[c-nsp] Multilink PPP Problems

[Rodney Dunn]

Do you have dCEF on?

This bundle doesn't show up as disbributed in 'sh ppp multilink'.

Don't ever configure anything other than keepalives on the member
link of the bundle.

Don't ever turn off any form of route-cache unless you know it's
a valid workaround to a bug and you are waiting for it to get
fixed.

Rodney

On Fri, Nov 04, 2005 at 09:50:03AM -0500, Adam Piasecki wrote:
> 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
> !
> _______________________________________________
> cisco-nsp mailing list  cisco-nsp at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-nsp
> archive at http://puck.nether.net/pipermail/cisco-nsp/