Unable to Ping Serial Interfaces but both Up Up!

[flexkikr11]

Hi there Experts just badly needed a wonderful help for my Home Lab issue as I'm about to give up. Couldn't get the two interfaces pingable. I have got R1 and R2 connected via DCE/DTE cross-over serial cable and have configs for both routers shown below:

R1#sh run

Building configuration...

Current configuration : 811 bytes

!

version 12.1

no service single-slot-reload-enable

service timestamps debug uptime

service timestamps log uptime

service password-encryption

!

hostname R1

!

boot bootstrap tftp c2500-i-l.121-27b_4.bin 255.255.255.255

enable secret 5 $1$mdza$1Tcbw2xIy1KQ8XQy1mcHk0

enable password 7 05000F0433

!

ip subnet-zero

no ip domain-lookup

!

interface Ethernet0

ip address 192.168.1.1 255.255.255.0

!

interface Serial0

ip address 172.16.10.1 255.255.255.0

no keepalive

clockrate 64000

!

interface Serial1

ip address 172.16.11.1 255.255.255.0

no keepalive

clockrate 64000

!

interface BRI0

no ip address

no ip route-cache

no ip mroute-cache

shutdown

!

ip classless

R1#

R1#sh ip int brief

Interface IP-Address OK? Method Status Protocol

BRI0 unassigned YES NVRAM administratively down down

BRI0:1 unassigned YES unset administratively down down

BRI0:2 unassigned YES unset administratively down down

Ethernet0 192.168.1.1 YES NVRAM up up

Serial0 172.16.10.1 YES NVRAM up up

Serial1 172.16.11.1 YES NVRAM down down

R1#

R1#sh controllers s 0

HD unit 0, idb = 0x12797C, driver structure at 0x12DD08

buffer size 1524 HD unit 0, V.35 DCE cable, clockrate 64000

cpb = 0x2, eda = 0x4140, cda = 0x4000

RX ring with 16 entries at 0x4024000

00 bd_ptr=0x4000 pak=0x12F1F8 ds=0x4027FC4 status=80 pak_size=0

01 bd_ptr=0x4014 pak=0x12F44C ds=0x4028680 status=80 pak_size=0

02 bd_ptr=0x4028 pak=0x12F6A0 ds=0x4028D3C status=80 pak_size=0

03 bd_ptr=0x403C pak=0x12F8F4 ds=0x40293F8 status=80 pak_size=0

04 bd_ptr=0x4050 pak=0x12FB48 ds=0x4029AB4 status=80 pak_size=0

05 bd_ptr=0x4064 pak=0x12FD9C ds=0x402A170 status=80 pak_size=0

06 bd_ptr=0x4078 pak=0x12FFF0 ds=0x402A82C status=80 pak_size=0

07 bd_ptr=0x408C pak=0x130244 ds=0x402AEE8 status=80 pak_size=0

08 bd_ptr=0x40A0 pak=0x130498 ds=0x402B5A4 status=80 pak_size=0

09 bd_ptr=0x40B4 pak=0x1306EC ds=0x402BC60 status=80 pak_size=0

10 bd_ptr=0x40C8 pak=0x130940 ds=0x402C31C status=80 pak_size=0

11 bd_ptr=0x40DC pak=0x130B94 ds=0x402C9D8 status=80 pak_size=0

12 bd_ptr=0x40F0 pak=0x130DE8 ds=0x402D094 status=80 pak_size=0

13 bd_ptr=0x4104 pak=0x13103C ds=0x402D750 status=80 pak_size=0

14 bd_ptr=0x4118 pak=0x131290 ds=0x402DE0C status=80 pak_size=0

15 bd_ptr=0x412C pak=0x1314E4 ds=0x402E4C8 status=80 pak_size=0

16 bd_ptr=0x4140 pak=0x131738 ds=0x402EB84 status=80 pak_size=0

cpb = 0x2, eda = 0x4800, cda = 0x4800

TX ring with 1 entries at 0x4024800

00 bd_ptr=0x4800 pak=0x000000 ds=0x4047E98 status=80 pak_size=285

01 bd_ptr=0x4814 pak=0x000000 ds=0x4048C10 status=80 pak_size=285

0 missed datagrams, 0 overruns

0 bad datagram encapsulations, 0 memory errors

0 transmitter underruns

0 residual bit errors

run out of characters will post the next configs on the next reply

[John Blakley · Accepted solution]

Personally, I think you have a cable or interface problem. Do you have another cable you can try?

John

[John Blakley]

Oh, another thing:

Can you post "sh controllers S0" from both routers?

[flexkikr11]

R1#show controllers s 0

HD unit 0, idb = 0x12797C, driver structure at 0x12DD08

buffer size 1524 HD unit 0, V.35 DCE cable, clockrate 64000

cpb = 0x2, eda = 0x4014, cda = 0x4028

RX ring with 16 entries at 0x4024000

00 bd_ptr=0x4000 pak=0x1314E4 ds=0x402E4C8 status=80 pak_size=328

01 bd_ptr=0x4014 pak=0x12F1F8 ds=0x4027FC4 status=80 pak_size=328

02 bd_ptr=0x4028 pak=0x12F44C ds=0x4028680 status=80 pak_size=328

03 bd_ptr=0x403C pak=0x12EFA4 ds=0x4027908 status=80 pak_size=104

04 bd_ptr=0x4050 pak=0x12F6A0 ds=0x4028D3C status=80 pak_size=104

05 bd_ptr=0x4064 pak=0x12F8F4 ds=0x40293F8 status=80 pak_size=104

06 bd_ptr=0x4078 pak=0x12FB48 ds=0x4029AB4 status=80 pak_size=104

07 bd_ptr=0x408C pak=0x12FD9C ds=0x402A170 status=80 pak_size=104

08 bd_ptr=0x40A0 pak=0x12FFF0 ds=0x402A82C status=80 pak_size=328

09 bd_ptr=0x40B4 pak=0x130244 ds=0x402AEE8 status=80 pak_size=328

10 bd_ptr=0x40C8 pak=0x130498 ds=0x402B5A4 status=80 pak_size=328

11 bd_ptr=0x40DC pak=0x1306EC ds=0x402BC60 status=80 pak_size=328

12 bd_ptr=0x40F0 pak=0x130940 ds=0x402C31C status=80 pak_size=328

13 bd_ptr=0x4104 pak=0x130B94 ds=0x402C9D8 status=80 pak_size=328

14 bd_ptr=0x4118 pak=0x130DE8 ds=0x402D094 status=80 pak_size=328

15 bd_ptr=0x412C pak=0x13103C ds=0x402D750 status=80 pak_size=328

16 bd_ptr=0x4140 pak=0x131290 ds=0x402DE0C status=80 pak_size=328

cpb = 0x2, eda = 0x4800, cda = 0x4800

TX ring with 1 entries at 0x4024800

00 bd_ptr=0x4800 pak=0x000000 ds=0x4006140 status=80 pak_size=285

01 bd_ptr=0x4814 pak=0x000000 ds=0x40067FC status=80 pak_size=285

0 missed datagrams, 0 overruns

0 bad datagram encapsulations, 0 memory errors

0 transmitter underruns

0 residual bit errors

R1#

R2#sh controllers s 0

HD unit 0, idb = 0x29F1D4, driver structure at 0x2A05F0

buffer size 1524 HD unit 0, V.35 DTE cable

cpb = 0xE2, eda = 0x4140, cda = 0x4000

RX ring with 16 entries at 0xE24000

00 bd_ptr=0x4000 pak=0x2C8578 ds=0xE27FC4 status=80 pak_size=0

01 bd_ptr=0x4014 pak=0x2C8860 ds=0xE28680 status=80 pak_size=0

02 bd_ptr=0x4028 pak=0x2C8B48 ds=0xE28D3C status=80 pak_size=0

03 bd_ptr=0x403C pak=0x2C8E30 ds=0xE293F8 status=80 pak_size=0

04 bd_ptr=0x4050 pak=0x2C9118 ds=0xE29AB4 status=80 pak_size=0

05 bd_ptr=0x4064 pak=0x2C9400 ds=0xE2A170 status=80 pak_size=0

06 bd_ptr=0x4078 pak=0x2C96E8 ds=0xE2A82C status=80 pak_size=0

07 bd_ptr=0x408C pak=0x2C99D0 ds=0xE2AEE8 status=80 pak_size=0

08 bd_ptr=0x40A0 pak=0x2C9CB8 ds=0xE2B5A4 status=80 pak_size=0

09 bd_ptr=0x40B4 pak=0x2C9FA0 ds=0xE2BC60 status=80 pak_size=0

10 bd_ptr=0x40C8 pak=0x2CA288 ds=0xE2C31C status=80 pak_size=0

11 bd_ptr=0x40DC pak=0x2CA570 ds=0xE2C9D8 status=80 pak_size=0

12 bd_ptr=0x40F0 pak=0x2CA858 ds=0xE2D094 status=80 pak_size=0

13 bd_ptr=0x4104 pak=0x2CAB40 ds=0xE2D750 status=80 pak_size=0

14 bd_ptr=0x4118 pak=0x2CAE28 ds=0xE2DE0C status=80 pak_size=0

15 bd_ptr=0x412C pak=0x2CB110 ds=0xE2E4C8 status=80 pak_size=0

16 bd_ptr=0x4140 pak=0x2CB3F8 ds=0xE2EB84 status=80 pak_size=0

cpb = 0xE2, eda = 0x4814, cda = 0x4814

TX ring with 1 entries at 0xE24800

00 bd_ptr=0x4800 pak=0x000000 ds=0xE4FA68 status=80 pak_size=328

01 bd_ptr=0x4814 pak=0x000000 ds=0xE4F3A0 status=80 pak_size=328

0 missed datagrams, 0 overruns

0 bad datagram encapsulations, 0 memory errors

0 transmitter underruns

0 residual bit errors

R2#

[flexkikr11]

yeah I just bought a new one from ebay that still covered with see thru plastic thing but it was working before with my old one, when i put the new one to serial 1 of both routers and found out that still unable to ping both interfaces and tried to pull out the old cable from S0's and connect to S1's in and still no luck and when I'm about to plug the old cable back to S0's its unable to ping both interfaces now. :-((

[flexkikr11]

you reckon the serial interfaces on two routers are failing?

[John Blakley · Accepted solution]

I have a hard time believing that the interfaces are bad, and I would be more hard pressed to believe that it was a bad cable.

You could try to manually specify hdlc encapsulation under the interfaces on both routers. HDLC is the default without specifying, but it's a L2 protocol meaning that you should be able to connect the cable, see the Up/Up status without having an address on the interface as long as HDLC was communicating with the other end.

You could also try ppp encapsulation and see if they come up. (I've never done the ppp encapsulation on a DCE/DTE cable.)

HTH,

John

[flexkikr11]

You were right john when i checked the rear panel of the router and see if there's anything wrong with the interfaces I have noticed that there's a few misalligned divider that's causing some female and male pins not to connect on both ends and what i did was i looked for a needle pin to fix it and when i plugged the cable in to both serial interfaces it works like i tried pinging the other router and it works but when i screwed it to make sure the it wont loose the connection again the issue went back again. There's nothing bent pins in crossover serial cable as I just bought it and it's brand new the causing of the problem is the freaking interfaces. My question now are these serial interfaces changeable? Can I purchase these anywhere else?

[John Blakley]

Unfortunately, AFAIK, you can't replace the interface without replacing the card. If these are 2500 series routers, the interfaces are built into the router (at least the two that I have are).

I'm glad you figured out what the problem was though; that can be frustrating. =)

John

[flexkikr11]

Yeah those are 2503s and when I opened the box that has a faulty serial interface I saw that its built-into the motherboard so no chance to just replace the serial interface. Yeah it was so really frustrating you know what I did? I get a needle pin and I took off the broken divider on female port and re-alligned the pins inside with the needle and tried re-plugging the serial cables and it works finally hehehe.. McGyver yeah?