Flapping between Router(2811) and Switch(2960)

harizmthaha · ‎07-24-2012

Hi,

we have cisco 2960 switch which is connected to a cisco 2811 router.

Anyone can help to fix the flapping issue between these two devices??

The following actions i have taken, but no result..

I have changed cables.

have set speed to 100 and duplex full on both the interfaces but the interfaces are showing up up still not getting connectivity..

same i have to auto on both sides still no result

what configurations should i set to resolve this issue...?

Regards

Hariz

bhargavdesai · ‎07-25-2012

Hi,

Does ports on both side shows down on interface status...?

Can you paste the configuration of Both ports....?

I hope you have tested the cable MIDI MIDIX....

any log messages....

Regards,

Bhargav

Alessio Andreoli · ‎07-25-2012

conf t

int f0/1! example

switchport none

switchport enca dot1q

sw mo trunk

speed 100

duplex full

end

!

wr

!

Let me know if layer three is involved on one of the two

Alessio

harizmthaha · ‎07-25-2012

Hi,

Bhargav and Alessio

Here's the configurations on that particular router and switch interface..

ROUTER INTERFACE

interface FastEthernet0/1

ip address 172.16.41.1 255.255.255.0

duplex full

speed 100

!

FastEthernet0/1 is up, line protocol is up

Hardware is MV96340 Ethernet, address is 0021.5589.1c69 (bia 0021.5589.1c69)

Internet address is 172.16.41.1/24

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

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

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

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

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

Last input 00:00:27, output 00:00:02, 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

9262 packets input, 2002840 bytes

Received 271 broadcasts, 109 runts, 0 giants, 0 throttles

129 input errors, 20 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog

0 input packets with dribble condition detected

13500 packets output, 9195662 bytes, 0 underruns

0 output errors, 0 collisions, 2 interface resets

0 babbles, 0 late collision, 0 deferred

0 lost carrier, 0 no carrier

0 output buffer failures, 0 output buffers swapped out

SWITCH INTERFACE

interface GigabitEthernet0/24

description *** LINK TO ROUTER ***

switchport access vlan 2

switchport mode access

!

GigabitEthernet0/24 is up, line protocol is up (connected)

Hardware is Gigabit Ethernet, address is 0021.1c0f.5598 (bia 0021.1c0f.5598)

Description: *** LINK TO ROUTER ***

MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,

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

Encapsulation ARPA, loopback not set

Keepalive not set

Half-duplex, 10Mb/s, link type is auto, media type is 10/100/1000BaseTX

input flow-control is off, output flow-control is unsupported

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

Last input 00:00:31, output 00:00:01, 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 1000 bits/sec, 1 packets/sec

5 minute output rate 1000 bits/sec, 1 packets/sec

22985 packets input, 11141288 bytes, 0 no buffer

Received 5196 broadcasts (0 multicasts)

0 runts, 41 giants, 0 throttles

643 input errors, 468 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog, 4182 multicast, 0 pause input

0 input packets with dribble condition detected

24865 packets output, 4151183 bytes, 0 underruns

0 output errors, 79 collisions, 1 interface resets

0 babbles, 36 late collision, 0 deferred

0 lost carrier, 0 no carrier, 0 PAUSE output

0 output buffer failures, 0 output buffers swapped out

Regards

Hariz

vincehgov · ‎07-25-2012

Hi Hariz,

Your output is showing that G 0/24 on your switch is 10/half.

When you say it is flapping, are you saying that the line protocol is going up and down?

-vg

bhargavdesai · ‎07-25-2012

Hi,

As Vincent said ....

SWITCH INTERFACE

Half-duplex, 10Mb/s, link type is auto, media type is 10/100/1000BaseTX

ROUTER INTERFACE

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

You should Hardcore both side with Speed and Duplex.

So put both the port on 100 Mbps Full Duplex

Speed 100

Duplex Full

H2H

Bhargav

harizmthaha · ‎07-26-2012

Hi

Vincent & Bhargav..

I have checked likewise too as i already told u in my first post..

there's no change still the port is showing up up

Regards

Hariz

nkarthikeyan · ‎07-26-2012

Hi Hariz,

What is the IOS and device exact model on both the devices. Let me check if there in known issues and workaround for the same.

Also let me know

If this is directly connected or through backbone???

Have you tried connecting your laptop/pc to both the switch and router interfaces????

to identify the bug is only with the complatability between those 2 devices or someother problem.

Please do rate if the given info helps.

vincehgov · ‎07-26-2012

When you set both sides to 100/full, what is the output?

I have ran into some issues between a cisco router and an adtran router where it wouldn't negotiate correctly. Even hard coding it didn't work.

Vince

harizmthaha · ‎07-26-2012

Hi

Vincent,,

When its flapping, the line protocol remains up and when sets 100/full on both sides its still up but not geeting connectivity..

Karthik here's the version details:-

SWITCH

------------------ show version ------------------

Cisco IOS Software, C2960 Software (C2960-LANBASEK9-M), Version 12.2(37)SE1, RELEASE SOFTWARE (fc1)

ROM: Bootstrap program is C2960 boot loader

BOOTLDR: C2960 Boot Loader (C2960-HBOOT-M) Version 12.2(25r)SEE1, RELEASE SOFTWARE (fc1)

System image file is "flash:/c2960-lanbasek9-mz.122-37.SE1.bin"

cisco WS-C2960G-24TC-L (PowerPC405) processor (revision D0) with 61440K/4088K bytes of memory.

2 Virtual Ethernet interfaces

24 Gigabit Ethernet interfaces

64K bytes of flash-simulated non-volatile configuration memory.

Model number : WS-C2960G-24TC-L

Switch Ports Model SW Version SW Image

------ ----- ----- ---------- ----------

* 1 24 WS-C2960G-24TC-L 12.2(37)SE1 C2960-LANBASEK9-M

Configuration register is 0xF

ROUTER

------------------ show version ------------------

Cisco IOS Software, 2800 Software (C2800NM-ADVIPSERVICESK9-M), Version 12.4(9)T7, RELEASE SOFTWARE (fc3)

ROM: System Bootstrap, Version 12.4(13r)T, RELEASE SOFTWARE (fc1)

System image file is "flash:c2800nm-advipservicesk9-mz.124-9.T7.bin"

Cisco 2811 (revision 53.50) with 249856K/12288K bytes of memory.

2 FastEthernet interfaces

2 Serial(sync/async) interfaces

2 Low-speed serial(sync/async) interfaces

1 Virtual Private Network (VPN) Module

DRAM configuration is 64 bits wide with parity enabled.

239K bytes of non-volatile configuration memory.

62720K bytes of ATA CompactFlash (Read/Write)

Configuration register is 0x2102

rgds

Hariz

bhargavdesai · ‎07-26-2012

When you hardcore both side with Speed and Dupex it is also advisable to put Nonegotiate on both side.

I would also like to know

"When its flapping, the line protocol remains up and when sets 100/full on both sides its still up but not geeting connectivity.."

How you check the connectivity. Do you find anything in LOG.

H2H

Bhargav