Definition of Managed Objects for the MANET Essential Connected Dominating Set (E-CDS) Process

This memo defines a portion of the Management Information Base (MIB) for use with network management protocols in the Internet community. In particular, it describes objects for configuring aspects of a process implementing the Essential-Connected Dominating Set (E-CDS) algorithm for Mobile Ad-Hoc Networks (MANETs). The E-CDS process transforms a 2-hop neighborhood topology information set for routers to dynamically perform relay self-election to form a Connected Dominating Set (CDS). The ECDS-MIB, an extension to the SMF-MIB , reports state information, performance metrics, and notifications. In addition to configuration, this additional state and performance information is useful to operators troubleshooting multicast forwarding problems.

For a detailed overview of the documents that describe the current Internet-Standard Management Framework, please refer to section 7 of . Managed objects are accessed via a virtual information store, termed the Management Information Base or MIB. MIB objects are generally accessed through the Simple Network Management Protocol (SNMP). Objects in the MIB are defined using the mechanisms defined in the Structure of Management Information (SMI). This memo specifies a MIB module that is compliant to the SMIv2, which is described in STD 58, , STD 58, and STD 58, .

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 .

The E-CDS algorithm provides method for implementing selection of Multipoint Relay nodes that define an estimate of the Minimum Connected Dominating Set (MCDS) flooding. The MCDS provides an efficient and complete coverage of the nodes comprising the MANET. The packet forwarding rules do not require knowledge of the previous hop. Routers that run Simplified Multicast Forwarding (SMF) and have E-CDS enabled can be mixed with routers that run SMF and Classic Flooding (CF) enabled without a problem, even when the CF nodes are not participating in the Neighborhood Discovery Protocol (NHDP) . Another benefit is that packets opportunistically received from non-symmetric neighbors may be forwarded without compromising flooding efficiency or correctness. Furthermore, multicast sources not participating in NHDP may freely inject their traffic and any neighboring E-CDS relays will properly forward the traffic. The E-CDS based relay set selection algorithm is defined in .

As mentioned in Overview Section, the ECDS-MIB is an extension to SMF-MIB. The SMF-MIB defines the management interfaces into the SMF process. The SMF process is a framework for efficient broadcast capabilities within a MANET. As part of the management interfaces, the SMF-MIB contains configuration objects required for the common management of all CDS processes. The SMF-MIB contains a capabilities table which lists the set of CDS algorithms supported by the specific router. However, the SMF-MIB does not define objects for configuration which are specific to the particular CDS process in question. Hence, it is required that additional MIB modules be defined for each new CDS process implemented on the router. In this sense, these additional MIB-modules extend the SMF-MIB.

| Selection | | | neighbor | Algorithm | |______________| info |_____________| \ / \ / neighbor\ /forwarding info* \ ____________ / status \ | | / `-->| Forwarding |<--' | Process | ~~~~~~~~~~~~~~~~>|____________|~~~~~~~~~~~~~~~~~> incoming packet, forwarded packets interface id*, and previous hop* Figure 1: SMF router Architecture. ]]> The various CDS algorithms are referred to as Relay Set Selection Algorithm (RSSA) within the SMF specification. The RSSAs can rely upon topology information gotten from the MANET NHDP, from the specific MANET routing protocol running on the node, or from Layer 2 information passed up to the higher layer protocol processes. In the ECDS process, nodes can select themselves as relays using a router identifier and a nodal metric known as "Router Priority" for all one-hop and two-hop neighbors. Changing the Router Priority can result in different realizations of CDSs for a given network topology.

The following definitions apply throughout this document: Control Objects - Objects which are initialized to default settings or set through the management interface defined by this MIB. State Objects - objects are automatically generated values which define the current operating state of the E-CDS process in the router. Performance Objects - objects are automatically generated values which help an administrator or automated tool to assess the performance of the CDS multicast process on the router and the overall multicasting performance within the MANET routing domain.

This section presents the structure of the ECDS-MIB module. The objects are arranged into the following groups: ecdsMIBNotifications - defines notifications that are associated with ECDS-MIB ecdsMIBObjects - defines objects as part of the structure of ECDS-MIB. These objects are divided as follows: Configuration Group - this group contains ECDS objects that configure specific options that determine the overall operation of ECDS process. State Group - this group contains ECDS objects that describe the state of the ECDS process. Performance Group - this groups contains ECDS objects that help operators to characterize the performance of the ECDS process as configured. ecdsMIBConformance - defines minimal and full conformance of the implementations of this ECDS-MIB module.

The textual conventions defined within the ECDS-MIB are as follows: EcdsStatus - is defined within the ECDS-MIB. This contains the current operational status of the E-CDS process on an interface.

The E-CDS device is configured with a set of controls. Some of the prominent configuration controls for the SMF E-CDS device follow: E-CDS Operational Mode (ecdsAdminStatus) - indicates that the router has E-CDS enabled. Router Identifier (ecdsRouterIDAddrType and ecdsRouterID) - indicates router's unique identifier in E-CDS neighborhood. Router Priority (ecdsConfiguredRouterPriority) - indicates nodal metric value for all one-hop and two-hop neighbors. Configuration method that computes Router Priority (ecdsConfiguredRtrPriMethod) - indicates what method the Router Priority is computed, i.e., dynamically configured, management configured, or other.

The state of an ECDS device can be retrieved from the following objects: E-CDS Configuration State (ecdsOperationStatus) - a state that indicates whether or not the ECDS process is enabled or disabled on the node. E-CDS Operational State (ecdsCurrentInEcds) - a state that indicates whether or not the node currently in or out of the Relay Set E-CDS Current Router Priority Value (ecdsCurrentRtRPriValue) - the Router Priority that is currently assigned to the device.

The E-CDS performance counters consist of per node objects: Counter of times the given node changed into or out of E-CDS (ecdsInEcdsChange). Counter of times the Router Priority has been changed (ecdsCurrentRtrPriValueChange).

The Notifications Sub-tree contains the list of notifications supported within the ECDS-MIB and their intended purpose or utility. These include: ecdsAdminStatusChange - this notification is sent when ecdsAdminStatus is changed. ecdsConfiguredMemberChange - this notification is sent when cdsConfiguredMember is changed. ecdsIfRtrPriChange - this notification is sent when ecdsIfRtrPri value is changed. ecdsRtrPriMethodChange - this notification is sent when ecdsConfiguredRtrPriMethod is changed.

The 'system' group in the SNMPv2-MIB is defined as being mandatory for all systems, and the objects apply to the entity as a whole. The 'system' group provides identification of the management entity and certain other system-wide data. The ECDS-MIB does not duplicate those objects.

This ECDS-MIB module is an extension of the SMF-MIB module in the sense previously discussed. To manage SMF router with ECDS-enabled, both SMF-MIB and ECDS-MIB implementations are required.

The textual conventions imported for use in the SMF-MIB are as follows: The MODULE-IDENTITY, OBJECT-TYPE, NOTIFICATION-TYPE, Counter32, Unsigned32, Integer32 and mib-2 textual conventions are imported from . The TEXTUAL-CONVENTION, RowStatus and TruthValue textual conventions are imported from . The MODULE-COMPLIANCE, OBJECT-GROUP and NOTIFICATION-GROUP textual conventions are imported from . The InetAddress, InetAddressType and InetAddressPrefixLength textual conventions are imported from .

This section discusses security implications of the choices made in this ECDS-MIB module. There are a number of management objects defined in this MIB module with MAX-ACCESS clause of read-write and/or read-create. Such objects maybe considered sensitive or vulnerable in some network environments. The support of SET operations in a non-secure environment without proper protection can have a negative effect on network operations. These are objects and their sensitivity/vulnerability: ecdsAdminStatus - this writable configuration object controls the operational status of the SMF ECDS process. If this setting is configured inconsistently across the MANET multicast domain, then the delivery of multicast data maybe also be inconsistent across the domain. ecdsRouterIDAddrType and ecdsRouterID - these writable configuration objects define the identifier (ID) of the SMF E-CDS process. These objects should be configured with a routable address defined on the local SMF E-CDS device. The ecdsRouterID is the logical identification that must be consistent across interoperating SMF E-CDS neighborhoods. The ecdsRouterID is recommended to be chosen as the numerically largest address contained in a node's 'Neighbor Address List' as defined in NHDP . ecdsConfiguredRtrPriMethod - this writable configuration object indicates how the value of Router Priority is computed. ecdsConfiguredRouterPriority - this writable configuration object indicates a nodal metric for all 1-hop and 2-hop neighbors. Relay routers use tuple of router identifier and router priority to compute self-election of MPR. ecdsConfiguredMember - this writable configuration object defines a set of forwarders for multicast forwarding. Sometimes, it is useful to force an agent to be included or excluded from the resulting CDS. This object is a switch to allow for this behavior. Mis-configuration of the object may cause the MANET flooding to break due to logical splits in the topology.

This document describes objects for configuring Essential Connected Dominating Set (E-CDS) process parameters on a router. This MIB module, denoted ECDS-MIB module, also reports state, performance information and notifications. Since it is an extension of SMF-MIB module, the same applicability examples can be found in SMF-MIB draft.

The MIB module in this document uses the following IANA-assigned OBJECT IDENTIFIER value recorded in the SMI Numbers registry:

This MIB document uses templates authored by D. Harrington which is based on contributions from the MIB Doctors, especially Juergen Schoenwaelder, Dave Perkins, C.M. Heard, and Randy Presuhn.

The authors would like to acknowledge the valuable comments from Ulrich Herberg in the early phases of the development of this MIB-module. Further, the authors would like to acknowledge to work of Brian Little and Ryan Morgan on their software development of the ECDS-MIB.

This section tracks the revision history in the development of this ECDS-MIB. It will be removed from the final version of this document. These changes were made from draft-nguyen-manet-ecds-mib-01 to draft-nguyen-manet-ecds-mib-02: Added references, applicability statement, security considerations, IANA considerations, acknowledgment. Added ecdsRouterIDAddrType object to go along with ecdsRouterID These changes were made from draft-nguyen-manet-ecds-mib-00 to draft-nguyen-manet-ecds-mib-01: Initial draft

This section contains the set of open issues related to the development and design of the ECDS-MIB. This section will not be present in the final version of the MIB and will be removed once all the open issues have been resolved. Does this MIB module need to include the MDR Level as a state object? Within the Security Section, we need to include a discussion of the problems caused by mis-configuring the ecdsRouterID, the ecdsConfigured RtrPriMethod, and the ecdsConfiguredRouterPriority objects. Once the SMF-MIB module is published, the references to the RFC must be updated. A careful review by the working group.

*************************************************************** * Note to the RFC Editor (to be removed prior to publication) * * * * 1) The reference to RFCXXXX within the DESCRIPTION clauses * * of the MIB module point to this draft and are to be * * assigned by the RFC Editor. * * * ***************************************************************