Proposed standard for the transmission of IP datagrams over FDDI Networks
RFC 1103
Document | Type |
RFC - Unknown
(June 1989; No errata)
Obsoleted by RFC 1188
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Authors | |||
Last updated | 2013-03-02 | ||
Stream | Legacy | ||
Formats | plain text html pdf htmlized bibtex | ||
Stream | Legacy state | (None) | |
Consensus Boilerplate | Unknown | ||
RFC Editor Note | (None) | ||
IESG | IESG state | RFC 1103 (Unknown) | |
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Responsible AD | (None) | ||
Send notices to | (None) |
Network Working Group D. Katz Request for Comments: 1103 Merit/NSFNET June 1989 A Proposed Standard for the Transmission of IP Datagrams over FDDI Networks Status of this Memo This RFC specifies a method of encapsulating the Internet Protocol (IP) [1] datagrams and Address Resolution Protocol (ARP) [2] requests and replies on Fiber Distributed Data Interface (FDDI) Networks. This RFC specifies a proposed protocol standard for the Internet community. Comments are welcome. Distribution of this memo is unlimited. Acknowledgment This memo draws heavily in both concept and text from RFC 1042 [3], written by Jon Postel and Joyce K. Reynolds of USC/Information Sciences Institute. Conventions The following language conventions are used in the items of specification in this document: "Must" or "Mandatory"--the item is an absolute requirement of the specification. "Should" or "Recommended"--the item should generally be followed for all but exceptional circumstances. "May" or "Optional"--the item is truly optional and may be followed or ignored according to the needs of the implementor. Introduction The goal of this specification is to allow compatible and interoperable implementations for transmitting IP datagrams and ARP requests and replies. The Fiber Distributed Data Interface (FDDI) specifications define a family of standards for Local Area Networks (LANs) that provides the Physical Layer and Media Access Control Sublayer of the Data Link Layer as defined by the ISO Open System Interconnection Reference Model (ISO/OSI). Documents are in various stages of progression Katz [Page 1] RFC 1103 IP Datagrams over FDDI Networks June 1989 toward International Standardization for Media Access Control (MAC) [4], Physical Layer Protocol (PHY) [5], Physical Layer Medium Dependent (PMD) [6], and Station Management (SMT) [7]. The family of FDDI standards corresponds to the IEEE 802 MAC layer standards [8, 9, 10]. The remainder of the Data Link Service is provided by the IEEE 802.2 Logical Link Control (LLC) service [11]. The resulting stack of services appears as follows: +-------------+ | IP/ARP | +-------------+ | 802.2 LLC | +-------------+ | FDDI MAC | +-------------+ | FDDI PHY | +-------------+ | FDDI PMD | +-------------+ This memo describes the use of IP and ARP in this environment. At this time, it is not necessary that the use of IP and ARP be consistent between FDDI and IEEE 802 networks, but it is the intent of this memo not to preclude Data Link Layer interoperability at such time as the standards define it. Packet Format IP datagrams and ARP requests and replies sent on FDDI networks must be encapsulated within the 802.2 LLC and Sub-Network Access Protocol (SNAP) data link layers and the FDDI MAC and physical layers. The SNAP must be used with an Organization Code indicating that the SNAP header contains the EtherType code (as listed in Assigned Numbers [12]). 802.2 LLC Type 1 communication (which must be implemented by all conforming 802.2 stations) is used exclusively. All frames must be transmitted in standard 802.2 LLC Type 1 Unnumbered Information format, with the DSAP and the SSAP fields of the 802.2 header set to the assigned global SAP value for SNAP [11]. The 24-bit Organization Code in the SNAP must be zero, and the remaining 16 bits are the EtherType from Assigned Numbers [12] (IP = 2048, ARP = 2054). Katz [Page 2] RFC 1103 IP Datagrams over FDDI Networks June 1989 ...--------+--------+--------+ MAC Header | FDDI MAC ...--------+--------+--------+ +--------+--------+--------+ | DSAP=K1| SSAP=K1| Control| 802.2 LLC +--------+--------+--------+ +--------+--------+---------+--------+--------+ |Protocol Id or Org Code =K2| EtherType | 802.2 SNAP +--------+--------+---------+--------+--------+ The total length of the LLC Header and the SNAP header is 8 octets. The K1 value is 170 (decimal). The K2 value is 0 (zero). The control value is 3 (Unnumbered Information). Address Resolution The mapping of 32-bit Internet addresses to 16-bit or 48-bit FDDI addresses must be done via the dynamic discovery procedure of the Address Resolution Protocol (ARP) [2]. Internet addresses are assigned arbitrarily on Internet networks.Show full document text