Definitions of Managed Objects for Classical IP and ARP Over ATM Using SMIv2 (IPOA-MIB)
Extracted elements (30)
InATMARP retransmission timeout and retry count are not controlled by ipoaLisTable objects and are considered implementation-dependent; a timeout of 60 seconds with retry count of 3 is suggested for SVCs, while PVC retry limits may need to be infinite to ensure eventual processing.
Local textual conventions (IpoaAtmAddr, IpoaAtmConnKind, etc.) are defined within the IPOA-MIB with an 'Ipoa' prefix rather than being imported from ATM-TC-MIB. This was done so that the IPOA-MIB could be advanced as a standards-based MIB without waiting for the ATM-TC-MIB to be finalized.
The ipoaLisTable is indexed by ipoaLisSubnetAddr (subnet address) rather than ifIndex because the same LIS can be reached via different ATM interfaces; the ipoaLisIfMappingTable provides the separate interface-to-LIS mapping.
The ipoaVcTable does not augment the ipNetToMediaTable (ARP cache) because the correspondence between the two tables is not necessarily one-to-one; multiple VCs can correspond to a single ARP cache entry.
An ipAddrEntry's ipAdEntAddr ANDed with its ipAdEntNetMask SHOULD equal the corresponding ipoaLisEntry's ipoaLisSubnetAddr, establishing the linkage between the standard IP address table and the IPOA LIS table.
An ipNetToMediaPhysAddress object should contain content conforming to the IpoaAtmAddr textual convention when used to hold an IPOA-MIB ATM Address, enabling the standard ARP cache table to store ATM addresses.
Deleting an ipoaArpRemoteSrvrEntry (by setting RowStatus to destroy(6)) must invalidate any ipoaArpClientSrvrInUse objects that reference the removed server's ATM address by setting them to a zero-length OCTET STRING.
The IANA ifType ipOverAtm(114) was created for systems that require a virtual IP over ATM interface layer. Systems that use this ifType SHOULD use ifStackTable to show the relationship to underlying ATM physical interfaces.
All IP and ARP over ATM entities, both clients and ATMARP Servers, are REQUIRED to support the Basic Support MIB Definitions, which include the LIS Table, LIS Interface Mapping Table, ATMARP Remote Server Table, ATM VC Table, ATM Config PVC Table, and Notifications.
An ATMARP Server MUST support the following notifications: ipoaDuplicateIpAddress, ipoaLisCreate, and ipoaLisDelete.
ATMARP Servers MUST additionally support the ATMARP Server Table (ipoaArpSrvrTable) and associated Notifications beyond the Basic Support MIB Definitions.
Both ATM clients and ATMARP Servers MUST support generation of the ipoaMtuExceeded notification.
Both ends of a PVC MUST have the same MTU value configured (ipoaConfigPvcDefaultMtu), defaulting to 9180 octets.
Each ipoaArpClientEntry MUST point to an ATM interface via its corresponding ipAddrEntry; the ipAddrTable's ipAdEntIfIndex points to an ATM interface's ifIndex as the attachment point for IP into an ATM network.
If a PVC is intended to be used to communicate with a remote ATMARP Server, the ipoaConfigPvcTable MUST be used to create and activate the PVC prior to activating a ipoaArpRemoteSrvrEntry.
Support of RFC 1695 (ATM-MIB) is REQUIRED for implementing the layers between AAL5 and ATM. The IPOA-MIB assumes ATM-MIB modeling as a prerequisite.
The ATMARP Client Table (ipoaArpClientTable) is the only additional MIB table that a client MUST implement beyond the Basic Support MIB Definitions.
The IF-MIB's ifStackTable SHOULD be used to show the relationship between virtual IP over ATM interfaces and the actual ATM physical interface layers when the ipOverAtm(114) ifType is used.
The ipoaConfigPvcTable MUST be supported when PVCs are intended to be supported, in order to enable setup of PVCs for use by IP.
Four notifications are defined: ipoaMtuExceeded (frame exceeds negotiated MTU), ipoaDuplicateIpAddress (ATMARP Server detects conflicting IP-to-ATM mapping), ipoaLisCreate (LIS entry created), and ipoaLisDelete (LIS entry deleted).
ipoaArpClientTable tracks per-client ATMARP statistics including InATMARP and ATMARP request/reply counts, invalid request counts, NAK counts, unknown opcode counts, and server non-response counts; indexed by ipAdEntAddr.
ipoaArpRemoteSrvrTable locally configures remote ATMARP Servers on a per-LIS and per-interface basis, indexed by ipoaLisSubnetAddr, ipoaArpRemoteSrvrAtmAddr, and ipoaArpRemoteSrvrIfIndex. An ifIndex of 0 allows a single shared VC.
ipoaArpSrvrTable tracks ATMARP Server statistics including InATMARP and ATMARP request/reply counts, invalid requests, NAKs sent, duplicate IP address detections, and unknown opcode counts; indexed by ipAdEntAddr and ipoaArpSrvrAddr.
ipoaLisTable defines Logical IP Subnets of which the system is a member, indexed by ipoaLisSubnetAddr (IP subnet address). It holds ATMARP control parameters including inactivity timer, min holding time, queue depth, max calls, cache entry age, retries, timeout, default peak cell rate, and active VC count.
ipoaVcTable tracks Virtual Circuits (SVCs and PVCs) per ARP cache entry, indexed by ipNetToMediaIfIndex, ipNetToMediaNetAddress, ipoaVcVpi, and ipoaVcVci. Fields include VC type, negotiated encapsulation type, and negotiated MTU.
The IPOA-MIB MODULE-IDENTITY is assigned OID { transmission 46 }, establishing the root of the IPOA-MIB object tree under the transmission subtree.
The conformance module specifies that agents are not required to support SET operations on sensitive LIS configuration objects (MTU, encapsulation, timers, retries, peak cell rate, ATM addresses, admin status) in the absence of adequate security. This guards against unauthorized reconfiguration via SNMP.
IpoaAtmAddr is an OCTET STRING of size 0..40 encoding ATM addresses by length: no address (0 octets), E.164 (8 octets), NSAP (20 octets), and concatenated address+subaddress variants up to 40 octets. E.164 is encoded in BCD format.
IpoaAtmConnKind is an INTEGER distinguishing VC call-control types: pvc(1), svcIncoming(2), svcOutgoing(3), spvcInitiator(4), spvcTarget(5). An spvcInitiator is always cross-connected to an svcOutgoing, and an spvcTarget to an svcIncoming.
IpoaEncapsType is an INTEGER encoding the VC encapsulation type: llcSnap(1), vcMuxed(2), or other(3). Default for new VCs is llcSnap(1).