# 蔡瀚興-讀書會-21/07/24
## <font color="ff0000">Introduction</font>
- SDF: Service Data Flow
- LTE network divides the user data stream into different SDFs according to different QoS
- Because the SDF is transmitted through the EPS bearer in the LTE network, the EPS bearer QoS is controlled in a manner to maintain the SDF QoS.

## <font color="ff0000">SDF and EPS Bearer</font>
- IP data packets are divided into **SDF data streams** and **EPS bearer data streams**

- **Packet filters:** Source IP address ,Destination IP address ,Source port number ,Destination port number ,and Protocol ID
### <font color="0000ff">SDF</font>
- 和用戶正在使用的服務相關聯的一組IP packet
- Different SDFs have different QoS class
- Filter by the SDF template
### <font color="0000ff">EPS Bearer</font>
- 具有相同QoS級別的聚合的SDFs數據流
- 當使用者需要的服務超過當前Default EPS Bearer能提供的QoS時，新Dedicate Bearer會建立來提供需求
- Dedicate Bearer is established with QoS different from the on already sent in the existing bearer
### <font color="0000ff">SDF and EPS Bearers in Figure1</font>
1. The IP flows arriving at a P-GW through a PDN are filtered to SDFs by using SDF templates
2. SDFs are mapped to EPS bearers as classified by using Traffic Flow Template(TFT)

## <font color="ff0000">QoS Parameters for SDF & EPS Bearer</font>
- **QCI(QoS Class Identifier)**: indicates performance
- **ARP(Allocation and Retention Priority)**
- **MBR(Maximum Bit Rate)**
- **GBR(Guaranteed Bit Rate)**
- **AMBR(Aggregated Maximum Bit Rate)**: Total bandwidth of multiple EPS Bearer
- **APN-AMBR**: maximum bandwidth that can be shared by all non-GBR bearer in a PDN
- **UE-AMBR**: maximum bandwidth that can be shared in a UE
### <font color="0000ff">SDF QoS Parameters</font>
1. **GBR SDF QoS parameters(Assigned by resource type):** QCI ,ARP ,GBR ,MBR
2. **Non-GBR SDF QoS parameters(network sesource aren't assigned):** QCI ,ARP ,MBR
3. An aggregate of SDFs with same QCI and ARP is mapped to one EPS bearer
### <font color="0000ff">EPS Bearer QoS Parameters</font>
1. **GBR bearer QoS parameters:** QCI ,ARP ,GBR ,MBR
2. **Non-GBR bearer QoS parameters:** QCI ,ARP ,APN-AMBR ,UE-AMBR
3. **Default bearer** = non-GBR
4. **Dedicated bearer** = non-GBR or GBR
5. Total APN-AMBR of all PDNs cannot exceed the UE-AMBR
### <font color="0000ff">Example</font>

## <font color="ff0000">QoS Provisioning and Enforcement</font>
### <font color="0000ff">QoS Provisioning</font>
#### **SDF QoS Provisioning:**
All parameters for SDFs are provisioned by PCRF
#### **EPS Bearer QoS Provisioning:**
- QoS parameters applied to the default bearer are provided to the HSS
- QoS parameters applied to a dedicated bearer are provisoned by PCRF
- Once authorized by PDRF, the QoS parameters provided by HSS to the default bearer can be modified

### <font color="0000ff">QoS Enforcement</font>
(Note) EPS bearer QoS parameters in SGW are the same as in PGW, except for APN-AMBR.
#### **SDF QoS Enforcement:**
- 到達PGW的IP數據流使用SDF templates過濾為不同的SDF，接著這些SDF由SDF QoS參數控制安裝在PGW中

#### **EPS Bearer QoS Enforcement:**

## <font color="ff0000">An Example for SDF and EPS Bearer QoS</font>

以下的例子用於,
1. UE is connected to a PDN (Internet)
2. UE communicates with the Internet through three bearers (one default bearer, one GBR bearer and one non-GBR bearer)
3. The ID they bear (EPS Bearer ID EBI) is 5, 8, 10.
### <font color="0000ff">QoS Operation in Downlink</font>

❶ [P-GW] 下行IP數據流到達

❷ [P-GW] IP數據包過濾(SDF Templates) 在這裡，五元組（源IP地址，目的IP地址，源端口，目的端口，協議ID）用來充當過濾規則。IP數據流1被分類為GBR SDF1，數據流2被分類為GBR SDF2，IP數據流3/4被分類為non-GBR SDF3，IP數據流5被分類為non-GBR SDF4.

❸ [P-GW] SDF QoS實施: MBR速率策略

❹ [P-GW] SDF – EPS 承載映射: IP 數據包過濾(Traffic Flow Templates; TFT) SDF1和SDF2映射到GBR專用承載EBI=10。SDF3被映射被non-GBR專用承載EBI=8，SDF4被映射為non-GBR默認承載EBI=5。

❺ [P-GW] EPS 承載QoS 實施: MBR/APN-AMBR 速率策略 對於GBR承載，MBR速率策略是使用下行MBR來執行，任何IP數據包超過指定下行MBR的都被丟棄。對於non-MBR承載，APN-AMBR速率策略被執行。也就是說，對於所有發往EBI=5/8的IP數據流都是適用速率策略，任何IP數據包超過指定的下行APN-AMBR的都被丟棄。

❻ [eNB] EPS 承載QoS 實施: UE-AMBR 調度 也就是說對於所有發往EBI=5/8的IP數據流都執行下行UE-AMBR。在圖5中，因為只有一個PDN，下行UE-AMBR和下行APN-AMBR是相等的。

### <font color="0000ff">QoS Operation in Uplink</font>
❶ [UE] 上行IP 數據流到達

❷ [UE] IP數據包過濾(TFT) 在這裡，IP和TCP/UDP協議頭中的五元組用於過濾規則。IP數據流1/2映射到GBR專用承載EBI=10，IP數據流3/4被映射到non-GBR專用承載EBI=8，IP數據流5被映射為默認承載EBI=5.

❸ [UE] EPS 承載QoS 實施: MBR/APN-AMBR速率策略 對於映射到GBR專用承載EBI=10的IP數據流，使用上行的MBR來執行速率策略，對於non-GBR專用承載EBI=5/8的所有IP數據流使用上行APN-AMBR來執行速率策略。

❹ [eNB] EPS 承載QoS 實施: MBR/UE-AMBR速率策略 認為只有一個PDN，上行UE-AMBR和上行APN-AMBR是相等的。

❺ [P-GW] 承載流量到達

❻ [P-GW] EPS 承載QoS 實施: APN-AMBR 速率策略 任何超過上行APN-AMBR的數據包都被丟棄。

❼ [P-GW] IP數據包過濾(SDF Templates) GBR專用承載EBI=10的IP數據流1/2被映射為SDF1/2。non-GBR專用承載EBI=8的IP數據流3/4被映射為SDF3/4。默認承載的IP數據流5被映射為SDF5.