Multiple PPP Multilinks in 7609 router

[f-m-s-2000]

We have Cisco 7609 routers in our network. We are using ppp multilinks between the sites. Because of the high traffic volume, we have to use multiple multilinks. 7609 router doesn't allow ppp multlink to span SIPs, so we use multiple mulitilinks between sites on different SIPs. OSPF for load balancing will be used. THE PROBLEM IS: when we define the second ppp multilink between two 7609 routers, the new multilink stays "inactive". Can we use multiple multilinks to the same router? We have enabled the command IP CEF DISTRIBUTED, but we still face the same problem". IOS used is: 122-18.SXF6

[spremkumar]

Hi

Can you post the configs related to multilink and physical link config binded to the same ?

Also can you post the outputs of show ip int brief and show interface multilink ?

regds

[f-m-s-2000]

Hello,

Thanks for your response, i removed some of the sh ip int breif coz i exceeded the max limit,

rgds

interface Multilink 122

bandwidth 4000

ip address 192.168.2.34 255.255.255.252

encapsulation ppp

no ip directed-broadcast

no ip proxy-arp

no ip redirects

no ip mroute-cache

ip route-cache

ppp multilink

multilink-group 122

interface Serial 2/0/0:1

no ip address

encapsulation ppp

no ip directed-broadcast

no ip proxy-arp

no ip redirects

no ip mroute-cache

ip route-cache cef

ppp multilink

multilink-group 122

interface Serial 2/0/1:1

no ip address

encapsulation ppp

no ip directed-broadcast

no ip proxy-arp

no ip redirects

no ip mroute-cache

ip route-cache cef

ppp multilink

multilink-group 122

7609#sh pp mu

Multilink26, bundle name is RTR-7609

Bundle up for 2d04h

Bundle is Distributed

5529 lost fragments, 38369916 reordered, 6 unassigned

14 discarded, 14 lost received, 83/255 load

0x3C98EA received sequence, 0xF6893A sent sequence

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

Se1/1/1:1, since 2d04h, no frags rcvd

Se1/0/1:1, since 2d04h, no frags rcvd

Se1/0/2:1, since 2d04h, no frags rcvd

Se1/0/0:1, since 1d07h, no frags rcvd

Se1/1/0:1, since 04:46:34, no frags rcvd

Multilink7, bundle name is RTR2-7609

Bundle up for 1w1d

Bundle is Distributed

0 lost fragments, 0 reordered, 0 unassigned

0 discarded, 0 lost received, 24/255 load

0x0 received sequence, 0x876730 sent sequence

Member links: 3 active, 0 inactive (max not set, min not set)

Se3/0/2:1, since 1w1d, no frags rcvd

Se3/0/1:1, since 12:28:52, no frags rcvd

Se3/0/0:1, since 12:28:52, no frags rcvd

Distributed fragmentation on. Fragment size 512. Multilink in Hardware.

Multilink6, bundle name is RTR3-7609

Bundle up for 2w3d

Bundle is Distributed

951 lost fragments, 649515071 reordered, 6 unassigned

97 discarded, 98 lost received, 86/255 load

0xBA15B9 received sequence, 0x2E367B sent sequence

Member links: 8 active, 0 inactive (max not set, min not set)

Se1/1/4:1, since 2w3d, no frags rcvd

Se1/1/5:1, since 2w3d, no frags rcvd

Se1/3/5:1, since 2w3d, no frags rcvd

Se1/3/4:1, since 2w3d, no frags rcvd

Se1/0/4:1, since 2d13h, no frags rcvd

Se1/0/5:1, since 2d13h, no frags rcvd

Se1/2/4:1, since 00:28:04, no frags rcvd

Se1/2/5:1, since 00:28:10, no frags rcvd

Multilink122 (inactive)

Member links: 2

Se2/0/0:1 (inactive)

Se2/0/1:1 (inactive)

sh inter mu 122

Multilink122 is down, line protocol is down

Hardware is multilink group interface

Description: Multilink ISB to Multilink LHR

Internet address is 192.168.2.34/30

MTU 1500 bytes, BW 4000 Kbit, DLY 100000 usec,

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

Encapsulation PPP, loopback not set

Keepalive set (10 sec)

DTR is pulsed for 2 seconds on reset

LCP Closed, multilink Closed

Closed: CDPCP, IPCP

Last input never, output never, output hang never

Last clearing of "show interface" counters 19:17:44

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 IP multicasts)

0 runts, 0 giants, 0 throttles

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

0 packets output, 0 bytes, 0 underruns

0 output errors, 0 collisions, 3 interface resets

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions

[spremkumar]

Hi

Can you post the output of both show interface serial 2/0/0:1 and serial 2/0/1:1 ?

I feel both your serial links are down which in turn affects the status of your multilink..

regds

[f-m-s-2000]

they show up down when added to the multilink

but show up up when removed from the multilink

and by the way, we have faced this same problem twice i.e 4 different 7609 routers

I am afraid this is a HW limitation

rgds

[jackyoung]

According to below link. Are you using PPP authentication for the MLPPP ? If yes, you have to use different username for different MLPPP bundles.

http://www.cisco.com/en/US/tech/tk713/tk507/technologies_configuration_example09186a0080093c1d.shtml

Hope this helps.

[f-m-s-2000]

Thanks for your response

We are not using authentication

Regards,

[amit-singh]

What's there at the far end to this box. Is that also configured for MLPPP.Your both the sides should be configured for MLPPP.

Paste the config frrm far end device.

What if you take the Multilink config out of the interface, does this become up/up.

-amit singh

[sourabhagarwal]

check status of serial interface Se2/0/0:1 and Se2/0/1:1 as they are are member of this multilink?

As both members are shown as inactive, I doubt that serial interfaces are UP.

Multilink122 (inactive)

Member links: 2

Se2/0/0:1 (inactive)

Se2/0/1:1 (inactive)

make sure, first your individual interfaces on both ends are up, "serial is up, line protocol is up", only then multilink will come UP.

[f-m-s-2000]

Thanx

As I mentioned in my last post, both serials show up up, but when added to the multlink they show up down

rgds

[f-m-s-2000]

Thanks.

Another 7609 router on the other end with exactly the same configuration

if i remove the multilink config, the serial inter shows up up

rgds

[spremkumar]

Hi

Can you try shutting and enabling the serial as well multilink interfaces using shut & no shut commands under the serial/multilink interface on both the ends?

We did face similar kinda erratic problems with multilink in 7206 routers which got recited by issuing shut/no shut commands.

regds

[f-m-s-2000]

I did , still the same

below the o/p of one serial after added to the multilink

sh inter serial 2/0/0:1

Serial2/0/0:1 is up, line protocol is down

Hardware is SPA-8XCHT1/E1

MTU 1500 bytes, BW 1984 Kbit, DLY 20000 usec,

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

Encapsulation PPP, crc 16, loopback not set

Keepalive set (10 sec)

LCP Listen, multilink Closed

Closed: CDPCP

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

Last clearing of "show interface" counters 22:48:00

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 10

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

239712 packets input, 4528824 bytes, 0 no buffer

Received 0 broadcasts (0 IP multicasts)

0 runts, 0 giants, 0 throttles

774 input errors, 59 CRC, 306 frame, 0 overrun, 0 ignored, 406 abort

238856 packets output, 4446582 bytes, 0 underruns

0 output errors, 0 collisions, 27927 interface resets

0 output buffer failures, 0 output buffers swapped out

14 carrier transitions no alarm present

Timeslot(s) Used:1-31, subrate: 64Kb/s, transmit delay is 0 flags

[amit-singh]

I see a lots of input errors under the serial interface.There are 14 carrier transitions for this interface i.e means interface came up but went down due to some issue.

Please troubleshoot the imput error problem first. It seems like there is some physical link problem. Get on a call with your Telco and troubleshoot the local loop and remote loop checking.

-amit singh

[f-m-s-2000]

Those statistics are kinda old. I can assure you that the media is very clean. Please make note that this problem has been noticed on 4 different E1's

rgds