IP over Cable Data Network (IPCDN) H. Abramson Internet Draft Motorola Document: June 1999 Category: Informational Docsis 1.1 IGMP MIB 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. Copyright (c) Society (1999). All Rights Reserved. 1. Abstract This memo defines a portion of the Management Information Base (MIB) for use with network management protocols in the Internet community. In particular, it defines a basic set of managed objects for SNMP-based management of DOCSIS 1.1 IGMPv2 compliant interfaces. This memo specifies a MIB module in a manner that is compliant to the SNMP SMIv2 [5][6][7]. The set of objects are consistent with the SNMP framework and existing SNMP standards. This memo is a product of the IPCDN working group within the Internet Engineering Task Force. Comments are solicited and should be addressed to the working groupÆs mailing list at ipcdn@terayon.com and/or the author. 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]. Abramson Informational - Expires December 1999 1 Docsis 1.1 IGMPv2 MIB June 1999 3. The SNMP Management Framework The SNMP Management Framework presently consists of five major components: oAn overall architecture, described in RFC 2271 [1]. o Mechanisms for describing and naming objects and events for the purpose of management. The first version of this Structure of Management Information (SMI) is called SMIv1 and described in RFC 1155 [2], RFC 1212 [3] and RFC 1215 [4]. The second version, called SMIv2, is described in RFC 1902 [5], RFC 1903 [6] and RFC 1904 [7]. o Message protocols for transferring management information. The first version of the SNMP message protocol is called SNMPv1 and described in RFC 1157 [8]. A second version of the SNMP message protocol, which is not an Internet standards track protocol, is called SNMPv2c and described in RFC 1901 [9] and RFC 1906 [10]. The third version of the message protocol is called SNMPv3 and described in RFC 1906 [10], RFC 2272 [11] and RFC 2274 [12]. o Protocol operations for accessing management information. The first set of protocol operations and associated PDU formats is described in RFC 1157 [8]. A second set of protocol operations and associated PDU formats is described in RFC 1905 [13]. o A set of fundamental applications described in RFC 2273 [14] and the view-based access control mechanism described in RFC 2275 [15]. Managed objects are accessed via a virtual information store, termed the Management Information Base or MIB. Objects in the MIB are defined using the mechanisms defined in the SMI. This memo specifies a MIB module that is compliant to the SMIv2. A MIB conforming to the SMIv1 can be produced through the appropriate translations. The resulting translated MIB must be semantically equivalent, except where objects or events are omitted because no translation is possible (use of Counter64). Some machine readable information in SMIv2 will be converted into textual descriptions in SMIv1 during the translation process. However, this loss of machine readable information is not considered to change the semantics of the MIB. 4. Glossary The following non-ietf terms, used in this document, are derived either from normal cable system usage, or from the documents associated with the Data Over Cable Service Interface Specification process. Abramson Informational - Expires December 1999 2 Docsis 1.1 IGMPv2 MIB June 1999 CATV - Originally 'Community Antenna Television', now used to refer to any cable or hybrid fiber and cable system used to deliver video signals to a community. CM, Cable Modem - A CM acts as a 'slave' station in a DOCSIS compliant cable data system. CMTS, Cable Modem Termination System - A generic term covering a cable bridge or cable router in a head-end. A CMTS acts as the master station in a DOCSIS compliant cable data system. It is the only station that transmits downstream, and it controls the scheduling of upstream transmissions by its associated CMs. CPE, Customer Premise Equipment, non-Cable Modem IP Hosts attached to the Cable Modem. DOCSIS - 'Data Over Cable Interface Specification'. A term referring to the ITU-T J.112 Annex B standard for cable modem systems. [20] Downstream - From the head-end towards the subscriber. Head-end - The origination point in most cable systems of the subscriber video signals. Generally also the location of the CMTS equipment. MAC Packet - A DOCSIS PDU. RF - Radio Frequency. Upstream - From the subscriber towards the head-end. 5. Overview The Docsis Multicast CM and CMTS interconnect specification can be modelled by æsplittingÆ the traditional Internet Group Management Protocol (IGMP), [ ], interfaces into Host and Querier side interfaces. That is, to provide basic Docsis 1.1 Multicast capabilities, all NSI-facing interfaces (NSI on the CMTS and HFC- side on CM) need only present an IGMP Host interface to the external multicast network. All CPE-facing interfaces (HFC-side on CMTS and CPE-side on CM) need only present a Querier interface to CPE. This is in comparison to a Multicast Router model where each interface has both Host and Querier capabilities. Although not strictly prohibited by the RFI, a more symmetrical model, where the root of a Multicast group may be on the HFC/CPE-side, is discouraged. Thus, Querying is almost always expected to be in the downstream direction (initiated by an NSI Querier or the CMTS itself) and Host Membership Reporting is expected to be in the upstream direction (from CPE or active IGMP CM devices). Either way, the IGMPv2 MIB provides an excellent and standard means for managing multicast within a Docsis network. Abramson Informational - Expires December 1999 3 Docsis 1.1 IGMPv2 MIB June 1999 This description categorizes Docsis 1.1 devices into two classes of IGMP awareness as defined by the Docsis 1.1 RFI specification. o Passive IGMP devices - this refers to CM and/or CMTS devices that derive their IGMP timers from other æupstreamÆ Multicast Querier devices. This may be from a Multicast Router on the NSI (for the CMTS and/or CM) or the CMTS (for CMs). These devices also rely on ædownstreamÆ devices to transmit Membership Reports (CPE for a CM; CPE and/or Active CMs for a CMTS) to initiate and maintain connectivity. o Active IGMP devices - this refers to CM and/or CMTS devices with an active IGMP Querier and Host interface. This may be a proxy agent or a device with multicast routing capabilities. Timers for passive devices must be considered the derived values that are being used at the time of the SNMP GET (e.g., read-only). Timers for active devices must be considered the values that may be managed within the device. 6. Structure of the MIB The following describes the application of the IGMPv2 MIB to Docsis 1.1 devices. This is organized into application of the IGMPv2 MIB to CM and CMTS interfaces. Note: an additional policy table has been included to cover group access rules desired in previous proposals for this MIB to the IPCDN. These are included for discussion. It is also feasible that this capability be handled using the Cable Device MIBÆs IP Filter table. 6.1 Cable Modem igmpInterface Table This is the (conceptual) table listing the interfaces on which IGMP is enabled. Unless otherwise specified all interface indexes are associated with a CPE Side Interface. The only exception is for the igmpInterfaceProxyIfIndex, as described below. igmpInterfaceTable Comments ================== =============================== igmpInterfaceEntry An entry exists for each CM CPE Side Interface that supports the IGMP MIB igmpInterfaceIfIndex Corresponds to CM CPE Side Interface for which IGMP Querying is enabled. Zero applies to all CM CPE side interfaces Abramson Informational - Expires December 1999 4 Docsis 1.1 IGMPv2 MIB June 1999 NOTE: this value is to be interpreted as follows. Passive operation: all timers represent derived values as defined in the Docsis 1.1 RFI. Active operation: these are the values that are used by the CMÆs CPE-Side Querier. igmpInterfaceQueryInterval Refer to the IGMP MIB. igmpInterfaceStatus The activation of a row enables IGMP on this interface. The destruction of a row disables IGMP on this interface. Note: existence of this row indicates that IGMP and multicast capabilities exist on the CM. Non-existence of this row indicates that a CM is a non-igmp aware bridge, and must rely on other Layer 2 or Layer 3 sercices to block unwanted multicasts. igmpInterfaceVersion Docsis Compliant devices must support IGMP Version 2 or higher. Refer to the IGMP MIB. igmpInterfaceQuerier Passive Operation: IP Address of Upstream Querier Active Operation: the IP Address used by the CM when querying CPE- side hosts. Note: see introduction on non- docsis devices as the multicast querier. igmpInterfaceQueryMaxResponseTime Refer to the IGMP MIB and RFI. igmpInterfaceVersion1QuerierTimer Refer to the IGMP MIB and RFI. Abramson Informational - Expires December 1999 5 Docsis 1.1 IGMPv2 MIB June 1999 igmpInterfaceWrongVersionQueries Refer to the IGMP MIB and RFI. igmpInterfaceJoins Refer to the IGMP MIB and RFI. igmpInterfaceGroups This is the current number of active Multicast Groups on this CM CPE Side interface. igmpInterfaceRobustness Refer to the IGMP MIB and RFI. igmpInterfaceProxyIfIndex Refer to the IGMP MIB and RFI. igmpInterfaceLastMemberQueryIntvl Refer to the IGMP MIB and RFI. igmpInterfaceProxyIfIndex Passive operation: n/a Active operation: if the CM is proxying for CPE on the HFC- side, this refers to the CMÆs RF HFC Side Interface(s) ifIndex. igmpInterfaceQuerierUpTime Refer to the IGMP MIB and RFI. igmpInterfaceQuerierExpiryTime Passive operation: n/a Active operation: in a typical implementation this object will be zero to indicate that this CM, system, is the querier. Note: see introduction on HFC- side or CPE devices as the multicast querier. 6.2 Cable Modem igmpCache Table Note: the number of IP Multicast Groups supported by this device is defined as the maximum size of this table (implementation specific). This is the (conceptual) table that lists the IP Multicast Groups for which there are CPE Side Multicast Host Members on a CMCI Side interface. igmpCacheTable Comments Abramson Informational - Expires December 1999 6 Docsis 1.1 IGMPv2 MIB June 1999 ================== =============================== ==================== igmpCacheEntry An entry exists for each IP Multicast Group for which this entry contains information on the CPE Side Interface. igmpCacheAddress Corresponds to the IP Multicast Group for which this entry contains information. igmpCacheIfIndex Corresponds to the CPE Side interface entry that corresponds to this Multicast group. igmpCacheSelf This value should always be FALSE for the CM, as it should not be considered an active member of any IP Multicast groups. igmpCacheLastReporter Refer to the IGMP MIB. igmpCacheUpTime This should correspond to the time since the Multicast Group first became active through the CM. igmpCacheExpiryTime Refer to the IGMP MIB. igmpCacheStatus Refer to the IGMP MIB. igmpCacheVersion1HostTimer Refer to the IGMP MIB. 6.3 Cable Modem Termination System igmpInterface Table This is the (conceptual) table listing the interfaces on which IGMP is enabled. Unless otherwise specified all interface indexes are associated with a CPE Side Interface (HFC-side for CMTS). The only exception is for the igmpInterfaceProxyIfIndex, as described below. All Querier interfaces apply to downstream, transmitter, interfaces (e.g., as opposed to upstream receiver interfaces). Host and/or Querier interfaces supported by the CMTS on the NSI-side must follow the standard IGMPv2 MIB definitions. Note: in most cases, these objects only apply to CPE-side interfaces, as described in the introduction, above. Abramson Informational - Expires December 1999 7 Docsis 1.1 IGMPv2 MIB June 1999 igmpInterfaceTable Comments ================== =============================== igmpInterfaceEntry An entry exists for each CMTS HFC-Side Downstream (TX) Interface that supports the IGMP MIB Note: CMTS devices that do not manage IGMP on a per- transmitter basis may have a single entry that applies to all transmitters. igmpInterfaceIfIndex Corresponds to CM CPE Side Interface for which IGMP Querying is enabled. Zero applies to all CMTS HFC- side TX interfaces NOTE: this value is to be interpreted as follows. Passive operation: all timers represent derived values as defined in the Docsis 1.1 RFI. Active operation: these are the values that are used by the CMTSÆs HFC-Side Querier. igmpInterfaceQueryInterval Refer to the IGMP MIB. igmpInterfaceStatus The activation of a row enables IGMP on this interface. The destruction of a row disables IGMP on this interface. Note: existence of this row indicates that IGMP and multicast capabilities exist on the CMTS. Non-existence of this row indicates that a CMTS is a non-igmp aware multicast bridge, and must rely on other Layer 2 or Layer 3 sercices to block unwanted multicasts. igmpInterfaceVersion Docsis Compliant devices must support IGMP Version 2 or higher. Refer to the IGMP MIB. Abramson Informational - Expires December 1999 8 Docsis 1.1 IGMPv2 MIB June 1999 igmpInterfaceQuerier Passive Operation: IP Address of NSI-side Querier Active Operation: the IP Address used by the CMTS when querying HFC/CPE-side hosts. Note: see introduction on HFC- side CPE devices as the multicast querier. igmpInterfaceQueryMaxResponseTime Refer to the IGMP MIB and RFI. igmpInterfaceVersion1QuerierTimer Refer to the IGMP MIB and RFI. igmpInterfaceWrongVersionQueries Refer to the IGMP MIB and RFI. igmpInterfaceJoins Refer to the IGMP MIB and RFI. igmpInterfaceGroups This is the current number of active Multicast Groups on this CM CPE Side interface. igmpInterfaceRobustness Refer to the IGMP MIB and RFI. igmpInterfaceProxyIfIndex Refer to the IGMP MIB and RFI. igmpInterfaceLastMemberQueryIntvl Refer to the IGMP MIB and RFI. igmpInterfaceProxyIfIndex Passive operation: n/a Active operation: if the CMTS is proxying for CPE (or CMÆs) on the HFC-side, this refers to the CMTSÆs NSI-Side Interface(s) ifIndex that is providing proxy host services for the HFC. igmpInterfaceQuerierUpTime Refer to the IGMP MIB and RFI. igmpInterfaceQuerierExpiryTime Passive operation: n/a Abramson Informational - Expires December 1999 9 Docsis 1.1 IGMPv2 MIB June 1999 Active operation: in a typical implementation this object will be zero to indicate that this CMTS, system, is the querier. Again, this applies to the HFC- side TX (not an NSI interface). Note: see introduction on non- docsis devices as the multicast querier. 6.4 Cable Modem Termination System igmpCache Table Note: the number of IP Multicast Groups supported by this device on a given transmitter, or set of transmitters, is defined as the maximum size of this table (implementation specific). This is the (conceptual) table that lists the IP Multicast Groups for which there are CPE Side Multicast Host Members on a CMCI Side interface. igmpCacheTable Comments ================== =============================== igmpCacheEntry An entry exists for each IP Multicast Group for which this entry contains information on the HFC/ CPE Side Interface. igmpCacheAddress Corresponds to the IP Multicast Group for which this entry contains information. igmpCacheIfIndex Corresponds to the HFC-side Tx interface entry that corresponds to this Multicast group. igmpCacheSelf This value should always be FALSE for the CMTS, as it should not be considered an active member of any IP Multicast groups. igmpCacheLastReporter Refer to the IGMP MIB. igmpCacheUpTime This should correspond to the time since the Multicast Group first became active through the CM. igmpCacheExpiryTime Refer to the IGMP MIB. Abramson Informational - Expires December 1999 10 Docsis 1.1 IGMPv2 MIB June 1999 igmpCacheStatus Refer to the IGMP MIB. igmpCacheVersion1HostTimer Refer to the IGMP MIB. 6.4 Session Access Control Cache Table This policy table has been included to cover group access rules desired in previous proposals of this MIB to the IPCDN. These are included for discussion. It is also feasible that this capability be handled using the Cable Device MIBÆs IP Filter table. -- -- The IGMP Cache Policy Table -- igmpCachePolicyTable OBJECT-TYPE SYNTAX SEQUENCE OF IgmpCachePolicyEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION The (conceptual) table listing group access rules for the IP multicast groups on a particular interface. ::= { igmp 2 } igmpCachePolicyEntry An entry exists for each IP Multicast Group for which this entry contains information on the CPE Side Interface. igmpCachePolicyAddress Corresponds to the IP Multicast Group for which this access rule applies. igmpCachePolicyIfIndex Corresponds to the CPE Side interface entry that corresponds to this Multicast group. igmpCachePolicyType OBJECT-TYPE SYNTAX ... MAX-ACCESS read-create STATUS (proposed) DESCRIPTION PermanentMember Indicates that the group referred to by this entry does not require a Membership Response to General Queries to maintain active Group status on this interface and that IGMP Host Proxying for this session shall be maintained, as applicable, on the igmpInterfaceProxyIfIndex. DownstreamOnly Indicates that the session may be active on this interface (e.g., joined), but no sending of multicast data for this session is permitted. Abramson Informational - Expires December 1999 11 Docsis 1.1 IGMPv2 MIB June 1999 UptreamOnly Indicates that data may only be transmitted upstream through this interface. Both Indicates that full multicast transmission and reception is permitted for this group through this interface. DEFVAL { ... } ::= {igmpCachePolicyType 9 } 7. Security Considerations This MIB relates to a system which will provide metropolitan public internet access to multicast services. As such, improper manipulation of the objects represented by this MIB may result in unauthorized access to these services. 9. References 1 To Be Added: Radio Frequency Interface Specification, MIBs, IGMPv2, IGMP MIB draft-09 10. Acknowledgments to be added (Paul Gray) 11. Author's Addresses Howard D. Abramson Motorola 20 Cabot Boulevard Mansfield, MA 02048 Phone: 508.261.5686> Email: h.abramson@motorola.com Full Copyright Statement Copyright (C) The Internet Society (date). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implmentation may be prepared, copied, published and distributed, in whole or in part, without restriction of any Abramson Informational - Expires December 1999 12 Docsis 1.1 IGMPv2 MIB June 1999 kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into Abramson Informational - Expires December 1999 13