Problems with back to Serials to 4500

wildfire · April 2005

I am having a very frustrating problem with my 4500

it has 8 serial ports and in my lab it has back to back connections to other router (2500, 2600, 3600 etc)

The problem is that only some of the links work at different times!

I have set the 4500 to be DTE for all links as it was hving a fit doing the timing, so heres the problem

one link will work and another wont, so I tried swapping the cables and nothing, then try swapping ports on the 4500 and the fault swaps around (so youd think it was the other router) restart the router and the one that woked before now may not work and the other might work, its like a damm lottery ticket!

Ive tried various combinations with various routers! its unique to my 4500! sometimes only 2 ports wil work sometimes 6! but like I said its no the ports becuase I move a working link to another port and it still works!

the links that dont work often show serial down line protocol down, but the DCD is up and the DSR is up

any ideas?

tunerX · April 2005

1) Are the interfaces sync, sync/async, or async?
2) What kind of cables are you using to connect them?
3) What is the keepalive set at on both ends of each link?
4) What do you get when you show interfaces (errors, resets, ... etc)
5) How much shared memory do you have?
6) What happens when you remove both of the modules and run them one at a time, in different slots?

wildfire · April 2005

1) 4500 ports are Sync and the ports I am connecting to are all sync bar one async (async to synce one works fine)

2) DTE - DCE Back to back V.35 from a seller called katyscables (ebay)

3) Default 10 Secs tried making it smaller and larger no difference

4) The interface resets itself about 10 times per minute with some combinations DCD=UP DSR=UP rest is down, Serial is down

5) 4mb (From 32Mb Dram)

6) Tried this no difference

Ive manager to get six ports working its wierd. The NP-4T modules on the 4500s have a series of light indications on the back, I plug one cable in and no change, plug another in it recognises that cable as DTE or DCE! turn the router off and back on it doesnt like that cable, yet all my other links work from my 2500s to 2600s and 3620s. Its just this 4500 is fussy about which cables will work at certain times! even when it does work the carrier transitions are none on some ports and 58 on another port over a 24 hour period!

Its the most annoying fault ever, Im just assuming that its very temprimental! had to redesign my rack slightly as I managed to get 6 ports to work (wanted all

so Im going to leave it at that. If the cables stay connected to the 4500 it works ok, if I remove one and put it back in it may not work again!

Heres one of the 4500 as the DTE
Serial4 is down, line protocol is down
Hardware is HD64570
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 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 (size/max/drops); 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)
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, 235 interface resets
0 output buffer failures, 0 output buffers swapped out
0 carrier transitions
DCD=down DSR=down DTR=up RTS=up CTS=down

And one as DCE

serial7 is down, line protocol is down
Hardware is HD64570
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 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 (size/max/drops); 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)
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, 157 interface resets
0 output buffer failures, 0 output buffers swapped out
8 carrier transitions
DCD=up DSR=up DTR=down RTS=down CTS=up

Working one

Serial0 is up, line protocol is up
Hardware is HD64570
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
Encapsulation HDLC, loopback not set, keepalive set (10 sec)
Last input 00:00:03, output 00:00:04, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0 (size/max/drops); Total output drops: 0
Queueing strategy: weighted fair
Output queue: 0/1000/64/0 (size/max total/threshold/drops)
Conversations 0/1/256 (active/max active/max total)
Reserved Conversations 0/0 (allocated/max allocated)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
13189 packets input, 1136027 bytes, 0 no buffer
Received 13189 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
11540 packets output, 706222 bytes, 0 underruns
0 output errors, 0 collisions, 2 interface resets
0 output buffer failures, 0 output buffers swapped out
41 carrier transitions
DCD=up DSR=up DTR=up RTS=up CTS=up

Intresting one port didnt work but I put the DTE end into loopback then shut and no shut, then no loop and the serial came up and line up!!!

Only worked with one port though

Problems with back to Serials to 4500

Comments