[c-nsp] Troubleshooting IPv6 throughput on a GSR 12410

Aaron Daubman daubman at gmail.com
Thu Dec 15 09:23:29 EST 2005


Greetings,

I'm generating a fixed ipv6 flow (1230 byte frames) at 80025 fps (~787Mbps).
What's concerning is that only between 58000 and 59000 fps are being
received out the other end.

The setup is: IXIA==>(GigE)GSR(OC-48)==>IXIA

The generated flow hits my GSR on a port on a Modular Gbe Line card:
---snip---
interface GigabitEthernet2/0/0
 no ip address
 no ip directed-broadcast
 load-interval 30
 negotiation auto
 ipv6 address 2001:411:0:1::1/64
 ipv6 enable
 ipv6 cef
 ipv6 router isis
---snip---
http://www.cisco.com/en/US/products/hw/modules/ps2710/products_data_sheet09186a00800886fe.html
"The Modular GbE Line Card maintains line-rate performance for IP
forwarding and MPLS switching with a dedicated Layer 3 lookup ASIC."


It exits via a CHOC-48 port running at OC-48c:
---snip---
controller SONET 0/0
 sts-1 1 - 48 pos
!...
interface POS0/0:1
 no ip address
 no ip directed-broadcast
 encapsulation ppp
 load-interval 30
 carrier-delay msec 0
 ipv6 address 2001:410:0:1::1/64
 ipv6 enable
 ipv6 cef
 ipv6 router isis
 crc 32
 pos scramble-atm
 no ppp lcp fast-start
 no ppp link reset
---snip---
http://www.cisco.com/en/US/products/hw/modules/ps2710/products_data_sheet09186a0080092078.html
"Pioneering the 10G-enabled high-speed provider edge—The 1-Port
CHOC-48 ISE card concentrates one full-duplex 2.5 Gbps OC-48/STM-16
port in one line card, providing a high-speed, high-performance
customer aggregation solution that enables service providers to scale
network architectures cost effectively. By deploying the 1-Port
CHOC-48 ISE in the Cisco 12000 Series, customers benefit from linear
performance scalability, carrier-class reliability, a complete range
of form-factors, and scalable 10-gigabit networking."

I'm trying to find where the problem is but haven't been able to hunt
it down so far - what am I missing?

the usual suspects:
-------------------------------------------------------------------------------------------------------------------------------------
GSR-1#show interfaces g2/0/0 stats
GigabitEthernet2/0/0
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor      52257   64178956      14488   18436468
             Route cache          0          0          0          0
         Distributed cef  379227710 464933159159          0          0
                   Total  379279967 464997338115      14488   18436468

GSR-1#show interfaces g2/0/0 switching
GigabitEthernet2/0/0
          Throttle count          0
        Drops         RP          0         SP          0
  SPD Flushes       Fast          0        SSE          0
  SPD Aggress       Fast          0
 SPD Priority     Inputs       9469      Drops          0

     Protocol       Path    Pkts In   Chars In   Pkts Out  Chars Out
        Other    Process          0          0       8789     527340
            Cache misses          0
                    Fast          0          0          0          0
               Auton/SSE          0          0          0          0
           IP    Process          0          0          0          0
            Cache misses          0
                    Fast          0          0          0          0
               Auton/SSE   98585226 124696570095          0          0
         CLNS    Process        680     953574      12146   17372600
            Cache misses          0
                    Fast          0          0          0          0
               Auton/SSE          0          0          0          0
          CDP    Process          0          0       1471     557482
            Cache misses          0
                    Fast          0          0          0          0
               Auton/SSE          0          0          0          0
         IPv6    Process      51577   63225382        871     506386
            Cache misses          0
                    Fast          0          0          0          0
               Auton/SSE  280916911 340571435372          0          0

GSR-1#show interfaces p0/0:1 stats
POS0/0:1
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor       9613    3415048      20949   45407918
             Route cache          0          0          0          0
         Distributed cef          0          0  274989018 334386645892
                   Total       9613    3415048  275009967 334432053810

GSR-1#show interfaces p0/0:1 switching
POS0/0:1
          Throttle count          0
        Drops         RP          0         SP          0
  SPD Flushes       Fast          0        SSE          0
  SPD Aggress       Fast          0
 SPD Priority     Inputs       9612      Drops          0

     Protocol       Path    Pkts In   Chars In   Pkts Out  Chars Out
        Other    Process          0          0       8850     141588
            Cache misses          0
                    Fast          0          0          0          0
               Auton/SSE          0          0          0          0
           IP    Process          0          0          0          0
            Cache misses          0
                    Fast          0          0          0          0
               Auton/SSE 18446744073709551615 18446744073709551600    
176432  214542536
         CLNS    Process        816    3274268      11811   44913733
            Cache misses          0
                    Fast          0          0          0          0
               Auton/SSE          0          0          0          0
         IPv6    Process          2        120        290     352640
            Cache misses          0
                    Fast          0          0          0          0
               Auton/SSE          0          0  274917221 334299340736


GSR-1#sh cef interface g2/0/0
GigabitEthernet2/0/0 is up (if_number 6)
  Corresponding hwidb fast_if_number 6
  Corresponding hwidb firstsw->if_number 6
  Internet Protocol processing disabled
  Hardware idb is GigabitEthernet2/0/0 (6)
  Software idb is GigabitEthernet2/0/0 (6)
  Fast switching type 1, interface type 69
  IP Distributed CEF switching enabled
  IP Null turbo vector
  Input fast flags 0x0, Output fast flags 0x0, Flags 0x80000
  ifindex 8(8)
  Slot 2 Slot unit 0 VC -1
  Transmit limit accumulator 0x0 (0x0)
  IP MTU 1500

GSR-1#sh cef int p0/0:1
POS0/0:1 is up (if_number 13)
  Corresponding hwidb fast_if_number 13
  Corresponding hwidb firstsw->if_number 13
  Internet Protocol processing disabled
  Interface is marked as point to point interface
  Packets switched to this interface are dropped:
  Hardware idb is POS0/0:1 (13)
  Software idb is POS0/0:1 (13)
  Fast switching type 7, interface type 11
  IP Distributed CEF switching enabled
  IP Null turbo vector
  Input fast flags 0x0, Output fast flags 0x0, Flags 0x80021
  ifindex 16(16)
  Slot 0 Slot unit 0 VC 1
  Transmit limit accumulator 0x0 (0x0)
  IP MTU 4470

GSR-1#sh int g2/0/0
GigabitEthernet2/0/0 is up, line protocol is up
  Small Factor Pluggable Optics okay
  Hardware is GigMac 10 Port GigabitEthernet, address is
0012.44e0.00cc (bia 0012.44e0.00cc)
  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec, rely 255/255, load 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full Duplex, 1000Mbps, link type is autonegotiation, media type is SX
  output flow-control is unsupported, input flow-control is off
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:04, output 00:00:01, output hang never
  Last clearing of "show interface" counters 00:01:25
  Queueing strategy: fifo
  Output queue 0/40, 0 drops; input queue 0/75, 0 drops
  30 second input rate 787565000 bits/sec, 80296 packets/sec
  30 second output rate 0 bits/sec, 0 packets/sec
     6984657 packets input, 8563192362 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 watchdog, 11 multicast, 0 pause input
     42 packets output, 47877 bytes, 0 underruns
     Transmitted 0 broadcasts
     0 output errors, 0 collisions, 0 interface resets
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 pause output
     0 output buffer failures, 0 output buffers swapped out
GSR-1#sh int p0/0:1

POS0/0:1 is up, line protocol is up
  Hardware is Packet over SONET
  MTU 4470 bytes, BW 2488000 Kbit, DLY 100 usec, rely 255/255, load 58/255
  Encapsulation PPP, crc 32, loopback not set
  Keepalive set (10 sec)
  Scramble enabled
  Carrier delay is 0 msec
  LCP Open
  Listen: CDPCP
  Open: OSICP, IPV6CP
  Last input 00:00:05, output 00:00:04, output hang never
  Last clearing of "show interface" counters 00:01:39
  Queueing strategy: fifo
  Output queue 0/40, 0 drops; input queue 0/75, 0 drops
        Available Bandwidth 2395851 kilobits/sec
  30 second input rate 6000 bits/sec, 0 packets/sec
  30 second output rate 575348000 bits/sec, 59143 packets/sec
     22 packets input, 53836 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
              0 parity
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     5925181 packets output, 7205044806 bytes, 0 underruns
     0 output errors, 0 applique, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out
     0 carrier transitions

GSR-1#sh proc cpu sorted 1min
CPU utilization for five seconds: 1%/0%; one minute: 0%; five minutes: 0%
 PID Runtime(ms)   Invoked      uSecs   5Sec   1Min   5Min TTY Process
  40       51184   1918112         26  0.15%  0.08%  0.06%   0 MBUS Config
   5       71660      8946       8010  0.00%  0.04%  0.05%   0 Check heaps
 177         524      2143        244  0.23%  0.04%  0.00%   0 Exec
  20       21984   1185029         18  0.00%  0.03%  0.01%   0 IPC Seat Manager
  68       23496    647513         36  0.00%  0.01%  0.00%   0 GSR RP CMD Event
  67       11776      1493       7887  0.00%  0.00%  0.00%   0 Per-minute Jobs
  23       13488    380633         35  0.00%  0.00%  0.00%   0 ARP Input
  30        1436    605628          2  0.00%  0.00%  0.00%   0 Mbus Agent Manag
   9           0         1          0  0.00%  0.00%  0.00%   0 LB  Daemon
  10           0       807          0  0.00%  0.00%  0.00%   0 MBUS Flash
  11        3072    379763          8  0.00%  0.00%  0.00%   0 MBUS System
  13           0    441206          0  0.00%  0.00%  0.00%   0 Test CPUHOG proc
  12           0     88235          0  0.00%  0.00%  0.00%   0 MBUS interface S
  14        1164     38441         30  0.00%  0.00%  0.00%   0 Fabric
  16        1668    176785          9  0.00%  0.00%  0.00%   0 PowerMgr Main
  17           0      1471          0  0.00%  0.00%  0.00%   0 IPC Dynamic Cach
   8           0         2          0  0.00%  0.00%  0.00%   0 Serial Backgroun
  15           0         1          0  0.00%  0.00%  0.00%   0 GoodieMgr Server
   7           0         2          0  0.00%  0.00%  0.00%   0 Timers
   6           8         8       1000  0.00%  0.00%  0.00%   0 Pool Manager
  19          12     88235          0  0.00%  0.00%  0.00%   0 IPC Periodic Tim

-----------------------------------------------------------------------------------------------------------------------------------

Any ideas?  How do I hunt down where these missing 20000fps are getting dropped?

Thanks,
     ~Aaron



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