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34368 Kbps 8448 Kbps 97728 Kbps 6312 Kbps x4 x4 x4 64 kbps 1544 kbps x2 44736 kbps 32064 kbps 97728 kbps x3 x30 x24 x3 x7 x5 x3PDH
T-Carrier
Japan Single Channel E4 E3 E2 E1 T1 J1 T2 J2 J3 J4 T3 6312 kbps U.S. and Canada3152 kbps x2
T1c J1c
worldwide
Fig. 1 PDH and T-carrier hierarchies 139264 kbps
34368 kbps
8448 kbps
2048 kbps
ALBEDO is a manufacturer of test, measurement and monitoring solutions. We supply tools to install, troubleshoot and maintain those infrastructures that support voice, video, internet and data applications. ALBEDO core expertise range from SyncE, GbE, E1, TDM, Jitter/Wander, QoS, and SLA technologies that we have implemented on WAN EMULATORS, Filtering / Aggregation TAPS, hand-held TESTERS, and MONITORING Systems
Fig. 2 The E1 frame is the first hierarchy level.
Gigabit Ethernet protocols, Gigabit Ethernet Alarms, Gigabit Ethernet test, Gigabit Ethernet test, Gigabit Ethernet test, Gigabit Ethernet tester
Fig. 3 The A multiplexer calculates and writes the CRC code, and the multiplexer B reads and checks the code. REBE (bit E=1)
CRC-4 Writer CRC-4 Reader
2
2 Errors
Multiplexer A Multiplexer B
Error Indication Reader Error Indication Writer
. . . . . . 64 64 2 Mbps 64 kbps 64 kbps CRC-4 Reader 34
Fig. 4 The PDH hierarchy .64 2 34 140 8 34 34 Mbps 2 8 x 4 34 Mbps 8 Mbps 2 Mbps
64 kbps
.64 2 2 8 34 x 4 x 4 x 30 2 Mbps x 16 140 Mbps 2 140 2 Mbps x 64 34 140 140 Mbps 140 MbpsE1
E2
E3
E4
E1
E3
E1
E4
E4
or x 31Standard Binary Rate Size Frame/s Code Amplitude Attenuation
G.704/732 2,048 kbps±50 ppm 256 bits 8,000 HDB3 2.37-3.00V 6 dB
G.742 8,448 kbps±30 ppm 848 bits 9,962.2 HDB3 2.37V 6 dB
G.751 34,368 kbps±20 ppm 1536 bits 22,375.0 HDB3 1.00V 12 dB
G.751 139,264 kbps±15 ppm 2928 bits 47,562.8 CMI 1.00V 12 dB
Fig. 5 The higher PDH hierarchies. A bit-oriented justification process is used to fit tributaries created with clock impairments.
Gigabit Ethernet protocols, Gigabit Ethernet Alarms, Gigabit Ethernet test, Gigabit Ethernet test, Gigabit Ethernet test, Gigabit Ethernet tester
Fig. 6 PDH hierarchies are not synchronous, and variations can be expected in the bit rate clock - in this case a justification mechanism is implemented. If all Ji=1, then the Ri bit does not contain information. If all
Ji=0, then Ri contains information.
Ji Justification control bit of the ith tributary
R1R2R3R4 4 justification bits, one per tributary
8
34
8448 kbps (+5 ppm) 8448 kbps (+7 ppm) 8448 kbps (+2 ppm) 8448 kbps (-10 ppm) 34368 kbps (-10 ppm) A S T1T2T3T4 J1J2J3J4 J1J2J3J4R1R2 R4 1 T4 T1 T4 T1 R3 T1 T4FAS
n Multiplexer 0 1 C10 1 0 1 1 0 00 0S S S S 0 1 S S S S a 1b 1c 1d 1a16b16c16d16 c 2d 2 a 2b 2 a17b17c17d17 0 1 C20 1 0 1 1 S 0 1 S S S S a 3b 3c 3d 3a18b18c18d18 Frame 0 1 2 3Time Slot 0 Time Slot 16
S T1T2T3T4 1 T1
FAS
n 2 Mbps 2 Mbps CAS 8, 34, 140 MbpsRAI (bit A=1)
LOF AIS
: X : 1
Multiplexer B Network Element Multiplexer A AIS Formats: Alarm Management: 1 n RAI Formats: NE Network Element NE A A A A
Fig. 7 When a multiplexer detects an LOS or LOF, it sends an RAI to its partner multiplexer and forwards an AIS to the next NE.
ID Detection Criteria
AIS Alarm Indication Signal. It is detected if there are two or less zeros (ITU-T G.775).
LOF Loss of Frame alarm. It is raised after three consecutive frames with FAS error or three consecutive signalling bits (ITU-T G.706).
LOS Loss of Frame Signal alarm.
RAI Remote Alarm Indication. It is detected after three consecutive frames with the A bit equal to 1 (ITU-T G.732).
FAS error Frame Alignment Signal error, indicating an incorrect bit in the alignment word.
Bit error Bit sequence mismatch (when the transmitted pattern is known).
Code error Violation on coding sequence.
CRC-LOM Cyclic Redundancy Checksum - Loss of Multiframe. Activated if there is LOF, and deactivated after one correct FAS and two correct CRC-MFAS (ITU-T G.706).
CAS-LOM Channel-Associated Signalling - Loss of Multiframe. Raised after two consecutive MFAS errors or two multiframes with time slot 16 bits equal to 0 (ITU-T G.732).
CAS-MRAI Channel-Associated Signalling - Multiframe Remote Alarm Indication. Detected after two consecutive frames with the MRAI bit equal to 1 (ITU-T G.732).
CAS-MAIS Channel-Associated Signaling - Multiframe Alarm Indication Signal. Detected if there are less than three zeros in the time slot 16 during two consecutive multiframes.
CRC error Cyclic Redundancy Check error. Raised if one or more bits are erroneous, whenever CRC-LOM is off (ITU-T G.706).
REBE Remote End Block Error. Raised if the first bit of the frames 14 and 16 is 0 (ITU-T G.706).
Table 2 2 Mbps events: alarms, errors and event indications
Table 3 PDH events: alarms, errors and event indications for all the hierarchies
ID Explanation
AIS Alarm Indication Signal. This is detected if less than six zeros in a frame in the case of 140 Mbps, or less than three zeros in 34 Mbps and 8 Mbps.
LOF Loss of Frame alarm. Raised after four consecutive frames with FAS error
LOS Loss of Frame Signal alarm
RAI Remote Alarm Indication. Detected after two consecutive frames with A equals1
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DS2 x 7 x 24 DS1 x 4 44.736 Mbps 6.312 Mbps 1.544 Mbps 64 kbps DS0DS0
T1
T2
T3
DS1 DS3 x 24 DS1 x 2 64 kbpsDS0
T1
T1c
DS2 DS1c 3.152 Mbps 1.544 Mbps x 24 DS1 x 28 64 kbpsDS0
T1
T3
DS3 44.736 Mbps 1.544 Mbps M1 M12 M23 DS0 DS1 M1 M11c DS0 DS1 M1 M13Fig. 8 T-Carrier hierarchy (US)
Fig. 10 The DS2 frame or M12 multiplexing and DS3 frame.
Code e t ype p a at o
00110010 11111111 DS3 equipment failure Service Affecting (SA), requires quick attention 00011110 11111111 DS3 equipment failure Non-Service Affecting (NSA)
00000000 11111111 DS1 equipment failure Service Affecting (SA), requires quick attention 00001010 11111111 DS1 equipment failure Non-Service Affecting (NSA)
00011100 11111111 DS3 LOS Loss of Signal
00101010 11111111 Multiple DS1 LOS Multiple Loss of Signal in the DS1 tributaries 00111100 11111111 Single DS1 LOS Loss of Signal received from a DS1
00000000 11111111 DS3 OOF Out of Frame in the DS3 signal
00101100 11111111 DS2 AIS Alarm Indication Signal received from a DS2
Test and Measurement¡
NE In-Service-Measurement E1 E4 E1 NE NE E1 E1 E4 NE Test Equipment 2 Out-of-Service-Measurement (ISM) (OOSM) Pattern Generation Double or simple, frame analyzer 140 140 2 Error Detection SERIAL OUTPUT % ROUTE ALLOCATION OK DEGRADED BAD LIMIT LIMIT OK BAD Performance Measurement 140 2 2 140 140 e f: 70 07 06 02 05 .05Made
in EU
desig
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2
he AT-2048 is the ultimate E1 tester designed in 2011 & 2012for field engineers that are installing, commissioning and troubleshooting E1 links, Synchonization Networks, and Datacom circuits. This instrument, designed and manufactured in Europe by ALBEDO Telecom, is a brand new platform, incorporating the latest available electronics, consequently you will enjoy top performance, high accuracy and, of course, a very competitive price.
• All in one: E1, nx64, Datacom, Jitter, Wander, Frame Relay
• Double port • Pulse Mask
• RJ45 balanced interfaces
• New datacom interfaces with CISCO data cables • Display 480 x 272 TFT full color screen
• 2xUSB and Ethernet ports • High performance
• Extra rugged while lightweight (1kg) • VNC remote control
