0002 (UDP/IP) is not supported1 RoHC profile 0x0002 (UDP/IP) is supported Profile 0x0003 support indicator (see IETF RFC 3095 [33A] and IETF RFC 4815 [38A]) (octet 3 bit 2)0 RoHC profile 0x0003 (ESP/IP) is not supported1 RoHC profile 0x0003 (ESP/IP) is supported Profile 0x0004 support indicator (see IETF RFC 3843 [34A] and IETF RFC 4815 [38A]) (octet 3 bit 3)0 RoHC profile 0x0004 (IP) is not supported1 RoHC profile 0x0004 (IP) is supported Profile 0x0006 support indicator (see IETF RFC 6846 [40B]) (octet 3 bit 4)0 RoHC profile 0x0006 (TCP/IP) is not supported1 RoHC profile 0x0006 (TCP/IP) is supported Profile 0x0102 support indicator (see IETF RFC 5225 [39A]) (octet 3 bit 5)0 RoHC profile 0x0102 (UDP/IP) is not supported1 RoHC profile 0x0102 (UDP/IP) is supported Profile 0x0103 support indicator (see IETF RFC 5225 [39A]) (octet 3 bit 6)0 RoHC profile 0x0103 (ESP/IP) is not supported1 RoHC profile 0x0103 (ESP/IP) is supported Profile 0x0104 support indicator (see IETF RFC 5225 [39A]) (octet 3 bit 7)0 RoHC profile 0x0104 (IP) is not supported1 RoHC profile 0x0104 (IP) is supported Bits 8 is spare and shall be set to 0.MAX_CID (octet 4 and octet 5)This is the MAX_CID value as specified in 3GPP TS 36.323 [25]. It is encoded in binary coding with a value in the range from 1 to 16383.Additional IP header compression context parameters type (octet 6).The Additional IP header compression context parameters type octet indicates the profile associated with the profile-specific information in the Additional IP header compression context parameters container.Bits8 7 6 5 4 3 2 1 Type 0 0 0 0 0 0 0 0 0x0000 (No Compression) 0 0 0 0 0 0 0 1 0x0002 (UDP/IP) 0 0 0 0 0 0 1 0 0x0003 (ESP/IP) 0 0 0 0 0 0 1 1 0x0004 (IP)0 0 0 0 0 1 0 0 0x0006 (TCP/IP) 0 0 0 0 0 1 0 1 0x0102 (UDP/IP) 0 0 0 0 0 1 1 0 0x0103 (ESP/IP)0 0 0 0 0 1 1 1 0x0104 (IP)0 0 0 0 1 0 0 0 Other0 0 0 0 1 0 0 1 to1 1 1 1 1 1 1 1 SpareAdditional IP header compression context parameters container (octets 7 to n).Additional IP header compression context parameters container carries the profile-specific information (see IETF RFC 5795 [39B]). The maximum size is 251 octets.NOTE: If the Additional IP header compression context setup parameters container is included, then the Additional IP header compression context parameters type shall be included in the octet 6. |
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