[c-nsp] 6500 - SUP720 - IOS - traffic problem

Gabriel Mateiciuc mgabi at ase.ro
Sat Jan 5 09:14:50 EST 2008


Hello everyone,

Here's the environment i'm talking about:

#sh platform hardware capacity 
System Resources
  PFC operating mode: PFC3BXL
  Supervisor redundancy mode: administratively sso, operationally sso
  Switching resources: Module   Part number               Series      CEF
mode
                       1        WS-X6348-RJ-45           classic
CEF
                       2        WS-X6348-RJ-45           classic
CEF
                       3        WS-X6748-GE-TX            CEF720
CEF
                       4        WS-X6724-SFP              CEF720
CEF
                       5        WS-SUP720-3BXL        supervisor
CEF
                       6        WS-X6704-10GE             CEF720
CEF
                       7        WS-X6348-RJ-45           classic
CEF
                       8        WS-X6348-RJ-45           classic
CEF
                       9        WS-X6348-RJ-45           classic
CEF

CPU Resources
  CPU utilization: Module             5 seconds       1 minute       5
minutes
                   3                   0% /  0%             0%
0%
                   4                   0% /  0%             0%
0%
                   5  RP              32% / 11%            11%
11%
                   5  SP              14% /  1%             9%
9%
                   6                   0% /  0%             0%
0%
  Processor memory: Module   Bytes:       Total           Used
%Used
                    3                 219661760       94927184
43%
                    4                 219661760       94488840
43%
                    5  RP             927935472      132545832
14%
                    5  SP             912623676      218933576
24%
                    6                 219661760       94944424
43%
  I/O memory: Module         Bytes:       Total           Used
%Used
              5  RP                    67108864       11891816
18%
              5  SP                    67108864       11891760
18%

EOBC Resources
  Module                     Packets/sec     Total packets     Dropped
packets
  3          Rx:                       7         280576601
3
             Tx:                       1          24002677
0
  4          Rx:                       7         280574860
3
             Tx:                       3          15260689
0
  5  RP      Rx:                      72         141474821
4066
             Tx:                      59         109863281
0
  5  SP      Rx:                      11          41664038
4697
             Tx:                      20          64613234
0
  6          Rx:                       8         280576597
2
             Tx:                       2           8779278
0

VLAN Resources
  VLANs: 4094 total, 149 VTP, 240 extended, 14 internal, 3691 free

L2 Forwarding Resources
           MAC Table usage:   Module  Collisions  Total       Used
%Used
                              5                0  65536       2604
4%
          
             VPN CAM usage:                       Total       Used
%Used
                                                    512          0
0%
L3 Forwarding Resources
             FIB TCAM usage:                     Total        Used
%Used
                  72 bits (IPv4, MPLS, EoM)     524288        5558
1%
                 144 bits (IP mcast, IPv6)      262144           5
1%

                     detail:      Protocol                    Used
%Used
                                  IPv4                        5558
1%
                                  MPLS                           0
0%
                                  EoM                            0
0%

                                  IPv6                           2
1%
                                  IPv4 mcast                     3
1%
                                  IPv6 mcast                     0
0%

            Adjacency usage:                     Total        Used
%Used
                                               1048576         635
1%

     Forwarding engine load:
                     Module       pps   peak-pps
peak-time
                     5        7865738    8282714  22:21:27 UTC+2 Fri Jan 4
2008

CPU Rate Limiters Resources
             Rate limiters:       Total         Used      Reserved
%Used
                    Layer 3           9            4             1
44%
                    Layer 2           4            2             2
50%

ACL/QoS TCAM Resources
  Key: ACLent - ACL TCAM entries, ACLmsk - ACL TCAM masks, AND - ANDOR,
       QoSent - QoS TCAM entries, QOSmsk - QoS TCAM masks, OR - ORAND,
       Lbl-in - ingress label, Lbl-eg - egress label, LOUsrc - LOU source,
       LOUdst - LOU destination, ADJ - ACL adjacency

  Module ACLent ACLmsk QoSent QoSmsk Lbl-in Lbl-eg LOUsrc LOUdst  AND  OR
ADJ
  5          1%     2%     1%     1%     1%     1%     0%     3%   0%  0%
1%

QoS Policer Resources
  Aggregate policers: Module                      Total         Used
%Used
                      5                            1024            1
1%
  Microflow policer configurations: Module        Total         Used
%Used
                                    5                64            1
1%

Switch Fabric Resources
  Bus utilization: current: 71%, peak was 81% at 22:53:20 UTC+2 Fri Jan 4
2008
  Fabric utilization:     Ingress                    Egress
    Module  Chanl  Speed  rate  peak                 rate  peak

    3       0        20G   35%   48% @20:38 27Dec07   26%   36% @20:44
04Jan08
    3       1        20G   40%   48% @23:00 04Jan08   34%   43% @22:21
03Jan08
    4       0        20G   43%   55% @15:57 03Jan08   48%   63% @20:33
27Dec07
    5       0        20G   13%   18% @21:42 02Jan08    9%   17% @22:52
04Jan08
    6       0        20G    0%    1% @01:30 25Dec07    0%    2% @11:27
30Dec07
    6       1        20G   33%   48% @20:26 27Dec07   45%   54% @22:36
03Jan08
  Switching mode: Module                                        Switching
mode
                  3
truncated
                  4
truncated
                  5                                               flow
through
                  6
truncated

Interface Resources
  Interface drops:
    Module    Total drops:    Tx            Rx      Highest drop port:  Tx
Rx
    1                       7353          2166                           1
38
    2                   24609502        144685                          14
40
    3                      42130    8135613761                           7
2
    4                     160468   49040038842                          17
6
    5                    1354908        184496                           1
2
    6                      12027        286149                           1
1
    7                   29461165        218697                          33
37
    8                    2033449           282                          10
10
    9                   24030508        408094                          36
29

  Interface buffer sizes:
    Module                            Bytes:     Tx buffer           Rx
buffer
    1                                               112640
6144
    2                                               112640
6144
    3                                              1221120
152000
    4                                              1221120
152000
    6                                             14622592
1914304
    7                                               112640
6144
    8                                               112640
6144
    9                                               112640
6144


And for those having enough patience to read the details, here's the
question/problem:
On the 4-th linecard (6724-SFP) we have links grouped in etherchannels
(4xGigabit backbone links), with respect to keeping most of the
etherchannels with their ports grouped on the same asic/linecard. The
load-balancing used is src-dst-ip. Looking at the figures above I guess
anyone would say there are plenty of resources left yet our graphs/interface
summary shows us that somere between 40-50% fabric utilization, both ingress
and egress, there is a problem with the forwarding performance (also seen
looking at the high IQD counters):

* GigabitEthernet4/1       0 3938121308    0    56 557290000  100095
620339000  94591    0
* GigabitEthernet4/2       0 3909192601    0   304 562387000  94364
602164000  93503    0
* GigabitEthernet4/3       0 3909817998    0  1113 561663000  94280
847735000  113865    0
* GigabitEthernet4/4       0 3939072687    0    53 557529000  95337
643992000  95015    0

Now, other (posibly) relevant information from the config:

ip cef event-log traceback-depth 0
ip cef table consistency-check error-message
ip cef table consistency-check auto-repair
ip cef load-sharing algorithm original 
mls ip cef load-sharing simple
fabric switching-mode allow truncated
fabric buffer-reserve queue
fabric buffer-reserve low - that seemed to help a lot (over 10% boost in
performance)

Did anyone hit similar problems with low performance on fabric enabled
linecards ? Any recommended configuration/IOS version ?

Cheers,


Gabriel Mateiciuc
Academia de Studii Economice
Departamentul Reţele
Echipa Infrastructura - infrastructura at ase.ro 






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