Internet-Draft Mike Davison Cisco Systems July 10, 1997 ILMI-Based Server Discovery for MARS Status of this Memo This document was submitted to the IETF Internetworking Over NBMA Working Group (ion). Publication of this document does not imply acceptance by the Internetworking Over NBMA Working Group of any ideas expressed within. Comments should be submitted to the ion@nexen.com mailing list. Distribution of this memo is unlimited. This memo is 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. Internet Drafts may be updated, replaced, or obsoleted by other documents at any time. It is not appropriate to use Internet Drafts as reference material or to cite them other than as a "working draft" or "work in progress". Please check the lid-abstracts.txt listing contained in the internet-drafts shadow directories on nic.ddn.mil, nnsc.nsf.net, nic.nordu.net, ftp.nisc.src.com, or munnari.oz.au to learn the current status of any Internet Draft. Abstract This memo defines how ILMI-based Server Discovery, which provides a method for ATM-attached hosts and routers to dynamically determine the ATM address of servers, shall be used to locate MARS servers. Davison Expires January 10, 1998 [Page 1] Internet Draft July 10, 1997 1. Introduction Presently, configuring a host or router to use MARS [1] is cumbersome and error-prone since it requires at least one ATM addresses to be statically configured on each host or router in the network. Further, it is impossible to implement a diskless host to use MARS since local configuration is required. ILMI-based Server Discovery, hereafter refered to as "server discovery," provides a solution to these problems. A brief overview of the Service Registry MIB, as defined by the ATM Forum, is provided in this memo. The reader should consult [2] for a complete description of this MIB, but the information contained here is sufficient for an understanding of its use to support MARS server discovery. 2. ILMI 4.0 Service Registry MIB Server discovery utilizes the Service Registry MIB defined by the ATM Forum in ILMI Specification Version 4.0 [2]. To support the existing framework for IP over ATM, as embodied by ATMARP and MARS, ATM switches must support the Service Registry MIB. A row in the service registry table [2] is defined as: AtmfSrvcRegEntry ::= SEQUENCE { atmfSrvcRegPort INTEGER, atmfSrvcRegServiceID OBJECT IDENTIFIER, atmfSrvcRegATMAddress AtmAddress, atmfSrvcRegAddressIndex INTEGER, atmfSrvcRegParm1 OCTET STRING } The definition of each field in this structure is: atmfSrvcRegPort - The port number for which this entry contains management information. The value of zero may be used to indicate the ATM interface over which a management request was received. atmfSrvcRegServiceID - This is the service identifier which uniquely identifies the type of service at the address provided in the table. (See Appendix for MARS OID.) atmfSrvcRegATMAddress - This is the full address of the service. Davison Expires January 10, 1998 [Page 2] Internet Draft July 10, 1997 The ATM client will use this address to establish a connection with the service. atmfSrvcRegAddressIndex - An arbitrary integer to differentiate multiple rows containing different ATM addresses for the same service on the same port. atmfSrvcRegParm1 - An octet string whose size and meaning is determined by the value of atmfSrvcRegServiceID. The service registry table is indexed by atmfSrvcRegPort, atmfSrvcRegServiceID and atmfSrvcRegAddressIndex. 3. Service Parameter String A generic parameter string is defined in the service registry table, thus allowing protocol-specific parameters to be specified. To be consistant with [1], the parameter string for MARS shall be: mar$pro.type 16 bits Protocol type mar$pro.snap 40 bits Optional SNAP extentension to protcol type mar$plen 8 bits Length of protocol address (a) mar$addr a octets Network address mar$mask a octets Network mask Where mar$pro.type - See [1]. (IP is 0x0800) mar$pro.snap - See [1]. (IP is 0) mar$plen - Length of the protocol address. (IP is 4) mar$addr - Network address represented in network byte order mar$mask - Network mask represented in network byte order 4. MARS Client Behavior An MARS client will access the service registry table via ILMI using the SNMP GetNext operator to "sweep" (SNMP parlance for a linear search) beginning with {Port = 0, ServiceID = , Index = 0} while holding the port number and the serviceID constant. (Port Davison Expires January 10, 1998 [Page 3] Internet Draft July 10, 1997 number 0 is used within ILMI to indicate "this port.") An MARS client with no local configuration, such as a diskless workstation, must use the row with the lowest index value if multiple MARS servers, possibly for multiple networks, are listed. MARS clients that have local IP configuration must use a row that has the appropriate IP address. For example, consider the case where an IP router has 3 logical interfaces defined on a single physical interface with IP addresses 1.0.0.1/8, 128.10.0.1/16 and 171.69.150.226/24. The router will sweep the service registry table looking for a rows that have atmfSrvcRegParm1 values as shown below: Network number/mask atmfSrvcRegParm1 ---------------------- ---------------------------------- 1.0.0.1/8 8.0. 1.0.0.0. 255.0.0.0 128.10.0.1/16 8.0. 128.10.0.0. 255.255.0.0 171.69.150.1/24 8.0. 171.69.150.0. 255.255.255.0 When the correct atmfSrvcRegParm1 values are located, the router may then establish an SVC to the selected server and perform the appropriate protocol operations. Rudundant MARS servers are supported with multiple rows in the service registry table. This list of MARS servers is ordered with the primary MARS server having the lowest index value. The MARS client must attempt to utilize the primary MARS server before utilizing a secondary MARS server. Adminstrators must ensure that the listed MARS servers are sychronized via (SCCP draft for MARS not yet available). 5. MARS Server Behavior An MARS server shall be locally configured. The MARS server may retreive the MARS service registry data to validate the results. If an incorrect row is retreived the error may be flagged in a locally significant way. 6. Relationship with PNNI Augmented Routing An augmented version PNNI ("PNNI Augmented Routing," or PAR) [4] is being developed by the ATM Forum. PAR could potentially distribute data such as MARS server addresses. Further, the ATM Forum developing a proxy mechanism for PAR (Proxy PAR) [5] that would allow a UNI- attached host or router to access PAR data without a full PAR Davison Expires January 10, 1998 [Page 4] Internet Draft July 10, 1997 implmentation. These mechanisms offer a promising way to manage the service registry tables maintained on each switch in an ATM network, yet would not require changes to the mechanism defined in this memo. Hosts and routers will continue to utilize ILMI-based server discovery and network administrators could manage the service registry data with local configuration or via PAR and Proxy PAR. 7. Security Considerations Security considerations are not discussed in this memo. Appendix - MARS Server Discovery MIB SERVER-DISCOVERY-MARS DEFINITIONS ::= BEGIN -- -- This OID names MARS within the context of server discovery. -- It does not name any managed objects. -- serverDiscoveryMARS OBJECT IDENTIFIER ::= END References [1] Armitage, G., "Support for Multicast over UNI 3.0/3.1 based ATM Networks," Bellcore, November, 1996. [2] ATM Forum, "Integrated Local Management Interface (ILMI) Specification Version 4.0," af-ilmi-0065.000, September, 1996. [3] Reynolds, J., Postel, J., "Assigned Numbers," IETF standard 2, October 1994. [4] Callon, R., et al., "An Overview of PNNI Augmented Routing," ATM-Forum 96-0354, April, 1996. [5] Przygienda, T., and Droz, P., "Proxy PAR," ATM-Forum 97-0495, July, 1997. Davison Expires January 10, 1998 [Page 5] Internet Draft July 10, 1997 Author's Address Mike Davison Cisco Systems 170 West Tasman Drive San Jose, California 95134 Phone: (408) 526-4000 EMail: mike.davison@cisco.com Davison Expires January 10, 1998 [Page 6]