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serial interface will not open 2

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OV105

Technical User
Feb 15, 2010
34
US
Hi,

I was practicing static routing and ran into a problem with the serial interfaces on router 2. I erased the startup-config and executed a reload. I configured serial0 interface and verified the ip address and ip route were correct. I issued the no shutdown command and ctrl Z to get back to the enable prompt. Using the show ip interface command I noticed serial0 was listed as "manual down."

Router 2 and 3 are the same model and IOS version. In the bootup process for router 2 I saw a message saying, NVRAM invalid, possibly due to write erase. Using IOS help, I ran some show commands to see if I could find anything out of the ordinary with the interfaces on this router. I did a show queue command on serial0 and nothing came up. On serial1 the router returned with Ethernet, Null and Serial information.

I noticed serial1 showed administratively down. So I removed the ip address and ip route from serial0 and configured it on serial1. Using a, show ip interface command, I noticed serial1 went into "manual" down.

Does any one have any advice on what the problem may be, or any other steps that may shed light on why the serial interfaces on this router will not open?

Thanks in advance...

 
POst a sh run form each router por favor.

NI!

lol

/

tim@tim-laptop ~ $ sudo apt-get install windows
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Couldn't find package windows...Thank Goodness!
 
Show run from

Router 1

Router#show run
Building configuration...

Current configuration : 629 bytes
!
version 12.3
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
ip subnet-zero
ip cef
!
!
!
!
!
!
!
interface Ethernet0/0
no ip address
shutdown
half-duplex
!
interface TokenRing0/0
no ip address
shutdown
ring-speed 16
!
interface Serial1/0
no ip address
shutdown
!
interface Serial1/1
no ip address
shutdown
!
interface Serial1/2
no ip address
shutdown
!
interface Serial1/3
no ip address
shutdown
!
no ip http server
ip classless
!
!
!
line con 0
line aux 0
line vty 0 4
!
!
end

Interesting thing about the data above. On a hunch I bypassed Serial1/0 on router1 that was connected to Serial0 on Router2 (the interface I cannot open.) I reconfigured Router1 serial1/1 and 1/2 with the ip, mask and clock rate I was using in the static routing lab. I did a copy run start after the last command in the lab.

Router 2

ZR2#show run
Building configuration...

Current configuration:
!
version 11.2
no service password-encryption
no service udp-small-servers
no service tcp-small-servers
!
hostname ZR2
!
enable password Pacific
!
partition flash 2 8 8
!
!
interface Ethernet0
no ip address
shutdown
!
interface Ethernet1
no ip address
shutdown
!
interface Serial0
ip address 192.168.1.2 255.255.255.0
!
interface Serial1
no ip address
shutdown
!
no ip classless
ip route 193.1.1.0 255.255.255.0 192.168.1.1
!
line con 0
line aux 0
line vty 0 4
password Atlantic
login
!
end

Router 3

ZR3#show run
Building configuration...

Current configuration : 550 bytes
!
version 12.1
no service single-slot-reload-enable
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname ZR3
!
enable password Pacific
!
!
!
!
!
ip subnet-zero
!
!
!
!
interface Ethernet0
no ip address
shutdown
!
interface Ethernet1
no ip address
shutdown
!
interface Serial0
ip address 193.1.1.3 255.255.255.0
!
interface Serial1
no ip address
shutdown
!
ip classless
ip http server
!
queue-list 1 interface Serial0 1
!
line con 0
line aux 0
line vty 0 4
password Atlantic
login
!
end
 
From what you said what could ping what and what could not ping what...

ZR1 cannot ping ZR2
That tells me there is something wrong with the serial interface of either ZR1 or ZR2 (config, physical, etc).

ZR1 can ping ZR3 Serial0
Good---nothing wrong with router ZR1

ZR2 cannot ping any one
Something definitely wrong with S0, ZR2 (physical, config)

ZR3 cannot ping ZR2
Again, ZR2 serial, S0

ZR3 can ping ZR1 Serial0, but not Serial1
There is definitely something wrong with S0, ZR2---ZR1, S0 cannot ping because it must be up/up, and so ZR3 cannot use that interface (S0 of ZR1) to get to ZR2 because ZR2 S0 is down.

Now let's look at the configs...

I still don't see the results of whatever serial is connected to ZR2 from ZR1.

Please post the following...

sh cdp nei det from ZR2

sh ip int bri from ZR1 and ZR2

sh run from ZR1

Let me know what serial interfaces are connected to ZR2 and ZR3 from ZR1

I am suspecting root cause to be
1.cable from ZR1 to ZR2
2.serial WIC-1t in ZR2

show cdp neighbors detail from ZR2 will eliminate (or confirm) layer 1 issues of ZR2, s0

/



tim@tim-laptop ~ $ sudo apt-get install windows
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Couldn't find package windows...Thank Goodness!
 
Topology:

ZR1 – S0 (DCE) ip 192.168.1.1 255.255.255.0
To
ZR2 – S0 (DTE) ip 192.168.1.2 255.255.255.0
ip route 193.1.1.0 255.255.255.0 192.168.1.1

ZR1 – S1 (DCE) ip 193.1.1.1 255.255.255.0
To
ZR3 – S0 (DTE) ip 193.1.1.3 255.255.255.0
ip route 192.168.1.0 255.255.255.0 193.1.1.1

ZR2 - Result of [show controllers]
Router 1

Router#show run
interface Ethernet0/0
no ip address
shutdown
half-duplex
!
interface TokenRing0/0
no ip address
shutdown
ring-speed 16
!
interface Serial1/0
no ip address
shutdown
!
interface Serial1/1
no ip address
shutdown
!
interface Serial1/2
no ip address
shutdown
!
interface Serial1/3
no ip address
shutdown
!

Am i missing something ?
I didn't know serial interface could work in bridge mode ...

burt i believe in you man, so when you say nothing wrong with config, i get confused as to why no ip address on any of the R1 interfaces...


We must go always forward, not backward
always up, not down and always twirling twirling towards infinity.
 
He said since they didn't show up (thinking ZR1 was the problem), he stated that he transferred the IP address configs to the serial WICs in module 1 (s1/0, s1/1). I questioned the same thing in my reply.

Thanks for the compliment. Just tell my wife and my boss now!lol

/

tim@tim-laptop ~ $ sudo apt-get install windows
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Couldn't find package windows...Thank Goodness!
 
Now let's look at the configs...

I still don't see the results of whatever serial is connected to ZR2 from ZR1."

Meaning no IP address on s0/0 and s0/1...

See? lol

/

tim@tim-laptop ~ $ sudo apt-get install windows
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Couldn't find package windows...Thank Goodness!
 
The Static Lab called for:

ZR1 S1/0 (DCE) 192.168.1.1 255.255.255.0
connects to
ZR2 Serial0 (DTE) 192.168.1.2 255.255.255.0
ip route 193.1.1.0 255.255.255.0 192.168.1.1

ZR1 S1/1 (DCE) 193.1.1.1 255.255.255.0
connects to
ZR3 Serial0 (DTE) 193.1.1.3 255.255.255.0
ip route 192.168.1.0 255.255.255.0 193.1.1.1

After configuring all of the requirements of the lab, every interface “except” ZR2 Serial0 came up. I erased the startup configs and began the lab from step one. ZR2 Serial0 showed “manual down.”

I began troubleshooting at the physical level and all was well. Using IOS help I searched through the “show” commands. I compared the data of each interface and the only thing I found that was different from the rest was ZR2 Serial0 had no data for “Fair Queueing.” I am not familiar with this, so I had no idea if it was a player in this problem. After spending hours on research with no successful solution, I posted to this group. By the way, thank you one and all for your responses!!!

Next event in this saga, came yesterday from a hunch. I knew ZR1 Serial1/1 was working fine, so I wondered what the results would be if I by-passed ZR1 Serial1/0. So, I re-programmed ZR1 to use Serial1/1 and Serial1/2 and Bingo! ZR2 Serial0 state changed to up/up. All connected interfaces on all three routers were now, for the first time, in the up/up state.

Just to be absolutely certain, I reconfigured router ZR1 to use original Serial1/0 and 1/1 iinterfaces. Serial0 on ZR2 went into manually down. So now I was certain the problem was isolated to ZR1 Serial1/0.

About a half hour ago, I took a DTE/DCE cable and connected the DCE end to ZR3 Serial0 and the DTE end to ZR1 Serial1/0 and was surprised when I saw Serial1/0 go into the up state. About 10 seconds after that my laptop went into reboot. When the computer came up, I repeated my last sequence, Serial1/0 came up, and then the laptop again, went into reboot. Not sure why that happened (twice, no less), but I figured I’d go back to the configuration that worked which moving away from Serial1/0 and using Serial1/1 and Serial1/2.

I emailed the company I purchased the lab kit from and they want me to send in the Serial 4/AS interface so they can check it out.

I have to tell you, I’m bothered by one more thing. Acting once again on a hunch, I reversed the DTE/DCE cable. Serial1/0 on router ZR1 came up! About ten seconds passed before computer just shut right down. After the reboot, I repeated the last sequence. The result was the same, so I figured I would go with the configuration that worked.

So, can anyone explain to me what and why this happened?
 
Yes, you had the cable upside down. They fit both ways. Unfortunately i have done this too. This is why it is so important to have a lab. You can't F@%! up cabling in a simulator.

CCNP
 
Cripes, this is confusing because the DCE side provides the clock rate for the DTE side. Router ZR1 is configured to be the DCE side and router's ZR2 and ZR3 are configured to be the DTE side, but yet when I connected the cable backwards Serial1/0 came up! I must be missing something, somewhere.
 
Here's what you posted...

interface Serial1/0
no ip address
shutdown
!
interface Serial1/1
no ip address
shutdown
!
interface Serial1/2
no ip address
shutdown
!
interface Serial1/3
no ip address
shutdown
!
no ip http server
ip classless
!
!
!
line con 0
line aux 0
line vty 0 4
!
!
end

Interesting thing about the data above. On a hunch I bypassed Serial1/0 on router1 that was connected to Serial0 on Router2 (the interface I cannot open.) I reconfigured Router1 serial1/1 and 1/2 with the ip, mask and clock rate I was using in the static routing lab. I did a copy run start after the last command in the lab.

There are no ip addresses configured on ANY serial interfaces in ZR1!

Post the latest configs that work.

/

tim@tim-laptop ~ $ sudo apt-get install windows
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Couldn't find package windows...Thank Goodness!
 

ZR1#show running-config
Building configuration...

Current configuration : 786 bytes
!
version 12.3
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname ZR1
!
boot-start-marker
boot-end-marker
!
enable password Atlantic
!
no aaa new-model
ip subnet-zero
ip cef
!
!
!
!
!
!
!
interface Ethernet0/0
no ip address
shutdown
half-duplex
!
interface TokenRing0/0
no ip address
shutdown
ring-speed 16
!
interface Serial1/0
no ip address
clock rate 64000
!
interface Serial1/1
ip address 192.168.1.1 255.255.255.0
clock rate 64000
!
interface Serial1/2
ip address 193.1.1.1 255.255.255.0
clock rate 64000
!
interface Serial1/3
no ip address
shutdown
!
no ip http server
ip classless
!
!
!
line con 0
exec-timeout 0 0
logging synchronous
line aux 0
line vty 0 4
password Pacific
login
!
!
end
 

Serial1/0 is down, line protocol is down
Hardware is CD2430 in sync mode
MTU 1500 bytes, BW 128 Kbit, 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 0/0/32 (active/max active/max total)
Reserved Conversations 0/0 (allocated/max allocated)
Available Bandwidth 96 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 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, 839 interface resets
0 output buffer failures, 0 output buffers swapped out
0 carrier transitions
DCD=down DSR=down DTR=down RTS=down CTS=down
Serial1/1 is up, line protocol is up
Hardware is CD2430 in sync mode
Internet address is 192.168.1.1/24
MTU 1500 bytes, BW 128 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation HDLC, loopback not set
Keepalive set (10 sec)
Last input 00:00:05, output 00:00:09, output hang 08:10:40
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 0/1/32 (active/max active/max total)
Reserved Conversations 0/0 (allocated/max allocated)
Available Bandwidth 96 kilobits/sec
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
3104 packets input, 182910 bytes, 0 no buffer
Received 3104 broadcasts, 0 runts, 0 giants, 0 throttles
2 input errors, 2 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
3569 packets output, 371758 bytes, 0 underruns
0 output errors, 0 collisions, 22 interface resets
0 output buffer failures, 0 output buffers swapped out
7 carrier transitions
DCD=up DSR=up DTR=up RTS=up CTS=up
Serial1/2 is up, line protocol is up (looped)
Hardware is CD2430 in sync mode
Internet address is 193.1.1.1/24
MTU 1500 bytes, BW 128 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation HDLC, loopback not set
Keepalive set (10 sec)
Last input 00:00:06, output 00:00:06, 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 0/1/32 (active/max active/max total)
Reserved Conversations 0/0 (allocated/max allocated)
Available Bandwidth 96 kilobits/sec
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
3011 packets input, 209024 bytes, 0 no buffer
Received 3011 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
3009 packets output, 209988 bytes, 0 underruns
0 output errors, 0 collisions, 21 interface resets
0 output buffer failures, 0 output buffers swapped out
15 carrier transitions
 
sh run and sh int and sh cdp nei det from ZR2...


/

tim@tim-laptop ~ $ sudo apt-get install windows
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Couldn't find package windows...Thank Goodness!
 
Today I picked up a copy of the Cisco Portable Command Guide. Very good purchase for me! Inside was a static lab using three routers.

On my three routers I performed an erase startup config and reload and then programmed them according to the lab. I am convinced that the problem is with the 4A/S card in ZR1, serial1/0 and not ZR2.

As with the previous static routing lab, I used Serial1/0 and Serial1/1 on ZR1. On the previousw lab, Serial1/0 was connected to ZR2 serial0.

On the static lab I finished programming about a hour ago, the serial connections were different as were DTE/DCE in/out hookup. Once again, I had trouble with ZR2, but this time it was with Serial1. Yesterday Serial0 was the problem and Serial1 was working fine, but this new lab called for the connection to be made on Serial1.

I altered the static lab and bypassed Serial1/0 on ZR1. So instead of using Serial1/0 and 1/1, I used Serial1/1 and 1/2. As soon as I did this I noticed all of the connected interfaces were showing up/up. To verify, from ZR1 I was able to telnet into ZR2 and ZR3 without any problem. Then, from each router I was able to ping the ip's of the other two routers in this lab.

I really hate to send this card in for repair as it causes a big delay in practicing the labs, but it looks as though I do not have a choice.

Before I do, is there anything you can suggest that may show me if this interface, Serial1/0, is down for a reason I may not be aware of due to my inexperience in programming routers? I really want to be sure that I checked every possible cause of why this interface will not open.

From what I've learned in my studies, an interface that shows down/down indicates a physical problem with the physical connection. I know my DTE/DCE cables are fine. The down/down status eliminates an encapsulation or clock rate misconfiguration. I want to be absolutely sure that the interface is not shut down due to a programming error I may possibly have made and and did not catch.

Thanks again for everyone's help! I will work a few more labs before I send the card off. I'm on a roll and I really hate to break my stride right now [big grin] however I will send it off by Wednesday if no one has any recommendations.

By the way, anyone online from the east coast of Florida?

 
The interface will not open if the other side is down! You need to config the routers as you had them when they did not work, and do a sh cdp nei det from ZR1 and ZR2. If you do not see output from ZR2, then I would bet that WIC-1T is bad.

/

tim@tim-laptop ~ $ sudo apt-get install windows
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Couldn't find package windows...Thank Goodness!
 
I configured the initial static route and the problem is still there. I then configured for the next static lab and ZR1 S1/0 will not open. Moving off of that interface, the labs work fine, so I think it's time to send the WIC-1T in for repair.

Thanks to one and all!!
 
Stars?:)

/

tim@tim-laptop ~ $ sudo apt-get install windows
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Couldn't find package windows...Thank Goodness!
 
Stars? Can you give me a little more information?
 
Ahh, got it. No need for more info. I'm learning :)
 
Thanks!

"Will work for stars!"lol

/

tim@tim-laptop ~ $ sudo apt-get install windows
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Couldn't find package windows...Thank Goodness!
 
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