cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
428
Views
0
Helpful
30
Replies
Frequent Contributor

Re: Connecting two 1751 w/serial interfaces

Have you tried HDLC encap ? Your LCP is not coming up in PPP , If you change to HDLC encap and you still get protocol down , you need to investigate the CSU being misconfigured ,

Can tou paste in a sh serial X from the B router

dal Beginner
Beginner

Re: Connecting two 1751 w/serial interfaces

I have tried HDLC to no avail. I can post sh serial X from the B router - but that will be later as I have no connection to remote router at this point. Should I go back to HDLC at this point?

Highlighted
Frequent Contributor

Re: Connecting two 1751 w/serial interfaces

It is the easiest to configure , as long as it a Cisco box that is attached on the other end , I would use HDLC .

dal Beginner
Beginner

Re: Connecting two 1751 w/serial interfaces

Yes, two identical cisco 1751 brand spankin new on each side. Let me ask you another question, If the remote router "B" is still on PPP encap aand I have changed the host router "A" to HDLC - should i be able to get a s0/0 is up - line protocol up on the host side? Thanks for all your advice - has been a big help so far.

Frequent Contributor

Re: Connecting two 1751 w/serial interfaces

no you must use the same encap on each end HDLC>>>HDLC or PPP >>.PPP , If you are using boxes from differnet vendors on a point to point link you have to use PPP.

dal Beginner
Beginner

Re: Connecting two 1751 w/serial interfaces

I know for communication between the two routers each encap has to be the same. But will that in itself cause the message "int s0/0 is up - line protocol down"? I can get the "line protocol" to stay up for a minute or two - and back down.

Frequent Contributor

Re: Connecting two 1751 w/serial interfaces

Yes it will, What brings up and keeps up your line protocol the the tranmitting and receipt of keepalive packets . The line protocol will drop after 3 keepalives are missed .

dal Beginner
Beginner

Re: Connecting two 1751 w/serial interfaces

Thanks - I am heading to the remote site to switch the encap & clock rate. I had already posted the debug info before I got to this post.

Frequent Contributor

Re: Connecting two 1751 w/serial interfaces

I thought you said this is using an external CSU that is provided by the Telco , Who is providing clock , you may not need to set clock on the serial interface , Also the config on the B router can't be the same if you are providing clock on the B router , Does the B router have a DTE or a DCE cable attached ?

dal Beginner
Beginner

Re: Connecting two 1751 w/serial interfaces

It has the v.35 winchester cable. True - using external csu/dsu. Telcom said we would need to set the clock - for me, I thought with serial connection it did not matter.

Frequent Contributor

Re: Connecting two 1751 w/serial interfaces

Either the csu/dsu or the provider will have to supply clock , You can supply clock on a serial interface with a DCE cable attached , I wouls not recommend this for a long haul wide area connection . If you have access the the Csu's configure one to provide clock and the other to look for clock from the network.

dal Beginner
Beginner

Re: Connecting two 1751 w/serial interfaces

I am now in the process of setting to default configuration on both. I will put each on it's own subnet and see what happens. Will let you know.

dal Beginner
Beginner

Re: Connecting two 1751 w/serial interfaces

take a look at the following config. I reset both router to defaults (erased) and started from scratch. Router "A" is now on 192.168.0.21 and Router "B" 192.168.10.22 - each on their own subnets. The s0/0 line protocol still toggles up/down about every 10 seconds - toggling faster than before, but still not remaining up. HDLC on both ends. I have called the telecom - "they are investigating", but state everything appears fine from their site. Thanks

sh config

Using 786 out of 29688 bytes

!

version 12.2

service timestamps debug uptime

service timestamps log uptime

service password-xxx!

hostname CiscoA

!

enable password xxxx

!

memory-size iomem 25

ip subnet-zero

no ip domain lookup

!

!

!

!

!

interface FastEthernet0/0

description connected to EthernetLAN_1

ip address 192.168.0.21 255.255.255.0

no keepalive

speed auto

!

interface Serial0/0

description connected to CiscoB

ip unnumbered FastEthernet0/0

no logging event link-status

!

router rip

version 2

network 192.168.0.0

no auto-summary

!

ip classless

no ip http server

!

!

snmp-server community public RO

snmp-server enable traps tty

!

line con 0

exec-timeout 0 0

password xxx

login

line aux 0

line vty 0 4

password xxxx

login

!

end

*****************************************

CiscoA#sh interface fastethernet0/0

FastEthernet0/0 is up, line protocol is up

Hardware is PQUICC_FEC, address is 000b.466b.3bf0 (bia 000b.466b.3bf0)

Description: connected to EthernetLAN_1

Internet address is 192.168.0.21/24

MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive not set

Full-duplex, 100Mb/s, 100BaseTX/FX

ARP type: ARPA, ARP Timeout 04:00:00

Last input 00:00:02, output 00:00:19, 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)

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

30 packets input, 4027 bytes

Received 30 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog

0 input packets with dribble condition detected

7 packets output, 1625 bytes, 0 underruns

3 output errors, 0 collisions, 3 interface resets

0 babbles, 0 late collision, 0 deferred

3 lost carrier, 0 no carrier

0 output buffer failures, 0 output buffers swapped out

******************************************

CiscoA#sh int s0/0

Serial0/0 is up, line protocol is up

Hardware is PowerQUICC Serial

Description: connected to CiscoB

Interface is unnumbered. Using address of FastEthernet0/0 (192.168.0.21)

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,

reliability 247/255, txload 1/255, rxload 1/255

Encapsulation HDLC, loopback not set

Keepalive set (10 sec)

Last input 00:00:04, output 00:00:03, 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: 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 1158 kilobits/sec

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

21 packets input, 504 bytes, 0 no buffer

Received 21 broadcasts, 0 runts, 0 giants, 0 throttles

9 input errors, 0 CRC, 9 frame, 0 overrun, 0 ignored, 0 abort

63 packets output, 8512 bytes, 0 underruns

0 output errors, 0 collisions, 12 interface resets

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions

DCD=up DSR=up DTR=up RTS=up CTS=up

CiscoA#

Frequent Contributor

Re: Connecting two 1751 w/serial interfaces

the config looks ok , what about the B router config ? ALso did you find out who is providing clock ? "Find out from the telco . Also who owns the Csu's , like I said before either one of the cs's or the telco is going to have to supply clock.

dal Beginner
Beginner

Re: Connecting two 1751 w/serial interfaces

After weeks of telcom stating everything is ok on their end, we find out they have a bad v.35 jack on the host side. Plugged my config back in on both routers and they work. Thanks for hanging in there with me and helping out.

CreatePlease to create content
Content for Community-Ad
July's Community Spotlight Awards