[c-nsp] Multilink PPP Problems

[Adam Piasecki]

Our Router...
Cisco 7507
RSP4/256mb
VIP2/50 - PA-MC-4T1
IP CEF Distributed enabled
IOS: 12.2(15)T9

I've been through just about every thread on this site, yet seem to be at a
dead end. We have 4T1's configured as a MLPPP. I'm currently loosing
anywhere from 10% - 20% packet loss across the MLPPP Group. I get 0% packet
loss when the link is running 1mb/s or below. It doesn't seem to be a CPU or
bandwidth issue. We have other Multilink groups in the same router that
don't have this problem. I do notice that the T1's are taking on more
interface resets then others. Could this be bad hardware??? All of the T1's
are running clean, no input errors. If you guys have any idea it would be
greatly appreciated, Thanks!

This is what im seeing accross the MultilinkGroup,

Reply from X.X.X.X: bytes=32 time=51ms TTL=243
Reply from X.X.X.X: bytes=32 time=56ms TTL=243
Reply from X.X.X.X: bytes=32 time=91ms TTL=243
Reply from X.X.X.X: bytes=32 time=827ms TTL=243
Reply from X.X.X.X: bytes=32 time=3464ms TTL=243
Reply from X.X.X.X: bytes=32 time=36ms TTL=243
Reply from X.X.X.X: bytes=32 time=2218ms TTL=243
Request timed out. -- > discarded fragments/bytes increases
Request timed out. -- > discarded fragments/bytes increases
Reply from X.X.X.X: bytes=32 time=325ms TTL=243
Reply from X.X.X.X: bytes=32 time=29ms TTL=243
Reply from X.X.X.X: bytes=32 time=57ms TTL=243


border02.ash.wa#show int multilink2
Multilink2 is up, line protocol is up
Hardware is multilink group interface
Internet address is X.X.X.X/30
MTU 1500 bytes, BW 6144 Kbit, DLY 100000 usec,
reliability 255/255, txload 174/255, rxload 28/255
Encapsulation PPP, LCP Open, multilink Open
Open: CDPCP, IPCP, loopback not set
DTR is pulsed for 2 seconds on reset
Last input 00:00:00, output never, output hang never
Last clearing of "show interface" counters 21:07:07
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/300 (size/max)
5 minute input rate 677000 bits/sec, 501 packets/sec
5 minute output rate 4215000 bits/sec, 526 packets/sec
10750067 packets input, 1982828510 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
12016199 packets output, 4107837519 bytes, 0 underruns
0 output errors, 0 collisions, 9 interface resets
0 output buffer failures, 0 output buffers swapped out
0 carrier transitions

border02.ash.wa#show ppp multilink
Multilink2, bundle name is FCPS-Border
Bundle up for 00:54:41, 123/255 load
Receive buffer limit 48768 bytes, frag timeout 1000 ms
0/0 fragments/bytes in reassembly list
66 lost fragments, 171117 reordered
88/18454 discarded fragments/bytes, 66 lost received
0x1EBCAA received sequence, 0x4E4A87 sent sequence
Member links: 4 active, 0 inactive (max not set, min not set)
Se1/0/2:0, since 00:54:41
Se1/0/1:0, since 00:54:41
Se1/0/0:0, since 00:54:41
Se1/0/3:0, since 00:54:41

border02.ash.wa#show int multilink2 stat
Multilink2
Switching path Pkts In Chars In Pkts Out Chars Out
Processor 130942 12207915 16951 4261658
Route cache 10845988 2006805759 12237587 53208943
Distributed cache 0 0 0 0
Total 10976930 2019013674 12254538 57470601




Our Config
--------------------------------------------------------------------------
interface Multilink2
ip access-group AZ-IN1131111977 in
ip access-group AZ-IN1131111977 out
ppp multilink
multilink-group 2
hold-queue 300 out
!
interface Serial1/0/0:0
bandwidth 1544
no ip address
ip access-group AZ-IN1131114133 in
ip access-group AZ-IN1131114133 out
encapsulation ppp
no ip route-cache
load-interval 30
tx-queue-limit 26
down-when-looped
no fair-queue
ppp multilink
multilink-group 2
!
interface Serial1/0/1:0
bandwidth 1544
no ip address
ip access-group AZ-IN1131114133 in
ip access-group AZ-IN1131114133 out
encapsulation ppp
no ip route-cache
load-interval 30
tx-queue-limit 26
down-when-looped
no fair-queue
ppp multilink
multilink-group 2
!
interface Serial1/0/2:0
bandwidth 1544
no ip address
ip access-group AZ-IN1131114133 in
ip access-group AZ-IN1131114133 out
encapsulation ppp
no ip route-cache
load-interval 30
tx-queue-limit 26
down-when-looped
no fair-queue
ppp multilink
multilink-group 2
!
interface Serial1/0/3:0
bandwidth 1544
no ip address
ip access-group AZ-IN1131114133 in
ip access-group AZ-IN1131114133 out
encapsulation ppp
no ip route-cache
load-interval 30
tx-queue-limit 26
down-when-looped
no fair-queue
ppp multilink
multilink-group 2
!

--------------------------------------------------------------------------
Customer Config

interface Multilink1
ip address X.X.X.X X.X.X.X
ppp multilink
ppp multilink group 1
!
interface Serial0/0/0
bandwidth 1544
no ip address
encapsulation ppp
service-module t1 timeslots 1-24
ppp multilink
ppp multilink group 1
!
interface Serial0/1/0
bandwidth 1544
no ip address
encapsulation ppp
service-module t1 timeslots 1-24
ppp multilink
ppp multilink group 1
!
interface Serial0/2/0
bandwidth 1544
no ip address
encapsulation ppp
service-module t1 timeslots 1-24
ppp multilink
ppp multilink group 1
!
interface Serial0/3/0
bandwidth 1544
no ip address
encapsulation ppp
service-module t1 timeslots 1-24
ppp multilink
ppp multilink group 1
!