📄 rfc2320.txt
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3.1.3. ATMARP Remote Server Table
Entries in the ipoaArpRemoteSrvrTable exists to locally configure the
remote ATMARP Servers that exist on a per LIS and interface basis.
Classical IP and ARP over ATM [3] requires that at least one ATMARP
Server be configured per LIS where SVC traffic is intended. PVC usage
doesn't require use of ATMARP. No ipoaArpRemoteSrvrTable entries
SHOULD be configured for a LIS where only PVCs will be used. An entry
in the ipoaArpRemoteSrvrTable is indexed by the subnet address of the
LIS (ipoaLisSubnetAddr), the ATM address of the remote ATMARP Server
(ipoaArpRemoteSrvrAtmAddr) and an interface ifIndex
(ipoaArpRemoteSrvrIfIndex) value.
The object ipoaArpRemoteSrvrIpAddr in an ipoaArpRemoteSrvrEntry is set
with the IP Address of the Remote ATMARP Server when a VC to the
Remote ATMARP Server is established. A value of 0.0.0.0 SHOULD be
used when the IP address of the Remote ATMARP Server is not known.
Once ipoaArpRemoteSrvrIpAddr is set then the ipoaVcTable can be
searched using ipoaArpRemoteSrvrIfIndex and ipoaArpRemoteSrvrIpAddr to
find the VC in use to the Remote ATMARP Server.
ipoaArpRemoteSrvrIfIndex is defined to have the textual convention of
InterfaceIndexOrZero. Adding ipoaArpRemoteSrvrIfIndex to the index
clause allows a system to have a VC to a ATMARP Remote Server on a per
LIS and interface basis. An entry in this table SHOULD exist for each
interface on a per LIS basis. Each interface would then have a
separate VC to the Remote ATMARP Server for ATMARP purposes.
An implementation that wants to use a single VC MAY use an
ipoaArpRemoteSrvrIfIndex value of 0 when configuring an
ipoaArpRemoteSrvrEntry for the associating LIS. If
ipoaArpRemoteSrvrIfIndex is 0 then an implementation dependent method
MAY be used for finding the VPI and VCI of the VC in use to the Remote
ATMARP Server. For example, search the ipoaVcTable for a match
between ipNetToMediaNetAddress and ipoaArpRemoteSrvrIpAddr from an
ipoaArpRemoteSrvrEntry, ignoring ipNetToMediaIfIndex. Since a single
VC is being used the first match SHOULD correspond to the correct VC.
Greene, et al. [Page 7]
RFC 2320 IP and ARP over ATM (IPOA) MIB April 1998
If a PVC is intended to be used to communicate with a remote ATMARP
Server then the ipoaConfigPvcTable MUST be used to create and activate
the PVC prior to activating a ipoaArpRemoteSrvrEntry.
The object ipoaArpRemoteSrvrRowStatus allows for row creation and
deletion of entries in the ipoaArpRemoteSrvrTable. The objects
ipoaArpRemoteSrvrAdminStatus and ipoaArpRemoteSrvrOperStatus exist to
control and reflect the operational use of a Remote ATMARP Server
defined by an ipoaArpRemoteSrvrEntry. The object
ipoaArpRemoteSrvrOperStatus SHOULD have a value of up(1) when an SVC
has been established to the Remote ATMARP Server or if using a PVC
when the InATMARP reply with the IP Address of the Remote ATMARP
Server has been received. The value of down(2) SHOULD be used to
indicate that a VC to the Remote ATMARP Server doesn't exist.
3.1.4. ATM VC Table
An entry in the ipoaVcTable SHOULD have at least one corresponding
ipNetToMediaTable entry. Both tables use the ipNetToMediaTable's
indexes ipNetToMediaIfIndex and ipNetToMediaNetAddress. The
ipoaVcTable has the additional indexes ipoaVcVpi and ipoaVcVci. An
ipoaVcEntry exists for every VC per ATM interface per destination IP
address. Refer to the following diagram that illustrates the
relationship between ipoaVcTable and the ipNetToMediaTable:
ipoaVcTable ipNetToMediatable
------------------------------ ----------------------------
| ipNetToMediaIfIndex | | ipNetToMediaIfIndex |
| ipNetToMediaNetAddress | | ipNetToMediaNetAddress |
| ipoaVcVpi | | |
| ipoaVcVci | | |
| ipoaVcType | | |
| ---> use IpoaAtmAddr TC | | ipNetToMediaPhysAddress |
| ipoaVcNegotiatedEncapsType | | |
| ipoaVcNegotiatedMtu | | |
| | | ipNetToMediaType |
------------------------------ ----------------------------
ipoaVcType indicates if the entry is for an SVC or a PVC. An
ipoaVcEntry, corresponding to an PVC, is created automatically when an
ipoaConfigPvcEntry is created and the IP Address at the end of the PVC
is discovered. The associating ipNetToMediaTable entry would have its
ipNetToMediaType set to static(4). ipNetToMediaTable entries created
during ATMARP processing have a ipNetToMediaType of dynamic(3). The
process to locally configuring an ipNetToMediaTable entry and an
ipoaVcTable entry for an SVC without using ATMARP is not within the
scope of this document.
Greene, et al. [Page 8]
RFC 2320 IP and ARP over ATM (IPOA) MIB April 1998
The objects ipoaVcVpi and ipoaVcVci are defined to have a MAX-ACCESS
of not-accessible since they are only used for purposes of indexing an
entry in the ipoaVcTable.
3.1.5. ATM Config PVC Table
An entry in the ipoaVcTable is created after the InATMARP reply is
successfully received for an ipoaConfigPvcEntry during its activation.
InATMARP should return the IP Address of the other end of the PVC in
order to have the needed indexes to create an ipNetToMediaEntry and an
ipoaVcEntry.
The corresponding ARP Cache entry SHOULD be deleted whenever a PVC
becomes unusable.
A Network Management Station wanting to create a PVC at a particular
system for use as an IP transport would:
o use the ATM-MIB, reference [4], to create the PVC
o use the ipoaConfigPvcTable in the IPOA-MIB to configure
the PVC for use by IP
Refer to the following diagram that illustrates the relationship
between the ipoaVcTable and the ipoaConfigPvcTable:
ipoaVcTable ipoaConfigPvcTable
------------------------------ ----------------------------
| ipNetToMediaIfIndex | | ipNetToMediaIfIndex |
| ipNetToMediaNetAddress | | |
| ipoaVcVpi | | ipoaConfigPvcVpi |
| ipoaVcVci | | ipoaConfigPvcVci |
| ipoaVcType | | |
| | | ipoaConfigPvcDefaultMtu |
| ipoaVcNegotiatedEncapsType | | |
| ipoaVcNegotiatedMtu | | |
| | | ipoaConfigPvcRowStatus |
------------------------------ ----------------------------
When the ipoaVcEntry is created its ipoaVcType will be set to pvc(1),
its ipoaVcNegotiatedEncapsType set to llcSnap(1), and its
ipoaVcNegotiatedMtu set to 9180 octets by default. Classical IP and
ARP over ATM [3] allows use of other MTU values for PVCs but considers
the selection of a value other than 9180 to be out of scope.
ipoaConfigPvcDefaultMtu can be used to configure the MTU to be used
for the PVC. Both ends MUST have the same value configured. The
associating ipNetToMediaTable entry would have its ipNetToMediaType
set to static(4).
Greene, et al. [Page 9]
RFC 2320 IP and ARP over ATM (IPOA) MIB April 1998
Changing ipoaConfigPvcRowStatus from active(1) to notInService(2) or
from active(1) to destroy(6) has the side-effect of removing the
corresponding ipNetToMediaTable, ipoaVcTable, and ipoaConfigPvcTable
entries.
3.1.6. Notifications
Both ATM clients and ATMARP Servers MUST support generation of an
ipoaMtuExceeded notification.
3.2. Client Supported MIB Definitions
The ATMARP Client Table is the only additional MIB table that a client
MUST implement.
Greene, et al. [Page 10]
RFC 2320 IP and ARP over ATM (IPOA) MIB April 1998
3.2.1. ATMARP Client Table
An entry in the ipoaArpClientTable SHOULD have a corresponding
ipAddrTable entry where both are indexed by the same ipAdEntAddr
value. Refer to the following diagram that illustrates the
relationship between ipoaArpClientTable and ipAddrTable entries:
ipoaArpClientTable ipAddrTable
----------------------------------- ------------------------
| ipAdEntAddr | | ipAdEntAddr |
| | | ipAdEntNetMask |
| | | ipAdEntIfIndex |
| ipoaArpClientAtmAddr | | |
| ipoaArpClientSrvrInUse | | |
| ipoaArpClientInArpInReqs | | |
| ipoaArpClientInArpOutReqs | | |
| ipoaArpClientInArpInReplies | | |
| ipoaArpClientInArpOutReplies | | |
| ipoaArpClientInArpInvalidInReqs | | |
| ipoaArpClientInArpInvalidOutReqs| | |
| ipoaArpClientArpInReqs | | |
| ipoaArpClientArpOutReqs | | |
| ipoaArpClientArpInReplies | | |
| ipoaArpClientArpOutReplies | | |
| ipoaArpClientArpInNaks | | |
| ipoaArpClientArpOutNaks | | |
| ipoaArpClientArpUnknownOps | | |
| ipoaArpClientArpNoSrvrResps | | |
| ipoaArpClientRowStatus | | |
| | | ipAdEntBcastAddr |
| | | ipAdEntReasmMaxSize |
----------------------------------- ------------------------
Both tables have the same index, ipAdEntAddr. The ipAddrTable's
ipAdEntNetMask when ANDed with its corresponding ipAdEntAddr yield the
subnet of the LIS which can be used as an index into the ipoaLisTable
(ipoaLisSubnetAddr). The ipAddrTable's ipAdEntIfIndex points to an
interface ifTable entry via an ifIndex value. The attachment point
for IP into an ATM network is via an ATM interface's ifIndex. Each
ipoaArpClientEntry MUST point to an ATM interface via its
corresponding ipAddrEntry.
ipoaArpClientAtmAddr is the local ATM address associated with the
corresponding ATM ifTable entry. ipoaArpClientSrvrInUse is the ATM
address of the ATMARP Server being used for a particular client. If
SVCs are not being used then the value of this object is a zero-length
OCTET STRING.
Greene, et al. [Page 11]
RFC 2320 IP and ARP over ATM (IPOA) MIB April 1998
It is sometimes possible for a system to have multiple IP addresses
configured within the same IP subnet. The indexing of this table
would seem to preclude that. However, it is possible to have
additional entries in the ipAddrTable with the same ifIndex and with
the same subnet address. The mechanism for adding these multiple
entries to the ipAddrTable (which is read-only) is beyond the scope of
this document.
The counter object ipoaArpClientInArpInvalidInReqs is "The number of
times that this client detected an invalid InATMARP request." This
object SHOULD be incremented when processing fails for an InATMARP
request (e.g., for incorrect InATMARP request structure fields). The
object ipoaArpClientInArpInvalidOutReqs is defined as "The number of
times that this client did not receive an InATMARP reply." This is
different from ipoaArpClientArpNoSrvrResps which counts the number of
times no response was received from an ATMARP request.
InATMARP retransmission processing is not controlled by objects in the
ipoaLisTable. In general, the ipoaLisTable objects relate to ATMARP
Server processing. Configuration of InATMARP retransmission
processing is considered to be implementation dependent and not
defined by the IPOA-MIB.
Implementations SHOULD use local policy for defining both InATMARP
timeout and retry count values. This policy would be expected to
differ for sending an InATMARP Request over a PVC as opposed to an
SVC. For transmission of an InATMARP Request over a SVC a timeout of
60 seconds with a retry count of 3 is suggested. InATMARP
transmission over a PVC should differ since its retry limit may need
to be infinite in order to ensure that InATMARP Request processing
eventually occurs.
3.3. Server Supported MIB Definitions
ATMARP Servers MUST support:
o ATMARP Server Table
o Notifications
as defined in the following sections. This table exists only on a
system where at least one ATMARP Server is present.
3.3.1. ATMARP Server Table
This table defines the list of ATMARP Servers within a LIS. Each
entry of the table defines each ATMARP Server's ATM address, the LIS
it is a member of, and various InATMARP and ATMARP statistics.
Greene, et al. [Page 12]
RFC 2320 IP and ARP over ATM (IPOA) MIB April 1998
An entry in this table provides information about an ATMARP Server
within a LIS and is indexed by ipAdEntAddr (a local IP Address from an
IP Address Table entry) and ipoaArpSrvrAddr (an ATM Address associated
with the ATMARP Server).
Entries MAY be created by a management application using the
ipoaArpSrvrRowStatus object. Entries in this table MAY also be
created by the system and not by a management application, for example
via ILMI.
Entries in this table MAY be deleted by setting the
ipoaArpSrvrRowStatus object to destroy(6). This includes entries that
were added by the system and not by a management application.
On a host that supports multiple ATMARP Servers where the local IP
address being associated with each ATMARP Server is the same (for
example a non-multihomed host), the ATM Address (ipoaArpSrvrAddr)
uniquely identifies a particular ATMARP Server. On a host supporting
multiple ATMARP Servers having a single ATM Interface with a single
ATM Address, the ipAdEntAddr MUST be used to uniquely identify an
entry in the ipoaArpSrvrTable.
The indexing of the ipoaArpSrvrTable does not allow entries with the
same or no local IP Address (ipAdEntAddr) and the same ATM Address
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