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A strange interface problem on ASR1001X

Currently we have a router ASR-1001X and using 100M MSTP link leased from ISP to connect HQ corerouter.  The connectivity is UTP, so we inserted GE-T and configured 100M with no auto negotiation, the port is working fine as below


interface GigabitEthernet0/0/2
ip address X.X.X.X
no ip redirects
no ip unreachables
no ip proxy-arp
load-interval 30
speed 100
no negotiation auto


Yesterday I tried to change the link from cable to Fibre for upgrading the bandwidth by replacing the GE-T to GLC-LH-SMD on the same slot. After I inserted the SFP without change any configuration, the interface recognize the SFP but the link status could not change to up.  I found the "speed 100" was disppeared from the interface and "speed" command is no longer available from command line. Then I connected the fibre to another ASR1001X with same confugration (without "speed100") for testing, it was working fine. So i suspect the problem was caused by the "speed 100" was not really removed from the configuration which made the speed mode mismatch with ISP.


Now the change window has closed and we need to schedule another event to do the upgrading. So I would like to check if my suspect is correct ?  Shall we remove the "speed 100" under GE-T before changing to fibre module ?


Cisco IOS XE Software, Version 16.07.02
Cisco IOS Software [Fuji], ASR1000 Software (X86_64_LINUX_IOSD-UNIVERSALK9-M), Version 16.7.2, RELEASE SOFTWARE (fc3)
Technical Support:
Copyright (c) 1986-2018 by Cisco Systems, Inc.
Compiled Tue 29-May-18 19:30 by mcpre


Below is the show interface output with GE-T module, currently working fine

GigabitEthernet0/0/2 is up, line protocol is up
Hardware is BUILT-IN-2T+6X1GE, address is 286f.7f7e.de84 (bia 286f.7f7e.de84)
Internet address is X.X.X.X/30
MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec,
reliability 255/255, txload 1/255, rxload 4/255
Encapsulation ARPA, loopback not set
Keepalive not supported
Full Duplex, 100Mbps, link type is force-up, media type is T
output flow-control is on, input flow-control is on
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:14:08, output 00:14:08, output hang never
Last clearing of "show interface" counters never
Input queue: 0/375/0/0 (size/max/drops/flushes); Total output drops: 12022
Queueing strategy: Class-based queueing
Output queue: 0/40 (size/max)
30 second input rate 1843000 bits/sec, 360 packets/sec
30 second output rate 574000 bits/sec, 262 packets/sec
12829944 packets input, 7338499108 bytes, 0 no buffer
Received 0 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
1 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 22046 multicast, 0 pause input
13686291 packets output, 4410557832 bytes, 0 underruns
0 output errors, 0 collisions, 2 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out
7 carrier transitions

Hall of Fame Community Legend

Re: A strange interface problem on ASR1001X

Fibre optic modules have only one speed and duplex settings.

Re: A strange interface problem on ASR1001X

Thanks for the reply. But the problem is the port could not be up after we directly switched to Fiber SFP, and the link is working good in another ASR with same port configuration. The only thing I can found is we configured “speed 100” under GT-E which was not removed before switch to Fiber. So I suspect the “speed 100” is still working even it was disappeared from the port. Just want to make sure whether this is the root cause.
Hall of Fame Community Legend

Re: A strange interface problem on ASR1001X

Could be an IOS bug.
Remove the "speed 100" command and replace the SFP (from copper to fibre) and see if it improve things.
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