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Community Member

Slow Network.

Hi all,

This is just an general question. We have two subnets on our network. Both these networks are routed. We have Cisco 1721 Router. It has only one Ethernet Module. We cannot user another. It is the gateway for subnet1 and subnet2. subnet2 gateway is defined as secondary. We have several cisco 2950 series switches. All our server are in subnet1.

Now to say, anyone in subnet2 trying to access resourses like servers, network printers which are in subnet1, the responce time is very slow. Like you click on a file to save / print, it takes long time. Whereas users on subnet1 have no problems (since all resources are on same subnet).

I guess we need to either upgrade the router or connect a layer 3 switch.

Is the network on subnet2 experiencing slow response since its gateway is defines as secondary ? I mean to ask, does this effect in any such way ?

Please give some suggestions. Hope am clear.

thanks,

abc.

3 ACCEPTED SOLUTIONS

Accepted Solutions
Purple

Re: Slow Network.

Look at the device interface settings on whatever is connected to the other end . That end must be 100/full also , you appear to be taking a lot of crc's . The interface is not overloaded , the 5 minute input and output rate is less than 1 meg per sec . Suspect a link mismatch .

Community Member

Re: Slow Network.

Try setting both sides to autonegotiate if you haven't already, to clear up the CRC/input errors/etc. The traffic is routed through that Ethernet interface, so if it's taking errors you are certain to see some degredation.

I've had problems with 2950s being hardcoded recently, as well as the devices on the opposite end being hardcoded. Same symptoms as yourself.

Blue

Re: Slow Network.

Setting both sides to auto is worth a try, but if that doesn't help you need to try another switch port. If still seeing errors the next step would be to swap out the router.

15 REPLIES
Purple

Re: Slow Network.

That is your problem most likely as it has to be routed from one address range to another. It is also a 10 meg half duplex link and any utilization above like 35% will start to see degradation on response time . Look at the utlization on that interface and figure out how much load there is on it . A layer 2/3 switch would be much faster if you don't need serial links .

Blue

Re: Slow Network.

Both your subnets are on the same layer 2 broadcast domain, but must talk to each other through the router. This is not a really optimum situation, but shouldn't cause the slowness unless your traffic levels are exceeding the ability of the router. Can you post the output of a show interface fas0? Are you seeing any errors? A duplex mismatch could be another explanation for slowness.

Please rate helpful posts.

Dave

Community Member

Re: Slow Network.

Hi,

Thanks for reply.

Please find the output as below,

R1#show int fastEthernet 0

FastEthernet0 is up, line protocol is up

Hardware is PQUICC_FEC, address is 000d.285a.9024 (bia 000d.285a.9024)

Internet address is 192.168.4.1/24

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

reliability 254/255, 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 00:00:00, output 00:00:00, output hang never

Last clearing of "show interface" counters never

Input queue: 2/75/12140/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue: 0/40 (size/max)

5 minute input rate 473000 bits/sec, 89 packets/sec

5 minute output rate 474000 bits/sec, 85 packets/sec

517118065 packets input, 4228616988 bytes

Received 28549825 broadcasts, 0 runts, 0 giants, 0 throttles

4978622 input errors, 4978594 CRC, 0 frame, 28 overrun, 0 ignored

0 watchdog

0 input packets with dribble condition detected

455906349 packets output, 3363327833 bytes, 5243 underruns

5243 output errors, 0 collisions, 4 interface resets

0 babbles, 0 late collision, 0 deferred

0 lost carrier, 0 no carrier

0 output buffer failures, 0 output buffers swapped out

I agree that the router is over-loaded. Like we have Email Server at HO. So mail traffic is huge throughout the day.

Can i use 2950 switch to route the traffic between these networks rather than going to the router ? Will that make difference if possible ?

Thanks again.

abc.

Community Member

Re: Slow Network.

A 2950 is a layer 2 switch, so no.

Also, look at the CRCs in the output above. Clear your counters and let it run for an hour and check it again.

Purple

Re: Slow Network.

Look at the device interface settings on whatever is connected to the other end . That end must be 100/full also , you appear to be taking a lot of crc's . The interface is not overloaded , the 5 minute input and output rate is less than 1 meg per sec . Suspect a link mismatch .

Community Member

Re: Slow Network.

Hi,

Sorry for late response. Hope excused.

The other end is a switch and is 100/full.

How to resolve the CRC errors ?

How to check the link mismatch ?

thanks,

abc.

Blue

Re: Slow Network.

Can you post a show interface from the switch side?

Did you clear counters on both sides to confirm the CRCs errors are incrementing?

You could have a bad cable. Do you have a new, or known good, cable you could replace it with?

Community Member

Re: Slow Network.

Hi,

Thanks for reply,

I cleared the counters on Router. Yet there are CRC errors. Yet there are CRC errors in the Router. I will change the cable with a branded good cable.

then will clear the counters again and post the sh int from Router and Switch together.

Thanks,

abc.

Community Member

Re: Slow Network.

Hi,

I changed the cables with new/good ones.

Then cleared the counters.

Yet there are CRC errors.

Further to mention, The router is not directly connected to the switch. We have a compression router in between. The connection from router goes to this device and then to the switch. (Sorry, i did not mention that in earlier post).

But i disconnected the compression router and connected the main router directly to the switch. Yet the CRC errors are incrementing.

There are no such errors on the Switch Port it is connected to.

Please find the sh int output in the attached files. The "First" is with compression router connected, "Second" is without it/direct to the switch.

To mention, the ping from subnet1 to subnet2 or vice versa, drops packets (with request time out) with every 15-20 replies.

Hope i am clear. Thanks,

abc.

Blue

Re: Slow Network.

The switch show interface indicates an input/output rate of 0. Are you sure that is the correct interface? Does a show cdp neighbors confirm this?

Community Member

Re: Slow Network.

Yes, cdp neighbors shows it is connected to this switch on fa 0/3 port.

Also i changed the cable with new one. Its confirmed.

here is the output from the switch

Switch#sh int fa 0/3

FastEthernet0/3 is up, line protocol is up

Hardware is Fast Ethernet, address is 000b.5f6d.d383 (bia 000b.5f6d.d383)

MTU 1500 bytes, BW 100000 Kbit, DLY 1000 usec,

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

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Full-duplex, 100Mb/s

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

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

Last input 00:00:11, output 00:00:00, output hang never

Last clearing of "show interface" counters 23:12:30

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

2484915 packets input, 1380529566 bytes, 0 no buffer

Received 32473 broadcasts, 0 runts, 0 giants, 0 throttles

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

0 watchdog, 19193 multicast, 0 pause input

0 input packets with dribble condition detected

3123516 packets output, 1150719639 bytes, 0 underruns

10 output errors, 14 collisions, 0 interface resets

0 babbles, 10 late collision, 39 deferred

0 lost carrier, 0 no carrier, 0 PAUSE output

0 output buffer failures, 0 output buffers swapped out

Thanks,

abc.

Community Member

Re: Slow Network.

Try setting both sides to autonegotiate if you haven't already, to clear up the CRC/input errors/etc. The traffic is routed through that Ethernet interface, so if it's taking errors you are certain to see some degredation.

I've had problems with 2950s being hardcoded recently, as well as the devices on the opposite end being hardcoded. Same symptoms as yourself.

Blue

Re: Slow Network.

Setting both sides to auto is worth a try, but if that doesn't help you need to try another switch port. If still seeing errors the next step would be to swap out the router.

Community Member

Re: Slow Network.

Hi,

Well, to clear myself, i set both sides to auto as below,

Switch(config)#int fa 0/3

Switch(config-if)#speed auto

Router(config)#int fa 0

Rotuer(config-if)#speed auto

Yet i do not see any input/output packets in the switch. But there are no CRC errors on the Router doing sh int fa 0. Today its off day. May be i can give the exact results tommorrow. The output is as below,

Router#sh int fa 0

FastEthernet0 is up, line protocol is up

Hardware is PQUICC_FEC, address is 000d.285a.9024 (bia 000d.285a.9024)

Internet address is 192.168.4.1/24

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 00:00:00, output 00:00:00, output hang never

Last clearing of "show interface" counters 00:20:53

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 31000 bits/sec, 12 packets/sec

5 minute output rate 29000 bits/sec, 10 packets/sec

37936 packets input, 12235932 bytes

Received 3491 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

34658 packets output, 12164590 bytes, 0 underruns

0 output errors, 0 collisions, 0 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#sh int fa 0/3

FastEthernet0/3 is up, line protocol is up

Hardware is Fast Ethernet, address is 000b.5f6d.d383 (bia 000b.5f6d.d383)

MTU 1500 bytes, BW 100000 Kbit, DLY 1000 usec,

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

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Full-duplex, 100Mb/s

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

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

Last input 00:00:42, output 00:00:01, output hang never

Last clearing of "show interface" counters 00:23:43

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

34869 packets input, 13125241 bytes, 0 no buffer

Received 462 broadcasts, 0 runts, 0 giants, 0 throttles

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

0 watchdog, 332 multicast, 0 pause input

0 input packets with dribble condition detected

39742 packets output, 13005237 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

0 babbles, 0 late collision, 0 deferred

0 lost carrier, 0 no carrier, 0 PAUSE output

0 output buffer failures, 0 output buffers swapped out

Thanks,

abc.

Community Member

Re: Slow Network.

Hi,

After setting both sides to auto and changing the cables, there are no CRC errors now. Seems the network response was slow due to bad cables. The Switch was showing input/output packets during business hours. And there is considerable difference than before.

R1#sh int fa 0

FastEthernet0 is up, line protocol is up

Hardware is PQUICC_FEC, address is 000d.285a.9024 (bia 000d.285a.9024)

Internet address is 192.168.4.1/24

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 00:00:00, output 00:00:00, output hang never

Last clearing of "show interface" counters 1d05h

Input queue: 1/75/364/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue: 0/40 (size/max)

5 minute input rate 55000 bits/sec, 23 packets/sec

5 minute output rate 60000 bits/sec, 19 packets/sec

11658615 packets input, 2652381494 bytes

Received 387879 broadcasts, 0 runts, 0 giants, 0 throttles

554 input errors, 0 CRC, 0 frame, 554 overrun, 0 ignored

0 watchdog

0 input packets with dribble condition detected

11108427 packets output, 3065956084 bytes, 2542 underruns

2542 output errors, 0 collisions, 0 interface resets

0 babbles, 0 late collision, 0 deferred

0 lost carrier, 0 no carrier

0 output buffer failures, 0 output buffers swapped out

Thanks to all of you.

abc.

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