| Network Working Group | H. Li |
| Internet-Draft | Huawei Technologies Co., Ltd. |
| Intended status: Experimental | T. Haag |
| Expires: January 25, 2020 | B. Witschurke |
| Deutsche Telekom | |
| July 24, 2019 |
Access Extensions for the Access Node Control Protocol
draft-lihawi-ancp-protocol-access-extension-02
The purpose of this document is to specify extensions to ANCP (Access Node Control Protocol) (RFC6320) to support PON as described in RFC6934 and some other DSL Technologies including G.fast. This document updates RFC6320 by modifications to terminologies, flows and specifying new TLV types.
This document updates RFC6320 by modifications to terminologies, flows and specifying new TLV types.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119.
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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.
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
For the detailed protocol specification of this capability, see Section 6 of RFC6320.
o Capability Type: Access Line Configuration = 0x02
For the detailed protocol specification of this capability, see Section 7 of RFC6320.
o Capability Type: Access Remote Line Connectivity Testing = 0x04
For the detailed protocol specification of this capability, see Section 8 of RFC6320.
Add following new DSL-Type values.
Value: 32-bit unsigned integer
DSL sub TLVs are listed in Section 6.5 of RFC6320. G.Fast requires beside existing TLVs the following new TLVs.
Type: 0x1008 Expected Throughput at L2 (ETR) upstream
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: 0x1009 Expected Throughput at L2 (ETR) downstream
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: 0x100A
Description: Reports the attainable expected Throughput at L2 (ITU-T G.997.2, clause 7.11.2.2) upstream
Length: 4 bytes
Value: Rate in kbits/s as a 32-bit unsigned integer
Type: 0x100B
Description: Reports the attainable expected Throughput at L2 (ITU-T G.997.2, clause 7.11.2.2) downstream
Length: 4 bytes
Value: Rate in kbits/s as a 32-bit unsigned integer
Type: 0x100C
Description: Reports the Gamma data rate (GDR) (ITU-T G.997.2, clause 7.11.1.3) upstream
Length: 4 bytes
Value: Rate in kbits/s as a 32-bit unsigned integer
Type: 0x100D
Description: Reports the Gamma data rate (GDR) (ITU-T G.997.2, clause 7.11.1.3) downstream
Length: 4 bytes
Value: Rate in kbits/s as a 32-bit unsigned integer
Type: 0x100E
Description: Reports the Attainable Gamma data rate (ATTGDR) (ITU-T G.997.2, clause 7.11.2.3) upstream
Length: 4 bytes
Value: Rate in kbits/s as a 32-bit unsigned integer
Type: 0x100F
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.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TCP/IP Encapsulating Header (Section 3.2) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ANCP General Message Header |
+ (Section 3.6.1) +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Unused (20 bytes) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|x|x|x|x|x|x|x|x| Message Type | Tech Type | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| # of TLVs | Extension Block length (bytes)|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Access line identifying TLV(s) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ACCESS-Line-Attributes TLV |
~ (MANDATORY in Port Up, OPTIONAL in Port Down) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Format of the ANCP Port Up and Port Down Event Messages for PON Topology Discovery
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 her are remain unchanged applied to 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 attrbutes of RFC6320, such as TLV0x0090, are valid for PON and not repeated here..
Type: 0x1001
Description: Indicates the type of PON transmission system in use.
Length: 4 bytes
Value: 32-bit unsigned integer
Type: 0x1002
Description: ONT/ONU downstream average data rate L2
Length: 4 bytes
Value: Rate in kbits/s as a 32-bit unsigned integer
Type: 0x1003
Description: ONT/ONU downstream peak data rate L2
Length: 4 bytes
Value: Rate in kbits/s as a 32-bit unsigned integer
Type: 0x1004
Description: ONT/ONU upstream maximum data rate L2
Length: 4 bytes
Value: Rate in kbits/s as a 32-bit unsigned integer
Type: 0x1005
Description: ONT/ONU upstream assured data rate L2
Length: 4 bytes
Value: Rate in kbits/s as a 32-bit unsigned integer
Type: 0x1006
Description: PON Tree upstream maximum data rate L2
Length: 4 bytes
Value: Rate in kbits/s as a 32-bit unsigned integer
Type: 0x1007
Description: PON Tree downstream maximum data rate L2
Length: 4 bytes
Value: Rate in kbits/s as a 32-bit unsigned integer
This document defines following sets of TLVs for PON, some of them have defined by RFC6320 and are referenced here for completeness:
+----------+--------------------------------------------+-----------+ | Type Code| TLV Name | Reference | +----------+--------------------------------------------+-----------+ | 0x0000 | Reserved | RFC 6320 | | 0x0001 | Access-Loop-Circuit-ID | RFC 6320 | | 0x0002 | Access-Loop-Remote-ID | RFC 6320 | | 0x0003 | Access-Aggregation-Circuit-ID-ASCII | RFC 6320 | | 0x0005 | Service-Profile-Name | RFC 6320 | | 0x0006 | Access-Aggregation-Circuit-ID-Binary | RFC 6320 | | 0x0011 | Command | RFC 6320 | | 0x0012 | PON-Access-Line-Attributes | RFC xxxx | | 0x1001 | PON-Access-Type | RFC xxxx | | 0x1002 | ONT/ONU-Average-Data-Rate-Downstream | RFC xxxx | | 0x1003 | ONT/ONU-Peak-Data-Rate-Downstream | RFC xxxx | | 0x1004 | ONT/ONU-Maximum-Data-Rate-Upstream | RFC xxxx | | 0x1005 | ONT/ONU-Assured-Data-Rate-Upstream | RFC xxxx | | 0x1006 | PON-Tree-Maximum-Data-Rate-Upstream | RFC xxxx | | 0x1007 | PON-Tree-Maximum-Data-Rate-Downstream | RFC xxxx | | 0x1008 | Expected Throughput (ETR) upnstream | RFC xxxx | | 0x1009 | Expected Throughput (ETR)-downstream | RFC xxxx | | 0x100A | Attainable Expected Throughput (ATTETR) upstream | RFC xxxx | | 0x100B | Attainable Expected Throughput (ATTETR)-downstream | RFC xxxx | | 0x100C | Guaranteed Data Rate (GDR)-upnstream | RFC xxxx | | 0x100D | Guaranteed Data Rate (GDR) downstream | RFC xxxx | | 0x100E | Attainable Guaranteed Data Rate (ATTGDR)-upstream | RFC xxxx | | 0x100F | Attainable Guaranteed Data Rate (ATTGDR)-downstream | RFC xxxx | | 0x0106 | Status-Info | RFC 6320 | | 0x1000 | Target (single access line variant) | RFC 6320 | +----------+--------------------------------------------+-----------+
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.
| [RFC2119] | Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997. |
| [RFC6320] | Wadhwa, S., Moisand, J., Haag, T., Voigt, N. and T. Taylor, "Protocol for Access Node Control Mechanism in Broadband Networks", RFC 6320, DOI 10.17487/RFC6320, October 2011. |
| [RFC6934] | Bitar, N., Wadhwa, S., Haag, T. and H. Li, "Applicability of the Access Node Control Mechanism to Broadband Networks Based on Passive Optical Networks (PONs)", RFC 6934, DOI 10.17487/RFC6934, June 2013. |
| [RFC5515] | Mammoliti, V., Pignataro, C., Arberg, P., Gibbons, J. and P. Howard, "Layer 2 Tunneling Protocol (L2TP) Access Line Information Attribute Value Pair (AVP) Extensions", RFC 5515, DOI 10.17487/RFC5515, May 2009. |
| [TR-156_Issue-3] | Forum, T. B., "Using GPON Access in the context of TR-101", November 2012. |