Unable to to get to routers connected via serial ports

[Padoke]

I have a home lab set up and I'm working my way through ICND1 so please forgive me in advance for "rookie" mistakes. 

R2 has two serial ports:

1.) R2 Serial 0/0/0 is working fine and can connect to R1 Serial 0/0/0 and ping is successful 

2.) R2 Serial 0/1/0 is offline while connected to R3 Serial 0/0/0.

I've attempted no shut down commands to bring the interface up with no luck. One thing I have noticed on R2 Serial 0/1/0, it has a Queueing strategy: Weighted-fair. All of my other Serial ports on all of my other routers have Queueing strategy: fifo. Could this be causing the connection issue between R2 Serial 0/1/0 and R3 Serial 0/0/0?

Thanks in advance!

[Georg Pauwen]

Hello,

provided you are using the correct cable (DTE/DCE), typically the serial port on the DCE end needs to have the 'clock rate'command configured.

Is the port down/down or up/down ?

[Padoke]

R2 Serial 0/1/0 is down/down and so is R3 Serial 0/0/0. No shutdown commands have been issued on both interfaces. The IP addresses fall in the same subnet.

I issued a "erase startup-config" on R2 and R3 and reloaded them both just to make sure I didn't have some odd configuration hanging around.

I'm using T1 DSU Serial cables that were made from Cat 5e cabling. I have also tested the cables to verify they are operational and both DSU Serial cables I'm using are working. Both cables work when connecting from R2 S0/0/0 to R1 S0/0/0 and pings are successful with both cables.

[luis_cordova]

Hi @Padoke ,

Just to discard:
Are both ends of the  link UP?

Do you have any type of PPP implemented?

Regards

[Padoke]

Both ends of the link are down/down. No custom PPP implementation.

[Georg Pauwen]

Hello,

post the output of 'show interfaces serial 0/1/0' from R2, and 'show interfaces serial 0/1/0' from R3.

[Padoke]

Here is  the output of R2 S0/1/0 and R3 S0/0/0 from "show interface" command:

R2#sho int s0/1/0
Serial0/1/0 is down, line protocol is down
Hardware is GT96K with integrated T1 CSU/DSU
Internet address is 10.1.1.2/30
MTU 1500 bytes, BW 1536 Kbit/sec, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation HDLC, loopback not set
Keepalive set (10 sec)
Last input never, output never, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: weighted fair
Output queue: 0/1000/64/0 (size/max total/threshold/drops)
Conversations 0/0/256 (active/max active/max total)
Reserved Conversations 0/0 (allocated/max allocated)
Available Bandwidth 1152 kilobits/sec
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
0 packets input, 0 bytes, 0 no buffer
Received 0 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
0 packets output, 0 bytes, 0 underruns
0 output errors, 0 collisions, 7 interface resets
0 unknown protocol drops
0 output buffer failures, 0 output buffers swapped out
0 carrier transitions
DCD=down DSR=up DTR=up RTS=up CTS=down

-------------------------------------------------------------------------

R3#sho int s0/0/0
Serial0/0/0 is down, line protocol is down
Hardware is GT96K with integrated T1 CSU/DSU
Internet address is 10.1.1.1/30
MTU 1500 bytes, BW 1536 Kbit/sec, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation HDLC, loopback not set
Keepalive set (10 sec)
Last input 01:57:24, output 01:57:22, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
18 packets input, 2308 bytes, 0 no buffer
Received 18 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
16 packets output, 1899 bytes, 0 underruns
0 output errors, 0 collisions, 244 interface resets
0 unknown protocol drops
0 output buffer failures, 0 output buffers swapped out
4 carrier transitions
DCD=down DSR=up DTR=up RTS=up CTS=down

[luis_cordova]

Hi @Padoke ,

Again to discard:
If you are occupying the same HWIC in R2, the interface in R2 should be Serial 0/0/1.
Could you verify that?

Regards

[Padoke]

In R2 I have an HWIC installed in slot HWIC 0 that is connected to R1 HWIC 0. In R2 I have an HWIC installed in HWIC 1 that is connected to HWIC 0 in R3.

[luis_cordova]

Hi @Padoke ,

Could you share an image (photo) of the back of R2, where the connected HWICs are displayed?

I'm sorry if it's annoying

Regards

[Padoke]

No worries at all and no apologies required. I really appreciate the help!

R1 is on the bottom

R2 is in the middle

R3 is on the top

[Georg Pauwen]

Hello,

could be a cabling problem. Try the cable from R1 to R2 on the link between R2 and R3...

[Padoke]

R2 S0/1/0 is still down/down after swapping cables

I've attached another screenshot of the interfaces after swapping cables 

[luis_cordova]

Hi @Padoke ,

Share the result of these commands(R2 and R3)

#show service-module s x/x/x

#test service-module s x/x/x

Where x is the corresponding number

Regards 

[Padoke]

R2#show service-module s0/1/0
Interface Serial0/1/0
Module type is T1/fractional
Hardware revision is 1.2, Software revision is 20161004,
Image checksum is 0x4347ED, Protocol revision is 0.1
Transmitter is sending remote alarm.
Receiver has loss of signal, loss of frame,
Framing is ESF, Line Code is B8ZS, Current clock source is line,
Fraction has 24 timeslots (64 Kbits/sec each), Net bandwidth is 1536 Kbits/sec.
Last module self-test (done at startup): Passed
Last clearing of alarm counters 01:32:58
loss of signal : 1, current duration 01:32:41
loss of frame : 1, current duration 01:32:41
AIS alarm : 0,
Remote alarm : 0,
Module access errors : 0,
Total Data (last 6 15 minute intervals):
0 Line Code Violations, 0 Path Code Violations
0 Slip Secs, 5400 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins
0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 5400 Unavail Secs
Data in current interval (173 seconds elapsed):
0 Line Code Violations, 0 Path Code Violations
0 Slip Secs, 173 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins
0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 173 Unavail Secs
R2#test serv
R2#test service-module s0/1/0
SERVICE_MODULE(Serial0/1/0): Performing service-module self test
R2#
*Sep 4 21:04:16.923: SERVICE_MODULE(Serial0/1/0): self test finished: Passed

--------------------------------------------------------------------------------

R3#sho service-module s0/0/0
Interface Serial0/0/0
Module type is T1/fractional
Hardware revision is 1.2, Software revision is 20161004,
Image checksum is 0x4347ED, Protocol revision is 0.1
Transmitter is sending remote alarm.
Receiver has loss of signal, loss of frame,
Framing is ESF, Line Code is B8ZS, Current clock source is line,
Fraction has 24 timeslots (64 Kbits/sec each), Net bandwidth is 1536 Kbits/sec.
Last module self-test (done 00:00:56): Passed
Last clearing of alarm counters 06:33:26
loss of signal : 3, current duration 03:20:22
loss of frame : 3, current duration 03:20:22
AIS alarm : 0,
Remote alarm : 0,
Module access errors : 0,
Total Data (last 26 15 minute intervals):
19281 Line Code Violations, 0 Path Code Violations
0 Slip Secs, 23273 Fr Loss Secs, 16 Line Err Secs, 0 Degraded Mins
0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 23273 Unavail Secs
Data in current interval (180 seconds elapsed):
0 Line Code Violations, 0 Path Code Violations
0 Slip Secs, 180 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins
0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 180 Unavail Secs
R3#test serv
R3#test service-module s0/0/0
SERVICE_MODULE(Serial0/0/0): Performing service-module self test
R3#
*Sep 4 20:54:39.546: SERVICE_MODULE(Serial0/0/0): self test finished: Passed