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netmanager.co.nz
Beginner

Cisco 871 Maximum WAN speed

I've just connected via pppoe to a fibre 70/40mbs service but only get around 12mbs bandwidth. The FE4 interface reports running at 100mbs Full Duplex so was wondering if the dialer interface has some kind of limit around 12mbs?

If the router is limited to 10/12mbs of WAN throughout can someone recommend and similar router with greater WAN throughput more suitable for a fibre service.

1 ACCEPTED SOLUTION

Accepted Solutions
paolo bevilacqua
Hall of Fame Master

Check attached document.

View solution in original post

24 REPLIES 24
fb_webuser
Frequent Contributor

I believe you must be using speedtest.net or any other site to measure the speed of your connection. Below steps can be followed to rectify the cause.

1. try "ping -f -l XXXX yahoo.com from your PC

2. check till what value of xxxx you are able to ping yahoo.com

3. XXXX value will be from 1 to 1500 and you can start testing it with value of 1400 (+/-)

4. Once you get the maximum value of XXXX, you can apply the same on VLAN interface of you switch by the command as per below.

ip tcp adjust-mss XXX

Check the result

HTH

Amit

---

Posted by WebUser Amit Goyal from Cisco Support Community App

Web User wrote:

I believe you must be using speedtest.net or any other site to measure the speed of your connection. Below steps can be followed to rectify the cause.

1. try "ping -f -l XXXX yahoo.com from your PC

2. check till what value of xxxx you are able to ping yahoo.com

3. XXXX value will be from 1 to 1500 and you can start testing it with value of 1400 (+/-)

4. Once you get the maximum value of XXXX, you can apply the same on VLAN interface of you switch by the command as per below.

ip tcp adjust-mss XXX

Check the result

HTH

Amit

---

Posted by WebUser Amit Goyal from Cisco Support Community App

There is no need to do all this stuff. The recommended value is always 1452, altough some suggest to make it smaller to better fit certain size packets in ATM cell multiples.

thanks - it was already set at 1452.

paolo bevilacqua
Hall of Fame Master

Check attached document.

View solution in original post

that performance table agrees with the 12.8mbs I got on a speedtest.

you certainly need to take a large jump in price bracket to get a cisco router capable of operating at 100mbs!

The choices available appear to be

891/892 - 50mbs

ISR 1861 - 74mbs

ISR G2 1941 - 150mbs

With the 891/892 being the clostest in price bracket to the 871

The smaller the part number, the cheaper the price. You should also look at the 1921.

Thanks for the nice rating and good luck!

the 1921 is missing from the performance table - can i assume it will be similar to the ISR G2 1941?

Check this other document.

Just want to let you know that the values in both PDF files are expressed in HALF duplex and without any encryption.

thanks - at the suggestion of someone else i turned off IPS on the WAN interface, changed the mss-adjust to 1400 from 1452 and ran another speedtest and carried out a 700mb iso download. FE4 is running at 100mbs Full Duplex.

The ISO came down at around 1.6MB/s andf the end of the down load the WAN and dialer interfaces looked like this towards the end of the download

Dialer0 is up, line protocol is up (spoofing)

Hardware is Unknown

Internet address is xxx.xxx.xxx.xxx/32

MTU 1500 bytes, BW 56 Kbit, DLY 20000 usec,

     reliability 255/255, txload 36/255, rxload 29/255

Encapsulation PPP, loopback not set

Keepalive set (10 sec)

DTR is pulsed for 1 seconds on reset

Interface is bound to Vi1

Last input never, output never, output hang never

Last clearing of "show interface" counters 3d00h

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 0/0/16 (active/max active/max total)

     Reserved Conversations 0/0 (allocated/max allocated)

     Available Bandwidth 42 kilobits/sec

5 minute input rate 12298000 bits/sec, 1167 packets/sec

5 minute output rate 329000 bits/sec, 553 packets/sec

     654966 packets input, 800368904 bytes

     340987 packets output, 41305791 bytes

Bound to:

Virtual-Access1 is up, line protocol is up

Hardware is Virtual Access interface

MTU 1500 bytes, BW 56 Kbit, DLY 20000 usec,

     reliability 255/255, txload 236/255, rxload 166/255

Encapsulation PPP, LCP Open

Open: IPCP

PPPoE vaccess, cloned from Dialer0

Vaccess status 0x44, loopback not set

Keepalive set (10 sec)

Interface is bound to Di0 (Encapsulation PPP)

Last input 00:00:25, output never, output hang never

Last clearing of "show interface" counters 10:52:27

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 11779000 bits/sec, 1152 packets/sec

5 minute output rate 348000 bits/sec, 562 packets/sec

     629866 packets input, 799917746 bytes, 0 no buffer

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

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

     316043 packets output, 40668851 bytes, 0 underruns

     0 output errors, 0 collisions, 0 interface resets

     0 output buffer failures, 0 output buffers swapped out

     0 carrier transitions

FastEthernet4 is up, line protocol is up

Hardware is PQUICC_FEC, address is 001a.e322.c7d6 (bia 001a.e322.c7d6)

Description: Outside Interface

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

     reliability 255/255, txload 1/255, rxload 30/255

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 00:00:35, output 00:00:01, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/14/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue: 0/40 (size/max)

5 minute input rate 12123000 bits/sec, 1167 packets/sec

5 minute output rate 350000 bits/sec, 568 packets/sec

     674395 packets input, 827604365 bytes

     Received 9499 broadcasts, 0 runts, 0 giants, 41 throttles

     43 input errors, 0 CRC, 0 frame, 0 overrun, 43 ignored

     0 watchdog

     0 input packets with dribble condition detected

     345898 packets output, 42782641 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

Does this calulation look right? 1200 packets / second with 1400 byte packets - 12.8mbs?

Virtual-Access1 is up, line protocol is up

Hardware is Virtual Access interface

MTU 1500 bytes, BW 56 Kbit, DLY 20000 usec,

reliability 255/255, txload 236/255, rxload 166/255

It's going as fast as it can.  236*254 is equivalent to 92.54%.

so is that the pppoe dialer interface? the FE4 WAN interface is only showing 30/255 RX load so the download is only consuming 11.76% of available bandwidth which could appear to be correct given the 12mbs max doewnload speed.

Connect PC direclty to ISP mode and test.

If much difference, you will need to upgrade router. At that point you can get one with V/ADSL interface directly.

chad patterson
Beginner

I maintain a Cisco 871 at my office, and I consistently get around 30Mbps down and 8Mbps up, but that is due to my cable companies speed limitiations applied upon me.

     So the document that is marked as the correct answer, cannot possiblybe the correct answer. You can get AT LEAST twice the speed you are currently getting. You should unmark that, and reinvestigate the real cause of the issue.

perhaps it's your MTU:

MTU 1500 bytes, BW 56 Kbit, DLY 20000 usec,

Follow this link to help you how to determine the proper MTU size for your network ( it's probably 1476). My WAN mtu is set to 1500, but the WAN interface a fastethernet interface connected to a cable router. For a ppp connection, the packet handling will be different.