4G NAS Attach Accept · 编解码说明
本页面提供 3GPP TS 24.301 R17.11 协议中移动性注册管理消息（EPS Mobility Management Messages）
Attach Accept 的编解码演示。
Attach Accept 由网络侧发送，用于通知 UE 其注册请求已被允许。
编码（Encode）过程由网络侧实现，将消息编码为符合协议规范的二进制；解码（Decode）过程由 UE 侧实现，
将接收到的二进制消息还原为可读的消息结构。
消息定义 Attach Accept
| IEI | Information Element | Presence | Format | Length (octets) |
|---|---|---|---|---|
| — | Protocol discriminator | M | V | 1/2 |
| — | Security header type | M | V | 1/2 |
| — | Attach accept message identity | M | V | 1 |
| — | EPS attach result | M | V | 1/2 |
| — | Spare half octet | M | V | 1/2 |
| — | T3412 value | M | V | 1 |
| — | TAI list | M | LV | 7–97 |
| — | ESM message container | M | LV-E | 5–n |
| 50 | GUTI | O | TLV | 13 |
| 13 | Location area identification | O | TV | 6 |
| 23 | MS identity | O | TLV | 7–10 |
| 53 | EMM cause | O | TV | 2 |
| 17 | T3402 value | O | TV | 2 |
| 59 | T3423 value | O | TV | 2 |
| 4A | Equivalent PLMNs | O | TLV | 5–47 |
| 34 | Emergency number list | O | TLV | 5–50 |
| 64 | EPS network feature support | O | TLV | 3–4 |
| F- | Additional update result | O | TV | 1 |
| 5E | T3412 extended value | O | TLV | 3 |
| 6A | T3324 value | O | TLV | 3 |
| 6E | Extended DRX parameters | O | TLV | 3 |
| 65 | DCN-ID | O | TLV | 4 |
| E- | SMS services status | O | TV | 1 |
| D- | Non-3GPP NW provided policies | O | TV | 1 |
| 6B | T3448 value | O | TLV | 3 |
| C- | Network policy | O | TV | 1 |
| 6C | T3447 value | O | TLV | 3 |
| 7A | Extended emergency number list | O | TLV-E | 7–65538 |
| 7C | Ciphering key data | O | TLV-E | 35–2291 |
| 66 | UE radio capability ID | O | TLV | 3–n |
| B- | UE radio capability ID deletion indication | O | TV | 1 |
| 35 | Negotiated WUS assistance information | O | TLV | 3–n |
| 36 | Negotiated DRX parameter in NB-S1 mode | O | TLV | 3 |
| 38 | Negotiated IMSI offset | O | TLV | 4 |
| 1D | Forbidden TAIs for roaming | O | TLV | 3–6008 |
| 1E | Forbidden TAIs for regional provision | O | TLV | 3–6008 |