Frame Relay DTE MIB: Management Information Base for Frame Relay DTEs Using SMIv2
The SNMP objects a router or host uses to report on its Frame Relay link, its virtual circuits and their errors.
Brown, C. and F. Baker, "Management Information Base for Frame Relay DTEs Using SMIv2", RFC 2115, DOI 10.17487/RFC2115, September 1997, <https://www.rfc-editor.org/info/rfc2115>.
@misc{rfc2115,
series = {Request for Comments},
number = 2115,
howpublished = {RFC 2115},
publisher = {RFC Editor},
doi = {10.17487/RFC2115},
url = {https://www.rfc-editor.org/info/rfc2115},
author = {C. Brown and F. Baker},
title = {{Management Information Base for Frame Relay DTEs Using SMIv2}},
pagetotal = 32,
year = 1997,
month = sep,
} RFC text
Contents
Network Working Group C. Brown
Request for Comments: 2115 Cadia Networks, Inc.
Obsoletes: 1315 F. Baker
Category: Standards Track Cisco Systems
September 1997
Management Information Base for Frame Relay DTEs
Using SMIv2
1. Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
2. Abstract
This memo defines a portion of the Management Information Base (MIB)
for use with network management protocols in TCP/IP- based internets.
In particular, it defines objects for managing Frame Relay interfaces
on DTEs.
Table of Contents
1 Status of this Memo ................................... 1
2 Abstract .............................................. 1
3 The SNMPv2 Network Management Framework ............... 2
4 Overview .............................................. 2
4.1 Frame Relay Operational Model ....................... 2
4.2 Textual Conventions ................................. 6
4.3 Structure of MIB .................................... 6
5 Changes from RFC 1315 ................................. 6
6 Definitions ........................................... 8
6.1 Data Link Connection Management Interface ........... 9
6.2 Circuit Table ....................................... 14
6.3 Error Table ......................................... 22
6.4 Trap Management ..................................... 25
7 Security Issues ....................................... 30
8 Acknowledgments ....................................... 30
9 Authors' Addresses .................................... 31
10 References ........................................... 31
3. The SNMPv2 Network Management Framework
The major components of the SNMPv2 Network Management framework are
described in the documents listed below.
o RFC 1902 [1] defines the Structure of Management
Information (SMI), the mechanisms used for describing and
naming objects for the purpose of management.
o STD 17, RFC 1213 [2] defines MIB-II, the core set of
managed objects (MO) for the Internet suite of protocols.
o RFC 1905 [3] defines the protocol used for network access
to managed objects.
The framework is adaptable/extensible by defining new MIBs to suit
the requirements of specific applications/protocols/situations.
Managed objects are accessed via a virtual information store, the
MIB. Objects in the MIB are defined using the subset of Abstract
Syntax Notation One (ASN.1) defined in the SMI. In particular, each
object type is named by an OBJECT IDENTIFIER, which is an
administratively assigned name. The object type together with an
object instance serves to uniquely identify a specific instantiation
of the object. For human convenience, often a textual string, termed
the descriptor, is used to refer to the object type.
4. Overview
4.1. Frame Relay Operational Model
For the purposes of understanding this document, Frame Relay is
viewed as a multi-access media, not as a group of point- to-point
connections. This model proposes that Frame Relay is a single
interface to the network (physical connection) with many destinations
or neighbors (virtual connections). This view enables a network
manager the ability to group all virtual connections with their
corresponding physical connection thereby allowing simpler
diagnostics and trouble shooting.
With the extension of the interfaces MIB, it is possible to configure
frame relay DLCs as individual interfaces and create ifTable entries
for each. This is not recommended and is not directly supported by
this MIB. Additionally, in the presence of demand circuits creation
of individual ifEntries for each is not possible.
Should the user wish to group DLCs together to associate them with a
higher layer, or to associate a DLC with an unnumbered point-to-point
service, the frame relay DTE MIB provides an entry in the
frCircuitEntry record. For example, suppose one were to configure a
company proprietary protocol to run above several of the frame relay
VCs. The basic layering would look something like the following:
IP (ipaddrEntry 1 ) IP (ipaddrEntry 2) IP (ipaddrEntry 3)
| | |
| | |
| | proprietary protocol
| | layer (ifIndex 3)
| | |
| | |
DLCI 20 DLCI 30 DLCI 40/41/42
(ifIndex 2) (ifIndex 2) (ifIndex 2,
logical ifIndex 3)
| | |
| | |
|____________________|_____________________|
|
|
FR DLMCI (ifIndex.2)
|
|
Physical Interface (ifIndex.1)
A configuration which specified that DLCI 40, 41,and 42 were associated
with a proprietary protocol layer, while DLCI 20 and 30 were to run IP
directly can now be expressed using a combination of frCircuitIfIndex
and frCircuitLogicalIfIndex. In this particular case DLCIs 40, 41 and
42 would use frCircuitIfIndex equal to the frame relay interface level
(2) while their frCircuitLogicalIfIndex would indicate the proprietary
protocol (3). DLCIs 20 and 30 would have both instances set to the frame
relay interface (2).
Object Meaning for Frame Relay Interface
______ _____________________________________
ifDescr As per DESCRIPTION in RFC 1573.
ifType The value allocated for Frame Relay
Interfaces - frameRelay (32).
ifMtu Set to maximum frame size in octets for
this frame relay interface.
ifSpeed The access rate for the frame relay
interface. This could be different from
the speed of the underlying physical
interface, e.g. in a fractional T1 case
the access rate could be 384 kbits/s (the
value reported in this object) whereas the
speed of the underlying interface would be
1.544 Mbits/s (the value reported in the
instance of ifSpeed for the ifEntry with
type ds1).
ifPhysAddress The primary address for this interface
assigned by the Frame Relay interface
provider. An octet string of zero length
if no address is used for this interface.
ifAdminStatus As per DESCRIPTION in RFC 1573.
ifOperStatus As per DESCRIPTION in RFC 1573.
ifLastChange As per DESCRIPTION in RFC 1573.
ifInOctets The number of received octets. This
includes not only the information field
(user data) but also the frame relay header
and CRC.
ifInUcastPkts The number of frames received on non-
multicast DLCIs
ifInDiscards The number of frames that were successfully
received but were discarded because of
format errors or because the VC was not
known. Format errors, in this case, are
any errors which would prevent the system
from recognizing the DLCI and placing the
error in the frCircuitDiscard category.
ifInErrors The number of received frames that are
discarded, because of an error.
Possible errors can be the following: the
frame relay frames were too long or were
too short, the frames had an invalid or
unrecognized DLCI values, or incorrect
header values.
ifInUnknownProtos Number of unknown or unsupported
upper layer protocol frames received
and discarded.
ifOutOctets The number of received octets. This
includes not only the information field
(user data) but also the frame relay header
and CRC.
ifOutUcastpkts The number of frames sent.
ifOutDiscards The number of frames discarded in the
transmit direction.
ifOutErrors The number of frames discarded in the
egress direction, because of errors.
ifName As per DESCRIPTION in RFC 1573.
ifInMulticastPkts The number of unerrored frames received
on a multicast DLCI.
ifInBroadcastPkts Always zero (0) as there are no broadcast
frames.
ifOutMulticastPkts The number of frames transmitted over a
multicast DLCI.
ifOutBroadcastPkts Always zero (0) as there are no broadcast
frames.
ifHCInOctets Only required when ifSpeed >= 155 Mbits/s.
See
details for ifInOctets.
ifHCOutOctets Only required when ifSpeed >= 155 Mbits/s.
See
details for ifInOctets.
ifLinkUpDownTrapEnble As per DESCRIPTION in RFC 1573.
ifHighSpeed The access rate of the frame relay interface
measured in Mbits/s. If the access rate is
less than 1 Mbits/s, this object returns 0.
ifPromiscuousMode Set to false(2).
ifConnectorPresent Set to false(2).
4.2. Textual Conventions
One new data type is introduced as a textual convention in this MIB
document. This textual convention enhances the readability of the
specification and can ease comparison with other specifications if
appropriate. It should be noted that the introduction of this
textual conventions has no effect on either the syntax nor the
semantics of any managed objects. The use of this is merely an
artifact of the explanatory method used. Objects defined in terms of
one of these methods are always encoded by means of the rules that
define the primitive type. Hence, no changes to the SMI or the SNMP
are necessary to accommodate this textual conventions which is
adopted merely for the convenience of readers and writers in pursuit
of the elusive goal of clear, concise, and unambiguous MIB documents.
The new data type is DLCI. DLCI refers to the range 0..DLCINumber,
and is used to refer to the valid Data Link Connection Indices.
DLCINumber is, by definition, the largest possible DLCI value
possible under the configured Q.922 Address Format.
4.3. Structure of MIB
The MIB is composed of three groups, one defining the Data Link
Connection Management Interface (DLCMI), one describing the Circuits,
and a third describing errors.
During normal operation, Frame Relay virtual circuits will be added,
deleted and change availability. The occurrence of such changes is of
interest to the network manager and therefore, one trap is defined,
intended to be corollary to the SNMP "Link Up" and "Link Down" traps.
5. Changes from RFC 1315
Below are listed the changes from the previously published version
this document, which was RFC 1315:
o The MIB module was converted from SMIv1 to SMIv2 format.
Note: due to this, the table indices have access of
"read-only" instead of "not-accessible", which is the
typical value for index objects in SMIv2.
o The module name was changed from RFC1315-MIB to FRAME-
RELAY-DTE-MIB.
o The textual convention "Index" was dropped from the MIB
module and "InterfaceIndex" from the interfaces MIB
module, IF-MIB, was used in its place.
o Objects frDlcmiStatus and frDlcmiRowStatus were added to
table frDlcmiTable.
o Added values "itut933A(5)" (from CCITT Q933 Annex A) and
"ansiT1617D1994(6)" (from ANSI T1.617a-1994 Annex D) to
the enumerations for object frDlcmiState.
o The labels for the enumerated values for object
frDlcmiAddressLen were renamed to remove their hyphens as
required by SMIv2.
o Added clarification that the "management virtual circuit"
(i.e. DLCI 0) is a member of the circuit table.
o Added the following objects to table frCircuitTable:
frCircuitMulticast, frCircuitType, frCircuitDiscards,
frCircuitReceivedDEs, frCircuitSentDEs,
frCircuitLogicalIfIndex, and frCircuitRowStatus.
o The definition of object frCircuitReceivedOctets was
clarified as to which octets were counted.
o Added the objects frErrFaults and frErrFaultTime to table
frErrTable.
o Added clarification to the values of object frErrType.
o Added size on definition of object frErrData and
clarified what data to capture.
o Changed identififier for OID value { frameDelayDTE 4 }
from frame-relay-globals to frameRelayTrapControl.
o Added object frTrapMaxRate.
o Created object groups frPortGroup, frCircuitGroup,
frTrapGroup, frErrGroup, frPortGroup0, frCircuitGroup0,
frTrapGroup0, and frErrGroup0.
o Created notification group frNotificationGroup.
o Created module compliances frCompliance and
frCompliance0.
o Added ranges to objects frCircuitCommittedBurst,
frCircuitExcessBurst, and frCircuitThroughput.
6. Definitions
FRAME-RELAY-DTE-MIB DEFINITIONS ::= BEGIN
IMPORTS
MODULE-IDENTITY, OBJECT-TYPE, Counter32,
Integer32, NOTIFICATION-TYPE FROM SNMPv2-SMI
TEXTUAL-CONVENTION, RowStatus, TimeStamp FROM SNMPv2-TC
MODULE-COMPLIANCE, OBJECT-GROUP,
NOTIFICATION-GROUP FROM SNMPv2-CONF
transmission FROM RFC1213-MIB
InterfaceIndex FROM IF-MIB;
-- Frame Relay DTE MIB
frameRelayDTE MODULE-IDENTITY
LAST-UPDATED "9705010229Z" -- Thu May 1 02:29:46 PDT 1997
ORGANIZATION "IETF IPLPDN Working Group"
CONTACT-INFO
" Caralyn Brown
Postal: Cadia Networks, Inc.
1 Corporate Drive
Andover, Massachusetts 01810
Tel: +1 508 689 2400 x133
E-Mail: cbrown@cadia.com
Fred Baker
Postal: Cisco Systems
519 Lado Drive
Santa Barbara, California 93111
Tel: +1 408 526 425
E-Mail: fred@cisco.com"
DESCRIPTION
"The MIB module to describe the use of a Frame Relay
interface by a DTE."
REVISION "9705010229Z" -- Thu May 1 02:29:46 PDT 1997
DESCRIPTION
"Converted from SMIv1 to SMIv2. (Thus, indices are
read-only rather than being not-accessible.) Added
objects and made clarifications based on implementation
experience."
REVISION "9204010000Z"
DESCRIPTION
"Published as RFC 1315, the initial version of this MIB
module."
::= { transmission 32 }
--
-- the range of a Data Link Connection Identifier
--
DLCI ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"The range of DLCI values. Note that this varies by
interface configuration; normally, interfaces may use
0..1023, but may be configured to use ranges as large
as 0..2^23."
SYNTAX Integer32(0..8388607)
--
-- Data Link Connection Management Interface
-- The variables that configure the DLC Management Interface.
frDlcmiTable OBJECT-TYPE
SYNTAX SEQUENCE OF FrDlcmiEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The Parameters for the Data Link Connection Management
Interface for the frame relay service on this
interface."
REFERENCE
"American National Standard T1.617-1991, Annex D"
::= { frameRelayDTE 1 }
frDlcmiEntry OBJECT-TYPE
SYNTAX FrDlcmiEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The Parameters for a particular Data Link Connection
Management Interface."
INDEX { frDlcmiIfIndex }
::= { frDlcmiTable 1 }
FrDlcmiEntry ::=
SEQUENCE {
frDlcmiIfIndex InterfaceIndex,
frDlcmiState INTEGER,
frDlcmiAddress INTEGER,
frDlcmiAddressLen INTEGER,
frDlcmiPollingInterval Integer32,
frDlcmiFullEnquiryInterval Integer32,
frDlcmiErrorThreshold Integer32,
frDlcmiMonitoredEvents Integer32,
frDlcmiMaxSupportedVCs DLCI,
frDlcmiMulticast INTEGER,
frDlcmiStatus INTEGER,
frDlcmiRowStatus RowStatus
}
frDlcmiIfIndex OBJECT-TYPE
SYNTAX InterfaceIndex
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The ifIndex value of the corresponding ifEntry."
::= { frDlcmiEntry 1 }
frDlcmiState OBJECT-TYPE
SYNTAX INTEGER {
noLmiConfigured (1),
lmiRev1 (2),
ansiT1617D (3), -- ANSI T1.617 Annex D
ansiT1617B (4), -- ANSI T1.617 Annex B
itut933A (5), -- CCITT Q933 Annex A
ansiT1617D1994 (6) -- ANSI T1.617a-1994 Annex D
}
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"This variable states which Data Link Connection
Management scheme is active (and by implication, what
DLCI it uses) on the Frame Relay interface."
REFERENCE
"American National Standard T1.617-1991, American
National Standard T1.617a-1994, ITU-T Recommendation
Q.933 (03/93)."
::= { frDlcmiEntry 2 }
frDlcmiAddress OBJECT-TYPE
SYNTAX INTEGER {
q921 (1), -- 13 bit DLCI
q922March90 (2), -- 11 bit DLCI
q922November90 (3), -- 10 bit DLCI
q922 (4) -- Final Standard
}
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"This variable states which address format is in use on
the Frame Relay interface."
::= { frDlcmiEntry 3 }
frDlcmiAddressLen OBJECT-TYPE
SYNTAX INTEGER {
twoOctets (2),
threeOctets (3),
fourOctets (4)
}
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"This variable states the address length in octets. In
the case of Q922 format, the length indicates the
entire length of the address including the control
portion."
::= { frDlcmiEntry 4 }
frDlcmiPollingInterval OBJECT-TYPE
SYNTAX Integer32 (5..30)
UNITS "seconds"
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"This is the number of seconds between successive
status enquiry messages."
REFERENCE
"American National Standard T1.617-1991, Section D.7
Timer T391."
DEFVAL { 10 }
::= { frDlcmiEntry 5 }
frDlcmiFullEnquiryInterval OBJECT-TYPE
SYNTAX Integer32 (1..255)
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"Number of status enquiry intervals that pass before
issuance of a full status enquiry message."
REFERENCE
"American National Standard T1.617-1991, Section D.7
Counter N391."
DEFVAL { 6 }
::= { frDlcmiEntry 6 }
frDlcmiErrorThreshold OBJECT-TYPE
SYNTAX Integer32 (1..10)
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"This is the maximum number of unanswered Status
Enquiries the equipment shall accept before declaring
the interface down."
REFERENCE
"American National Standard T1.617-1991, Section D.5.1
Counter N392."
DEFVAL { 3 }
::= { frDlcmiEntry 7 }
frDlcmiMonitoredEvents OBJECT-TYPE
SYNTAX Integer32 (1..10)
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"This is the number of status polling intervals over
which the error threshold is counted. For example, if
within 'MonitoredEvents' number of events the station
receives 'ErrorThreshold' number of errors, the
interface is marked as down."
REFERENCE
"American National Standard T1.617-1991, Section D.5.2
Counter N393."
DEFVAL { 4 }
::= { frDlcmiEntry 8 }
frDlcmiMaxSupportedVCs OBJECT-TYPE
SYNTAX DLCI
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The maximum number of Virtual Circuits allowed for
this interface. Usually dictated by the Frame Relay
network.
In response to a SET, if a value less than zero or
higher than the agent's maximal capability is
configured, the agent should respond badValue"
::= { frDlcmiEntry 9 }
frDlcmiMulticast OBJECT-TYPE
SYNTAX INTEGER {
nonBroadcast (1),
broadcast (2)
}
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"This indicates whether the Frame Relay interface is
using a multicast service."
::= { frDlcmiEntry 10 }
frDlcmiStatus OBJECT-TYPE
SYNTAX INTEGER {
running (1), -- init complete, system running
fault (2), -- error threshold exceeded
initializing (3) -- system start up
}
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"This indicates the status of the Frame Relay interface
as determined by the performance of the dlcmi. If no
dlcmi is running, the Frame Relay interface will stay
in the running state indefinitely."
::= { frDlcmiEntry 11 }
frDlcmiRowStatus OBJECT-TYPE
SYNTAX RowStatus
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"SNMP Version 2 Row Status Variable. Writable objects
in the table may be written in any RowStatus state."
::= { frDlcmiEntry 12 }
--
-- A Frame Relay service is a multiplexing service. Data
-- Link Connection Identifiers enumerate virtual circuits
-- (permanent or dynamic) which are layered onto the underlying
-- circuit, represented by ifEntry. Therefore, each of the entries
-- in the Standard MIB's Interface Table with an IfType of
-- Frame Relay represents a Q.922 interface. Zero or more
-- virtual circuits are layered onto this interface and provide
-- interconnection with various remote destinations.
-- Each such virtual circuit is represented by an entry in the
-- circuit table. The management virtual circuit (i.e. DLCI 0)
-- is a virtual circuit by this definition and will be represented
-- with an entry in the circuit table.
-- Circuit Table
-- The table describing the use of the DLCIs attached to
-- each Frame Relay Interface.
frCircuitTable OBJECT-TYPE
SYNTAX SEQUENCE OF FrCircuitEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A table containing information about specific Data
Link Connections (DLC) or virtual circuits."
::= { frameRelayDTE 2 }
frCircuitEntry OBJECT-TYPE
SYNTAX FrCircuitEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The information regarding a single Data Link
Connection. Discontinuities in the counters contained
in this table are indicated by the value in
frCircuitCreationTime."
INDEX { frCircuitIfIndex, frCircuitDlci }
::= { frCircuitTable 1 }
FrCircuitEntry ::=
SEQUENCE {
frCircuitIfIndex InterfaceIndex,
frCircuitDlci DLCI,
frCircuitState INTEGER,
frCircuitReceivedFECNs Counter32,
frCircuitReceivedBECNs Counter32,
frCircuitSentFrames Counter32,
frCircuitSentOctets Counter32,
frCircuitReceivedFrames Counter32,
frCircuitReceivedOctets Counter32,
frCircuitCreationTime TimeStamp,
frCircuitLastTimeChange TimeStamp,
frCircuitCommittedBurst Integer32,
frCircuitExcessBurst Integer32,
frCircuitThroughput Integer32,
frCircuitMulticast INTEGER,
frCircuitType INTEGER,
frCircuitDiscards Counter32,
frCircuitReceivedDEs Counter32,
frCircuitSentDEs Counter32,
frCircuitLogicalIfIndex InterfaceIndex,
frCircuitRowStatus RowStatus
}
frCircuitIfIndex OBJECT-TYPE
SYNTAX InterfaceIndex
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The ifIndex Value of the ifEntry this virtual circuit
is layered onto."
::= { frCircuitEntry 1 }
frCircuitDlci OBJECT-TYPE
SYNTAX DLCI
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The Data Link Connection Identifier for this virtual
circuit."
REFERENCE
"American National Standard T1.618-1991, Section 3.3.6"
::= { frCircuitEntry 2 }
frCircuitState OBJECT-TYPE
SYNTAX INTEGER {
invalid (1),
active (2),
inactive (3)
}
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"Indicates whether the particular virtual circuit is
operational. In the absence of a Data Link Connection
Management Interface, virtual circuit entries (rows)
may be created by setting virtual circuit state to
'active', or deleted by changing Circuit state to
'invalid'.
Whether or not the row actually disappears is left to
the implementation, so this object may actually read as
'invalid' for some arbitrary length of time. It is
also legal to set the state of a virtual circuit to
'inactive' to temporarily disable a given circuit.
The use of 'invalid' is deprecated in this SNMP Version
2 MIB, in favor of frCircuitRowStatus."
DEFVAL { active }
::= { frCircuitEntry 3 }
frCircuitReceivedFECNs OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"Number of frames received from the network indicating
forward congestion since the virtual circuit was
created. This occurs when the remote DTE sets the FECN
flag, or when a switch in the network enqueues the
frame to a trunk whose transmission queue is
congested."
REFERENCE
"American National Standard T1.618-1991, Section 3.3.3"
::= { frCircuitEntry 4 }
frCircuitReceivedBECNs OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"Number of frames received from the network indicating
backward congestion since the virtual circuit was
created. This occurs when the remote DTE sets the BECN
flag, or when a switch in the network receives the
frame from a trunk whose transmission queue is
congested."
REFERENCE
"American National Standard T1.618-1991, Section 3.3.4"
::= { frCircuitEntry 5 }
frCircuitSentFrames OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of frames sent from this virtual circuit
since it was created."
::= { frCircuitEntry 6 }
frCircuitSentOctets OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of octets sent from this virtual circuit
since it was created. Octets counted are the full
frame relay header and the payload, but do not include
the flag characters or CRC."
::= { frCircuitEntry 7 }
frCircuitReceivedFrames OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"Number of frames received over this virtual circuit
since it was created."
::= { frCircuitEntry 8 }
frCircuitReceivedOctets OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"Number of octets received over this virtual circuit
since it was created. Octets counted include the full
frame relay header, but do not include the flag
characters or the CRC."
::= { frCircuitEntry 9 }
frCircuitCreationTime OBJECT-TYPE
SYNTAX TimeStamp
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The value of sysUpTime when the virtual circuit was
created, whether by the Data Link Connection Management
Interface or by a SetRequest."
::= { frCircuitEntry 10 }
frCircuitLastTimeChange OBJECT-TYPE
SYNTAX TimeStamp
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The value of sysUpTime when last there was a change in
the virtual circuit state"
::= { frCircuitEntry 11 }
frCircuitCommittedBurst OBJECT-TYPE
SYNTAX Integer32(0..2147483647)
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"This variable indicates the maximum amount of data, in
bits, that the network agrees to transfer under normal
conditions, during the measurement interval."
REFERENCE
"American National Standard T1.617-1991, Section
6.5.19"
DEFVAL { 0 } -- the default indicates no commitment
::= { frCircuitEntry 12 }
frCircuitExcessBurst OBJECT-TYPE
SYNTAX Integer32(0..2147483647)
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"This variable indicates the maximum amount of
uncommitted data bits that the network will attempt to
deliver over the measurement interval.
By default, if not configured when creating the entry,
the Excess Information Burst Size is set to the value
of ifSpeed."
REFERENCE
"American National Standard T1.617-1991, Section
6.5.19"
::= { frCircuitEntry 13 }
frCircuitThroughput OBJECT-TYPE
SYNTAX Integer32(0..2147483647)
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"Throughput is the average number of 'Frame Relay
Information Field' bits transferred per second across a
user network interface in one direction, measured over
the measurement interval.
If the configured committed burst rate and throughput
are both non-zero, the measurement interval, T, is
T=frCircuitCommittedBurst/frCircuitThroughput.
If the configured committed burst rate and throughput
are both zero, the measurement interval, T, is
T=frCircuitExcessBurst/ifSpeed."
REFERENCE
"American National Standard T1.617-1991, Section
6.5.19"
DEFVAL {0} -- the default value of Throughput is
-- "no commitment".
::= { frCircuitEntry 14 }
frCircuitMulticast OBJECT-TYPE
SYNTAX INTEGER {
unicast (1),
oneWay (2),
twoWay (3),
nWay (4)
}
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"This indicates whether this VC is used as a unicast VC
(i.e. not multicast) or the type of multicast service
subscribed to"
REFERENCE
"Frame Relay PVC Multicast Service and Protocol
Description Implementation: FRF.7 Frame Relay Forum
Technical Committe October 21, 1994"
DEFVAL {unicast}
-- the default value of frCircuitMulticast is
-- "unicast" (not a multicast VC).
::= { frCircuitEntry 15 }
frCircuitType OBJECT-TYPE
SYNTAX INTEGER {
static (1),
dynamic (2)
}
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"Indication of whether the VC was manually created
(static), or dynamically created (dynamic) via the data
link control management interface."
::= { frCircuitEntry 16 }
frCircuitDiscards OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of inbound frames dropped because of format
errors, or because the VC is inactive."
::= { frCircuitEntry 17 }
frCircuitReceivedDEs OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"Number of frames received from the network indicating
that they were eligible for discard since the virtual
circuit was created. This occurs when the remote DTE
sets the DE flag, or when in remote DTE's switch
detects that the frame was received as Excess Burst
data."
REFERENCE
"American National Standard T1.618-1991, Section 3.3.4"
::= { frCircuitEntry 18 }
frCircuitSentDEs OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"Number of frames sent to the network indicating that
they were eligible for discard since the virtual
circuit was created. This occurs when the local DTE
sets the DE flag, indicating that during Network
congestion situations those frames should be discarded
in preference of other frames sent without the DE bit
set."
REFERENCE
"American National Standard T1.618-1991, Section
3.3.4"
::= { frCircuitEntry 19 }
frCircuitLogicalIfIndex OBJECT-TYPE
SYNTAX InterfaceIndex
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"Normally the same value as frDlcmiIfIndex, but
different when an implementation associates a virtual
ifEntry with a DLC or set of DLCs in order to associate
higher layer objects such as the ipAddrEntry with a
subset of the virtual circuits on a Frame Relay
interface. The type of such ifEntries is defined by the
higher layer object; for example, if PPP/Frame Relay is
implemented, the ifType of this ifEntry would be PPP.
If it is not so defined, as would be the case with an
ipAddrEntry, it should be of type Other."
::= { frCircuitEntry 20 }
frCircuitRowStatus OBJECT-TYPE
SYNTAX RowStatus
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"This object is used to create a new row or modify or
destroy an existing row in the manner described in the
definition of the RowStatus textual convention.
Writable objects in the table may be written in any
RowStatus state."
::= { frCircuitEntry 21 }
--
-- Error Table
-- The table describing errors encountered on each Frame
-- Relay Interface.
frErrTable OBJECT-TYPE
SYNTAX SEQUENCE OF FrErrEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A table containing information about Errors on the
Frame Relay interface. Discontinuities in the counters
contained in this table are the same as apply to the
ifEntry associated with the Interface."
::= { frameRelayDTE 3 }
frErrEntry OBJECT-TYPE
SYNTAX FrErrEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The error information for a single frame relay
interface."
INDEX { frErrIfIndex }
::= { frErrTable 1 }
FrErrEntry ::=
SEQUENCE {
frErrIfIndex InterfaceIndex,
frErrType INTEGER,
frErrData OCTET STRING,
frErrTime TimeStamp,
frErrFaults Counter32,
frErrFaultTime TimeStamp
}
frErrIfIndex OBJECT-TYPE
SYNTAX InterfaceIndex
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The ifIndex Value of the corresponding ifEntry."
::= { frErrEntry 1 }
frErrType OBJECT-TYPE
SYNTAX INTEGER {
unknownError(1),
receiveShort(2),
receiveLong(3),
illegalAddress(4),
unknownAddress(5),
dlcmiProtoErr(6),
dlcmiUnknownIE(7),
dlcmiSequenceErr(8),
dlcmiUnknownRpt(9),
noErrorSinceReset(10)
}
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The type of error that was last seen on this interface:
receiveShort: frame was not long enough to allow
demultiplexing - the address field was incomplete,
or for virtual circuits using Multiprotocol over
Frame Relay, the protocol identifier was missing
or incomplete.
receiveLong: frame exceeded maximum length configured for this
interface.
illegalAddress: address field did not match configured format.
unknownAddress: frame received on a virtual circuit which was not
active or administratively disabled.
dlcmiProtoErr: unspecified error occurred when attempting to
interpret link maintenance frame.
dlcmiUnknownIE: link maintenance frame contained an Information
Element type which is not valid for the
configured link maintenance protocol.
dlcmiSequenceErr: link maintenance frame contained a sequence
number other than the expected value.
dlcmiUnknownRpt: link maintenance frame contained a Report Type
Information Element whose value was not valid
for the configured link maintenance protocol.
noErrorSinceReset: no errors have been detected since the last
cold start or warm start."
::= { frErrEntry 2 }
frErrData OBJECT-TYPE
SYNTAX OCTET STRING (SIZE(1..1600))
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"An octet string containing as much of the error packet
as possible. As a minimum, it must contain the Q.922
Address or as much as was delivered. It is desirable
to include all header and demultiplexing information."
::= { frErrEntry 3 }
frErrTime OBJECT-TYPE
SYNTAX TimeStamp
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The value of sysUpTime at which the error was
detected."
::= { frErrEntry 4 }
frErrFaults OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of times the interface has gone down since
it was initialized."
::= { frErrEntry 5 }
frErrFaultTime OBJECT-TYPE
SYNTAX TimeStamp
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The value of sysUpTime at the time when the interface
was taken down due to excessive errors. Excessive
errors is defined as the time when a DLCMI exceeds the
frDlcmiErrorThreshold number of errors within
frDlcmiMonitoredEvents. See FrDlcmiEntry for further
details."
::= { frErrEntry 6 }
--
-- Frame Relay Trap Control
frameRelayTrapControl OBJECT IDENTIFIER ::= { frameRelayDTE 4 }
-- the following highly unusual OID is as it is for compatibility
-- with RFC 1315, the SNMP V1 predecessor of this document.
frameRelayTraps OBJECT IDENTIFIER ::= { frameRelayDTE 0 }
frTrapState OBJECT-TYPE
SYNTAX INTEGER { enabled(1), disabled(2) }
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"This variable indicates whether the system produces
the frDLCIStatusChange trap."
DEFVAL { disabled }
::= { frameRelayTrapControl 1 }
frTrapMaxRate OBJECT-TYPE
SYNTAX Integer32 (0..3600000)
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"This variable indicates the number of milliseconds
that must elapse between trap emissions. If events
occur more rapidly, the impementation may simply fail
to trap, or may queue traps until an appropriate time."
DEFVAL { 0 } -- no minimum elapsed period is specified
::= { frameRelayTrapControl 2 }
-- Data Link Connection Management Interface Related Traps
frDLCIStatusChange NOTIFICATION-TYPE
OBJECTS { frCircuitState }
STATUS current
DESCRIPTION
"This trap indicates that the indicated Virtual Circuit
has changed state. It has either been created or
invalidated, or has toggled between the active and
inactive states. If, however, the reason for the state
change is due to the DLCMI going down, per-DLCI traps
should not be generated."
::= { frameRelayTraps 1 }
-- conformance information
frConformance OBJECT IDENTIFIER ::= { frameRelayDTE 6 }
frGroups OBJECT IDENTIFIER ::= { frConformance 1 }
frCompliances OBJECT IDENTIFIER ::= { frConformance 2 }
-- compliance statements
frCompliance MODULE-COMPLIANCE
STATUS current
DESCRIPTION
"The compliance statement "
MODULE -- this module
MANDATORY-GROUPS { frPortGroup, frCircuitGroup }
GROUP frErrGroup
DESCRIPTION
"This optional group is used for debugging Frame Relay
Systems."
GROUP frTrapGroup
DESCRIPTION
"This optional group is used for the management of
asynchronous notifications by Frame Relay Systems."
GROUP frNotificationGroup
DESCRIPTION
"This optional group defines the asynchronous
notifications generated by Frame Relay Systems."
OBJECT frDlcmiRowStatus
MIN-ACCESS read-only
DESCRIPTION
"Row creation is not required for the frDlcmiTable."
OBJECT frCircuitRowStatus
MIN-ACCESS read-only
DESCRIPTION
"Row creation is not required for the frCircuitTable."
::= { frCompliances 1 }
frCompliance0 MODULE-COMPLIANCE
STATUS current
DESCRIPTION
"The compliance statement for objects and the trap
defined in RFC 1315."
MODULE -- this module
MANDATORY-GROUPS { frPortGroup0, frCircuitGroup0 }
GROUP frErrGroup0
DESCRIPTION
"This optional group is used for debugging Frame Relay
Systems."
GROUP frTrapGroup0
DESCRIPTION
"This optional group is used for the management of
asynchronous notifications by Frame Relay Systems."
GROUP frNotificationGroup
DESCRIPTION
"This optional group defines the asynchronous
notifications generated by Frame Relay Systems."
::= { frCompliances 2 }
-- units of conformance
frPortGroup OBJECT-GROUP
OBJECTS {
frDlcmiIfIndex, frDlcmiState, frDlcmiAddress,
frDlcmiAddressLen, frDlcmiPollingInterval,
frDlcmiFullEnquiryInterval, frDlcmiErrorThreshold,
frDlcmiMonitoredEvents, frDlcmiMaxSupportedVCs,
frDlcmiMulticast, frDlcmiStatus, frDlcmiRowStatus
}
STATUS current
DESCRIPTION
"The objects necessary to control the Link Management
Interface for a Frame Relay Interface as well as
maintain the error statistics on this interface."
::= { frGroups 1 }
frCircuitGroup OBJECT-GROUP
OBJECTS {
frCircuitIfIndex, frCircuitDlci, frCircuitState,
frCircuitReceivedFECNs, frCircuitReceivedBECNs,
frCircuitSentFrames, frCircuitSentOctets,
frCircuitReceivedFrames, frCircuitReceivedOctets,
frCircuitCreationTime, frCircuitLastTimeChange,
frCircuitCommittedBurst, frCircuitExcessBurst,
frCircuitThroughput, frCircuitMulticast,
frCircuitType, frCircuitDiscards,
frCircuitReceivedDEs, frCircuitSentDEs,
frCircuitLogicalIfIndex, frCircuitRowStatus
}
STATUS current
DESCRIPTION
"The objects necessary to control the Virtual Circuits
layered onto a Frame Relay Interface."
::= { frGroups 2 }
frTrapGroup OBJECT-GROUP
OBJECTS { frTrapState, frTrapMaxRate }
STATUS current
DESCRIPTION
"The objects necessary to control a Frame Relay
Interface's notification messages."
::= { frGroups 3 }
frErrGroup OBJECT-GROUP
OBJECTS {
frErrIfIndex, frErrType, frErrData, frErrTime,
frErrFaults, frErrFaultTime
}
STATUS current
DESCRIPTION
"Objects designed to assist in debugging Frame Relay
Interfaces."
::= { frGroups 4 }
frNotificationGroup NOTIFICATION-GROUP
NOTIFICATIONS { frDLCIStatusChange }
STATUS current
DESCRIPTION
"Traps which may be used to enhance event driven
management of the interface."
::= { frGroups 5 }
frPortGroup0 OBJECT-GROUP
OBJECTS {
frDlcmiIfIndex, frDlcmiState, frDlcmiAddress,
frDlcmiAddressLen, frDlcmiPollingInterval,
frDlcmiFullEnquiryInterval, frDlcmiErrorThreshold,
frDlcmiMonitoredEvents, frDlcmiMaxSupportedVCs,
frDlcmiMulticast
}
STATUS current
DESCRIPTION
"The objects necessary to control the Link Management
Interface for a Frame Relay Interface as well as
maintain the error statistics on this interface from
RFC 1315."
::= { frGroups 6 }
frCircuitGroup0 OBJECT-GROUP
OBJECTS {
frCircuitIfIndex, frCircuitDlci, frCircuitState,
frCircuitReceivedFECNs, frCircuitReceivedBECNs,
frCircuitSentFrames, frCircuitSentOctets,
frCircuitReceivedFrames, frCircuitReceivedOctets,
frCircuitCreationTime, frCircuitLastTimeChange,
frCircuitCommittedBurst, frCircuitExcessBurst,
frCircuitThroughput
}
STATUS current
DESCRIPTION
"The objects necessary to control the Virtual Circuits
layered onto a Frame Relay Interface from RFC 1315."
::= { frGroups 7 }
frErrGroup0 OBJECT-GROUP
OBJECTS {
frErrIfIndex, frErrType, frErrData, frErrTime
}
STATUS current
DESCRIPTION
"Objects designed to assist in debugging Frame Relay
Interfaces from RFC 1315."
::= { frGroups 8 }
frTrapGroup0 OBJECT-GROUP
OBJECTS { frTrapState }
STATUS current
DESCRIPTION
"The objects necessary to control a Frame Relay
Interface's notification messages from RFC 1315."
::= { frGroups 9 }
END
7. Security Issues
Security issues for this MIB are entirely covered by the SNMP
Security Architecture, and have not been expanded within the contents
of this MIB.
8. Acknowledgments
This document was originally produced by the IP Over Large Public
Data Networks (IPLPDN) Working Group, and has since been carried on
in the PPP Working Group, sort of. Currently, the Ion Working Group
is its host.
Special thanks to James Watt of Newbridge Networks for his fine
suggestions and pastable text.
9. Authors' Addresses
Caralyn Brown
Cadia Networks, Inc.
1 Corporate Dirve
Andover, Massachusetts 01810
Telephone: +1 508 689 2400 x133
E-Mail: cbrown@cadia.com
Fred Baker
Cisco Systems
519 Lado Drive
Santa Barbara, California 93111
Telephone +1 408 526 4257
E-Mail: fred@cisco.com
10. References
[1] SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M.,
and S. Waldbusser, "Structure of Management Information
for Version 2 of the Simple Network Management Protocol
(SNMPv2)", RFC 1902, January 1996.
[2] McCloghrie, K., and M. Rose, Editors, "Management
Information Base for Network Management of TCP/IP-based
internets: MIB-II", STD 17, RFC 1213, Hughes LAN Systems,
Performance Systems International, March 1991.
[3] Case, J., Fedor, M., Schoffstall, M., and J. Davin. " A
Simple Network Management Protocol (SNMP)", STD 15, RFC
1157, SNMP Research, Performance Systems International,
MIT Lab for Computer Science, May 1990.
[4] SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M.,
and S. Waldbusser, "Protocol Operations for Version 2 of
the Simple Network Management Protocol (SNMPv2)", RFC
1905, January 1996.
[5] McCloghrie, K. and F. Kastenholz, "Evolution of the
Interfaces Group of MIB-II", RFC 1573, Hughes LAN
Systems, FTP Software, January 1994.
[6] T. Bradley, C. Brown, A. Malis, "Multiprotocol
Interconnect over Frame Relay", RFC 1490, 07/26/1993.
[7] International Telegraph and Telephone Consultative
Committee, "ISDN Data Link Layer Specification for Frame
Mode Bearer Services", CCITT Recommendation Q.922, 19
April 1991.
[8] American National Standard For Telecommunications -
Integrated Services Digital Network - Frame Relay Bearer
Service - Architectural Framework and Service
Description, ANSI T1.606-1991, 18 June 1991.
[9] American National Standard For Telecommunications -
Integrated Services Digital Network - Digital Subscriber
Signalling System No. 1 - Signaling Specification for
Frame Relay Bearer Service, ANSI T1.617-1991, 18 June
1991.
[10] American National Standard For Telecommunications -
Integrated Services Digital Network - Core Aspects of
Frame Protocol for Use with Frame Relay Bearer Service,
ANSI T1.618-1991, 18 June 1991.
ISO Plain Language
On this page
§3The SNMPv2 Framework and What This MIB Adds
The SNMPv2 network management framework has a few major components. RFC 1902 defines the Structure of Management Information, the mechanisms used for describing and naming objects for the purpose of management. STD 17, RFC 1213, defines MIB-II, the core set of managed objects for the Internet suite of protocols. RFC 1905 defines the protocol used for network access to managed objects. The framework is adaptable and extensible by defining new MIBs to suit the requirements of specific applications, protocols or situations.
Managed objects are accessed through a virtual information store, the MIB. Objects in the MIB are defined using the subset of Abstract Syntax Notation One (ASN.1) defined in the SMI, and each object type is named by an OBJECT IDENTIFIER, an administratively assigned name. The object type together with an object instance serves to uniquely identify a specific instantiation of the object, and for human convenience a textual string, termed the descriptor, is often used to refer to the object type.
This memo defines a portion of the MIB for use with network management protocols in TCP/IP-based internets, in particular objects for managing Frame Relay interfaces on Data Terminal Equipments (DTEs). The module is named FRAME-RELAY-DTE-MIB and sits at { transmission 32 } in the MIB-II tree.
SNMP managers read and write named objects, and a MIB is the catalogue of what those objects mean. This document adds the entries that describe a Frame Relay interface.
- frameRelayDTE (transmission 32)
- frDlcmiTable Link management parameters
- frCircuitTable One row per virtual circuit
- frErrTable Errors seen on each interface
- frameRelayTrapControl Trap enable and rate
§4.1Frame Relay as One Multi-Access Interface
For the purposes of this document, Frame Relay is viewed as a multi-access medium, not as a group of point-to-point connections. The model proposes that Frame Relay is a single interface to the network, the physical connection, with many destinations or neighbours, the virtual connections. This view lets a network manager group all the virtual connections with their physical connection, which allows simpler diagnostics and troubleshooting.
With the extension of the interfaces MIB it is possible to configure Frame Relay Data Link Connection Identifiers (DLCIs) as individual interfaces and create ifTable entries for each. The RFC says this is not recommended and is not directly supported by this MIB, and that in the presence of demand circuits it is not possible at all.
Where a user wants to group DLCIs together to associate them with a higher layer, or to associate a DLC with an unnumbered point-to-point service, the MIB provides two columns in the circuit table for it: frCircuitIfIndex, which is the interface the virtual circuit is layered onto, and frCircuitLogicalIfIndex, which points at the higher layer. The RFC's example runs a proprietary protocol over DLCIs 40, 41 and 42 and IP directly over DLCIs 20 and 30: the three DLCIs use the Frame Relay interface level for frCircuitIfIndex and the proprietary protocol for frCircuitLogicalIfIndex, while DLCIs 20 and 30 set both to the Frame Relay interface.
The RFC also lists how the standard interface objects are filled in for a Frame Relay interface. ifType takes the value allocated for Frame Relay interfaces, frameRelay (32). ifSpeed is the access rate for the Frame Relay interface, which can differ from the speed of the underlying physical interface: in a fractional T1 case the access rate could be 384 kbits/s while the underlying interface reports 1.544 Mbits/s. ifPhysAddress holds the primary address assigned by the Frame Relay interface provider, or a zero-length octet string if the interface has no address. ifInOctets and ifOutOctets count the information field, the user data, as well as the Frame Relay header and the CRC. ifInBroadcastPkts and ifOutBroadcastPkts are always zero, because there are no broadcast frames. ifHCInOctets and ifHCOutOctets are only required when ifSpeed is at least 155 Mbits/s, and ifHighSpeed returns 0 when the access rate is below 1 Mbits/s.
Frame Relay is one physical link carrying many virtual circuits, and the RFC asks managers to treat it that way, so that all the circuits on a link can be looked at together. Two columns in the circuit table say which interface each circuit sits on and which higher layer runs over it.
- ifTypeThe value allocated for Frame Relay interfaces: frameRelay (32).
- ifSpeedThe access rate of the Frame Relay interface, which can differ from the speed of the physical interface underneath it.
- Octet countersifInOctets and ifOutOctets count the user data, the Frame Relay header and the CRC.
- Broadcast countersifInBroadcastPkts and ifOutBroadcastPkts are always zero, because there are no broadcast frames.
- ifHCInOctets and ifHCOutOctetsOnly required when ifSpeed is at least 155 Mbits/s.
- ifHighSpeedThe access rate in Mbits/s, returning 0 when the rate is below 1 Mbits/s.
§6.1The Data Link Connection Management Interface
The MIB is composed of three groups: one defining the Data Link Connection Management Interface (DLCMI), one describing the circuits, and a third describing errors. The DLCMI group holds the parameters that configure the link management itself, and it references the American National Standard T1.617-1991, Annex D.
Each row of frDlcmiTable describes one DLCMI and is indexed by frDlcmiIfIndex. The row carries frDlcmiState, which states which Data Link Connection Management scheme is active and by implication what DLCI it uses, with values noLmiConfigured, lmiRev1, ansiT1617D for ANSI T1.617 Annex D, ansiT1617B for Annex B, itut933A for CCITT Q.933 Annex A, and ansiT1617D1994 for ANSI T1.617a-1994 Annex D. frDlcmiAddress states which address format is in use: q921 with a 13 bit DLCI, q922March90 with an 11 bit DLCI, q922November90 with a 10 bit DLCI, or q922, the final standard. frDlcmiAddressLen gives the address length in octets, two, three or four, and for the Q.922 format the length covers the entire address including the control portion.
The rest of the row holds the timing and limit parameters: frDlcmiPollingInterval, frDlcmiFullEnquiryInterval, frDlcmiErrorThreshold, frDlcmiMonitoredEvents and frDlcmiMaxSupportedVCs, the largest number of virtual circuits supported, which is expressed with the DLCI type. The row also carries frDlcmiMulticast, frDlcmiStatus and frDlcmiRowStatus.
The DLCI type is one new textual convention introduced by this MIB. It refers to the range 0 to DLCINumber, where DLCINumber is by definition the largest possible DLCI value under the configured Q.922 address format. The MIB notes that interfaces may normally use 0 to 1023 but may be configured to use ranges as large as 0 to 2^23, and gives the type as Integer32(0..8388607). Introducing the textual convention has no effect on the syntax or the semantics of any managed object: objects defined in terms of it are always encoded by the rules that define the primitive type, so no change to the SMI or to SNMP is needed.
The link management part of the MIB says which management scheme the interface uses, which DLCI numbering and address format apply, how often the link is polled, and how many errors are tolerated before the link is taken down.
| frDlcmiAddress | DLCI size |
|---|---|
| q921 | 13 bit DLCI |
| q922March90 | 11 bit DLCI |
| q922November90 | 10 bit DLCI |
| q922 | Final standard |
§6.2The Circuit Table
frCircuitTable holds a row for each Data Link Connection, or virtual circuit, attached to a Frame Relay interface, and each row is indexed by frCircuitIfIndex and frCircuitDlci. Discontinuities in the counters in this table are indicated by the value in frCircuitCreationTime.
frCircuitState says whether the virtual circuit is operational, with values invalid, active and inactive. In the absence of a DLCMI, rows may be created by setting the state to active, and deleted by changing it to invalid, although whether the row actually disappears is left to the implementation, so the object may read as invalid for an arbitrary length of time. Setting the state to inactive temporarily disables a circuit. The use of invalid is deprecated in this SNMP version 2 MIB in favour of frCircuitRowStatus, and the default value is active.
The row carries a set of counters and timestamps. frCircuitReceivedFECNs and frCircuitReceivedBECNs count the two kinds of congestion notification the link reports. frCircuitSentFrames, frCircuitSentOctets, frCircuitReceivedFrames and frCircuitReceivedOctets count traffic, and frCircuitDiscards counts frames discarded. frCircuitReceivedDEs and frCircuitSentDEs count discard eligibility messages. frCircuitCreationTime and frCircuitLastTimeChange are timestamps. frCircuitCommittedBurst, frCircuitExcessBurst and frCircuitThroughput carry the traffic shaping parameters. frCircuitMulticast and frCircuitType describe the kind of circuit, frCircuitLogicalIfIndex points at a higher layer running over the circuit, and frCircuitRowStatus manages the row.
One row per virtual circuit records whether it is up, how many frames and octets it has carried in each direction, the congestion signals it has seen, and the traffic shaping values configured for it.
§6.3The Error Table
frErrTable describes errors seen on each Frame Relay interface, one row per interface, indexed by frErrIfIndex. Discontinuities in the counters in this table are the same as those that apply to the ifEntry associated with the interface.
frErrType records the type of the error last seen on the interface, with ten values: unknownError, receiveShort for a frame too short to demultiplex because the address field was incomplete or, for virtual circuits using Multiprotocol over Frame Relay, the protocol identifier was missing or incomplete, receiveLong for a frame exceeding the maximum length configured for the interface, illegalAddress for an address field that did not match the configured format, unknownAddress for a frame received on a virtual circuit that was not active or administratively disabled, and four values for problems with the link maintenance frames the DLCMI uses: dlcmiProtoErr, dlcmiUnknownIE, dlcmiSequenceErr and dlcmiUnknownRpt. The last value, noErrorSinceReset, means no errors have been detected since the last cold start or warm start.
frErrData is an octet string holding as much of the error packet as possible, with a size of 1 to 1600 octets. As a minimum it must contain the Q.922 address or as much as was delivered, and it is desirable to include all header and demultiplexing information. frErrTime is the value of sysUpTime when the error was detected. frErrFaults counts how many times the interface has gone down since it was initialised, and frErrFaultTime is the value of sysUpTime when the interface was taken down because of excessive errors, which is defined as the DLCMI exceeding the frDlcmiErrorThreshold number of errors within frDlcmiMonitoredEvents.
The error table records the last thing that went wrong on an interface, how many times the interface has dropped, and how much of the offending packet could be saved.
- 1unknownError — An error of a kind the MIB does not name.
- 2receiveShort — The frame was too short to demultiplex.
- 3receiveLong — The frame exceeded the maximum length configured for the interface.
- 4illegalAddress — The address field did not match the configured format.
- 5unknownAddress — A frame arrived on a virtual circuit that was not active.
- 6dlcmiProtoErr — An error occurred while interpreting a link maintenance frame.
- 7dlcmiUnknownIE — A link maintenance frame carried an invalid information element type.
- 8dlcmiSequenceErr — A link maintenance frame carried an unexpected sequence number.
- 9dlcmiUnknownRpt — A link maintenance frame carried an invalid report type.
- 10noErrorSinceReset — No errors have been detected since the last cold or warm start.
§6.4Traps and Conformance
During normal operation, Frame Relay virtual circuits are added, deleted and change availability. Those changes matter to the network manager, so one trap is defined, intended as a corollary to the SNMP Link Up and Link Down traps: frDLCIStatusChange, whose OBJECTS clause is frCircuitState. It indicates that the indicated virtual circuit has changed state, meaning it has been created or invalidated, or has toggled between the active and inactive states. If the reason for the state change is that the DLCMI has gone down, per-DLCI traps should not be generated.
The trap is controlled by two objects. frTrapState says whether the system produces the frDLCIStatusChange trap, with values enabled and disabled and a default of disabled. frTrapMaxRate is the number of milliseconds that must elapse between trap emissions, in the range 0 to 3600000, with a default of 0, which means no minimum elapsed period is specified. If events occur more rapidly, the implementation may simply fail to trap, or may queue traps until an appropriate time.
The module also carries conformance information, with the object identifiers frConformance, frGroups and frCompliances under frameRelayDTE, and a compliance statement frCompliance whose mandatory groups are frPortGroup and frCircuitGroup, with frErrGroup and frTrapGroup treated differently.
One notification tells the manager that a virtual circuit came up or went down. It is off by default, and the manager can set a minimum gap between notifications so a flapping link does not flood it.
§5Changes From RFC 1315
RFC 2115 lists the changes from the previously published version, RFC 1315. The module was converted from SMIv1 to SMIv2, which means that the table indices have access of read-only instead of not-accessible, the typical value for index objects in SMIv2. The module name was changed from RFC1315-MIB to FRAME-RELAY-DTE-MIB, and the textual convention 'Index' was dropped in favour of InterfaceIndex from the interfaces MIB module.
Two objects were added to the DLCMI table, frDlcmiStatus and frDlcmiRowStatus, and the enumerations for frDlcmiState gained two values, itut933A and ansiT1617D1994. The labels for the enumerated values of frDlcmiAddressLen were renamed to remove their hyphens, as SMIv2 requires, and it was clarified that the management virtual circuit, DLCI 0, is a member of the circuit table.
Seven objects were added to the circuit table: frCircuitMulticast, frCircuitType, frCircuitDiscards, frCircuitReceivedDEs, frCircuitSentDEs, frCircuitLogicalIfIndex and frCircuitRowStatus. The definition of frCircuitReceivedOctets was clarified as to which octets were counted. In the error table, frErrFaults and frErrFaultTime were added, the values of frErrType were clarified, and a size was added to the definition of frErrData along with an explanation of what data to capture. The object identifier for frameDelayDTE 4 was moved from frame-relay-globals to frameRelayTrapControl, and frTrapMaxRate was added. The RFC also created a set of object groups, a notification group and the compliance statements frCompliance and frCompliance0, and added ranges to frCircuitCommittedBurst, frCircuitExcessBurst and frCircuitThroughput.
This version is the earlier RFC 1315 rewritten in the newer management definition language, with more objects in the tables and clarifications about how the counters are counted.
§7Security
The RFC states that security issues for this MIB are entirely covered by the SNMP Security Architecture, and have not been expanded within the contents of this MIB. The module defines no new security mechanisms of its own; the protection of the objects it defines is a matter for the SNMP framework in use.
The document adds no security rules. Access to these objects is protected, or not, by the SNMP framework the deployment uses.