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453
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Bandwidth Limits

mdeckard
Level 1
Level 1

Hello,

 

I am very new to networking and just set up a home lab. I have a 2901 router connected to my 1g fiber home internet. The router connects to a 2960x switch. Once everything was connected to the internet I did speed test and got 260mbps up and 285mbps down. Can someone explain why I am getting slower speeds? I know it's not a bandwidth issue because I did a speed test on the only device connected to the switch. Is there a bandwidth limiter in either the router or switch that can change/cap the throughput that each device gets?  Any help would be appreciated.
Thanks!

4 Replies 4

Joseph W. Doherty
Hall of Fame
Hall of Fame

"Once everything was connected to the internet I did speed test and got 260mbps up and 285mbps down."

For a 2901, that's pretty good.  Cisco recommends a 2901 for 25 Mbps.

See attachment for all the details.

I am a bit puzzled at this statement in the OP " I know it's not a bandwidth issue because I did a speed test on the only device connected to the switch". Pretty clearly it IS a bandwidth issue. Perhaps the intent was that it was not a bandwidth sharing or contention issue? I accept that testing with a single connected device does eliminate any possible contention or bandwidth sharing issues.

The fundamental issue here seems to be that the performance of the network is not as good as the user expected. We do not have any details about the configurations and so can not rule out the possibility of a configuration issue (perhaps something like a duplex mismatch on Ethernet that can cause many dropped frames). But my guess is that Joseph has identified the issue as limitations of the platform for the 2901.

HTH

Rick

Excellent question.

I took "I know it's not a bandwidth issue because I did a speed test on the only device connected to the switch." as meaning, a PC was directly connected to the Internet connection (often the usual comparative test), but Rick is correct, what exactly was tested, between the two tests, isn't clear.

Technically, a 2960x is wire-speed capable, but although the 2901 has gig ports, it doesn't guarantee gig throughput (a common misunderstanding of many ISRs performance capacity, i.e. assuming an ISR can guarantee wire-speed on all its ports).

BTW, one confirmation of ISRs performance capacity, when you do a speed test, check the overall CPU utilization.  If you're hitting close to 100%, you've hit the router's performance limit.)

Yes, I meant bandwidth sharing. I did a show int on each interface and found several of them were set to different speed and duplexes. I changed them all to speed 1000 duplex full to match the router set to Full Duplex, 1Gbps. However, the ports I made changes on are shut down saying not connected. I don't believe it's an issue with the connections not being crossovers because for one they gig ports should auto MDI/MDIX and they are connected to a router. Below are the configs for the ports. Gig 0/0 is local the local network, Gig0/1 is internet access.


router#show int gig0/0
GigabitEthernet0/0 is up, line protocol is up
Hardware is CN Gigabit Ethernet, address is 84b2.6106.a098 (bia 84b2.6106.a098)
Internet address is 192.168.100.1/24
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full Duplex, 1Gbps, media type is RJ45
output flow-control is unsupported, input flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:11, 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: 2
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 63000 bits/sec, 17 packets/sec
5 minute output rate 124000 bits/sec, 19 packets/sec
1871473 packets input, 1271578720 bytes, 0 no buffer
Received 1498 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
9676 input errors, 0 CRC, 0 frame, 9676 overrun, 0 ignored
0 watchdog, 1489 multicast, 0 pause input
3335149 packets output, 4087943460 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
1 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out

router#show int gig0/1
GigabitEthernet0/1 is up, line protocol is up
Hardware is CN Gigabit Ethernet, address is 84b2.6106.a099 (bia 84b2.6106.a099)
Internet address is 192.168.0.2/24
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full Duplex, 1Gbps, media type is RJ45
output flow-control is unsupported, input flow-control is XON
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:02, 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: 35
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 115000 bits/sec, 15 packets/sec
5 minute output rate 55000 bits/sec, 12 packets/sec
3463140 packets input, 4097385555 bytes, 8 no buffer
Received 131731 broadcasts (0 IP multicasts)
0 runts, 0 giants, 4 throttles
72980 input errors, 0 CRC, 0 frame, 72980 overrun, 0 ignored
0 watchdog, 0 multicast, 0 pause input
1878316 packets output, 1269247025 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
30 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out

Switch#show int gig4/0/3
GigabitEthernet4/0/3 is down, line protocol is down (notconnect)
Hardware is Gigabit Ethernet, address is 5061.bf9c.c783 (bia 5061.bf9c.c783)
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s, 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 never, output never, 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
0 packets input, 0 bytes, 0 no buffer
Received 0 broadcasts (0 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 0 multicast, 0 pause input
0 input packets with dribble condition detected
0 packets output, 0 bytes, 0 underruns
0 output errors, 0 collisions, 1 interface resets
0 unknown protocol drops
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

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