Quality-of-Service Option for Proxy Mobile IPv6
Extracted elements (25)
QoS signaling is strictly between the LMA and MAG mobility entities and does not result in per-flow state or signaling to any other node in the network, deliberately avoiding the complexity and scalability concerns of end-to-end QoS reservation protocols.
The LMA is designated as the sole allocator of SR-IDs to guarantee uniqueness within the scope of a mobility session and to avoid collisions when both the LMA and MAG may independently initiate concurrent QoS Service Requests. MAG-initiated requests use SR-ID=0 as a sentinel until the LMA assigns a real value.
The QoS architecture is grounded in the Differentiated Services Architecture (RFC 2474/2475) rather than per-flow RSVP-style reservation. The PMIPv6 domain is assumed to be DiffServ-enabled end-to-end, and the LMA/MAG are the natural enforcement points because they are already the tunnel entry/exit points for all mobile node traffic.
The specified QoS attributes are access-technology agnostic but are explicitly designed to be compatible with 3GPP (AMBR, GBR, ARP from TS 22.115/TS 23.402) and IEEE 802.11e QoS classifications; Appendices A, B, and C provide informative mapping tables for 3GPP LTE, IEEE 802.11e, and Broadband Network Gateway deployments.
A receiver MUST ignore any received QoS option whose Operational Code field is set to a reserved value (6-255). Reserved bits in the TC field MUST be initialized to (0) by the sender and MUST be ignored by the receiver.
In the QoS Traffic Selector attribute, TS Format value (0) is reserved and MUST NOT be used. Value (1) selects the IPv4 Binary Traffic Selector (RFC 6088 Section 3.1); value (2) selects the IPv6 Binary Traffic Selector (RFC 6088 Section 3.2).
The denial of a QoS Service Request MUST NOT result in removal of the mobility session for that mobile node. This constraint applies at both the LMA (when rejecting a MAG-initiated request) and the MAG (when rejecting an LMA-initiated request).
The S flag in Per-Session-Agg-Max-DL-Bit-Rate (Type 3) and Per-Session-Agg-Max-UL-Bit-Rate (Type 4) attributes MUST NOT be set to (1) when there is no Service Identifier associated with the current mobility session.
The Service Request Identifier (SR-ID) is always allocated by the local mobility anchor. A MAG initiating a new QoS Service Request MUST set SR-ID to (0) in the initial request; the LMA assigns the actual SR-ID value and includes it in the response.
When the LMA accepts a MAG-initiated QoS Service Request, it assigns a SR-ID to each accepted request and copies all QoS option instances from the PBU into the PBA with OC set to RESPONSE; if only partial support is possible, unacceptable QoS options are omitted and acceptable ones carry OC set to NEGOTIATE with SR-ID reset to (0).
When the LMA receives a Proxy Binding Update with Handoff Indicator (HI) hint = 3 (inter-MAG handover), the LMA MUST include in the Proxy Binding Acknowledgement all QoS option(s) for each QoS Service Request that is active for that mobile node, enabling the new MAG to allocate QoS resources on the new path.
The Operational Code (OC) field defines the nature of each QoS request: RESPONSE(0), ALLOCATE(1), DE-ALLOCATE(2), MODIFY(3), QUERY(4), NEGOTIATE(5). Values 6-255 are reserved; a receiver MUST ignore any QoS option bearing a reserved OC value.
The Quality-of-Service (QoS) option (Type 58) is a new PMIPv6 mobility header option used by LMAs and MAGs to negotiate QoS parameters for a mobile node's IP flows. It can be carried in PBU, PBA, UPN, and UPA messages; multiple instances may appear in a single message, each representing a distinct QoS Service Request.
This document defines a new 'QoS Attribute' sub-registry under PMIPv6 parameters with types 1-11 assigned herein, types 12-254 for future allocation, and types 0/255 reserved. It also registers PBA status code 179 (CANNOT_MEET_QOS_SERVICE_REQUEST), UPN Notification Reason 5 (QOS_SERVICE_REQUEST), and UPA status code 130 (CANNOT_MEET_QOS_SERVICE_REQUEST).
The QoS option is conveyed within PMIPv6 signaling messages (PBU, PBA, UPN, UPA) and therefore inherits the security model of RFC 5213, which mandates IPsec protection for MAG-LMA signaling. Without this protection, unauthorized QoS ALLOCATE or MODIFY requests could allow an attacker to manipulate traffic priority, exhaust network resources, or preempt existing sessions via the Allocation-Retention-Priority mechanism.
QoS negotiation transitions: (1) initiator sends ALLOCATE → (2a) peer returns RESPONSE with status 0 (accepted, QoS rules installed) or (2b) peer returns CANNOT_MEET_QOS_SERVICE_REQUEST with NEGOTIATE and revised attributes (counter-proposal, SR-ID reset to 0) → (3) initiator may re-send ALLOCATE with revised parameters. MODIFY updates an existing request by SR-ID; DE-ALLOCATE releases it; QUERY retrieves currently active requests.
Aggregate-Max-DL-Bit-Rate (Type 6) and Aggregate-Max-UL-Bit-Rate (Type 7), both Length 6, carry a 16-bit Reserved field followed by a 32-bit unsigned integer in bits per second; when used with QoS-Traffic-Selector, enforcement is at flow level for the identified target flows.
Each QoS Attribute uses a TLV encoding with Type (8-bit), Length (8-bit, excluding Type and Length fields), and Value (variable). Type 0 and Type 255 are reserved and cannot be used; types 1-11 are defined by this specification; types 12-254 are reserved for future allocation.
Guaranteed-DL-Bit-Rate (Type 8, Length 6) and Guaranteed-UL-Bit-Rate (Type 9, Length 6) encode the assured bit rate commitment as a 16-bit Reserved field plus a 32-bit unsigned integer in bits per second; the network is assumed to reserve resources for these values.
Per-MN-Agg-Max-DL-Bit-Rate (Type 1, Length 6) and Per-MN-Agg-Max-UL-Bit-Rate (Type 2, Length 6) each carry a 16-bit Reserved field followed by a 32-bit unsigned integer in bits per second representing an aggregate limit across all mobility sessions for the mobile node; the QoS-Traffic-Selector attribute does not apply to these attributes.
Per-Session-Agg-Max-DL-Bit-Rate (Type 3, Length 6) and Per-Session-Agg-Max-UL-Bit-Rate (Type 4, Length 6) each include a 1-bit S flag (extend scope to sessions sharing the same Service Identifier), a 1-bit E flag (exclude GBR flows from measurement), a 14-bit Reserved field, and a 32-bit bit-rate value in bits per second.
The Allocation-Retention-Priority attribute (Type 5, Length 2) packs Priority-Level (PL, 4-bit, values 1-15 where 1 is highest priority), Preemption-Capability (PC, 2-bit: Enabled=0/Disabled=1), and Preemption-Vulnerability (PV, 2-bit: Enabled=0/Disabled=1) into the last 8 bits preceded by an 8-bit Reserved field.
The QoS option requires 4n alignment and encodes: Type (8-bit, value 58), Length (8-bit), SR-ID (8-bit Service Request Identifier), TC (8-bit Traffic Class: 6-bit DSCP + 2-bit reserved), OC (8-bit Operational Code), Reserved (24-bit), followed by zero or more TLV-encoded QoS Attributes.
The QoS Traffic Selector attribute (Type 10, variable length) contains an 8-bit Reserved field, an 8-bit TS Format field (reusing the namespace from RFC 6089), and a variable-length Traffic Selector field; it scopes the DSCP marking and all co-located per-flow QoS attributes to the identified IP flows.
The QoS Vendor-Specific Attribute (Type 11, variable length) carries a 16-bit Reserved field, a 32-bit SMI Vendor ID (from IANA Private Enterprise Numbers), and an 8-bit Sub-Type managed by the vendor; multiple instances with different Sub-Type values are permitted in a single QoS option.