Re: Multilink PPP only half of the bandwidth

horvaia · ‎09-07-2006

Hello,

I have a 10 Mbit line with one of my customers. The problem is that he can only

use the half of the bandwidth. I'm using

Multilink PPP to join the five 2 Mbit (1984) E1s. What can be te problem?

Here is the show commands from my side:

Multilink2, bundle name is Internet

Bundle up for 2w4d

1016 lost fragments, 14458402 reordered, 0 unassigned

583 discarded, 0 lost received, 112/255 load

0x1D8935 received sequence, 0x629CE1 sent sequence

Member links: 5 active, 0 inactive (max not set, min not set)

Se1/1:1, since 2w4d, last rcvd seq 1D8930

Se6/0:1, since 1w6d, last rcvd seq 1D8931

Se5/1:1, since 2w4d, last rcvd seq 1D8932

Se2/1:1, since 2w0d, last rcvd seq 1D8933

Se5/0:1, since 2w0d, last rcvd seq 1D8934

#sh interfaces multilink 2

Multilink2 is up, line protocol is up

Hardware is multilink group interface

Description: Multilink

Internet address is 192.168.4.57/30

MTU 1500 bytes, BW 9920 Kbit, DLY 100000 usec,

reliability 255/255, txload 110/255, rxload 5/255

Encapsulation PPP, loopback not set

Keepalive set (10 sec)

DTR is pulsed for 2 seconds on reset

LCP Open, multilink Open

Open: IPCP, CDPCP

Last input 00:00:03, output never, output hang never

Last clearing of "show interface" counters 5d22h

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 19597

Queueing strategy: fifo

Output queue: 0/40 (size/max)

5 minute input rate 226000 bits/sec, 256 packets/sec

5 minute output rate 4307000 bits/sec, 396 packets/sec

30197569 packets input, 3605082885 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

48094316 packets output, 59755166 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions

Thanks,

Andras

shah.chintan · ‎09-07-2006

Hi Andras,

Can you please check show output of each serial interface and see what is BW there you see. Whether 1984 kbps or Half of it ?

Can you send configuration of interface multilink 2 and configuration under each serial interface which are part of Multilink2

Rgds

Chintan

Rgds

Chintan

horvaia · ‎09-07-2006

Hi Chintan,

Please check the attached txt file.

(every serial link has 1984 setup).

Thanks,

Andras

shah.chintan · ‎09-07-2006

Hi,

I'm not able to open. Can you send me the same txt file through mail.

chintan@motorola.com

rgds

chintan

horvaia · ‎09-07-2006

Hi,

I sent you the txt file.

Thanks,

Andras

Edison Ortiz · ‎09-07-2006

Andras,

Your config looks fine. However, I'm very concerned about this:

Total output drops: 19597

Can you clear the counter and see if this amount increases ?

I also recommend implementing interleaving, see:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fqos_c/fqcprt6/qcflfi.htm

horvaia · ‎09-08-2006

well it is increasing:

take a look:

Multilink2 is up, line protocol is up

Hardware is multilink group interface

Description: Internet Multilink

Internet address is 192.168.4.57/30

MTU 1500 bytes, BW 9920 Kbit, DLY 100000 usec,

reliability 255/255, txload 70/255, rxload 4/255

Encapsulation PPP, loopback not set

Keepalive set (10 sec)

DTR is pulsed for 2 seconds on reset

LCP Open, multilink Open

Open: IPCP, CDPCP

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

Last clearing of "show interface" counters 6d23h

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 39028

Queueing strategy: fifo

Output queue: 0/40 (size/max)

5 minute input rate 177000 bits/sec, 184 packets/sec

5 minute output rate 2760000 bits/sec, 306 packets/sec

42151064 packets input, 757973590 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

67458849 packets output, 2152133113 bytes, 0 underruns

0 output errors, 0 collisions, 2 interface resets

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions

after this post I issued a clear counter on

this interface we will see

but this is significantly increasing

why could it be?

jackyoung · ‎09-07-2006

Did you try to enable "ip route-cache cef" or "ip route-cache distributed" and enable FIFO ?

What is the CPU loading ? If it is high, try to disable the ppp multilink fragmentation.

Check below for info. :

http://www.cisco.com/en/US/tech/tk713/tk628/technologies_configuration_example09186a00800a5efa.shtml

horvaia · ‎09-08-2006

Hi,

Queueing strategy: fifo.

And look the sh ip int mult2 output:

(cef is enabled)

#sh ip interface multilink 2

Multilink2 is up, line protocol is up

Internet address is 192.168.4.57/30

Broadcast address is 255.255.255.255

Address determined by non-volatile memory

Peer address is 192.168.8.82

MTU is 1500 bytes

Helper address is not set

Directed broadcast forwarding is disabled

Outgoing access list is not set

Inbound access list is Internet

Proxy ARP is enabled

Security level is default

Split horizon is enabled

ICMP redirects are always sent

ICMP unreachables are always sent

ICMP mask replies are never sent

IP fast switching is enabled

IP fast switching on the same interface is enabled

IP Flow switching is disabled

IP CEF switching is enabled

IP CEF Feature Fast switching turbo vector

IP multicast fast switching is enabled

IP multicast distributed fast switching is disabled

IP route-cache flags are Fast, CEF

Router Discovery is disabled

IP output packet accounting is disabled

IP access violation accounting is disabled

TCP/IP header compression is disabled

RTP/IP header compression is disabled

Probe proxy name replies are disabled

Policy routing is disabled

Network address translation is disabled

WCCP Redirect outbound is disabled

WCCP Redirect inbound is disabled

WCCP Redirect exclude is disabled

BGP Policy Mapping is disabled

And here I'm a litle bit confused. What is the peer address?

This the peer addres is owned by another customer. Could it be a

problem? How did the router get this ip address? I didn't setup this.

Thanks,

Andras

horvaia · ‎09-08-2006

I forgot. The cpu utilization:

CPU utilization for five seconds: 4%/4%; one minute: 5%; five minutes: 5%

jackyoung · ‎09-08-2006

Can you please also check the queueing of serial is FIFO ?

Try to follow the example and test again.

horvaia · ‎09-08-2006

The queing on the serial interfaces:

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

Queueing strategy: weighted fair [suspended, using FIFO]

FIFO output queue 6/40, 0 drops

on the multilink interface:

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 259

Queueing strategy: fifo

(so the output drops are rising.)

Now I will read the document you sent.

jackyoung · ‎09-08-2006

I have another idea that did you verify the link throughput w/o using MLPPP ? e.g. use HDLC or PPP only.

I suggest to disable PPP for one link and test the thourghput of this link to isolate the problem is the link itself or the router.

If you disable the MLPPP and able to use the throughput up to 2Mbps, I belive it is the problem of the router, may be software bug or other issue. We need to isolate the problem first.

horvaia · ‎09-08-2006

thanks for the idea. I'm able to check it

only monday. We also changed the queing method

to fifo as you suggested, but the result is

the same. the customer can only use 5.5 Mbit

instead of 10 Mbit. What does full-duplex mean

in a Multilink configuration?

Thanks,

Andras

mmorris11 · ‎09-08-2006

I have a MLPPP link with 6 T1s on my network. I swapped some routers around in our datacenter and mixed up the order of the T1s. The throughput went to crap. I went through and physically repositioned the T1s in ascending mirrored order and things went back to normal. It turns out that MLPPP literally does a round robin with the data and order is really important. I got the hunch from this guide:

http://www.cisco.com/en/US/customer/products/hw/modules/ps2033/products_white_paper09186a0080091d4b.shtml

HTH