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3GPP Service Data Flows - LTE / HSPA / EPC ‘knowledge nuggets’
- 1. 1 LTE / HSPA / EPC knowledge nuggets Red Banana Wireless Ltd – Copyright 2013 www.red-banana.org www.4g-seminar.com 3GPP Service Data Flows 3GPP Service Data Flows LTE / HSPA / EPC ‘knowledge nuggets’ Neil Wiffen - nwiffen@red-banana.org More free downloads at www.red-banana.org Public Seminar details – www.4g-seminar.com
- 2. 2 LTE / HSPA / EPC knowledge nuggets Red Banana Wireless Ltd – Copyright 2013 www.red-banana.org www.4g-seminar.com 3GPP Service Data Flows • EPS provides IP connectivity between a UE and a PDN – PDN Connectivity Service – Supports the transport of one or more Service Data Flows (SDFs) • SDF – An aggregate set of packet flows that matches an SDF Template • SDF Template – The set of SDF filters in a PCC rule • SDF Filter – A set of packet flow header parameter values/ranges – Used to identify one or more of the packet flows constituting an SDF Service Data Flow (SDF)
- 3. 3 LTE / HSPA / EPC knowledge nuggets Red Banana Wireless Ltd – Copyright 2013 www.red-banana.org www.4g-seminar.com 3GPP Service Data Flows • Filter based on packet header characteristics – IP header only • Source / destination IP address • Protocol ID • Type Of Service (TOS) / Traffic Class / Flow Label • IPSec Security Parameter Index (SPI) • Individual values or ranges – IP + Transport Layer header • Source / destination port numbers • Individual values or ranges – IP + Transport Layer + Application Layer • E.g. application version information / state information • May be used to support filtering with respect to a service data flow based on the transport and application protocols used above IP • These filters must be pre-configured in the PCEF Service Data Flow (SDF) Filter
- 4. 4 LTE / HSPA / EPC knowledge nuggets Red Banana Wireless Ltd – Copyright 2013 www.red-banana.org www.4g-seminar.com 3GPP Service Data Flows SDF filters Incoming Packet Flow A A B A C B C Filter evaluation (e.g. pattern-matching) B C Packet Headers match filter A,B or C Filter for SDF 2 Rule processing (gating / credit control / authorization etc.) QoS Control PCEF PGW Outgoing Packets for SDF 1 Outgoing Packets for SDF 2 A Filters for SDF 1
- 5. 5 LTE / HSPA / EPC knowledge nuggets Red Banana Wireless Ltd – Copyright 2013 www.red-banana.org www.4g-seminar.com 3GPP Service Data Flows QoS Concepts in the EPS S-GW P-GW ENb EUTRAN EPC EPS External PDN PDN Connectivity Service One or more SDFs (PCC controlled) One or more EPS bearers (NAS/EPC controlled)
- 6. 6 LTE / HSPA / EPC knowledge nuggets Red Banana Wireless Ltd – Copyright 2013 www.red-banana.org www.4g-seminar.com 3GPP Service Data Flows Bearer QoS Parameters for Scheduling • QoS Class Identifier • Class of service per bearer • Guaranteed Bit Rate • Maximum Bit Rate • Allocation and Retention Policy • Aggregate Maximum Bit Rates • UE-AMBR - limited by a subscription parameter in HSS • APN-AMBR - limited by a subscription parameter per APN in HSS • HSS defines the 'EPS subscribed QoS profile' • Contains bearer level QoS parameter values for the default bearer • Defined for each PDN subscription context
- 7. 7 LTE / HSPA / EPC knowledge nuggets Red Banana Wireless Ltd – Copyright 2013 www.red-banana.org www.4g-seminar.com 3GPP Service Data Flows QCI Characteristics QCI Resource Type Priority Packet Delay Budget Packet Error Loss Rate Example Services 1 GBR 2 100 ms 10-2 Conversational Voice 2 4 150 ms 10-3 Conversational Video (Live Streaming) 3 3 50 ms 10-3 Real Time Gaming 4 5 300 ms 10-6 Non-Conversational Video (Buffered Streaming) 5 Non-GBR 1 100 ms 10-6 IMS Signalling 6 6 300 ms 10-6 Video (Buffered Streaming) TCP-based (e.g., www, e-mail, chat, ftp, p2p file sharing, progressive video, etc.) 7 7 100 ms 10-3 Voice, Video (Live Streaming) Interactive Gaming 8 8 300 ms 10-6 Video (Buffered Streaming) TCP-based (e.g., www, e-mail, chat, ftp, p2p file sharing, progressive video, etc.) 9 9
- 8. 8 LTE / HSPA / EPC knowledge nuggets Red Banana Wireless Ltd – Copyright 2013 www.red-banana.org www.4g-seminar.com 3GPP Service Data Flows • QCI = 5 • P-CSCF details – Provided as Protocol Options from PGW / MME – Or P-CSCF ‘discoverable’ in PDN • PGW configured for routing to IMS platform • PCC rules support SIP/IMS signalling Default Bearer for IMS Signalling
- 9. 9 LTE / HSPA / EPC knowledge nuggets Red Banana Wireless Ltd – Copyright 2013 www.red-banana.org www.4g-seminar.com 3GPP Service Data Flows EPS Bearers and QoS • QoS is controlled at the EPS bearer level • All traffic mapped to the same EPS bearer receive the same bearer level packet forwarding treatment • Providing different bearer level packet forwarding treatment requires separate EPS bearers • One EPS bearer is established when the UE connects to a PDN • Remains established throughout the lifetime of the PDN connection • Provides always-on IP connectivity to that PDN • Default bearer • Additional EPS bearers can be established to same PDN connection • Dedicated bearers • Distinction between default and dedicated is transparent to the SGW and ENB
- 10. 10 LTE / HSPA / EPC knowledge nuggets Red Banana Wireless Ltd – Copyright 2013 www.red-banana.org www.4g-seminar.com 3GPP Service Data Flows QoS and TFT SGW PGW UL Traffic Flow Aggregates DL Traffic Flow Aggregates UL TFT DL TFT UL TFT RB ID RB ID S1 TEID S1 TEID S5/S8 TEID S5/S8 TEID DL TFTRB ID S1 TEID S1 TEID S5/S8 TEID EPS Bearer with defined QoS Packet Filters - applied to each uplink IP-datagram (QoS control) Packet Filters - applied to each downlink IP-datagram (QoS control) UL / DL QoS managed by ENB scheduler UL QoS managed by ENB ‘router’ DL QoS managed by SGW ‘router’
- 11. 11 LTE / HSPA / EPC knowledge nuggets Red Banana Wireless Ltd – Copyright 2013 www.red-banana.org www.4g-seminar.com 3GPP Service Data Flows Backup slides
- 12. 12 LTE / HSPA / EPC knowledge nuggets Red Banana Wireless Ltd – Copyright 2013 www.red-banana.org www.4g-seminar.com 3GPP Service Data Flows What clients say about us: „We are very proud of our products and so it is important to us to have complete confidence in the people who represent us before our customers. Neil Wiffen’s ability to develop unparalled levels of enthusiasm for his subject matter is a key reason for selecting him as our preferred supplier of out-sourced customer training... In deeply technical areas he is able to convey both the micro and the macro levels of detail, skilfully creating the overview which provides the context for the crucial nuggets of detail.” Andy Richards, Operations Manager, Anritsu Ltd. Washington DC: Atlanta GA: Dallas/Austin TX: Register now at: 4G-Seminar.com
Editor's Notes
- The Evolved Packet System provides IP connectivity between a UE and a PLMN external packet data network. This is referred to as PDN Connectivity Service.The PDN Connectivity Service supports the transport of traffic flow aggregate(s), consisting of one or more Service Data Flows (SDFs).The concept of SDF is defined in the context of Policy and Charging Control (PCC) and is not explicitly visible in the NAS signalling.service data flow: An aggregate set of packet flows that matches a service data flow template.service data flow template: The set of service data flow filters in a PCC rule, required for defining a service data flow.service data flow filter: A set of packet flow header parameter values/ranges used to identify one or more of the packet flows constituting a service data flow.
- Service data flow filters identifying the service data flow may:be a pattern for matching the IP 5 tuple (source IP address, destination IP address, source port number, destination port number, protocol ID of the protocol above IP). In the pattern:a value left unspecified in a filter matches any value of the corresponding information in a packet;an IP address may be combined with a prefix mask;port numbers may be specified as port ranges.the pattern can be extended by the Type of Service (TOS) (IPv4) / Traffic class (IPv6) and Mask;consist of the destination IP address, protocol ID of the protocol above IP, the Type of Service (TOS) (IPv4) / Traffic class (IPv6) and Mask and the IPSec Security Parameter Index (SPI);consist of the destination IP address, the Type of Service (TOS) (IPv4) / Traffic class (IPv6) and Mask and the Flow Label (IPv6).extend the packet inspection beyond the possibilities described above and look further into the packet and/or define other operations (e.g. maintaining state). Such service data flow filters must be predefined in the PCEF.Such filters may be used to support filtering with respect to a service data flow based on the transport and application protocols used above IP. This shall be possible for HTTP and WAP. This includes the ability to differentiate between TCP, Wireless-TCP according to WAP 2.0, WDP, etc, For downlink traffic, the downlink parts of all the service data flow templates associated with the IP‑CAN session for the destination address are candidates for matching in the detection process.
- The Evolved Packet System provides IP connectivity between a UE and an external packet data network. This is referred to as PDN Connectivity Service.The PDN Connectivity Service supports the transport of traffic flow aggregate(s), consisting of one or more Service Data Flows (SDFs).An SDF is an aggregate set of packet flows that match a set of service data flow filters in a PCC rule (known as a service data flow template) and is defined in the context of PCC . SDFs are not explicitly visible in the NAS signalling
- The scheduling input parameters related to QoS for EPS-bearers include:- QoS Class Identifier (QCI) which is a scalar value which identifies a particular service or class of services per bearer- Guaranteed Bit Rate (GBR) and Maximum Bit Rate (MBR) are values used to assist the scheduling process to accept/modify/drop bearers in case of resource limitation . The GBR denotes the bit rate that can be expected to be provided by a GBR bearer. The MBR limits the bit rate that can be expected to be provided by a GBR bearer (e.g. excess traffic may get discarded by a rate shaping function). Again these values are assigned per bearer- Allocation and Retention Policy (ARP) – per bearer- The UE‑AMBR is limited by a subscription parameter stored in the HSS. The MME shall set the UE‑AMBR to the sum of the APN‑AMBR of all active APNs up to the value of the subscribed UE‑AMBR. The UE‑AMBR limits the aggregate bit rate that can be expected to be provided across all Non‑GBR bearers of a UE (e.g. excess traffic may get discarded by a rate shaping function). Each of those Non‑GBR bearers could potentially utilize the entire UE‑AMBR- The APN‑AMBR is a subscription parameter stored per APN in the HSS. It limits the aggregate bit rate that can be expected to be provided across all Non‑GBR bearers and across all PDN connections of the same APN (e.g. excess traffic may get discarded by a rate shaping function). Each of those Non‑GBR bearers could potentially utilize the entire APN‑AMBRThe HSS defines, for each PDN subscription context, the 'EPS subscribed QoS profile' which contains the bearer level QoS parameter values for the default bearer (QCI and ARP) and the subscribed APN-AMBR value
- The QCI characteristics describe the packet forwarding treatment that a Service Data Flow (SDF) aggregate receives edge-to-edge between a UE and a Policy and Charging Enforcement Function (PCEF) in terms of the following performance characteristics:- Resource Type (GBR or Non-GBR);- Priority;- Packet Delay Budget;- Packet Error Loss Rate.The Resource Type determines if dedicated network resources related to a service or bearer level Guaranteed Bit Rate (GBR) value are permanently allocated (e.g. by an admission control function in the ENB). GBR SDF aggregates are therefore typically authorized "on demand" which requires dynamic policy and charging control. The Packet Delay Budget (PDB) defines an upper bound for the time that a packet may be delayed between the UE and the PCEF. For a certain QCI the value of the PDB is the same in uplink and downlink. The purpose of the PDB is to support the configuration of scheduling and link layer functionsEvery QCI (GBR and Non-GBR) is associated with a Priority level. Priority level 1 is the highest Priority level. The Priority levels shall be used to differentiate between SDF aggregates of the same UE, and it shall also be used to differentiate between SDF aggregates from different UEs.The Packet Error Loss Rate (PELR) defines an upper bound for the rate of SDUs (e.g. IP packets) that have been processed by the sender of a link layer protocol (e.g. RLC in E‑UTRAN) but that are not successfully delivered by the corresponding receiver to the upper layer (e.g. PDCP in E‑UTRAN). Thus, the PELR defines an upper bound for a rate of non congestion related packet losses. The purpose of the PELR is to allow for appropriate link layer protocol configurations (e.g. RLC and HARQ in E‑UTRAN). For a certain QCI the value of the PELR is the same in uplink and downlink.
- For an IMS client on the UE to connect to an IMS, the network must provide a Default Bearer that is capable of supporting the appropriate Quality of Service (QoS) for IMS signalling and also the client must be provided with, or be able to discover the Proxy Call Session Control Function (P-CSCF) entry point to the IMS platform.Additionally, the gateway must be configured with the appropriate Policy and Charging Control (PCC) rules to allow Session Initiation Protocol (SIP) signalling, and have routing policies that enables the forwarding of packets from the UE to the appropriate P-CSCF.The Quality of Service Class Identifier (QCI) specified by 3GPP for IMS signalling is 5
- An EPS bearer is the level of granularity for bearer level QoS control in the EPC/E-UTRAN. That is, all traffic mapped to the same EPS bearer receive the same bearer level packet forwarding treatment (e.g. scheduling policy, queue management policy, rate shaping policy, RLC configuration, etc.). Providing different bearer level packet forwarding treatment requires separate EPS bearers.One EPS bearer is established when the UE connects to a PDN, and that remains established throughout the lifetime of the PDN connection to provide the UE with always-on IP connectivity to that PDN. That bearer is referred to as the default bearer. Any additional EPS bearer that is established for the same PDN connection is referred to as a dedicated bearer.
- Uplink and Downlink Traffic Flow Templates are the sets of packet filters that allow mapping of traffic to EPS bearers in the Uplink and Downlink directions. Every dedicated EPS bearer is associated with a TFT. The UE uses the UL TFT for mapping traffic to an EPS bearer in the uplink direction. The PCEF (for GTP-based S5/S8) or the BBERF (for PMIP-based S5/S8) uses the DL TFT for mapping traffic to an EPS bearer in the downlink direction.The UE may use the UL TFT and DL TFT to associate EPS Bearer Activation or Modification procedures to an application and to traffic flow aggregates of the application. Therefore the PDN GW shall, in the Create Dedicated Bearer Request and the Update Bearer Request messages, provide all available traffic flow description information (e.g. source and destination IP address and port numbers and the protocol information)The EPS bearer traffic flow template (TFT) is the set of all packet filters associated with that EPS bearer, and for the UE, the evaluation precedence order of the packet filters making up the UL TFTs is signalled from the P‑GW to the UE as part of any appropriate TFT operations
- Uplink and Downlink Traffic Flow Templates are the sets of packet filters that allow mapping of traffic to EPS bearers in the Uplink and Downlink directions. Every dedicated EPS bearer is associated with a TFT. The UE uses the UL TFT for mapping traffic to an EPS bearer in the uplink direction. The PCEF (for GTP-based S5/S8) or the BBERF (for PMIP-based S5/S8) uses the DL TFT for mapping traffic to an EPS bearer in the downlink direction.The UE may use the UL TFT and DL TFT to associate EPS Bearer Activation or Modification procedures to an application and to traffic flow aggregates of the application. Therefore the PDN GW shall, in the Create Dedicated Bearer Request and the Update Bearer Request messages, provide all available traffic flow description information (e.g. source and destination IP address and port numbers and the protocol information)The EPS bearer traffic flow template (TFT) is the set of all packet filters associated with that EPS bearer, and for the UE, the evaluation precedence order of the packet filters making up the UL TFTs is signalled from the P‑GW to the UE as part of any appropriate TFT operations
- Uplink and Downlink Traffic Flow Templates are the sets of packet filters that allow mapping of traffic to EPS bearers in the Uplink and Downlink directions. Every dedicated EPS bearer is associated with a TFT. The UE uses the UL TFT for mapping traffic to an EPS bearer in the uplink direction. The PCEF (for GTP-based S5/S8) or the BBERF (for PMIP-based S5/S8) uses the DL TFT for mapping traffic to an EPS bearer in the downlink direction.The UE may use the UL TFT and DL TFT to associate EPS Bearer Activation or Modification procedures to an application and to traffic flow aggregates of the application. Therefore the PDN GW shall, in the Create Dedicated Bearer Request and the Update Bearer Request messages, provide all available traffic flow description information (e.g. source and destination IP address and port numbers and the protocol information)The EPS bearer traffic flow template (TFT) is the set of all packet filters associated with that EPS bearer, and for the UE, the evaluation precedence order of the packet filters making up the UL TFTs is signalled from the P‑GW to the UE as part of any appropriate TFT operations