the accumulation period. An EXZ increments the LCV by one
regardless of the length of the zero string. (Also known as
CV-L. See T1.231 section 7.4.1.1.)
P-bit Coding Violation (PCV) Error Event
For all DS3 applications, a coding violation error event is a
P-bit Parity Error event. A P-bit Parity Error event is the
occurrence of a received P-bit code on the DS3 M-frame that is
not identical to the corresponding locally-calculated code (See
T1.231 section 7.1.1.2.1).
C-bit Coding Violation (CCV) Error Event
For C-bit Parity and SYNTRAN DS3 applications, this is the
count of coding violations reported via the C-bits. For C-bit
Parity, it is a count of CP-bit parity errors occurring in the
accumulation interval. For SYNTRAN, it is a count of CRC-9
errors occurring in the accumulation interval (See T1.231
section 7.1.1.2.2).
2.4.2. Performance Parameters
All performance parameters are accumulated in fifteen minute
intervals and up to 96 intervals (24 hours worth) are kept by an
agent. Fewer than 96 intervals of data will be available if the
agent has been restarted within the last 24 hours. In addition,
there is a rolling 24-hour total of each performance parameter.
There is no requirement for an agent to ensure fixed relationship
between the start of a fifteen minute interval and any wall clock;
however some agents may align the fifteen minute intervals with
quarter hours.
Performance parameters are of types PerfCurrentCount,
PerfIntervalCount and PerfTotalCount. These textual conventions are
all Gauge32, and they are used because it is possible for these
objects to decrease. Objects may decrease when Unavailable Seconds
occurs across a fifteen minutes interval boundary. See Unavailable
Seconds discussion later in this section.
Line Errored Seconds (LES)
A Line Errored Second is a second in which one or more CV
occurred OR one or more LOS defects. (Also known as ES-L.
See T1.231 section 7.4.1.2.)
P-bit Errored Seconds (PES)
An PES is a second with one or more PCVs OR one or more Out
of Frame defects OR a detected incoming AIS. This gauge is
not incremented when UASs are counted. (Also known as ESP-P.
See T1.231 section 7.4.2.2.)
P-bit Severely Errored Seconds (PSES)
A PSES is a second with 44 or more PCVs OR one or more Out of
Frame defects OR a detected incoming AIS. This gauge is not
incremented when UASs are counted. (Also known as SESP-P.
See T1.231 section 7.4.2.5.)
C-bit Errored Seconds (CES)
An CES is a second with one or more CCVs OR one or more Out
of Frame defects OR a detected incoming AIS. This count is
only for the SYNTRAN and C-bit Parity DS3 applications. This
gauge is not incremented when UASs are counted. (Also known
as ESCP-P. See T1.231 section 7.4.2.2.)
C-bit Severely Errored Seconds (CSES)
A CSES is a second with 44 or more CCVs OR one or more Out of
Frame defects OR a detected incoming AIS. This count is only
for the SYNTRAN and C-bit Parity DS3 applications. This
gauge is not incremented when UASs are counted. (Also known
as SESCP-P. See T1.231 section 7.4.2.5.)
Severely Errored Framing Seconds (SEFS)
A SEFS is a second with one or more Out of Frame defects OR a
detected incoming AIS. This item is not incremented during
unavailable seconds. (Also known as SAS-P. See T1.231
section 7.4.2.6.)
Unavailable Seconds (UAS)
UAS are calculated by counting the number of seconds that the
interface is unavailable. The DS3 interface is said to be
unavailable from the onset of 10 contiguous PSESs, or the
onset of the condition leading to a failure (see Failure
States). If the condition leading to the failure was
immediately preceded by one or more contiguous PSESs, then
the DS3 interface unavailability starts from the onset of
these PSESs. Once unavailable, and if no failure is present,
the DS3 interface becomes available at the onset of 10
contiguous seconds with no PSESs. Once unavailable, and if a
failure is present, the DS3 interface becomes available at
the onset of 10 contiguous seconds with no PSESs, if the
failure clearing time is less than or equal to 10 seconds.
If the failure clearing time is more than 10 seconds, the DS3
interface becomes available at the onset of 10 contiguous
seconds with no PSESs, or the onset period leading to the
successful clearing condition, whichever occurs later. With
respect to the DS3 error counts, all counters are incremented
while the DS3 interface is deemed available. While the
interface is deemed unavailable, the only count that is
incremented is UASs.
Note that this definition implies that the agent cannot
determine until after a ten second interval has passed
whether a given one-second interval belongs to available or
unavailable time. If the agent chooses to update the various
performance statistics in real time then it must be prepared
to retroactively reduce the PES, PSES, CES, and CSES counts
by 10 and increase the UAS count by 10 when it determines
that available time has been entered. It must also be
prepared to adjust the PCV, CCV, and SEFS count as necessary
since these parameters are not accumulated during unavailable
time. Similarly, it must be prepared to retroactively
decrease the UAS count by 10 and increase the PES, CES, PCV,
and CCV counts as necessary upon entering available time. A
special case exists when the 10 second period leading to
available or unavailable time crosses a 900 second statistics
window boundary, as the foregoing description implies that
the PCV, CCV, PES, CES, PSES, CSEC, SEFS, and UAS counts for
the PREVIOUS interval must be adjusted. In this case
successive GETs of the affected dsx3IntervalPSESs and
dsx3IntervalUASs objects will return differing values if the
first GET occurs during the first few seconds of the window.
The agent may instead choose to delay updates to the various
statistics by 10 seconds in order to avoid retroactive
adjustments to the counters. A way to do this is sketched in
Appendix B.
In any case, a linkDown trap shall be sent only after the agent has
determined for certain that the unavailable state has been entered,
but the time on the trap will be that of the first UAS (i.e., 10
seconds earlier). A linkUp trap shall be handled similarly.
According to [ANSI-T1.231] unavailable time begins at the _onset_ of
10 contiguous severely errored seconds -- that is, unavailable time
starts with the _first_ of the 10 contiguous SESs. Also, while an
interface is deemed unavailable all counters for that interface are
frozen except for the UAS count. It follows that an implementation
which strictly complies with this standard must _not_ increment any
counters other than the UAS count -- even temporarily -- as a result
of anything that happens during those 10 seconds. Since changes in
the signal state lag the data to which they apply by 10 seconds, an
ANSI-compliant implementation must pass the one-second statistics
through a 10-second delay line prior to updating any counters. That
can be done by performing the following steps at the end of each one
second interval.
i) Read near/far end CV counter and alarm status flags from the
hardware.
ii) Accumulate the CV counts for the preceding second and compare
them to the ES and SES threshold for the layer in question.
Update the signal state and shift the one-second CV counts
and ES/SES flags into the 10-element delay line. Note that
far-end one-second statistics are to be flagged as "absent"
during any second in which there is an incoming defect at the
layer in question or at any lower layer.
iii) Update the current interval statistics using the signal state
from the _previous_ update cycle and the one-second CV counts
and ES/SES flags shifted out of the 10-element delay line.
This approach is further described in Appendix B.
2.4.3. Performance Defects
Failure States:
The Remote Alarm Indication (RAI) failure, in SYNTRAN
applications, is declared after detecting the Yellow Alarm
Signal on the alarm channel. See ANSI T1.107a-1990 [ANSI-
T1.107a]. The Remote Alarm Indication failure, in C-bit
Parity DS3 applications, is declared as soon as the presence
of either one or two alarm signals are detected on the Far
End Alarm Channel. See [ANSI-T1.107]. The Remote Alarm
Indication failure may also be declared after detecting the
far-end SEF/AIS defect (aka yellow). The Remote Alarm
Indication failure is cleared as soon as the presence of the
any of the above alarms are removed.
Also, the incoming failure state is declared when a defect
persists for at least 2-10 seconds. The defects are the
following: Loss of Signal (LOS), an Out of Frame (OOF) or an
incoming Alarm Indication Signal (AIS). The Failure State is
cleared when the defect is absent for less than or equal to
20 seconds.
Far End SEF/AIS defect (aka yellow)
A Far End SEF/AIS defect is the occurrence of the two X-bits
in a M-frame set to zero. The Far End SEF/AIS defect is
terminated when the two X-bits in a M-frame are set to one.
(Also known as SASCP-PFE. See T1.231 section 7.4.4.2.6)
Out of Frame (OOF) defect
A DS3 OOF defect is detected when any three or more errors in
sixteen or fewer consecutive F-bits occur within a DS3 M-
frame. An OOF defect may also be called a Severely Errored
Frame (SEF) defect. An OOF defect is cleared when reframe
occurs. A DS3 Loss of Frame (LOF) failure is declared when
the DS3 OOF defect is consistent for 2 to 10 seconds. The
DS3 OOF defect ends when reframe occurs. The DS3 LOF failure
is cleared when the DS3 OOF defect is absent for 10 to 20
seconds. (See T1.231 section 7.1.2.2.1)
An E3 OOF defect is detected when four consecutive frame
alignment signals have been incorrectly received in there
predicted positions in an E3 signal. E3 frame alignment
occurs when the presence of three consecutive frame alignment
signals have been detected.
Loss of Signal (LOS) defect
The DS3 LOS defect is declared upon observing 175 +/- 75
contiguous pulse positions with no pulses of either positive
or negative polarity. The DS3 LOS defect is terminated upon
observing an average pulse density of at least 33% over a
period of 175 +/- 75 contiguous pulse positions starting with
the receipt of a pulse. (See T1.231 section 7.1.2.1.1)
Alarm Indication Signal (AIS) defect
The DS3 AIS is framed with "stuck stuffing." This implies
that it has a valid M-subframe alignments bits, M-frame
alignment bits, and P bits. The information bits are set to
a 1010... sequence, starting with a one (1) after each M-
subframe alignment bit, M-frame alignment bit, X bit, P bit,
and C bit. The C bits are all set to zero giving what is
called "stuck stuffing." The X bits are set to one. The DS3
AIS defect is declared after DS3 AIS is present in contiguous
M-frames for a time equal to or greater than T, where 0.2 ms
<= T <= 100 ms. The DS3 AIS defect is terminated after AIS
is absent in contiguous M-frames for a time equal to or
greater than T. (See T1.231 section 7.1.2.2.3)
The E3 binary content of the AIS is nominally a continuous
stream of ones. AIS detection and the application of
consequent actions, should be completed within a time limit
of 1 ms.
2.4.4. Other Terms
Circuit Identifier
This is a character string specified by the circuit vendor,
and is useful when communicating with the vendor during the
troubleshooting process (see M.1400 [ITU-T-M.1400] for
additional information).
Proxy
In this document, the word proxy is meant to indicate an
application which receives SNMP messages and replies to them
on behalf of the devices which implement the actual DS3/E3
interfaces. The proxy may have already collected the
information about the DS3/E3 interfaces into its local
database and may not necessarily forward the requests to the
actual DS3/E3 interface. It is expected in such an
application that there are periods of time where the proxy is
not communicating with the DS3/E3 interfaces. In these
instances the proxy will not necessarily have up-to-date
configuration information and will most likely have missed
the collection of some statistics data. Missed statistics
data collection will result in invalid data in the interval
table.
3. Object Definitions
DS3-MIB DEFINITIONS ::= BEGIN
IMPORTS
MODULE-IDENTITY, OBJECT-TYPE,
NOTIFICATION-TYPE, transmission
FROM SNMPv2-SMI -- [RFC2578]
DisplayString, TimeStamp, TruthValue
FROM SNMPv2-TC -- [RFC2579]
MODULE-COMPLIANCE, OBJECT-GROUP,
NOTIFICATION-GROUP
FROM SNMPv2-CONF -- [RFC2580]
InterfaceIndex
FROM IF-MIB -- [RFC2863]
PerfCurrentCount, PerfIntervalCount,
PerfTotalCount
FROM PerfHist-TC-MIB; -- [RFC3593]
ds3 MODULE-IDENTITY
LAST-UPDATED "200409080000Z" -- September 08, 2004
ORGANIZATION "IETF AToM MIB Working Group"
CONTACT-INFO
"WG charter:
http://www.ietf.org/html.charters/atommib-charter.html
Mailing Lists:
General Discussion: atommib@research.telcordia.com
To Subscribe: atommib-request@research.telcordia.com
Editor: Orly Nicklass
Postal: RAD Data Communications, Ltd.
Ziv Tower, 24 Roul Walenberg
Tel Aviv, Israel, 69719
Tel: +9723 765 9969
E-mail: orly_n@rad.com"
DESCRIPTION
"The is the MIB module that describes
DS3 and E3 interfaces objects.
Copyright (c) The Internet Society (2004). This
version of this MIB module is part of RFC 3896;
see the RFC itself for full legal notices."
REVISION "200409080000Z" -- September 08, 2004
DESCRIPTION
"The RFC 3896 version of this MIB module.
The key changes made to this MIB module
since its publication in RFC 2496 are as follows:
(1) The dsx3FracIfIndex SYNTAX matches the description range.
(2) Reference was added to Circuit Identifier object.
(3) Usage of ifStackTable section was updated.
(4) Align the DESCRIPTION clauses of few statistic objects with
thenear end definition, the far end definition and with
RFC 3593.
(5) Add new value, dsx3M13, to dsx3LineType."
REVISION "199808012130Z"
DESCRIPTION
"The RFC 2496 version of this MIB module.
The key changes made to this MIB module
since its publication in RFC 1407 are as follows:
(1) The Fractional Table has been deprecated.
(2) This document uses SMIv2.
(3) Values are given for ifTable and ifXTable.
(4) Example usage of ifStackTable is included.
(5) dsx3IfIndex has been deprecated.
(6) The definition of valid intervals has been clarified
for the case where the agent proxied for other devices.
In particular, the treatment of missing intervals has
been clarified.
(7) An inward loopback has been added.
(8) Additional lineStatus bits have been added for Near End
in Unavailable Signal State, Carrier Equipment Out of
Service.
(9) A read-write line Length object has been added.
(10) Added a lineStatus last change, trap and enabler.
(11) Textual Conventions for statistics objects have
been used.
(12) A new object, dsx3LoopbackStatus, has been introduced to
reflect the loopbacks established on a DS3/E3 interface
and the source to the requests. dsx3LoopbackConfig
continues to be the desired loopback state while
dsx3LoopbackStatus reflects the actual state.
(13) A dual loopback has been added to allow the setting of
an inward loopback and a line loopback at the same time.
(14) An object has been added to indicated whether or not
this is a channelized DS3/E3.
(15) A new object has been added to indicate which DS1 is to
set for remote loopback."
REVISION "199301252028Z"
DESCRIPTION
"Initial version, published as RFC 1407."
::= { transmission 30 }
-- The DS3/E3 Near End Group
-- The DS3/E3 Near End Group consists of four tables:
-- DS3/E3 Configuration
-- DS3/E3 Current
-- DS3/E3 Interval
-- DS3/E3 Total
-- the DS3/E3 Configuration Table
dsx3ConfigTable OBJECT-TYPE
SYNTAX SEQUENCE OF Dsx3ConfigEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The DS3/E3 Configuration table."
::= { ds3 5 }
dsx3ConfigEntry OBJECT-TYPE
SYNTAX Dsx3ConfigEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"An entry in the DS3/E3 Configuration table."
INDEX { dsx3LineIndex }
::= { dsx3ConfigTable 1 }
Dsx3ConfigEntry ::=
SEQUENCE {
dsx3LineIndex InterfaceIndex,
dsx3IfIndex InterfaceIndex,
dsx3TimeElapsed INTEGER,
dsx3ValidIntervals INTEGER,
dsx3LineType INTEGER,
dsx3LineCoding INTEGER,
dsx3SendCode INTEGER,
dsx3CircuitIdentifier DisplayString,
dsx3LoopbackConfig INTEGER,
dsx3LineStatus INTEGER,
dsx3TransmitClockSource INTEGER,
dsx3InvalidIntervals INTEGER,