IXIA OC12 ATM/POS Load Modules
This chapter provides details about OC12 ATM/POS (LM622MR) load module specifications and features.
The OC12 ATM/POS (LM622MR) load module enables high performance testing of routers and broadband aggregation devices such as DSLAMs and PPP termination systems. The board accommodates pluggable PHYs: The features available for these load modules are included in the Port Features by Port Type matrix, which is located on the ixiacom.com website under Support/User Guides/Spreadsheets.
- 1310 nm multimode optics with dual-SC connectors
- Small Form-factor Pluggable (SFP) socket. Ixia offers 1310 nm singlemode and multimode transceivers with LC connectors; others may be purchased independently.
The LM622MR load module is shown in the following figure.
Figure: LM622MR Load Module with Pluggable PHYs Installed
Part Numbers
The currently available part numbers are shown in the following table. Items without a Price List Names entry are no longer available.
Load Module | Part Number | Description |
---|---|---|
LM622MR |
LM622MR |
2-port ATM/Packet over SONET Load Module. Supports 622 and 155 Mbps data rates. Requires the purchase of 2 PHY modules (OC3OC12PHY or OC3OC12PHY-SFP) and the OPTATMMR and/or OPTPOSMR operational mode option. |
LM622MR-512 |
LM622MR-512 |
2-port ATM/Packet over SONET Load Module. Supports 622 and 155 Mbps data rates. Requires the purchase of 2 PHY modules (OC3OC12PHY or OC3OC12PHY-SFP) and the OPTATMMR and/or OPTPOSMR operational mode option. |
OPTATMMR |
ATM operational mode option for LM622MR. |
|
OPTPOSMR |
OC12c/OC3c Packet over SONET (POS) operational mode option for LM622MR. |
|
OC3OC12PHY |
Single-port OC-3/OC-12 PHY module for the ATM/Packet over SONET Load Module. 1310 nm multimode optics with dual SC connectors. |
|
OC3OC12PHY-SFP |
Single-port OC-3/OC-12 PHY module for the ATM/Packet over SONET Load Module. Requires one SFP pluggable transceiver (not included). |
|
SFP-OC12MM1310D |
Multirate (OC-3, OC-12) SFP transceiver. 1310 nm, multimode with dual LC connectors. Supports diagnostic features. |
|
SFP-OC12SM1310D |
Multirate (OC-3, OC-12) SFP transceiver. 1310 nm, single mode with dual LC connectors. Supports diagnostic features. |
OC12 POS 622 Specifications
The OC12c POS specifications for the LM622MR load module are contained in the following table.
LM622MR | LM622MR-512 | |
---|---|---|
# ports |
2 |
2 |
Data Rate |
1-100% of OC12/OC3 speeds |
1-100% of OC12/OC3 speeds |
Connector |
Changeable physical interface (PHY) per port:
|
Changeable physical interface (PHY) per port:
PHY clock-in and clock-out:
|
CPCU RAM |
256 |
512 |
Capture buffer size |
8 MB |
8 MB |
Captured packet size |
34 - 65535 bytes |
34 - 65535 bytes |
Streams per port |
255 Packet Streams |
255 Packet Streams |
Advanced streams |
160 |
160 |
Frame size: min-max |
35 - 65536 bytes (at full line rate)12 - 65536 bytes (otherwise) |
35 - 65536 bytes (at full line rate)12 - 65536 bytes (otherwise) |
Inter-frame gap: min-max |
1 ms - 4.294967 secs |
1 ms - 4.294967 secs |
Inter-burst gap: min-max |
1 ms - 4.294967 secs |
1 ms - 4.294967 secs |
Inter-stream gap: min-max |
1 ms - 4.294967 secs |
1 ms - 4.294967 secs |
Latency |
20 ns resolutionMinimum frame size of 33 bytes is required. |
20 ns resolutionMinimum frame size of 33 bytes is required. |
ATM Specifications
The ATM load module specifications for the LM622MR are contained in the following table.
LM622MR/LM622MR-512 | |
---|---|
# ports |
2 |
Data Rate |
0-100% of OC-12/OC-3 speeds |
Connector |
Changeable physical interface (PHY) per port:
PHY clock-in and clock-out:
|
Capture buffer size |
8 MB |
Captured packet size |
49 - 64K bytes (Note 1) |
Streams per port |
4096 shared by 15 interleaved transmit engines |
Frame size: min-max |
40 - 65,536 bytes (Note 1) |
Latency |
20 ns resolution |
(Note 1) ATM ports transmits a packet of 65568 bytes, including the header. The receive buffer, however, is restricted to 65536 bytes. The last 32 bytes of a maximum size packet is not visible in the capture buffer.
ATM related specifications are detailed in the following table.
Parameter | Specification |
---|---|
Encapsulation |
|
Virtual Circuits |
65,536 VC ids distributed among 4,096 unique streams |
Cell Header Format |
UNI or NNI per port |
ATM Framing |
AAL5, Constant Bit Rate (CBR) or Unspecified Bit Rate (UBR) |
Physical Interfaces
Two pluggable physical interfaces are available for the ATM card:
- OC3OC12PHY: Single OC3/OC12 port module. 1310 nm multimode optics with dual-SC connectors. This module is shown in the following figure. The optical characteristics are expressed in the table below.
- OC3OC12PHY-SFP: Single OC3/OC12 port module. The PHY accommodates a SFP transceiver, which is not included with this part. Ixia offers two transceivers:
- SFP-OC12MM1310D: 1310nm multimode transceiver
- SFP-OC12SM1310D: 1310nm singlemode transceiver
Figure: OC3OC12PHY Physical Interface

Transmitter/Receiver | Specification | OC12/OC3 Multimode |
---|---|---|
Transmitter |
Fiber |
62.5um fiber |
Wavelength |
1270nm - 1380nm |
|
Mean Launched Power |
-20dBm to -14dBm |
|
Minimum Extinction Ratio |
10dB |
|
Safety |
LED based |
|
Receiver |
Fiber |
62.5um fiber |
Wavelength |
1100nm - 1600 nm |
|
Minimum Sensitivity (OC12) |
-26dBm |
|
Minimum Sensitivity (OC3) |
-30dBm |
|
Minimum Overload |
-14dBm |
The following figure shows an OC3OC12PHY-SFP with a transceiver partially inserted.
Figure: OC3OC12PHY-SFP

The optical characteristics for the two available transceivers are expressed in the following table.
Specification |
SFP-OC12MM1310D (62.5um fiber) |
SFP-OC12SM1310D (short reach) |
---|---|---|
Transmit Center Wavelength Min/Max |
1270 nm/1380 nm |
1260 nm/1360 nm |
Mean Launched Power Min/Max |
-20 dBm/-14 dBm |
-15 dBm/-8 dBm |
Minimum Extinction Ratio |
10dB |
8.2dB |
Safety |
LED based |
Laser based |
Receive Wavelength |
1100nm - 1600nm |
1100nm - 1600nm |
Minimum Sensitivity (OC12) |
-26dBm |
-23dBm |
Minimum Sensitivity (OC3) |
-30dBm |
-8dBm |
Minimum Overload |
-14dBm |
|
Dispersion (OC12) |
13ps/nm |
|
Dispersion (OC3) |
18ps/nm |
The clock-in/clock-out signal characteristics on both PHYs are described in the following tables.
Parameter | Characteristic |
---|---|
Connector |
Female SMA |
Impedance |
50 ohm ± 5%, AC coupled |
Absolute max input |
6V (DC plus half AC peak-to-peak) |
Frequency (OC12) |
77.76 MHz |
Frequency tolerance |
+/- 20ppm |
Duty Cycle |
40/60% of UI |
Jitter limits |
(12kHz to 5MHz) 12 ps rms |
Parameter | Characteristic |
---|---|
Connector |
Female SMA |
Impedance |
50 ohm ± 5%, AC coupled |
Amplitude |
1.3 Vpp minimum, into 50 W. (1.5 Vpp typical) |
Edge rates |
200ps to 340ps (20% to 80%) into 50W |
Duty cycle |
45% to 55% |
Jitter |
20ps max cycle to cycle, >1kHz |
Frequency (OC12) |
77.76 MHz (internal clock mode) |
Frequency (OC3) |
19.44 MHz (internal clock mode) |
Port LEDs
Each OC12c/OC3c port incorporates a set of 6 LEDs, as described in the following table.
LED Label | Usage |
---|---|
LOS |
Red during Loss of Signal and green otherwise. |
LOF |
Red during Loss of Frame and green otherwise. |
Tx |
Green while data is transmitted and blank otherwise. |
Rx |
Green while data is received and blank otherwise. |
Err |
Red on any receive error and blank otherwise. |
Trig |
Blank reserved for future use. |
Statistics
Statistics for ATM/POS cards, under various modes of operation, may be found in Statistics for ATM Modules.