DHC Working Group                                              B. Beser
Internet Draft                                                     3Com                         Pacific Broadband Communications
Document: draft-ietf-dhc-packetcable-00.txt                 March draft-ietf-dhc-packetcable-01.txt                October 2000
Category: Informational

         DHCP Option for PacketCable VoIP Client Configuration

Status of this Memo

   This document is an Internet-Draft and is NOT offered in accordance full conformance with
   all provisions of Section 10 of RFC2026 [1], and the author does not provide the
   IETF with any rights other than to publish as an Internet-Draft [1].

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups. Note that
   other groups may also distribute working documents as Internet-
   Drafts. Internet-Drafts are draft documents valid for a maximum of
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   as reference material or to cite them other than as "work in
   progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

1. Abstract

   The Voice over IP work carried over in the PacketCable project
   conducted by CableLabs. The configuration of the PacketCable Voice
   over IP client is achieved using DHCP messaging.

   This document contains the definition of the PacketCable VoIP Client
   configuration option.

2. Conventions used in this document

   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 [2].

3. DHCP Terminology

   o "DHCP client"

   A DHCP client or "client" is an Internet host using DHCP to obtain
   configuration parameters such as a network address.

   o "DHCP server"

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   A DHCP server of "server"is an Internet host that returns
   configuration parameters to DHCP clients.

   o "binding"

   A binding is a collection of configuration parameters, including at
   least an IP address, associated with or "bound to" a DHCP client.
   Bindings are managed by DHCP servers.

4. Introduction

   PacketCable is a project conducted by Cable Television Laboratories,
   Inc. (CableLabs) and its member companies aimed at identifying,
   qualifying, and supporting Internet-based voice and video products
   over cable systems. These products will represent new classes of
   services utilizing cable-based packet communication networks. New
   service classes include telephone calls and videoconferencing over
   cable networks and the Internet. The services would be delivered
   using the basic Internet Protocol (IP) technology that is used to
   send data via the Internet.

   The PacketCable embedded-MTA (MTA) is a single physical device with
   dual personality: a Cable Modem (CM) and a VoIP device. Both of
   these devices are administered by different entities. Both of the
   personalities have different IP addresses and different IP
   configurations.

   PacketCable project produced specifications of VoIP elements elements, which
   can be found in www.packetcable.com. The PacketCable VoIP Client uses
   DHCP for configration. configuration. Due to specific needs of PacketCable client a
   new DHCP option is needed. The new option is designed to have a
   number of sub-information sub-information, which is laid down in DHCP option fashion
   [3].

5. PacketCable VoIP Client Configuration Option

   The code for this option is TBD.

   The PacketCable VoIP Client Configuration option is used for by the
   PacketCable VoIP clients to identify a list of valid PacketCable
   specific network servers.

   The option contains sub-fields to contain information regarding these servers.

   The option looks is included in DHCP OFFER-s, and is laid out as depicted below at the DHCP OFFER.

   --------------------------------------------------------
   | TBD | Length | PacketCable VoIP Client Configuration |
   --------------------------------------------------------

   A client that recognizing the sub-fields sees the option as:
   below:

   -------------------------------------------------------------
   | TBD | Length | Subfield 1 | Subfield 2 | ... | Subfield n |
   -------------------------------------------------------------

   Each sub-field is in the form of:

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   ---------------------------------------------------
   | Sub-field Number | Length | Subfield information |
   ---------------------------------------------------

   Each sub-field of the PacketCable VoIP Client Configuration
   identifies a particular type of PacketCable server. Sub-field Sub-fields 1 identifies and
   2 identify the primary and secondary PacketCable network DHCP server,
   servers, sub-field 2 3 identifies the PacketCable service provider's
   SNMP entity, and sub-field 3 and sub-fields 4
   identifies and 5 identify the primary and
   secondary PacketCable network DNS servers. The Sub-fields are
   summarized below:

   --------------------------------------------------------------------
   |Option |Sub-field | Description and Comments                      |
   ====================================================================
   | TBD   |     1    | Telephony Service Provider Primary DHCP       |
   |       |          | Server Address| Address                                |
   |       |-----------------------------------------------------------
   |       |     2    | Telephony Service Provider Secondary DHCP     |
   |       |          | Server Address                                |
   |       |-----------------------------------------------------------
   |       |     3    | Telephony Service Provider SNMP Server Address|
   |       |-----------------------------------------------------------
   |       |     3     4    | Telephony Service Provider Network Primary    |
   |       |          | Domain Name Server Address                    |
   |       |-----------------------------------------------------------
   |       |     4     5    | Telephony Service Provider Network Secondary  |
   |       |          | Domain Name Server Address                    |
   --------------------------------------------------------------------

6. PacketCable VoIP Client option Sub-field Definitions

   The following parts provide detailed descriptions of each sub-field
   of DHCP PacketCable VoIP Client option. Note that UDP port numbers
   are normally standard values as defined in [4].  However, the format
   of the sub-field data fields defined here have a provision to
   optionally include  The port numbers for these systems
   MAY be omitted, if a port number
   other than the standard is required. If no port number is specified, the standard port number based on the definitions [4] is assumed.
   For example, the protocol ports are to be used as
   defined in [4]. E.g.:the standard DNS UDP port number is 42/udp. If
   non-standard port numbers are used, these MUST be appended as shown
   below.

6.1. Telephony Service Provider's DHCP Server Address

   The Telephony Service Provider's (TSP) DHCP Server Address identifies
   the DHCP server that will be used to obtain an MTA-unique IP address
   for a given telephony service provider's network administrative
   domain.
   This address can be configured as either an FQDN or as an IPv4
   address.

   The encoding of sub-field

   Sub-field 1 is as follows:

   --------------------------------------------------------------------
   |Sub-field | Value         | Description and Comments              |
   ====================================================================
   |     1    |[x.y.z.y]:port | Either the IP address or of the FQDN will|
   |          |---------------| be configured. The port number network's primary Telephony Service
   Provider DHCP server IP Address. Sub-field 2 is to the address of the
   network's secondary Telephony Service Provider DHCP server. Sub-field
   2 MAY be specified to identify a redundant or backup DHCP server.

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   The encoding syntax for sub-field 1 and sub-field 2 is as follows:

   ---------------------------------------------------------------------
   |Sub-field | Value         | Description and Comments               |
   =====================================================================
   | FQDN:port     1    |[x.y.z.y]:port | IP address of Primary TSP DHCP Server  |
   |          |               | The port number is to be used only if  |
   |          |               | different than well the default port number |
   |          |               | is to be used.                         |
   ---------------------------------------------------------------------
   |     2    |[x.y.z.y]:port | IP address of Secondary TSP DHCP Server|
   |          |               | The port number is to be used only if  |
   |          |               | different than the default port number |
   |          |               | is to be used.                         |
   --------------------------------------------------------------------
   ---------------------------------------------------------------------

6.2. Telephony Service Provider's SNMP Entity Address

   The Telephony Service Provider's SNMP Entity Address is the network
   address of the default server for a given telephony service
   provider's network administrative domain. The Telephony Service
   Provider's SNMP Entity Address component MUST be capable of accepting
   SNMP traps. This address can be configured as either an FQDN or as an
   IPv4 address.

   The encoding of sub-field 2 3 is as follows:

   --------------------------------------------------------------------
   |Sub-field | Value         | Description and Comments              |
   ====================================================================
   |     2     3    |[x.y.z.y]:port | Either the IP address or the FQDN will|
   |          |---------------| be configured. The port number is to  |
   |          | FQDN:port     | be used only if different than well the    |
   |          |               | default port number is to be used.    |
   --------------------------------------------------------------------

6.3. DNS system

   The Telephony Service Provider's DNS server is required to resolve a
   PacketCable device's FQDN into an IPv4 address. The DNS server's
   address MUST be specified in the IPv4 format.

   Sub-field 3 4 is the address of the network's primary DNS server and
   MUST be specified if sub-field 1 or sub-field 2 is in FQDN format. IP
   Address. Sub-field 4 5 is the address of the network's secondary DNS
   server. Sub-field 4 5 MAY be specified to identify a redundant or
   backup DNS server.

   The encoding syntax for sub-field 3 4 and sub-field 4 5 is as follows:

   --------------------------------------------------------------------

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   ---------------------------------------------------------------------
   |Sub-field | Value         | Description and Comments               |
   ====================================================================
   =====================================================================
   |     3     4    |[x.y.z.y]:port | Either the IP address of the telephony|
   |          |---------------| service providers primary Primary TSP DNS server. Server   |
   |          | FQDN:port               | Port will The port number is to be defined used only if different|  |
   |          |               | different than well-known port. the default port number |
   --------------------------------------------------------------------
   |     4          |               | is to be used.                         |
   ---------------------------------------------------------------------
   |     5    |[x.y.z.y]:port | Either the IP address of the telephony|
   |          |---------------| service providers secondary Secondary TSP DNS server| Server |
   | FQDN:port          | Port will               | The port number is to be defined used only if different|  |
   |          |               | different than well-known port. the default port number |
   --------------------------------------------------------------------
   |          |               | is to be used.                         |
   ---------------------------------------------------------------------

6.4. Procedure for adding call control server types

   A vendor may add a new sub-field by issuing an internet draft that
   contains the new sub-field.  The new sub-field code MUST be labeled
   "TBD."  This draft will then be submitted to the DHC working group,
   and, if accepted for inclusion in the DHCP specification, a sub-
   option field code is assigned and the sub-option specification is will
   be published as an RFC RFC, which updates will update this RFC.

6.5 Typical us of PacketCable VoIP Client Configuration option

           MTA
   --------------_______                                Telephony
   VoIP         CM              CM DHCP Server          DHCP Server
   |            |                       |                       |
   (MTA boots up)                       |                       |
   |            |                       |                       |
   |            | broadcast DISCOVER (1)|                       |
   |            |---------------------->|                       |
   |            |                       |                       |
   |            | CM IP configuration + |                       |
   |            | TSP DHCP Serv. IP@ (2)|                       |
   |            |<----------------------|                       |
   |  PCC (3)   |                       |                       |
   |<===========|                       |                       |
   |            |                       |                       |
   | unicast DISCOVER (4)                                       |
   |----------------------------------------------------------->|
   |            |                                               |
   |            |                       VoIP IP configuration + |
   |            |          PacketCable Client Configuration (5) |
   |<-----------------------------------------------------------|
   |            |                                               |
   (Telephony registration via                                  |
   Telephony Service Provider SNMP Server)                      |

   Figure 1 Typical MTA IP Configuration via DHCP

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   The PacketCable VoIP Client Configuration option is used on the DHCP
   messaging of both CM and VoIP device personalities. A typical MTA
   boot operation is depicted in Figure 1 and can be described as
   below:

   1. When MTA boots the CM personality sends a broadcast DISCOVER
   message with proper Vendor Client Identifier Option.

   2. The DHCP server gives a proper address from CM IP address pool,
   along with the PacketCable VoIP Client Configuration Option
   populated with (at least) Telephony Service Provider DHCP Server IP
   address(es).

   3. The CM passes the PacketCable Client Configuration (PCC)
   information to VoIP device.

   4. The VoIP device uses the information in the Telephony Service
   Provider IP DHCP Server Address field and unicasts the DISCOVER
   message to the address(es).

   5. Telephony Service Provider IP DHCP Server returns the IP
   configuration for VoIP personality and PacketCable Client
   Configuration information.

   From this point on the MTA uses the FQDN information for PacketCable
   SNMP server using Telephony Service Provider DNS servers, and
   registers for service.

7. Security Considerations

   This draft relies on DHCP currently provides no protocol [5] for authentication or security
   mechanisms.  Potential exposures to attack are discussed
   is section 7 and
   security, i.e. it does not provide either in excess of the protocol specification [5]. what DHCP is
   (or will be) providing.

9. References

   1. Bradner, S., "The Internet Standards Process -- Revision 3", BCP
   9, RFC 2026, October 1996.

   2. Bradner, S., "Key words for use in RFCs to Indicate Requirement
   Levels", BCP 14, RFC 2119, March 1997.

   3. Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
   Extensions", RFC-2132, March 1997.

   4. Reynolds, J., Postel, J., _ASSIGNED NUMBERS_, RFC 1340, July 1992.

   6.

   5. Droms, R., "Dynamic Host Configuration Protocol", RFC-2131, March
   1997.

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10.  Acknowledgments

   I would like to extend a heartfelt thanks to all those who
   contributed to the development of PacketCable Provisioning
   specification. Particular thanks are given Sasha Medvinsky, Raj
   Deshpande (Motorola), Angela Lyda, Rick Morris
   (Arris Interactive); Steven Bellovin (AT&T); Jiri Matousek (Bay
   Networks); Klaus Hermanns, Azita Kia, Michael Thomas, Rich Woundy
   (Cisco); Deepak Patil (Com21); Jeff Ollis, Rick Vetter (General Instrument); Vetter, Sasha
   Medvinsky, Raj Deshpande (Motorola); Roger Loots (Lucent); Roy
   Spitzer (Telogy), Aviv Goren (Terayon); and Prithivraj Narayanan
   (Wipro). Last but not least special thanks to Steve Gonczi (Network
   Engines) for suggestions.

11. Author's Addresses

   Burcak Beser
   3Com
   Mount Prospect, IL  60056
   Pacific Broadband Communications
   3103 North First Street,
   San Jose, CA, 95134
   Phone: (408) 468 6265
   Email: Burcak_Beser@3com.com Burcak@pbc.com

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