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New Member

PA-POS Back to Back

Dear Gurus,

I have 2 7206 with PA-POS-OC3SMI configure back to back, i have the interface up/up but i cannot ping the ip address with increaseing CRC. Below is my basic config.

7206-A
interface POS3/0
ip address 10.10.3.41 255.255.255.252
no keepalive
clock source internal
no cdp enable
end


7206-B
interface POS1/0
ip address 10.10.3.42 255.255.255.252
no keepalive
no cdp enable
end

TIA.

5 REPLIES
Hall of Fame Super Silver

Re: PA-POS Back to Back

Hello Jepoy,

I suspect the two PA are using a different CRC or one has scrambing enabled compare the output of

sh int pos

on both devices

crc can be crc16 or crc32 ; scrambling can be enabled or disabled.

or PA are different or they have different default settings in different IOS images

Edit:

also enable keepalive to be able to detect cabling errors

Hope to help

Giuseppe

New Member

Re: PA-POS Back to Back

Hi Guiseppe,

Thanks for the tips again, here's the output of my interfaces. Still i've hard encoded crc and enable keepalives, still the port is up but i cant even ping the local ip address on the pos.

7206-B#sh interfaces pos 1/0
POS1/0 is up, line protocol is up
  Hardware is Packet over Sonet
  Internet address is 10.10.3.42/30
  MTU 3000 bytes, BW 155000 Kbit, DLY 100 usec,
     reliability 152/255, txload 1/255, rxload 1/255
  Encapsulation HDLC, crc 32, loopback not set
  Keepalive set (10 secs)
  Scramble enabled
  Last input 00:00:00, output 02:38:03, output hang never
  Last clearing of "show interface" counters 09:06:32
  Input queue: 0/900/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: weighted fair
  Output queue: 0/1000/1500/0 (size/max total/threshold/drops)
     Conversations  0/1/256 (active/max active/max total)
     Reserved Conversations 0/0 (allocated/max allocated)
     Available Bandwidth 116250 kilobits/sec
  5 minute input rate 189000 bits/sec, 22 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     1123707 packets input, 2073838413 bytes, 0 no buffer
     Received 426371 broadcasts, 0 runts, 19874647 giants, 0 throttles
              0 parity
     71076982 input errors, 19932579 CRC, 0 frame, 31269756 overrun, 0 ignored,
0 abort
     1397 packets output, 35288 bytes, 0 underruns
     0 output errors, 0 applique, 6 interface resets
     0 output buffer failures, 0 output buffers swapped out
     6 carrier transitions


7206-A#sh interfaces pos 3/0
POS3/0 is up, line protocol is up
  Hardware is Packet over Sonet
  Description:
  Internet address is 10.10.3.41/30
  MTU 3000 bytes, BW 155000 Kbit, DLY 100 usec,
     reliability 146/255, txload 1/255, rxload 1/255
  Encapsulation HDLC, crc 32, loopback not set
  Keepalive set (10 secs)
  Scramble enabled
  Last input 02:39:04, output 02:37:48, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/900/0/0 (size/max/drops/flushes); Total output drops: 1
  Queueing strategy: weighted fair
  Output queue: 0/1000/1500/0 (size/max total/threshold/drops)
     Conversations  0/1/256 (active/max active/max total)
     Reserved Conversations 0/0 (allocated/max allocated)
     Available Bandwidth 116250 kilobits/sec
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     994783 packets input, 4038877857 bytes, 0 no buffer
     Received 947212 broadcasts, 2 runts, 780917 giants, 0 throttles
              0 parity
     2696244 input errors, 712031 CRC, 0 frame, 1203294 overrun, 0 ignored, 0 ab
ort
     1609 packets output, 42456 bytes, 0 underruns
     0 output errors, 0 applique, 13 interface resets
     0 output buffer failures, 0 output buffers swapped out
     22 carrier transitions

Hall of Fame Super Silver

Re: PA-POS Back to Back

Hello Jepoy,

I don't understand:

how is it possible to have an interface up/up with keepalive set when:

>> Last input 00:00:00, output 02:38:03, output hang never

>> Last input 02:39:04, output 02:37:48, output hang never

second interface should be up/down if keepalive is set.

I would try to reset the interface with

int pos3/0

shut

controller pos3/0

shut

and then unshut

you can also use enc ppp to take advantage of more advanced PPP debug ouput

Hope to help

Giuseppe

New Member

Re: PA-POS Back to Back

HI Guissepe,

The interface are down now, here's the full config and output.

7206-B#sh run interface pos 1/0
Building configuration...

Current configuration : 269 bytes
!
interface POS1/0
ip address 10.10.3.42 255.255.255.252
load-interval 30
crc 32
pos framing sdh
no pos report slos
no pos report slof
no pos report plop
no pos report sf-ber
no pos report b1-tca
no pos report b2-tca
no pos report b3-tca
no cdp enable
end
POS1/0 is up, line protocol is down
  Hardware is Packet over Sonet
  Internet address is 10.10.3.42/30
  MTU 4470 bytes, BW 155000 Kbit, DLY 100 usec,
     reliability 165/255, txload 1/255, rxload 1/255
  Encapsulation HDLC, crc 32, loopback not set
  Keepalive set (10 sec)
  Scramble disabled
  Last input 00:00:00, output 00:00:47, 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)
  30 second input rate 277000 bits/sec, 8 packets/sec
  30 second output rate 0 bits/sec, 0 packets/sec
     37642 packets input, 110066984 bytes, 0 no buffer
     Received 30006 broadcasts, 0 runts, 998465 giants, 0 throttles
              0 parity
     9002107 input errors, 920843 CRC, 0 frame, 7082799 overrun, 0 ignored, 0 ab
ort
     30 packets output, 1120 bytes, 0 underruns
     0 output errors, 0 applique, 6 interface resets
     0 output buffer failures, 0 output buffers swapped out


7206-A#sh run in pos 3/0
Building configuration...

Current configuration : 337 bytes
!
interface POS3/0
description :To LAOAG MPLS
ip address 10.10.3.41 255.255.255.252
no ip proxy-arp
load-interval 30
crc 32
clock source internal
pos framing sdh
no pos report slos
no pos report slof
no pos report plop
no pos report sf-ber
no pos report b1-tca
no pos report b2-tca
no pos report b3-tca
no cdp enable
end
#sh int pos 3/0
POS3/0 is up, line protocol is down
  Hardware is Packet over Sonet
  Description: :To LAOAG MPLS
  Internet address is 10.10.3.41/30
  MTU 4470 bytes, BW 155000 Kbit, DLY 100 usec,
     reliability 128/255, txload 1/255, rxload 1/255
  Encapsulation HDLC, crc 32, loopback not set
  Keepalive set (10 sec)
  Scramble disabled
  Last input 00:01:46, output 00:01:28, output hang never
  Last clearing of "show interface" counters 00:30:18
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  30 second input rate 0 bits/sec, 0 packets/sec
  30 second output rate 0 bits/sec, 0 packets/sec
     11279 packets input, 25728325 bytes, 0 no buffer
     Received 5763 broadcasts, 3 runts, 157481 giants, 0 throttles
              0 parity
     1077673 input errors, 207716 CRC, 0 frame, 712473 overrun, 0 ignored, 0 abo
rt
     38 packets output, 2192 bytes, 0 underruns
     0 output errors, 0 applique, 5 interface resets
     0 output buffer failures, 0 output buffers swapped out
     3 carrier transitions

Hall of Fame Super Silver

Re: PA-POS Back to Back

Hello Jepoy,

another thought:

being the two PA single mode, the signal may be too strong causing loss of frame delineation.

in this case the addition of a 5dB or 10DB in line attenuator could be a solution.

you can check this with

sh controller pos 3/0

see

http://www.fiberattenuator.com/

A way to build a home made attenuator is to wrap fiber cable over a pen to make strict curves but this can cause fiber damage

Hope to help

Giuseppe

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