Slow network speed between Primary and Secondary networks

Accretious · ‎04-13-2012

Scenario: One 2811 router, handful of Catalyst switches, 2 networks on one ethernet interface.

interface FastEthernet0/0

ip address y.y.250.1 255.255.255.128 secondary

ip address x.x.188.1 255.255.255.0

duplex full

speed 100

no mop enabled

!

Problem: Workstations in network x.x.188.0 have abysmal transfer speeds with workstations in y.y.250.0 network, and vice versa. We're talking a max of 3mbit when doing speed tests vs 80mbit when the workstations are in the same network.

Switch hooked to router has speed and duplex set to match router.

Any suggestions?

Leo Laohoo · ‎04-13-2012

duplex full

speed 100

Don't understand why these two lines are there unless your Catalyst switches are the old 2900XL/3500XL.

Can you please post the output to the command "sh int f0/0". I would also like to see the "sh interface" output to the switch directly connected to the router.

acampbell · ‎04-13-2012

Hi,

What default gateways are being used for each network ?

They should be using indidual gateway addresses of their own subnet ranges

x.x.188.aaa should be using x.x.188.1 and y.y.250.aaa should be using y.y.250.1

Regards

Alex

Regards, Alex. Please rate useful posts.

Joseph W. Doherty · ‎04-13-2012

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Posting

Interface stats show no errors?

3 Mb(it)ps or 3 MB(yte)ps? 3 Mbps is rather low for a 2811. Although the 2811 doesn't offer 100 Mbps performance, I've gotten as high as about 20 Mbps, duplex.

Is CEF supported and enabled? If not, route-cache active, including for same interface?

There might be some "odd" about using a secondary address and performance. Don't know, but you could trunk to the Ethernet interface and define two subinterfaces.

PS:

The higher rate transfer rate, when workstations on the same subnet, makes sense as they can then bypass the router. The older ISRs are designed for WAN bandwidths even though the have "high speed" LAN interfaces.

Accretious · ‎04-18-2012

leolaohoo:

2811_router#sh int fa0/0

FastEthernet0/0 is up, line protocol is up

Hardware is MV96340 Ethernet, address is x.x.5988 (bia x.x.5988)

Description: LAN

Internet address is x.x.188.1/24

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

reliability 255/255, txload 6/255, rxload 4/255

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: 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 1876000 bits/sec, 311 packets/sec

5 minute output rate 2565000 bits/sec, 328 packets/sec

1174273172 packets input, 397448584 bytes

Received 20742715 broadcasts, 735209 runts, 0 giants, 0 throttles

2292574 input errors, 1557365 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog

0 input packets with dribble condition detected

1229891806 packets output, 3977532888 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

3560_switch#sh int fa0/48

FastEthernet0/48 is up, line protocol is up (connected)

Hardware is Fast Ethernet, address is x.x.94b4 (bia x.x.94b4)

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

reliability 255/255, txload 3/255, rxload 4/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Full-duplex, 100Mb/s, media type is 10/100BaseTX

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

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

Last input 00:00:10, output 00:00:00, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 63254625

Queueing strategy: fifo

Output queue: 0/40 (size/max)

5 minute input rate 1856000 bits/sec, 246 packets/sec

5 minute output rate 1323000 bits/sec, 234 packets/sec

1229948999 packets input, 1135655270681 bytes, 0 no buffer

Received 1115139 broadcasts (679328 multicasts)

0 runts, 0 giants, 0 throttles

1 input errors, 1 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog, 679328 multicast, 0 pause input

0 input packets with dribble condition detected

1193314482 packets output, 866796695115 bytes, 0 underruns

0 output errors, 404641 collisions, 1 interface resets

0 babbles, 1571450 late collision, 0 deferred

0 lost carrier, 0 no carrier, 0 PAUSE output

0 output buffer failures, 0 output buffers swapped out

acampbell: The correct gateways are being applied.

JosephDoherty: See above output. Looks like there are errors. 3Megabits, not bytes. CEF is enabled.

acampbell · ‎04-18-2012

Hi,

Judging by the amount of incoming errors you are seeing

Received 20742715 broadcasts, 735209 runts, 0 giants, 0 throttles

2292574 input errors, 1557365 CRC, 0 frame, 0 overrun, 0 ignored

Can you post the config of the switchport you are connected to.

If it is hard coded to 100M full duplex I would replace the cable

Regards

Alex

Regards, Alex. Please rate useful posts.

Accretious · ‎04-18-2012

interface FastEthernet0/48

switchport trunk encapsulation dot1q

switchport mode trunk

duplex full

mls qos trust dscp

auto qos voip trust

macro description cisco-router

spanning-tree portfast trunk

spanning-tree bpduguard enable

!

As for the cable, that was the first thing I changed, as well as a different interface on the switch.

acampbell · ‎04-18-2012

Hi,

Your router is NOT a trunk, your switch will be sending tagged frames

I would set this switchport back to being an access port

!

interface FastEthernet0/48

no switchport mode trunk

no switchport trunk encapsulation dot1q

no switchport mode trunk

switchport host

duplex full

speed 100

no spanning-tree portfast trunk

switchport access vlan AAAA --- Replace this with the correct vlan for the router

!

Regards

Alex

Regards, Alex. Please rate useful posts.

Joseph W. Doherty · ‎04-18-2012

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Besides the number of CRC and runt errors, as noted by Alex, you got quite a few output drops on the 3560 too. Both are going to degrade your performance.

Accretious · ‎04-18-2012

acambell: Thank you. I will change those settings Friday afternoon so as not to disrupt any users.

JosephDoherty: Is there anything I can do about that?

Joseph W. Doherty · ‎04-18-2012

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Depends on whether your "too fast" is sustained or transient. For the former, perhaps not, athough since the 3560 is a L3 switch, you're only using the 2811 for WAN routing, right?

For the latter (transient), buffer tuning might might a difference. NB: Unsure it can be done if QoS isn't enabled.

Leo Laohoo · ‎04-18-2012

Alex and Joseph are both right.

The 3560 has high output drops and this is reflected on the router with high input drops. Basically the 3560 is pushing at wire speed and the 2800 just can't take it.

Can you try this: In the router, change the speed to 10 Mbps and clear the counters of the router and the switch. Observe for 4 hours if both counters increment. If they don't then you know where the problem is and you have a few options to choose from.

By the way, what is the WAN bandwidth?