Access Extensions for ANCP

RFC6934 introduces application of ANCP to PON. However, RFC6320 haven't been updated to support PON. Besides, DSL technology is also evolving. G.fast, VDSL2 Vectoring and VDSL2 Annex Q were introduced as upgraded versions to provide higher bandwidths for the last mile.. This document considers all existing Access technologies used in a Telco network, yet not supported by RFC6320 and specifies new TLVs accordingly.

This section repeats some definitions from RFC6320 and RFC6934, but also updates some definitions where appropriate. Access Node (AN): [RFC5851] Network device, usually located at a service provider central office or street cabinet that terminates access (local) loop connections from subscribers. In case the access loop is a Digital Subscriber Line (DSL), the Access Node provides DSL signal termination and is referred to as a DSL Access Multiplexer (DSLAM). In case the access loop is a Passive Optical Network (PON), the Access Node is referred to as an Optical Line Terminal (OLT). Optical Line Terminal (OLT): is located in the service provider's central office (CO) or street cabinet. It terminates and aggregates multiple PONs (providing fiber access to multiple premises or neighborhoods) on the subscriber side and interfaces with the Network Access Server (NAS) that provides subscriber management. Optical Network Terminal (ONT): terminates PON on the network side and provides PON adaptation. The subscriber side interface and the location of the ONT are dictated by the type of network deployment. For an FTTP deployment (with fiber all the way to the apartment or living unit), ONT has Ethernet (Fast Ethernet (FE) / Gigabit Ethernet (GE) / Multimedia over Coax Alliance (MoCA)) connectivity with the Home Gateway (HGW) / Customer Premises Equipment (CPE). In certain cases, one ONT may provide connections to more than one Home Gateway at the same time. Optical Network Unit (ONU): a generic term denoting a device that terminates any one of the distributed (leaf) endpoints of an Optical Distribution Network (ODN), implements a PON protocol, and adapts PON PDUs to subscriber service interfaces. In the case of a multi-dwelling unit (MDU) or multi-tenant unit (MTU), a multi-subscriber ONU typically resides in the basement or a wiring closet (FTTB case) and has FE/GE/Ethernet over native Ethernet link or over xDSL (typically VDSL2) connectivity with each CPE at the subscriber premises. In the case where fiber is terminated outside the premises (neighborhood or curb side) on an ONT/ONU, the last-leg-premises connections could be via existing or new copper, with xDSL physical layer (typically VDSL2). In this case, the ONU effectively is a "PON-fed DSLAM". In new FTTdp based deployments the access node is named DPU (Distribution Point Unit). Basically from ANCP perspective this node provides the same functionality. Besides VDSL2, G.fast is mature and widely deployed.

ANCP message formats remain the same as described in section 3.5.1 of RFC6320 when it is applied to PON. However, some message descriptions need to be modified to make them applicable to variant Access Networks, other than DSL specific. The ANCP Adjacency message is extended to other Access Technologies than DSL. Generalize the message format to following: The following capabilities are defined for ANCP: o Capability Type: Access Topology Discovery = 0x01 Access technology: ANY Length (in bytes): 0 Capability Data: NULL For the detailed protocol specification of this capability, see Section 6 of RFC6320. o Capability Type: Access Line Configuration = 0x02 Access technology: ANY Length (in bytes): 0 Capability Data: NULL For the detailed protocol specification of this capability, see Section 7 of RFC6320. o Capability Type: Access Remote Line Connectivity Testing = 0x04 Access technology: ANY Length (in bytes): 0 Capability Data: NULL For the detailed protocol specification of this capability, see Section 8 of RFC6320.

Add following new DSL-Type values. Value: 32-bit unsigned integer G.fast = 8 VDSL2 Annex Q = 9 SDSL bonded = 10 VDSL2 bonded = 11 G.fast bonded = 12 VDSL2 Annex Q bonded = 13

DSL sub TLVs are listed in Section 6.5 of RFC6320. G.Fast requires beside existing TLVs the following new TLVs.

Type: 0x009B Expected Throughput at L2 (ETR) upstream Description: Reports the expected throughput upstream after retransmission (ITU-T G.997.2, clause 7.11.1.2) Length: 4 bytes Value: Rate in kbits/s as a 32-bit unsigned integer Type: 0x009C Expected Throughput at L2 (ETR) downstream Description: Reports the expected throughput downstream after retransmission (ITU-T G.997.2, clause 7.11.1.2) Length: 4 bytes Value: Rate in kbits/s as a 32-bit unsigned integer

Type: 0x009D Attainable Expected Throughput (ATTETR) upstream Description: Reports the attainable expected Throughput upstream at L2 (ITU-T G.997.2, clause 7.11.2.2) Length: 4 bytes Value: Rate in kbits/s as a 32-bit unsigned integer Type: 0x009E Attainable Expected Throughput (ATTETR) downstream Description: Reports the attainable expected Throughput downstream at L2 (ITU-T G.997.2, clause 7.11.2.2) Length: 4 bytes Value: Rate in kbits/s as a 32-bit unsigned integer

Type: 0x009F Gamma data rate (GDR) upstream Description: Reports the Gamma data rate (GDR) upstream (ITU-T G.997.2, clause 7.11.1.3) Length: 4 bytes Value: Rate in kbits/s as a 32-bit unsigned integer Type: 0x00A0 Gamma Data Rate (GDR) downstream Description: Reports the Gamma data rate (GDR) downstream(ITU-T G.997.2, clause 7.11.1.3) Length: 4 bytes Value: Rate in kbits/s as a 32-bit unsigned integer

Type: 0x00A1 Attainable Gamma data rate (ATTGDR) upstream Description: Reports the Attainable Gamma data rate upstream (ATTGDR) (ITU-T G.997.2, clause 7.11.2.3) Length: 4 bytes Value: Rate in kbits/s as a 32-bit unsigned integer Type: 0x00A2 Attainable Gamma data rate (ATTGDR) downstream Description: Reports the Attainable Gamma data rate (ATTGDR) (ITU-T G.997.2, clause 7.11.2.3) downstream Length: 4 bytes Value: Rate in kbits/s as a 32-bit unsigned integer

This section describes topology discovery messages applied for PON. TLVs not addressed here remain the same as applied for DSL.

The format of the ANCP Port Up and Port Down Event messages is shown in Figure xx1. It has the same format as the one described in section 6.3 of RFC6320. The only difference is that DSL-Line-Attributes TLV is updated as Access-Line-Attributes TLV.

NOTE: TLVs MAY be in a different order from what is shown in this figure. Figure xx1: Format of the ANCP Port Up and Port Down Event Messages for PON Topology Discovery See Section 3.6.1 of RFC6320 for a description of the ANCP general message header. The Message Type field MUST be set to 80 for Port Up, 81 for Port Down. It is applicable to both DSL and PON based access systems. The 4-bit Result field MUST be set to zero (signifying Ignore). The 12-bit Result Code field and the 24-bit Transaction Identifier field MUST also be set to zeroes. Other fields in the general header MUST be set a as described in Section 3.6 of RFC6320. The five-word Unused field is a historical leftover. The handling of unused/reserved fields is described in Section 3.4 of RFC6320. The remaining message fields belong to the "extension block", and are described as follows: Extension Flags (8 bits): The flag bits denoted by 'x' are currently unspecified and reserved. Message Type (8 bits): Message Type has the same value as in the general header (i.e., 80 or 81). Tech Type (8 bits): MUST be set to 0x01 (PON). Reserved (8 bits): set as described in Section 3.4 of RFC6320. # of TLVs (16 bits): The number of TLVs that follow, not counting TLVs encapsulated within other TLVs. Extension Block Length (16 bits): The total length of the TLVs carried in the extension block in bytes, including any padding within individual TLVs. TLVs: One or more TLVs to identify a PON Access line and zero or more TLVs to define its characteristics.

Most ANCP messages involve actions relating to a specific access line. Thus, it is necessary to describe how PON access lines are identified within those messages. This section defines four TLVs for that purpose and provides an informative description of how they are used in PON. TLVs not addressed here remain unchanged as applied for DSL.

Type: 0x0001 Description: A locally administered human-readable string generated by or configured on the Access Node, uniquely identifying the corresponding access loop logical port on the user side of the Access Node, as described in Section 5.7 of [TR-156].. Length: Up to 63 bytes Value: ASCII string

Type: 0x0002 Description: An operator-configured string that uniquely identifies the user on the associated access line, as described in Section 5.7 of [TR-156]. Length: Up to 63 bytes Value: ASCII string

Type: 0x0012 Description: This TLV encapsulates attribute values of a PON access line serving a subscriber. Length: Variable (up to 1023 bytes) Value: One or more encapsulated TLVs corresponding to PON access line attributes. The PON-Access-Line-Attributes TLV MUST contain at least one TLV when it is present in a Port Up or Port Down message. The actual contents are determined by the AN control application. Technology-independent attributes of RFC6320, such as TLV0x0090, are valid for PON and not repeated here.

Type: 0x0097 Description: Indicates the type of PON transmission system in use. Length: 4 bytes Value: 32-bit unsigned integer OTHER = 0 GPON = 1 XG-PON1 = 2 TWDM-PON = 3 XGS-PON = 4 WDM-PON = 5 Unknown = 7

Type: 0x00b0 Description: ONT/ONU downstream average data rate L2 Length: 4 bytes Value: Rate in kbits/s as a 32-bit unsigned integer

Type: 0x00b1 Description: ONT/ONU downstream peak data rate L2 Length: 4 bytes Value: Rate in kbits/s as a 32-bit unsigned integer

Type: 0x00b2 Description: ONT/ONU upstream maximum data rate L2 Length: 4 bytes Value: Rate in kbits/s as a 32-bit unsigned integer

Type: 0x00b3 Description: ONT/ONU upstream assured data rate L2 Length: 4 bytes Value: Rate in kbits/s as a 32-bit unsigned integer

Type: 0x00b4 Description: PON Tree upstream maximum data rate L2 Length: 4 bytes Value: Rate in kbits/s as a 32-bit unsigned integer

Type: 0x00b5 Description: PON Tree downstream maximum data rate L2 Length: 4 bytes Value: Rate in kbits/s as a 32-bit unsigned integer

Type: 0x00b6 Description: Reserved Length: tbd Value: tbd

Type: 0x00b7 Description: Reserved Length: tbd Value: tbd

This document defines following sets of TLVs for PON, some of them have defined by RFC6320 and are referenced here for completeness:

There are no new security considerations beyond what is described in RFC6320 and RFC6934.

Many thanks to Norbert Voigt, John Gibbons, Sven Ooghe, Koen De Sagher and Sven Leimer for joint work reviewing the document and providing valuable comments to this document.