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cisco 2811 wic 1T:Serial0/0/0 is up, line protocol is down : how to resolve

nicanor00
Level 1
Level 1

I need to configure Cisco 2811 serial wic 1T but it doesn't work : Serial0/0/0 is up, line protocol is down

See the architecture in attachments

I don't know with type of equipment is used on remote side

See below the configuration of serial on remote site(the ISP have send it)

Serial4/7 is up, line protocol is up

Hardware is M8T-V.35

Description: CUS: ABCD

Internet address is 162.192.48.119/30

MTU 1500 bytes, BW 3584 Kbit, DLY 20000 usec,

reliability 247/255, txload 12/255, rxload 7/255

Encapsulation HDLC, crc 16, loopback not set

Keepalive set (10 sec)

Restart-Delay is 0 secs

See also the output command on my Cisco 2811 router in attachment

When I change the Cisco 2811 and use different router(not Cisco), it work

Please how can I solve this problem ?

19 Replies 19

Jerry Ye
Cisco Employee
Cisco Employee

Hi,

You can tried to put the following command to see if that fix the problem.

encapsulation ppp

Also, I see your have the following command

no ip route-cache cef

no ip route-cache

this will make the switch to use switch process the packets, and it can cause high CPU. You should consider to do

ip route-cache cef

ip route-cache

HTH,

jerry

cam

While I agree with Jerry that it is much better to use ip route-cache cef and ip route-cache, I do not believe that this is the fundamental problem.

In my experience there are several things that can cause line up line protocol down on serial interfaces. One of them is protocol mismatch (perhaps HFLC on one end and PPP on the other end). But if what is included in your post is accurate then both ends are using HDLC. Another thing that can cause this symptom is if one end is configured to use keepalives but the other end is configured with no keepalive. But it looks like both you and the provider are using keepalive.

Another thing that can cause the symptom is a problem with clocking. We can not tell from what is posted if it might be a problem with clocking. Perhaps if you would post the output of show controller we might have some useful information about this.

I also wonder if the problem might be a problem in connectivity. Can you verify that you are correctly connected?

As I look more closely at what you posted I notice that the output of show interface shows that Carrier Detect is down. I believe that this may also point to some connectivity problem.

While it is not part of the fundamental problem I would point out that there are problems in the addressing configured on your router. The interface configured on your serial interface does not match the address configured by the provider (check the first octet). Also the addresses on the Ethernet interfaces seems to be in the same subnet, which is not valid.

HTH

Rick

HTH

Rick

Thanks for your reply

Encapsulation PPP doesn't work

I forget one precision

When I configure encapsulation to HDLC, line protocol is up few second and then go back to line protocol down

When I use encapsulation PPP it doesn't work

Please I need help I am very disappointed

Hi cam,

I will agree with Rick to check your clocking, you can post the output of the show controller output.

Regards,

jerry

As I told you before,

I forget one precision

When I configure encapsulation to HDLC, line protocol is up few second and then go back to line protocol down

When I use encapsulation PPP it doesn't work

During the troubleshooting, I copied the show controller output(just the serial part)

You can see it in attachment

Now I am not near the equipment , but if you absolutely need the whole show controller output, I can go back and copy it

Thanks in advance for your help

HDLC is tring to come up. Since it cannot come up at all, line protocol will be up for a few second and goes back down. This is normal behavior.

Your show controller output is fine.

HTH,

jerry

According to your picture you have a Comtech CDM-600 modem in front of the Cisco router. This modem has a fairly extensive set of software-configured options for the serial connection. It looks like the configuration on the modem is what should be matched up with the configuration on the Cisco router's serial interface.

Assuming your satellite provider supports the modem (as well as the non-Cisco router?), I'd see if the provider can assist you in resolving this.

http://www.satcomnow.com/satcom/pdf/mn-cdm600_r7.pdf

Here is other documentation on the Comtech website.

http://www.satcomresources.com/Comtech-CDM-600-PSK-Digital-Satellite-Modem

make sure the PPP is configured on both side. what is your LCP indicate is it open , close, what stages that goes trough. you also need to chk the framing (ESF/B8ZS)

Hope this helps

fmjiang1966
Level 1
Level 1

Hi,

Please check your Serial0/0/0 IP address config:

On the SP side:

Internet address is 162.192.48.119/30

IP address for your S0/0/0:

160.192.50.120 255.255.255.252

They are not in the same subnet.

verify and correct, then test if it works.

Fuming

fmjiang1966
Level 1
Level 1

One more thing:

If your S0/0/0 address is:

160.192.50.120/30

Your default-route has problem:

ip route 0.0.0.0 0.0.0.0 160.192.48.119

You cann't reach gateway 160.192.48.119 because they are in different subnet.

I change the IP addrese but the problem is the same

interface FastEthernet0/0

description Connect To a

ip address 162.210.33.129 255.255.255.192

duplex auto

speed auto

!

interface FastEthernet0/1

description Connect To b

ip address 162.210.33.252 255.255.255.192

duplex auto

speed auto

!

interface Serial0/0/0

description To Internet

ip address 160.192.50.130 255.255.255.252

no ip route-cache cef

no ip route-cache

!

ip classless

ip route 0.0.0.0 0.0.0.0 160.192.50.129

the serial wic 1T is connected opposite Comtech CRS 340 card

I made some research on this card.

See below the caracteristic of this card Comtech CRS 340 card

CRS-340 - EIA-422/-232, LVDS, G.703 Mixed Interface

(1) 25-pin 'D' type female connector

EIA-422/-530 DCE, V.35, SYNC EIA-232, LVDS

(1) 15-pin 'D' type female connector

G.703 Balanced (DDI, DDO, IDI, IDO)

(2) BNC type female connectors

G.703 Unbalanced, (DDI, IDO)

I use the (1) 25-pin 'D' on Comtech CRS 340 card

Do you think that the WIC 1T card should work opposite the Comtech CRS 340 card

Hi,

But your SP side address is:

Serial4/7 is up, line protocol is up

Hardware is M8T-V.35

Description: CUS: ABCD

Internet address is 162.192.48.119/30

If your SP side address is:

160.192.50.129/30

Then I guess it will work.

Fuming

fmjiang1966
Level 1
Level 1

Hi,

Your IP address and subnet has problems.

Serial4/7 is up, line protocol is up

Hardware is M8T-V.35

Description: CUS: ABCD

Internet address is 162.192.48.119/30

162.192.48.119/30 is broadcast address of subnet 162.192.48.116/30.

162.192.48.116/30 has two usable addresses:

162.192.48.117 and 118.

162.192.48.119/30 cannot be used as interface address.

Fuming

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