The Questions about the Cisco 10GBASE X2 Module & SFP Compatibility

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There is a common question about the X2 and SFP Compatibility always asked by users in different cases.

The more detailed Qs you can read as follows:

Q1: “I have a X2-10GB-LX4 in a core switch, I need to connect a WLC8510 which uses SFP+ optics, is there a compatible SFP that will work?”

Q2: Issue One: “I have a 6506-E with WS-X6708-10Gig Modules and i have installed X2-10G-LX4 transceiver on them, on the other side i have a UCS 6120 and installed a SFP-10G-SR. The link between the 2 does not come up, what could be the reason for that? The distance between the 2 is 10 meters and i have already tried changing the cables.”

Issue Two: “If i connect the WS-X6708-10Gid module with X2-10GB-LR module and connect it to X2-10GB-LR on another 6506-E, the link comes up. That means there is no problem with the Module or the ios on the switch. But if connect X2-10GB-LX4 on 6506-E and X2-10GB-LX4 on the other side, the link does not come up. Any clue what could be the reason? I have already tried changing the transceiver.

Q3: “I need to connect two 6506 with X2-10GB-LX4, they reside in adjacent racks, so the patch cord length is no more than 10 meters. The X2-10GB-LX4 documentation is not clear about SMF ranges, it only notes that

“Another alternative for short reaches within the same location is to use a single-mode patch cable. There will be no saturation over single-mode fiber. Please note the 10GBASE-LX4 devices can reach up to 10km over single-mode fiber as per compliance to IEEE.”

The MMF notes are much clearer, they say I can use OM2 MMF with mode conditioning patchcords and 5db 1300nm attentuators, also I could use OM3 MMF with same attentuators, but that’s the configurations I’d prefer to avoid.

So could I just get an SMF patchcord and plug in to both tranceivers? Have I need to use attentuators or whatever else on such kind of link?”

Q4: “i need to know about situation that i need connection between SFP+ with X2. i have 4849 E-F and it just support SFP+ and in otherside i have 6509E and i can no find any Line Card with SFP+ Support and i should use 10G connection between them . Please show me the way that i can connect this two device.”

Q5:On 6500, i have X2-10GB-LX4 and on 3750-x i have SFP-10G-LRM=. Upon connecting the fiber cable, link is not getting up. i am searching for similar kind of problems faced by other ppl but only one reference i found out about their incompatibility, but i think it is not correct as cisco mention in the data sheet that they are compatible. Also, i checked the mode conditioning patch cord requirement for this but it is required for OM1 and OM2….and I am using OM3 patch cord.

Trying to solve this for couple of days, but still struggling. do let me know if you has experienced the same or know anything how it can work.”

Q6: “Is it possible for a Cisco 3750e with Cisco X2-10GB-LX4 to link to a Cisco SFP-10G-LRM in a 4507R+E. The intermediary Fibre is OM3 50 micron. Switches are Approx 70Mtr Apart. Or is there any known issue which would prevent a link establishment.”

…More Qs and problems are often asked by Cisco users. From the questions above we noticed that the more tips we need to consider while connecting the different Cisco Hardware and modules with X2-10G-LX4 ?

And now in this article we will talk about the compatibility of X2 and SFP.

Firstly, we need to know who the Cisco 10G X2 Module is. The Cisco10GBASE X2 modules offer customers a wide variety of 10 Gigabit Ethernet connectivity options for data center, enterprise wiring closet, and service provider transport applications.

Cisco 10GBASE X2 and Xenpak Modules

Main features of Cisco 10GBASE X2 modules include:

  1. ● Support 10GBASE Ethernet
  2. ● Hot-swappable input/output device plugs into an Ethernet X2 port of a Cisco switch or router to link the port with the network
  3. ● Provides flexibility of interface choice
  4. ● Supports “pay-as-you-populate” model
  5. ● Supports the Cisco quality identification (ID) feature that enables a Cisco switch or router to identify whether the module is certified and tested by Cisco
  6. ● Has optical interoperability with respective 10GBASE Xenpak, 10GBASE XFP and 10GBASE SFP+ modules on the same link

Cisco X2-10GB-CX4: The Cisco 10GBASE-CX4 Module supports link lengths of up to 15m on CX4 cable.

Cisco X2-10GB-T: The Cisco 10GBASE-T Module supports link lengths of up to 100m on CAT6A or CAT7 copper cable.

Cisco X2-10GB-LRM: The Cisco 10GBASE-LRM Module supports link lengths of 220m on standard Fiber Distributed Data Interface (FDDI) grade multimode fiber (MMF). To ensure that specifications are met over FDDI-grade, OM1 and OM2 fibers, the transmitter should be coupled through a mode conditioning patch cord. No mode conditioning patch cord is required for applications over OM3. For additional information on mode conditioning patch cord requirements please see:

The Cisco 10GBASE-LRM Module also supports link lengths of 300m on standard single-mode fiber (SMF, G.652).

Cisco X2-10GB-LX4: The Cisco 10GBASE-LX4 Module supports link lengths of 300m on standard FDDI grade MMF. To ensure that specifications are met, the transmitter output should be coupled through a mode conditioning patch cord. For additional information on mode conditioning patch cord requirements please see:

Cisco X2-10GB-SR: The Cisco 10GBASE-SR Module supports a link length of 26m on standard FDDI grade MMF. Using 2000 MHz*km MMF (OM3), up to 300m link lengths are possible. Using 4700 MHz*km MMF (OM4), up to 400m link lengths are possible.

Cisco X2-10GB-LR: The Cisco 10GBASE-LR Module supports a link length of 10 kilometers on standard single-mode fiber (SMF, G.652).

Cisco X2-10GB-ER: The Cisco 10GBASE-ER Module supports a link length of up to 40 kilometers on standard single-mode fiber (SMF, G.652).

Cisco X2-10GB-ZR: Supports link lengths of up to about 80 km on SMF. This interface is not part of the 10 Gigabit Ethernet standard but is built according to Cisco optical specifications.


Technical Specifications

Platform Support: Cisco X2 modules are supported on Cisco switches and routers. For more details, refer to the document Cisco Xenpak/X2 Compatibility Matrix.

Connectors and Cabling

Connectors: Dual SC/PC connector (-SR, -LR, -LRM, -LX4, -ER, -ZR); InfiniBand 4x connector (-CX4); RJ-45 connector (-T).

Note: For optical X2 modules, only connections with patch cords with PC or UPC connectors are supported. Patch cords with APC connectors are not supported. All cables and cable assemblies used must be compliant with the standards specified in the standards section.


X2 Port Cabling Specifications

X2 Port Cabling Specifications-


  1. ● IEEE 802.3ae (-LR, -SR, -LX4, -ER)
  2. ● IEEE 802.3ak (-CX4)
  3. ● IEEE 802.3aq (-LRM)
  4. ● IEEE 802.3an (-T)

The following Table shows the main optical characteristics for the Cisco X2 module. The Cisco X2-10GB-CX4 and X2-10GB-T are not optical modules and therefore are not listed in the Table.

Optical Transmit and Receive Specifications

Product Type Transmit Power (dBm)* Receive Power (dBm)* Transmit and Receive Wavelength Range (nm)
Maximum Minimum Maximum Minimum Transmit Receive
Cisco X2-10GB-SR 10GBASE-SR 850 nm MMF -1.2** -7.3 -1.0 -9.9 840 to 860
Cisco X2-10GB-LRM 10GBASE-LRM 1310 nm MMF 0.5 -6.5 0.5 -8.4 (in average)

and -6.4 (in OMA)***

1260 to 1355
Cisco X2-10GB-LX4 10GBASE-LX4 WWDM 1300 nm MMF -0.5 per lane -6.75 per lane in OMA -0.5 per lane -14.25 per lane in OMA Four lanes; overall range: 1269 to 1356
Cisco X2-10GB-LR 10GBASE-LR 1310 nm SMF 0.5 -8.2 0.5 -14.4 1260 to 1355 1260 to 1565****
Cisco X2-10GB-ER 10GBASE-ER 1550 nm SMF 4.0 -4.7 -1.0 -15.8 1530 to 1565 1260 to 1565****
  • * Transmitter and receiver power is in average, unless specified.
  • ** The launch power shall be the lesser of the class 1 safety limit or the maximum receive power. Class 1 laser requirements are defined by IEC 60825-1: 2001.
  • *** Both average and OMA specifications must be met simultaneously.
  • **** Even though the receiver can tolerate a wide wavelength range, the specifications are guaranteed for a signal within the transmit wavelength range.


X2-10GB-ZR Optical Parameters

X2-10GB-ZR Optical Parameters

Note: Parameters are specified over temperature and at end of life unless otherwise noted. When shorter distances of single-mode fiber are used, an inline optical attenuator must be used to avoid overloading and damaging the receiver.


  1. Dimensions (D x W x H): 91mm x 36mm x 13.46mm. Cisco X2s typically weigh under 300 grams
  2. Environmental Conditions and Power Requirements
  3. The operating temperature range is between 0 and 70°C (32 to 158°F); storage temperature range is -40 to 85°C (-40 to 185°F)
  4. The maximum power consumption per Cisco X2 module is 4W


Ordering Cisco X2 and Respective Cables

Ordering Cisco X2 and Respective Cables


Regulatory and Standards Compliance


  • GR-20-CORE: Generic Requirements for Optical Fiber and Optical Fiber Cable
  • GR-326-CORE: Generic Requirements for Single-Mode Optical Connectors and Jumper Assemblies
  • GR-1435-CORE: Generic Requirements for Multifiber Optical Connectors


  • Laser Class 1 21CFR-1040 LN#50 7/2001
  • Laser Class 1 IEC60825-1

…So the answers for the questions above you can find out from the Data Sheet of the Cisco 10GBASE X2 Modules. Pay attention to the key information and tips that are related to the main modules commonly used.


More Related Cisco Module Topics

Cisco 10GBASE SFP+ Modules Overview

Cisco XFP vs. SFP vs. SFP+

About Transceiver & Cisco Transceiver Modules

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