📄 rfc2558.txt
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any other value than sonetPathNoDefect(1).
ifLastChange sysUpTime at the last change in ifOperStatus.
ifName Textual name of the interface or an OCTET STRING
of zero length.
ifLinkUpDownTrapEnable Default value is disabled(2).
Just read-only access may be supported.
ifHighSpeed Set to rate of SONET/SDH path
in Mega-bits per second.
ifConnectorPresent Set to false(2).
ifAlias The (non-volatile) alias name for this interface
as assigned by the network manager.
3.4. Use of ifTable for SONET/SDH VTs/VCs
Only the ifGeneralInformationGroup needs to be supported.
ifTable Object Use for SONET/SDH VTs/VCs
===========================================
ifIndex Interface index.
ifDescr SONET/SDH VT/VC
ifType sonetVT(51)
ifSpeed Set to speed of VT/VC
(e.g., a VT1.5 has a rate of
1728000 bps.)
ifPhysAddress Circuit Identifier or OCTET STRING of zero length.
ifAdminStatus Supports read-only access.
The desired administrative status of the
interface.
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RFC 2558 SONET/SDH Objects March 1999
ifOperStatus This object assumes the value down(2),
if the object sonetVTCurrentStatus has
any other value than sonetVTNoDefect(1).
ifLastChange sysUpTime at the last change in ifOperStatus.
ifName Textual name of the interface or an OCTET STRING
of zero length.
ifLinkUpDownTrapEnable Default value is disabled(2).
Just read-only access may be supported.
ifHighSpeed Set to rate of VT in Mega-bits per second.
ifConnectorPresent Set to false(2).
ifAlias The (non-volatile) alias name for this interface
as assigned by the network manager.
3.5. SONET/SDH Terminology
The terminology used in this document to describe error conditions on
a SONET circuit as monitored by a SONET system are from the T1.231
[22][31][35]. The terminology used in this document to describe
error conditions on a SDH circuit as monitored by a SDH system are
from the CCITT G.783 [29]. Only the SONET Performance Monitoring
terminology is defined in this document. The definitions for SDH
Performance Monitoring terms are similar but not identical, and they
can be found in [29]. If the definition in this document does not
match the definition in the T1.231 document, the implementer should
follow the definition described in this document. In some cases
other or additional references are used as compared with the ones
cited above. This will be indicated in the text.
Section Loss Of Frame Failure (Out of Frame Event, Severely
Errored Frame Defect)
An Out of Frame (OOF) event (or Severely Errored Frame defect)
is the occurrence of four contiguous errored frame alignment
words. A frame alignment word occupies the A1 and A2 bytes of
an STS frame, and is defined in T1.105. The SEF defect is
terminated when two contiguous error-free frame words are
detected. Any implementation of the frame recovery circuitry
which achieves realignment following an OOF within the 250
microsecond (two frames) interval implied by this definition is
acceptable.
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RFC 2558 SONET/SDH Objects March 1999
A Loss of Frame (LOF) defect is declared when an OOF/SEF defect
persists for a period of 3 milliseconds. The LOF defect is
terminated when the incoming signal remains continuously in-
frame for a period of 1 ms to 3 ms.
A LOF failure is declared when the LOF defect persists for a
period of 2.5 +/- 0.5 seconds, except when an LOS defect or
failure is present. The LOF failure is cleared when the LOS
failure is declared, or when the LOF defect is absent for 10 +/-
0.5 seconds.
Loss of Signal
The Loss of Signal (LOS) defect is declared when no transitions
are detected on the incoming signal (before descrambling). The
LOS defect is detected upon observing 2.3 to 100 microseconds
of no transitions. The LOS defect is cleared after a 125
microsecond interval (one frame) during which no LOS defect is
detected.
The LOS failure is declared when the LOS defect persists for a
period of 2.5 +/- 0.5 seconds, or if LOS defect is present when
the criteria for LOF failure declaration have been met. The LOS
failure is cleared when the LOS defect is absent for a period of
10 +/- 0.5 seconds. Declaration of LOS failure clears any
existing LOF failure. Clearing the LOS failure allows immediate
declaration of the LOF failure if conditions warrant.
STS-Path Loss of Pointer
A Loss of Pointer (LOP) defect is declared when either a valid
pointer is not detected in eight consecutive frames, or when
eight consecutive frames are detected with the New Data Flag
(NDF) set to "1001" without a valid concatenation indicator (see
ANSI T1.105). A LOP defect is terminated when either a valid
pointer with a normal NDF set to "0110", or a valid
concatenation indicator is detected for three contiguous frames.
Incoming STS-Path AIS shall not result in the declaration of a
LOP defect.
An STS-Path LOP failure is declared when the STS-Path LOP defect
persists for a period of 2.5 +/- 0.5 seconds. A STS-Path LOP
failure is cleared when the STS-Path LOP defect is absent for 10
+/- 0.5 seconds.
VT Loss of Pointer
A VT LOP defect is declared when either a valid pointer is not
detected in eight consecutive VT superframes, or when eight
consecutive VT superframes are detected with the NDF set to
"1001" without a valid concatenation indicator. A VT LOP defect
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RFC 2558 SONET/SDH Objects March 1999
is terminated when either a valid pointer with a normal NDF set
to "0110", or a valid concatenation indicator is detected for
three contiguous VT superframes. Incoming VT-Path AIS shall not
result in declaring a VT LOP defect.
A VT LOP failure is declared when the VT LOP defect persists for
2.5 +/- 0.5 seconds. A VT LOP failure is cleared when the VT
LOP defect is absent for 10 +/- 0.5 seconds.
Line Alarm Indication Signal
A Line Alarm Indication Signal (L-AIS) is defined in ANSI
T1.105. The following criteria are specific to the L-AIS
defect:
-- Line AIS defect is detected as a "111" pattern in bits 6, 7,
and 8 of the K2 byte in five consecutive frames.
-- Line AIS defect is terminated when bits 6, 7, and 8 of the
K2 byte do not contain the code "111" for five consecutive
frames.
A Line AIS failure is declared when the Line AIS defect persists
for a period of 20.5 +/- 0.5 seconds. A Line AIS failure is
cleared when the Line AIS defect is absent for 10 +/- 0.5
seconds.
STS-Path Alarm Indication Signal
The STS-Path Alarm Indication Signal (AIS) is defined in ANSI
T1.105 as all ones in bytes H1, H2, and H3 as well as all ones
in the entire STS SPE. The following criteria are specific to
the STS-Path AIS defect:
-- STS-Path AIS defect is detected as all ones in bytes H1 and
H2 in three contiguous frames.
-- The STS-Path AIS defect is terminated when a valid STS
Pointer is detected with the NDF set to "1001" (inverted) for
one frame, or "0110" (normal) for three contiguous frames.
An STS-Path AIS failure is declared when the STS-Path AIS defect
persists for 2.5 +/- 0.5 seconds. An STS-Path AIS failure is
cleared when the STS-Path AIS defect is absent for 10 +/- 0.5
seconds.
VT-Path Alarm Indication Signal
The VT-Path Alarm Indication Signal (AIS) is only applicable for
VTs in the floating mode of operation. VT-Path AIS is used to
alert the downstream VT Path Terminating Entity (PTE) of an
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RFC 2558 SONET/SDH Objects March 1999
upstream failure. Upon detection of a failure, Line AIS, or
STS-Path AIS, an STS PTE will generate downstream VT-Path AIS if
the STS Synchronous Payload Envelope (SPE) is carrying floating
VTs. VT-Path AIS is specified in ANSI T1.105 as all ones in
bytes V1, V2, V3, and V4, as well as all ones in the entire VT
SPE. The following criteria are specific to VT-Path AIS defect:
-- VT-Path AIS defect is detected by a VT PTE as all ones in
bytes V1 and V2 in three contiguous VT superframes.
-- VT-Path AIS defect is terminated when valid VT pointer with
a valid VT size is detected with the NDF set to "1001"
(inverted) for one VT superframe, or "0110" (normal) for three
contiguous VT superframes are detected.
A VT-Path AIS failure is declared when the VT-Path AIS defect
persists for 2.5 +/- 0.5 seconds. A VT-Path AIS failure is
cleared when the VT-Path AIS defect is absent for 10 +/- 0.5
seconds.
Line Remote Defect Indication
Line Remote Defect Indication (RDI) (aka Line FERF) signal is
the occurrence of a "110" pattern in bit positions 6, 7, and 8
of the K2 byte in STS-1 #1 of the STS-N signal. Line RDI is
defined in ANSI T1.105. The following criteria are specific to
Line RDI defect:
-- Line RDI defect is a "110" code in bits 6, 7, and 8 of the
K2 byte of in STS-1 #1 in x consecutive frames, where x = 5
[31][35] or 10 [35].
-- Line RDI defect is terminated when any code other than "110"
is detected in bits 6, 7, and 8 of the K2 byte in x consecutive
frames, where x = 5 [31][35] or 10 [35].
A Line Remote Failure Indication (RFI) failure is declared when
the incoming Line RDI defects lasts for 2.5 +/- 0.5 seconds.
The Line RFI failure is cleared when no Line RDI defects are
detected for 10 +/- 0.5 seconds.
STS-Path Remote Defect Indication
STS-Path RDI (aka STS-Path FERF) signal shall be generated
within 100 milliseconds by the STS PTE upon detection of an AIS
or LOP defect. Transmission of the STS-Path RDI signal shall
cease within 100 milliseconds when the STS PTE no longer detects
STS-Path AIS or STS-Path LOP defect. The STS-Path RDI shall
accurately report the presence or absence of STS-Path AIS or
STS-Path LOP defects. STS-Path RDI defect is defined in ANSI
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RFC 2558 SONET/SDH Objects March 1999
T1.105. The following requirements are specific to the STS-Path
RDI defect:
-- STS-Path RDI is detected by all STS PTEs. STS-Path RDI is
detected by the upstream STS PTE as a "1" in bit five of the
Path Status byte (G1) for x consecutive frames, where x = 5 [31]
or 10 [35].
-- Removal of STS-Path Remote Defect Indication is detected by
a "0" in bit 5 of the G1 byte in x consecutive frames, where x =
5 [31] or 10 [35].
An STS-Path Remote Failure Indication (RFI) failure is declared
when the incoming STS-Path RDI defects lasts for 2.5 +/- 0.5
seconds. The STS-Path RFI failure is cleared when no STS-Path
RDI defects are detected for 10 +/- 0.5 seconds.
VT-Path Remote Defect Indication
VT Path RDI (aka VT Path FERF) signal shall be generated within
100 milliseconds by the VT PTE upon detection of a VT-Path AIS
or LOP defect. Transmission of the VT-Path RDI signal shall
cease within 100 milliseconds when the VT PTE no longer detects
VT-Path AIS or VT-Path LOP defect. The VT-Path RDI shall
accurately report the presence or absence of VT-Path AIS or VT-
Path LOP defects. VT-Path RDI defect is defined in ANSI T1.105.
The following requirements are specific to VT-Path RDI defect:
-- VT-Path RDI defect is the occurrence of a "1" in bit 4 of
the VT-Path Overhead byte (V5) in x consecutive frames, where x
= 5 [31] or 10 [35].
-- VT-Path RDI defect is terminated when a "0" is detected in
bit 4 of the VT-Path Overhead byte (V5) for x consecutive
frames, where x = 5 [31] or 10 [35].
A VT-Path Remote Failure Indication (RFI) (derived) failure is
declared when the incoming VT-Path RDI defects lasts for 2.5 +/-
0.5 seconds. The VT-Path RFI failure is cleared when no VT-Path
RDI defects are detected for 10 +/- 0.5 seconds.
VT-Path Remote Failure Indication
The VT-Path RFI signal is only required for the case of byte
synch mapped DS1s where the DS1 frame bit is not mapped. The
VT-Path RFI is specified in ANSI T1.105, where it is currently
called VT path yellow. When provided, the VT-Path RFI signal is
used to indicate the occurrence of far-end failures. When the
VT-Path RFI is not provided, far-end failures are derived from
local timing of the VT-Path RDI defect. The VT-Path RFI failure
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RFC 2558 SONET/SDH Objects March 1999
is declared within 5 ms of detecting the incoming VT-Path RFI
Signal. The VT-Path Remote Failure Indication (RFI) failure is
cleared within 50 ms of detecting the removal of the incoming
VT-Path RFI signal.
Coding Violation
Coding Violations (CV) are Bit Interleaved Parity (BIP) errors
that are detected in the incoming signal. CV counters are
incremented for each BIP error detected. That is, each BIP-8
can detect up to eight errors per STS-N frame, with each error
incrementing the CV counter. Section CVs shall be collected
using the BIP-8 in the B1 byte located in the Section Overhead
of STS-1 #1. Line CVs shall be collected using the BIP-8s in B2
bytes located in the Line Overhead of each STS-1 (since all CVs
on an STS-N line are counted together, this is equivalent to
counting each error in the BIP-8*N contained in the B2 bytes of
the STS-N Line Overhead). Thus, on an STS-N signal, up to 8 x N
CVs may occur in each frame. Path CVs shall be collected using
the BIP-8 in the B3 byte of the STS-Path Overhead of the STS
SPE. VT CVs shall be collected using the BIP-2 in the V5
overhead byte of the floating VT.
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