10G Twinax cable support ASR 1001-HX 10Gig ports

[deprasan]

• ASR 1002-HX is connected to another ASR and Nexus switch using 10G Twinax cable. Port turns up and working if auto negotiation is turned off (SFP+ works on same speed and doesn't negotiate).

TKCC2-GSET01-WN-01A#sh int TenGigabitEthernet0/1/0
TenGigabitEthernet0/1/0 is up, line protocol is up
Hardware is BUILT-IN-8X10G/1G, address is c4b2.3959.8520 (bia c4b2.3959.8520)
Description: TKCC2-GSET01-CR-01A_Eth1/12
Internet address is 172.23.104.65/31
MTU 1500 bytes, BW 10000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive not supported
Full Duplex, 10000Mbps, link type is force-up, media type is unknown media type

1. "show inventory" doesn't list Twinax cable
2.  Media type is unknown and Twinax is not listed in supported transceiver list for ASR 1001-HX

 https://www.cisco.com/c/en/us/td/docs/routers/asr1000/install/guide/1001HX_1002HX/b_ASR1001HX-1002HX_HIG/b_ASR1001HX-1002HX_HIG_chapter_01001.html#concept_5563EEA493F640209B47D488698E2AD9

• 10 G ports changes to down if Twinax cable is replaced with SFP-10G-SR-S transceiver (again it not available in the support transceiver list for ASR 1002-HX)

TKCC2-GSET01-WN-01A#sh int te0/1/0
TenGigabitEthernet0/1/0 is down, line protocol is down
Hardware is BUILT-IN-8X10G/1G, address is c4b2.3959.8520 (bia c4b2.3959.8520)
Description: TKCC2-GSET01-CR-01A_Eth1/12
Internet address is 172.23.104.65/31
MTU 1500 bytes, BW 10000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive not supported
Full Duplex, 10000Mbps, link type is force-up, media type is 10GBase-SR

== Another interface TenGigabitEthernet0/1/1 is up with same SFP+ transceiver. 

== There's another ASR 1001-HX, it has two interface up with 10GBase-SR module

TenGigabitEthernet0/1/1 is up, line protocol is up
Hardware is BUILT-IN-8X10G/1G, address is c4b2.3959.8521 (bia c4b2.3959.8521)
Description: TKCC2-GSET01-CR-01B_Eth1/1
Internet address is 172.23.104.69/31
MTU 1500 bytes, BW 10000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive not supported
Full Duplex, 10000Mbps, link type is force-up, media type is 10GBase-SR

• There's not much difference in terms of technical specifications between Twinax and SFP-10G-SR-S.
• ASR running 16.9.2 IOS-XE release

Questions:

++ Is it okay if Twinax cable used on 10G ports of ASR 1001-HX ?

++ Should we use only SFP+ transceivers in the list no matter there's not much technical difference ?

[Giuseppe Larosa]

Hello @deprasan ,

you should use optics listed as compatible with your network device for production network, because it gives you a sort of insurance that you are following the recommended guidelines. If in the future an issue will arise on the link having used a not listed not ufficially supported transcveir would be considered a wrong choice made by you.

see the following thread

https://community.cisco.com/t5/switching/does-asr-1001-x-support-twinax-cables/m-p/2911089

So i would not use an "unsupported" module on your router.

Hope to help

Giuseppe

[D Kendz]

I had this problem too.  I was using 3M Passive "CU" cables to connect to Nexus 9504.  Kept getting the same until I switched to Active Twinax (ACU) cables, which are a min. of 7m and so not ideal for short intra-cabinet runs, but nonetheless the links came up right away and I can see the cable/transceiver in Inventory.  This may be that Active is "best" for 10G and Cisco is forcing, or it could be a bug or "miss" in programming, but regardless using an Active Twinax cable should resolve this.