I saw this exact problem from a customer a few months ago. What his turned out to be was some extra latency on one of the T1 links. I don't remember if it was in one direction or not though.
How about trying the combinations of 2xT1 bundles to see if you can isolate one T1 as a particular problem? Capture 'sh ppp mul' on both sides when you are seeing the problem and not. Rodney On Fri, May 25, 2007 at 10:15:52PM -0400, Sean Shepard wrote: > I'm encountering an odd problem bonding T1 circuits with Multilink PPP > (Cisco 7206 down to a 2651XM). In this particular case, I've got three (3) > T-1 lines bonded together and, taking into account overhead, I'm getting > (via direct Ethernet -> laptop connection - no other traffic): > > 4.2 to 4.3 mbps downstream, but . > Only around 2.0 mbps upstream (tried two different "check my speed" sites). > > I was able to initiate multiple large packet repeating pings between the two > devices and the show interface statistics showed in the neighborhood of 4.0 > mbps in both directions. This put the CPU in the 60 to 70 percent > utilization range on the remote 2651XM device (with it originating about 50% > of the pings but not otherwise routing any traffic, Ethernet interface was > disconnected) 7206 Utilization (handling traffic for numerous locations) was > well under 10%. No ACLs or Policy-Maps at either end of the links. > > Any suggestions or insight on the problem are greatly appreciated. I've not > observed this kind of difference on various other 2xT1 (3 mbps) connections > that I've got in place but this is the first 3xT1. Thanks a bunch! > > > HOST END > Cisco 7206 (non VXR) > > interface Multilink2 > description Multilink (ch16-18) > ip unnumbered Loopback2 > ppp multilink > no ppp multilink fragmentation > multilink-group 2 > > interface Serial3/0:16 > description MLPPP #1 > mtu 1524 > no ip address > no ip redirects > encapsulation ppp > no fair-queue > no ppp lcp fast-start > ppp multilink > multilink-group 2 > ! > interface Serial3/0:17 > description MLPPP #2 > mtu 1524 > no ip address > no ip redirects > encapsulation ppp > no fair-queue > ppp multilink > multilink-group 2 > ! > interface Serial3/0:18 > description MLPPP #3 > mtu 1524 > no ip address > no ip redirects > encapsulation ppp > no fair-queue > ppp multilink > multilink-group 2 > > > > REMOTE END > CISCO 2651XM w/WIC-DSU-T1 Cards > IOS C2600 Version 12.3(6a) > > Router> show run (relevant sections) > > network-clock-participate slot 1 > no network-clock-participate wic 0 > no aaa new-model > ip subnet-zero > ip cef > ! > ! > ! > interface Multilink1 > description MultiLink PPP 3xT1 > ip address xx.xx.xx.xx xx.xx.xx.xx > no ip mroute-cache > load-interval 30 > ppp multilink > ppp multilink fragment disable > ppp multilink group 1 > ! > interface FastEthernet0/0 > description LAN Interface > ip address xx.xx.xx.xx 255.255.255.248 > speed auto > full-duplex > no cdp enable > ! > interface Serial0/0 > description MLPPP T1 1 > mtu 1524 > no ip address > encapsulation ppp > load-interval 120 > no fair-queue > ppp multilink > ppp multilink group 1 > ppp multilink endpoint none > ! > interface Serial0/1 > description MLPPP T1 2 > mtu 1524 > no ip address > encapsulation ppp > load-interval 120 > no fair-queue > ppp multilink > ppp multilink group 1 > ppp multilink endpoint none > ! > interface Serial1/0 > description MLPPP T1 3 > mtu 1524 > no ip address > encapsulation ppp > load-interval 120 > no fair-queue > ppp multilink > ppp multilink group 1 > ppp multilink endpoint none > ! > > > > ROUTER> show interface > > Serial0/0 is up, line protocol is up > Hardware is PQUICC with Fractional T1 CSU/DSU > Description: MLPPP T1 1 > MTU 1524 bytes, BW 1544 Kbit, DLY 20000 usec, > reliability 255/255, txload 1/255, rxload 1/255 > Encapsulation PPP, LCP Open, multilink Open, loopback not set > Last input 00:00:00, output 00:00:01, output hang never > Last clearing of "show interface" counters 05:13:27 > Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 > Queueing strategy: fifo > Output queue: 0/40 (size/max) > 2 minute input rate 0 bits/sec, 0 packets/sec > 2 minute output rate 0 bits/sec, 0 packets/sec > 179815 packets input, 246334673 bytes, 0 no buffer > Received 0 broadcasts, 0 runts, 0 giants, 0 throttles > 1 input errors, 0 CRC, 1 frame, 0 overrun, 0 ignored, 0 abort > 175062 packets output, 233229743 bytes, 0 underruns > 0 output errors, 0 collisions, 2 interface resets > 0 output buffer failures, 0 output buffers swapped out > 0 carrier transitions > DCD=up DSR=up DTR=up RTS=up CTS=up > > Serial0/1 is up, line protocol is up > Hardware is PQUICC with Fractional T1 CSU/DSU > Description: MLPPP T1 2 > MTU 1524 bytes, BW 1544 Kbit, DLY 20000 usec, > reliability 255/255, txload 1/255, rxload 1/255 > Encapsulation PPP, LCP Open, multilink Open, loopback not set > Last input 00:00:04, output 00:00:04, output hang never > Last clearing of "show interface" counters 05:13:35 > Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 > Queueing strategy: fifo > Output queue: 0/40 (size/max) > 2 minute input rate 0 bits/sec, 0 packets/sec > 2 minute output rate 0 bits/sec, 0 packets/sec > 179809 packets input, 246361009 bytes, 0 no buffer > Received 0 broadcasts, 0 runts, 0 giants, 0 throttles > 2 input errors, 1 CRC, 1 frame, 0 overrun, 0 ignored, 0 abort > 175057 packets output, 233616175 bytes, 0 underruns > 0 output errors, 0 collisions, 2 interface resets > 0 output buffer failures, 0 output buffers swapped out > 0 carrier transitions > DCD=up DSR=up DTR=up RTS=up CTS=up > > Serial1/0 is up, line protocol is up > Hardware is DSCC4 with integrated T1 CSU/DSU > Description: MLPPP T1 3 > MTU 1524 bytes, BW 1544 Kbit, DLY 20000 usec, > reliability 255/255, txload 1/255, rxload 1/255 > Encapsulation PPP, LCP Open, multilink Open, loopback not set > Last input 00:00:05, output 00:00:05, output hang never > Last clearing of "show interface" counters 05:13:40 > Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 > Queueing strategy: fifo > Output queue: 0/40 (size/max) > 2 minute input rate 0 bits/sec, 0 packets/sec > 2 minute output rate 0 bits/sec, 0 packets/sec > 179807 packets input, 246218180 bytes, 0 no buffer > Received 0 broadcasts, 0 runts, 0 giants, 0 throttles > 5 input errors, 0 CRC, 5 frame, 0 overrun, 0 ignored, 0 abort > 175054 packets output, 233403514 bytes, 0 underruns > 0 output errors, 0 collisions, 2 interface resets > 0 output buffer failures, 0 output buffers swapped out > 0 carrier transitions > DCD=up DSR=up DTR=up RTS=up CTS=up > > > > > > > > _______________________________________________ > cisco-nsp mailing list [email protected] > https://puck.nether.net/mailman/listinfo/cisco-nsp > archive at http://puck.nether.net/pipermail/cisco-nsp/ _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
