Monitoring DS1, E1, DS2 line with LoriotPro

Introduction

The goal of this How To is to explain how to use LoriotPro for the Monitoring of DS1 E1 line.

MIB description

The RFC 3895.mib describes objects used for managing DS1, E1, DS2 and E2 interfaces

This MIB obsoletes RFC 2495 and RFC 1406.

The DS1 Group consists of tables:

dsx1ConfigTable DS1 Configuration The DS1 Configuration table.
dsx1CurrentTable DS1 Current The DS1 current table contains various statistics being collected for the current 15 minute interval.
dsx1IntervalTable DS1 Interval The DS1 Interval Table contains various statistics collected by each DS1 Interface over the previous 24 hours of operation.  The past 24 hours are broken into 96 completed 15 minute intervals.  Each row in this table represents one such interval (identified by dsx1IntervalNumber) for one specific instance (identified by dsx1IntervalIndex).
dsx1TotalTable DS1 Total The DS1 Total Table contains the cumulative sum of the various statistics for the 24 hour period preceding the current interval.
dsx1FarEndCurrentTable DS1 Far End Current The DS1 Far End Current table contains various statistics being collected for the current 15 minute interval.  The statistics are collected from the far end messages on the Facilities Data Link.  The definitions are the same as described for the near-end information.
dsx1FarEndIntervalTable DS1 Far End Interval The DS1 Far End Interval Table contains various statistics collected by each DS1 interface over the previous 24 hours of operation.  The past 24 hours are broken into 96 completed 15 minute intervals. Each row in this table represents one such interval (identified by dsx1FarEndIntervalNumber) for one specific instance identified by dsx1FarEndIntervalIndex).
dsx1FarEndTotalTable DS1 Far End Total The DS1 Far End Total Table contains the cumulative sum of the various statistics for the 24 hour period preceding the current interval.
dsx1ChanMappingTable DS1 Channel Table The DS1 Channel Mapping table.  This table maps a DS1 channel number on a particular DS3 into an
ifIndex.  In the presence of DS2s, this table can be used to map a DS2 channel number on a DS3 into
an ifIndex, or used to map a DS1 channel number on a DS2 onto an ifIndex.
dsx1FracTable DS Fractionnal

This table is deprecated in favour of using ifStackTable.
The table was mandatory for systems dividing a DS1 into channels containing different data streams that are of local interest.  Systems which are indifferent to data content, such as CSUs, need not implement it.
The DS1 fractional table identifies which DS1 channels associated with a CSU are being used to support a logical interface, i.e., an entry in the interfaces table from the Internet-standard MIB.

For example, consider an application managing a North American ISDN Primary Rate link whose division is a 384 kbit/s H1 _B_ Channel for Video, a second H1 for data to a primary routing peer, and 12 64 kbit/s H0 _B_ Channels. Consider that some subset of the H0 channels are used for voice and the remainder are available for dynamic data calls.
We count a total of 14 interfaces multiplexed onto the DS1 interface. Six DS1 channels (for the sake of the example, channels 1..6) are used for Video, six more (7..11 and 13) are used for data, and the remaining 12 are in channels 12 and 14..24. Let us further imagine that ifIndex 2 is of type DS1 and refers to the DS1 interface, and that the interfaces layered onto it are numbered 3..16.
We might describe the allocation of channels, in the dsx1FracTable, as follows:
dsx1FracIfIndex.2. 1 = 3  dsx1FracIfIndex.2.13 = 4
dsx1FracIfIndex.2. 2 = 3  dsx1FracIfIndex.2.14 = 6
dsx1FracIfIndex.2. 3 = 3  dsx1FracIfIndex.2.15 = 7
dsx1FracIfIndex.2. 4 = 3  dsx1FracIfIndex.2.16 = 8
dsx1FracIfIndex.2. 5 = 3  dsx1FracIfIndex.2.17 = 9
dsx1FracIfIndex.2. 6 = 3  dsx1FracIfIndex.2.18 = 10
dsx1FracIfIndex.2. 7 = 4  dsx1FracIfIndex.2.19 = 11
dsx1FracIfIndex.2. 8 = 4  dsx1FracIfIndex.2.20 = 12
dsx1FracIfIndex.2. 9 = 4  dsx1FracIfIndex.2.21 = 13
dsx1FracIfIndex.2.10 = 4  dsx1FracIfIndex.2.22 = 14
dsx1FracIfIndex.2.11 = 4  dsx1FracIfIndex.2.23 = 15
dsx1FracIfIndex.2.12 = 5  dsx1FracIfIndex.2.24 = 16

For North American (DS1) interfaces, there are 24 legal channels, numbered 1 through 24.
For G.704 interfaces, there are 31 legal channels, numbered 1 through 31.  The channels (1..31) correspond directly to the equivalently numbered time-slots.

     

View of the tables in LoriotPro

DS1 Mib Branch

Description of the dsx1ConfigTable.

Object Description
dsx1LineIndex This object should be made equal to ifIndex.  The next paragraph describes its previous usage.
Making the object equal to ifIndex allows proper use of ifStackTable and ds0/ds0bundle mibs.
Previously, this object is the identifier of a DS1 Interface on a managed device.  If there is an ifEntry that is directly associated with this and only this DS1 interface, it should have the same value as ifIndex.  Otherwise, number the dsx1LineIndices with an unique identifier following the rules of hoosing a number that is greater than ifNumber and numbering the inside interfaces (e.g., equipment side) with even numbers and outside interfaces (e.g., network side) with odd numbers.
dsx1IfIndex This value for this object is equal to the value of ifIndex from the Interfaces table of MIB II (RFC 1213).
dsx1TimeElapsed The number of seconds that have elapsed since the beginning of the near end current error-measurement period. If, for some reason, such as an adjustment in the system's time-of-day clock, the current interval exceeds the maximum value, the agent will return the maximum value.
dsx1ValidIntervals The number of previous near end intervals for which data was collected.  The value will be 96 unless the interface was brought online within the last 24 hours, in which case the value will be the number of complete 15 minute near end intervals since the interface has been online.  In the case where the agent is a proxy, it is possible that
some intervals are unavailable.  In this case, this interval is the maximum interval number for which data is available.
dsx1LineType

This variable indicates  the  variety  of  DS1 Line  implementing  this  circuit.  The type of circuit affects the number of bits  per  second that  the circuit can reasonably carry, as well as the interpretation of the  usage  and  error statistics. The values, in sequence, describe:

TITLE SPECIFICATION
dsx1ESF Extended SuperFrame DS1 (T1.107)
dsx1D4 AT &T D4 format DS1 (T1.107)
dsx1E1 ITU-T Recommendation G.704 (Table 4a)
dsx1E1-CRC ITU-T Recommendation G.704 (Table 4b)
dsxE1-MF G.704 (Table 4a) with TS16 multiframing enabled
dsx1E1-CRC-MF G.704 (Table 4b) with TS16 multiframing enabled
dsx1Unframed DS1 with No Framing
dsx1E1Unframed E1 with No Framing (G.703)
dsx1DS2M12 DS2 frame format (T1.107)
dsx1E2 E2 frame format (G.704)
dsx1E1Q50 TS16 bits 5,7,8 set to 101, [in all other cases it is set to 111.](ITU-T G.704,table 14)
dsx1E1Q50CRC E1Q50 with CRC.

For clarification, the capacity for each E1 type is as listed below:

dsx1E1Unframed E1, no framing = 32 x 64k = 2048k
dsx1E1 or dsx1E1CRC E1, with framing,no signalling = 31 x 64k = 1984k
dsx1E1MF or dsx1E1CRCMF E1, with framing,signalling = 30 x 64k = 1920k
dsx1LineCoding

This variable describes the variety of Zero Code Suppression used on this interface, which in turn affects a number of its characteristics.

dsx1JBZS refers the Jammed Bit Zero Suppression, in which the AT&T specification of at least one pulse every 8 bit periods is literally implemented by forcing a pulse in bit 8 of each channel. Thus, only seven bits per channel, or 1.344 Mbps, is available for data.

dsx1B8ZS refers to the use of a specified pattern of normal bits and bipolar violations which are used to replace a sequence of eight zero bits.

ANSI Clear Channels may use dsx1ZBTSI, or Zero Byte Time Slot Interchange.

E1 links, with or without CRC, use dsx1HDB3 or dsx1AMI.

dsx1AMI refers to a mode wherein no zero code suppression is present and the line encoding does not solve the problem directly.  In this application, the higher layer must provide data which meets or exceeds the pulse density requirements, such as inverting HDLC data.

dsx1B6ZS refers to the user of a specified pattern of normal bits and bipolar violations which are used to replace a sequence of six zero bits.  Used for DS2.

dsx1SendCode

This variable indicates what type of code is being sent across the DS1 interface by the device. Setting this variable causes the interface to send the code requested.  The values mean:

dsx1SendNoCode sending looped or normal data
dsx1SendLineCode sending a request for a line loopback
dsx1SendPayloadCode sending a request for a payload loopback
dsx1SendResetCode sending a loopback termination request
dsx1SendQRS sending a Quasi-Random Signal  (QRS)  test pattern
dsx1Send511Pattern sending a 511 bit fixed test pattern
dsx1Send3in24Pattern sending a fixed test pattern of 3 bits set in 24
dsx1SendOtherTestPattern sending a test pattern  other  than  those described by this object
dsx1CircuitIdentifier This variable contains the transmission vendor's circuit identifier, for the purpose of facilitating troubleshooting.
dsx1LoopbackConfig

This variable represents the desired loopback configuration of the DS1 interface.  Agents supporting read/write access should return inconsistentValue in response to a requested loopback state that the interface does not
support.  The values mean:

dsx1NoLoop Not in the loopback state.  A device that is not capable of performing a loopback on the interface shall always return this as its value.
dsx1PayloadLoop The received signal at this interface is looped through the device.  Typically the received signal is looped back for retransmission after it has passed through the device's framing function.
dsx1LineLoop The received signal at this interface does not go through the device (minimum penetration) but is looped back out.
dsx1OtherLoop Loopbacks that are not defined here.
dsx1InwardLoop The transmitted signal at this interface is looped back and received by the same interface.What is transmitted onto the line is product dependent.
dsx1DualLoop Both dsx1LineLoop and dsx1InwardLoop will be active simultaneously.
dsx1LineStatus

This variable indicates the Line Status of the interface.  It contains loopback, failure, received 'alarm' and transmitted 'alarms information.
The dsx1LineStatus is a bit map represented as a sum, therefore, it can represent multiple failures (alarms) and a LoopbackState simultaneously.
dsx1NoAlarm must be set if and only if no other flag is set.
If the dsx1loopbackState bit is set, the loopback in effect can be determined from the dsx1loopbackConfig object.  The various bit positions are:

1 dsx1NoAlarm No alarm present
2 dsx1RcvFarEndLOF Far end LOF (a.k.a., Yellow Alarm)
4 dsx1XmtFarEndLOF Near end sending LOF Indication
8 dsx1RcvAIS Far end sending AIS
16 dsx1XmtAIS Near end sending AIS
32 dsx1LossOfFrame Near end LOF (a.k.a., Red Alarm)
64 dsx1LossOfSignal Near end Loss Of Signal
128 dsx1LoopbackState Near end is looped
256 dsx1T16AIS E1 TS16 AIS
512 dsx1RcvFarEndLOMF Far End Sending TS16 LOMF
1024 dsx1XmtFarEndLOMF Near End Sending TS16 LOMF
2048 dsx1RcvTestCode Near End detects a test code
4096 dsx1OtherFailure any line status not defined here
8192 dsx1UnavailSigState Near End in Unavailable Signal State
16384 dsx1NetEquipOOS Carrier Equipment Out of Service
32768  dsx1RcvPayloadAIS DS2 Payload AIS
65536 dsx1Ds2PerfThreshold DS2 Performance Threshold Exceeded
dsx1SignalMode

'none' indicates that no bits are reserved for signaling on this channel.

'robbedBit' indicates that DS1 Robbed Bit Signaling is in use.

'bitOriented' indicates that E1 Channel Associated Signaling is in use.

'messageOriented' indicates that Common Channel Signaling is in use either on channel 16 of an E1 link or channel 24 of a DS1.

dsx1TransmitClockSource

The source of Transmit Clock.

'loopTiming' indicates that the recovered receive clock is used as the transmit clock.

'localTiming' indicates that a local clock source is used or when an external clock is attached to the box containing the interface.

'throughTiming' indicates that recovered receive clock from another interface is used as the transmit clock.

'adaptive' indicates that the clock is recovered based on the data flow and not based on the physical layer

dsx1Fdl

This bitmap describes the use of  the facilities data link, and is the sum of the capabilities.
Set any bits that are appropriate:
other(1),
dsx1AnsiT1403(2),
dsx1Att54016(4),
dsx1FdlNone(8)

'other' indicates that a protocol  other  than one following is used.
'dsx1AnsiT1403' refers to the  FDL  exchange recommended by ANSI.
'dsx1Att54016' refers to ESF FDL exchanges.
'dsx1FdlNone' indicates that the device  does not use the FDL.

dsx1InvalidIntervals The number of intervals in the range from 0 to dsx1ValidIntervals for which no data is available.
This object will typically be zero except in cases where the data for some intervals are not available (e.g., in proxy situations).
dsx1LineLength The length of the ds1 line in meters. This objects provides information for line build out circuitry.  This object is only useful if the interface has configurable line build out circuitry.
dsx1LineStatusLastChange The value of MIB II's sysUpTime object at the time this DS1 entered its current line status state.  If the current state was entered prior to the last re-initialization of the proxy-agent, then this object contains a zero value.
dsx1LineStatusChangeTrapEnable Indicates whether dsx1LineStatusChange traps should be generated for this interface.
dsx1LoopbackStatus

This variable represents the current state of the loopback on the DS1 interface.  It contains information about loopbacks established by a manager and remotely from the far end.
The dsx1LoopbackStatus is a bit map represented as a sum, therefore is can represent multiple loopbacks simultaneously.
The various bit positions are:

1 dsx1NoLoopback
2 dsx1NearEndPayloadLoopback
4 dsx1NearEndLineLoopback
8 dsx1NearEndOtherLoopback
16 dsx1NearEndInwardLoopback
32 dsx1FarEndPayloadLoopback
64 dsx1FarEndLineLoopback
dsx1Ds1ChannelNumber This variable represents the channel number of the DS1/E1 on its parent DS2/E2 or DS3/E3.  A value of 0 indicated this DS1/E1 does not have a parent DS3/E3.
dsx1Channelization Indicates whether this ds1/e1 is channelized or unchannelized.  The value of enabledDs0 indicates that this is a DS1 channelized into DS0s.  The value of enabledDs1 indicated that this is a DS2 channelized into DS1s.  Setting this value will
cause the creation or deletion of entries in the ifTable for the DS0s that are within the DS1.
dsx1LineMode This setting puts the T1 framer into either long haul (CSU) mode or short haul (DSU) mode.
dsx1LineBuildOut Attenuation setting for T1 framer in long haul (CSU) mode.  The optional values are: -7.5dB, -15dB, -22.5dB and 0dB.

 

Terminology

AIS Alarm Indication Signal The Alarm Indication Signal failure is declared when an AIS defect is detected at the input and the AIS defect still exists after the Loss Of Frame failure (which is caused by the unframed nature of the 'all-ones' signal) is declared. The AIS failure is cleared when the Loss Of Frame failure is cleared.
LOF Loss Of Frame For T1 links, the Loss Of Frame failure is declared when an OOF or LOS defect has persisted for T seconds, where 2 <= T <= 10. The Loss Of Frame failure is cleared when there have been no OOF or LOS defects during a period T where 0 <= T <= 20.
LOMF Loss Of MultiFrame The Loss Of MultiFrame failure is declared when two consecutive multiframe alignment signals (bits 4 through 7 of TS16 of frame 0) have been received with an error. The Loss Of Multiframe failure is cleared when the first correct multiframe alignment signal is received. The Loss Of Multiframe failure can only be declared for E1 links operating with G.732 [18] framing (sometimes called "Channel Associated Signalling" mode).
LOS Loss Of Signal For T1, the Loss Of Signal failure is declared upon observing 175 +/- 75 contiguous pulse positions with no pulses of either positive or negative polarity. The LOS failure is cleared upon observing an average pulse density of at least 12.5% over a period of 175 +/- 75 contiguous pulse positions starting with the receipt of a pulse. For E1 links, the Loss Of Signal failure is declared when greater than 10 consecutive zeroes are detected