B. Beser Internet Draft 3Com Document: draft-ietf-dhc-packetcable-00.txt March 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 with Section 10 of RFC2026 [1], and the author does not provide the IETF with any rights other than to publish as an Internet-Draft 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 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. Internet Draft draft-beser-dhcp-packetcable-00.txt March 2000 o "DHCP server" 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. PacketCable project produced specifications of VoIP elements which can be found in www.packetcable.com. The PacketCable VoIP Client uses DHCP for configration. 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. PacketCable VoIP Client Configuration option is used for PacketCable VoIP clients to identify a list of valid PacketCable network servers. The option contains sub-fields to contain information regarding these servers. The option looks as depicted below at the DHCP OFFER. -------------------------------------------------------- | TBD | Length | PacketCable VoIP Client Configuration | -------------------------------------------------------- A client that recognizing the sub-fields sees the option as: ------------------------------------------------------------- | TBD | Length | Subfield 1 | Subfield 2 | ... | Subfield n | ------------------------------------------------------------- Internet Draft draft-beser-dhcp-packetcable-00.txt March 2000 Each sub-field is in the form of: --------------------------------------------------- | Sub-field Number | Length | Subfield information | --------------------------------------------------- Each sub-field of PacketCable VoIP Client Configuration identifies a particular type of PacketCable server. Sub-field 1 identifies the PacketCable network DHCP server, sub-field 2 identifies the PacketCable service provider's SNMP entity, and sub-field 3 and 4 identifies 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 DHCP Server Address| | |----------------------------------------------------------- | | 2 | Telephony Service Provider SNMP Server Address| | |----------------------------------------------------------- | | 3 | Telephony Service Provider Network Primary | | | | Domain Name Server | | |----------------------------------------------------------- | | 4 | Telephony Service Provider Network Secondary | | | | Domain Name Server | -------------------------------------------------------------------- 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 port numbers for these systems 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 standard DNS UDP port number is 42/udp. 6.1. Telephony Service Provider's DHCP Server Address The Telephony Service Provider's 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 1 is as follows: -------------------------------------------------------------------- |Sub-field | Value | Description and Comments | ==================================================================== | 1 |[x.y.z.y]:port | Either the IP address or the FQDN will| | |---------------| be configured. The port number is to | Internet Draft draft-beser-dhcp-packetcable-00.txt March 2000 | | FQDN:port | be used only if different than well | | | | 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 is as follows: -------------------------------------------------------------------- |Sub-field | Value | Description and Comments | ==================================================================== | 2 |[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 | | | | 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 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. Sub-field 4 is the address of the network's secondary DNS server. Sub-field 4 MAY be specified to identify a redundant or backup DNS server. The encoding syntax for sub-field 3 and sub-field 4 is as follows: -------------------------------------------------------------------- |Sub-field | Value | Description and Comments | ==================================================================== | 3 |[x.y.z.y]:port | Either the IP address of the telephony| | |---------------| service providers primary DNS server. | | | FQDN:port | Port will be defined only if different| | | | than well-known port. | -------------------------------------------------------------------- | 4 |[x.y.z.y]:port | Either the IP address of the telephony| | |---------------| service providers secondary DNS server| | | FQDN:port | Port will be defined only if different| | | | than well-known port. | -------------------------------------------------------------------- 6.4. Procedure for adding call control server types Internet Draft draft-beser-dhcp-packetcable-00.txt March 2000 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 published as an RFC which updates this RFC. 7. Security Considerations DHCP currently provides no authentication or security mechanisms. Potential exposures to attack are discussed is section 7 of the protocol specification [5]. 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. Droms, R., "Dynamic Host Configuration Protocol", RFC-2131, March 1997. 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); Roger Loots (Lucent); Roy Spitzer (Telogy), Aviv Goren (Terayon); and Prithivraj Narayanan (Wipro). 11. Author's Addresses Burcak Beser 3Com Mount Prospect, IL 60056 Email: Burcak_Beser@3com.com Internet Draft draft-ietf-dhcp-packetcable-00.txt March 2000