DHC Working Group B. Beser Internet Draft Pacific Broadband Communications Document: 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 in full conformance with all provisions of Section 10 of RFC2026 [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 six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet- Drafts 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" Beser Informational “ Expiration May 2000 1 PacketCable VoIP Client Configuration October 2000 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, which can be found in www.packetcable.com. The PacketCable VoIP Client uses DHCP for 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, 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 by the PacketCable VoIP clients to identify a list of valid PacketCable specific network servers. The option sub-fields contain information regarding these servers. The option is included in DHCP OFFER-s, and is laid out as depicted below: ------------------------------------------------------------- | TBD | Length | Subfield 1 | Subfield 2 | ... | Subfield n | ------------------------------------------------------------- Each sub-field is in the form of: Beser Informational “ Expires May 2000 2 PacketCable VoIP Client Configuration October 2000 --------------------------------------------------- | Sub-field Number | Length | Subfield information | --------------------------------------------------- Each sub-field of the PacketCable VoIP Client Configuration identifies a particular type of PacketCable server. Sub-fields 1 and 2 identify the primary and secondary PacketCable network DHCP servers, sub-field 3 identifies the PacketCable service provider's SNMP entity, and sub-fields 4 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 | | |----------------------------------------------------------- | | 2 | Telephony Service Provider Secondary DHCP | | | | Server Address | | |----------------------------------------------------------- | | 3 | Telephony Service Provider SNMP Server Address| | |----------------------------------------------------------- | | 4 | Telephony Service Provider Network Primary | | | | Domain Name Server Address | | |----------------------------------------------------------- | | 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]. The port numbers MAY be omitted, if the standard 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. Sub-field 1 is the address of the network's primary Telephony Service Provider DHCP server IP Address. Sub-field 2 is 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. Beser Informational “ Expires May 2000 3 PacketCable VoIP Client Configuration October 2000 The encoding syntax for sub-field 1 and sub-field 2 is as follows: --------------------------------------------------------------------- |Sub-field | Value | Description and Comments | ===================================================================== | 1 |[x.y.z.y]:port | IP address of Primary TSP DHCP Server | | | | The port number is to be used only if | | | | different than 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 3 is as follows: -------------------------------------------------------------------- |Sub-field | Value | Description and Comments | ==================================================================== | 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 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 4 is the address of the network's primary DNS server IP Address. Sub-field 5 is the address of the network's secondary DNS server. Sub-field 5 MAY be specified to identify a redundant or backup DNS server. The encoding syntax for sub-field 4 and sub-field 5 is as follows: Beser Informational “ Expires May 2000 4 PacketCable VoIP Client Configuration October 2000 --------------------------------------------------------------------- |Sub-field | Value | Description and Comments | ===================================================================== | 4 |[x.y.z.y]:port | IP address of Primary TSP DNS Server | | | | The port number is to be used only if | | | | different than the default port number | | | | is to be used. | --------------------------------------------------------------------- | 5 |[x.y.z.y]:port | IP address of Secondary TSP DNS Server | | | | The port number is to be used only if | | | | different than 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 will be published as an RFC, which 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 Beser Informational “ Expires May 2000 5 PacketCable VoIP Client Configuration October 2000 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 protocol [5] for authentication and security, i.e. it does not provide either in excess of 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. 5. Droms, R., "Dynamic Host Configuration Protocol", RFC-2131, March 1997. Beser Informational “ Expires May 2000 6 PacketCable VoIP Client Configuration October 2000 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 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, 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 Pacific Broadband Communications 3103 North First Street, San Jose, CA, 95134 Phone: (408) 468 6265 Email: Burcak@pbc.com Beser Informational “ Expires May 2000 7