Point to Point T1 with Cisco 1841 Routers

Hey, got a quick question here. I configured a couple of point to point 1841 routers for a new WAN to our remote office. Everything worked fine when i tested them here. I shipped the remote router out, had it hooked up and the circuit came up instantly. I setup monitoring and that night got a lot of alerts saying the circuit was down. I checked it in the morning and on my side, the router had a lot of CRC errors. I made sure framing, linecode, encapsulation was all good. both sides are using the line clocking etc. Its a full t1 and after running extended ping tests with a lot of drops i figured the line wasnt clean. Well Verizon tested the circuit 2 times and they said it was good. Any ideas? here is a running config and a sh int. Also if i clear the counters the errors will start to increase again on this end. Thanks.

Main Router no aaa new-model ! resource policy ! mmi polling-interval 60 no mmi auto-configure no mmi pvc mmi snmp-timeout 180 ip subnet-zero no ip cef ! ! no ip dhcp use vrf connected ! ! ! interface FastEthernet0/0 description inside interface ip address 10.1.99.2 255.255.255.0 duplex auto speed auto ! interface FastEthernet0/1 no ip address shutdown duplex auto speed auto ! interface Serial0/0/0 bandwidth 1500 ip address 192.168.101.1 255.255.255.252 encapsulation ppp ! router ospf 1 log-adjacency-changes network 10.1.99.0 0.0.0.255 area 0 network 192.168.101.0 0.0.0.3 area 0 ! ip classless ! ip http server ip http access-class 23 ip http authentication local ip http timeout-policy idle 60 life 86400 reques ! access-list 23 permit 10.10.10.0 0.0.0.7 access-list 23 permit 10.0.0.0 0.255.255.255

Serial0/0/0 is up, line protocol is up Hardware is GT96K with integrated T1 CSU/DSU Internet address is 192.168.101.1/30 MTU 1500 bytes, BW 1500 Kbit, DLY 20000 usec, reliability 240/255, txload 1/255, rxload 1/255 Encapsulation PPP, LCP Open Open: CDPCP, IPCP, loopback not set Keepalive set (10 sec) Last input 00:00:19, output 00:00:00, output hang never Last clearing of "show interface" counters 00:10:35 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 0/2/256 (active/max active/max total) Reserved Conversations 0/0 (allocated/max allocated) Available Bandwidth 1125 kilobits/sec 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 314 packets input, 28314 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants, 0 throttles 56 input errors, 56 CRC, 5 frame, 2 overrun, 0 ignored, 3 abort 364 packets output, 26460 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets 0 output buffer failures, 0 output buffers swapped out 0 carrier transitions DCD=up DSR=up DTR=up RTS=up CTS=up

40Wall-WAN-RT#

40Wall-WAN-RT#

Remote Router ! no aaa new-model ! resource policy ! mmi polling-interval 60 no mmi auto-configure no mmi pvc mmi snmp-timeout 180 ip subnet-zero no ip cef ! ! no ip dhcp use vrf connected ! ! ! ! interface FastEthernet0/0 description $ETH-LAN$$ETH-SW-LAUNCH$$INTF-INFO-FE 0$ ip address 10.12.11.1 255.255.255.0 duplex auto speed auto ! interface FastEthernet0/1 no ip address shutdown duplex auto speed auto ! interface Serial0/0/0 bandwidth 1500 ip address 192.168.101.2 255.255.255.252 encapsulation ppp ! router ospf 1 log-adjacency-changes network 10.12.11.0 0.0.0.255 area 0 network 192.168.101.0 0.0.0.3 area 0 ! ip classless ! ip http server ip http access-class 23 ip http authentication local ip http timeout-policy idle 60 life 86400 requests 10000 ! access-list 23 permit 10.10.10.0 0.0.0.7 access-list 23 permit 10.0.0.0 0.255.255.255

Serial0/0/0 is up, line protocol is up Hardware is GT96K with integrated T1 CSU/DSU Internet address is 192.168.101.2/30 MTU 1500 bytes, BW 1500 Kbit, DLY 20000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation PPP, LCP Open Open: CDPCP, IPCP, loopback not set Keepalive set (10 sec) Last input 00:00:00, output 00:00:00, output hang never Last clearing of "show interface" counters 00:18:49 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 0/1/256 (active/max active/max total) Reserved Conversations 0/0 (allocated/max allocated) Available Bandwidth 1125 kilobits/sec 5 minute input rate 1000 bits/sec, 1 packets/sec 5 minute output rate 1000 bits/sec, 1 packets/sec 768 packets input, 52763 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 763 packets output, 69578 bytes, 0 underruns 0 output errors, 0 collisions, 2 interface resets 0 output buffer failures, 0 output buffers swapped out 0 carrier transitions DCD=up DSR=up DTR=up RTS=up CTS=up

MaidenLn-WAN-RT# MaidenLn-WAN-RT#

Reply to
jason.polce
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Sounds like clock slips.

In a PtP circuit, both sides should NOT be recovering the clock from the line. One side should be driving the clock from internal, and the other side should be recovering the clock from the line.

Otherwise you get clock slips, and see exactly what you are seeing.

Reply to
Doug McIntyre

Thanks for the help, ill make the change now.

Reply to
jason.polce

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