排除故障Distributed EtherChannel造成的接口超出
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简介
EtherChannel套件用于提供高带宽互联。此条款讨论应用对思科在运行Supervisor 720的Catalyst 6500交换机的EtherChannel以PFC3A、PFC3B或者PFC3BXL在EtherChannel成员接口能造成超出增加的限制。此限制与Layer2转发引擎涉及并且仅适用对第2层EtherChannel。
先决条件
要求
本文档没有任何特定的要求。
使用的组件
本文档中的信息根据运行Supervisor引擎720的Cisco Catalyst 6500系列交换机。WS-X6704-10GE用于此实验室setup.WS-X6704-10GE是Catalyst 6500模块没有超额预订&有20 Gbps 2结构信道连接中的每一。
本文档中的信息都是基于特定实验室环境中的设备编写的。本文档中使用的所有设备最初均采用原始（默认）配置。如果您使用的是真实网络，请确保您已经了解所有命令的潜在影响。
问题
Catalyst 6500也许体验接口被超出，当Layer2被分配的EtherChannel (DEC)时配置。DEC是在转发卡德(DFC)模块的2或更多Distriubuted间的一EtherChannel。与在不同的结构信道连接的在同一个线路卡，然而2个成员接口的一EtherChannel没有认为DEC。
超出计数器帐户次数接收方硬件无法递交接收的数据到硬件缓冲。换句话说，输入速率流量超出了接收方的能力处理数据。
在某些情况下， DFC提供功能重新传布数据包。再通行在ACL或QoS可以用于执行另外的查找三重内容可编址存储器， Netflow表或者转发信息库(FIB) TCAM表。数据包再通行在特定信息包信息包流仅发生;其他数据包流不受影响。数据包的重写在模块发生;数据包然后转发回到另外处理的策略特性卡(PFC)。
在信息包转发期间，当曾经第2层DEC时，数据包再通行在入口模块要求。 如果Catalyst 6500在直通业务模式运行与3B/3BXL PFC模式一起，再通行为多模块L2 EtherChannel也要求。
关于直通业务模式的更多信息可用的在这里。
当结构利用率到达大约50%时，超出计数器能开始增加。
排除故障&验证
1) 发现在体验的EtherChannel的成员接口增加超出。
6500#show etherchannel summary
Flags: D - down P - bundled in port-channel
I - stand-alone s - suspended
H - Hot-standby (LACP only)
R - Layer3 S - Layer2
U - in use N - not in use, no aggregation
f - failed to allocate aggregator
M - not in use, no aggregation due to minimum links not met
m - not in use, port not aggregated due to minimum links not met
u - unsuitable for bundling
d - default port
w - waiting to be aggregated
Number of channel-groups in use: 2
Number of aggregators: 2
Group Port-channel Protocol Ports
------+-------------+-----------+-----------------------------------------------
10 Po10(SU) - Te2/1(P) Te3/1(P)
20 Po20(SU) - Te2/2(P) Te3/2(P)
2) 验证在成员接口的输入速率和超出计数器。
6500#show interfaces tenGigabitEthernet 2/1
TenGigabitEthernet2/1 is up, line protocol is up (connected)
Hardware is C6k 10000Mb 802.3, address is 0002.fcc1.21ac (bia 0002.fcc1.21ac)
MTU 1500 bytes, BW 10000000 Kbit, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 251/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 10Gb/s, media type is 10Gbase-SR
input flow-control is on, output flow-control is off
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output 00:00:51, output hang never
Last clearing of "show interface" counters 00:00:13
Input queue: 0/2000/5597178/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
30 second input rate 9868906000 bits/sec, 822409 packets/sec
30 second output rate 3000 bits/sec, 5 packets/sec
10968368 packets input, 16452552000 bytes, 0 no buffer
Received 0 broadcasts (0 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 5597195 overrun, 0 ignored
0 watchdog, 0 multicast, 0 pause input
0 input packets with dribble condition detected
79 packets output, 5596 bytes, 0 underruns
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
6500#show interfaces tenGigabitEthernet 2/2
TenGigabitEthernet2/2 is up, line protocol is up (connected)
Hardware is C6k 10000Mb 802.3, address is 0002.fcc1.21ad (bia 0002.fcc1.21ad)
MTU 1500 bytes, BW 10000000 Kbit, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 251/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 10Gb/s, media type is 10Gbase-SR
input flow-control is on, output flow-control is off
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output 00:00:26, output hang never
Last clearing of "show interface" counters 00:00:03
Input queue: 0/2000/45043/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
30 second input rate 9868149000 bits/sec, 822345 packets/sec
30 second output rate 2000 bits/sec, 4 packets/sec
8823464 packets input, 13233496000 bytes, 0 no buffer
Received 0 broadcasts (0 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 4575029 overrun, 0 ignored
0 watchdog, 0 multicast, 0 pause input
0 input packets with dribble condition detected
0 packets output, 0 bytes, 0 underruns
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
3) 发现这些接口是存在的模块。
6500#show module
Mod Ports Card Type Model Serial No.
--- ----- -------------------------------------- ------------------ -----------
2 4 CEF720 4 port 10-Gigabit Ethernet WS-X6704-10GE SAD07430301
3 4 CEF720 4 port 10-Gigabit Ethernet WS-X6704-10GE SAL1316NJD4
5 2 Supervisor Engine 720 (Active) WS-SUP720-3B JAF1224BFSQ
Mod MAC addresses Hw Fw Sw Status
--- ---------------------------------- ------ ------------ ------------ -------
2 0002.fcc1.21ac to 0002.fcc1.21af 1.2 12.2(14r)S5 12.2(33)SXI5 Ok
3 0024.c4f5.b2f4 to 0024.c4f5.b2f7 2.9 12.2(14r)S5 12.2(33)SXI5 Ok
5 001e.be6e.99b4 to 001e.be6e.99b7 5.6 8.5(4) 12.2(33)SXI5 Ok
Mod Sub-Module Model Serial Hw Status
---- --------------------------- ------------------ ----------- ------- -------
2 Centralized Forwarding Card WS-F6700-CFC SAD0743039A 1.1 Ok
3 Distributed Forwarding Card WS-F6700-DFC3B SAL1408BP0Y 4.8 Ok
5 Policy Feature Card 3 WS-F6K-PFC3B JAF1223BAPB 2.3 Ok
5 MSFC3 Daughterboard WS-SUP720 JAF1223BACM 3.1 Ok
Mod Online Diag Status
---- -------------------
2 Pass
3 Pass
5 Pass
4) 发现矩阵接口利用率与这些模块相应。
6500#show fabric utilization
slot channel speed Ingress % Egress %
2 0 20G 0 0
2 1 20G 49 0
3 0 20G 0 0
3 1 20G 0 50
5 0 20G 0 0
6500#show platform hardware capacity rewrite-engine performance slot 2
slot channel perf_id description packets total overruns
----+-------+-------+--------------------+--------------------+--------------+
2 0 0x235 FAB RX 0 41083 0
2 0 0x237 FAB RX 1 0 0
2 0 0x27B FAB TX 0 1904 0
2 0 0x27F FAB TX 1 0 0
2 0 0x350 REPLICATION ML3 0 0
2 0 0x351 REPLICATION ML2 0 0
2 0 0x352 RECIRC L2 0 0
2 0 0x353 RECIRC L3 0 0
2 0 0x34C SPAN TX 0 0 0
2 0 0x34D SPAN TX 1 0 0
2 0 0x34E SPAN RX 0 0 0
2 0 0x34F SPAN RX 1 0 0
2 0 0x354 SPAN TERMINATION 0 0
2 1 0x235 FAB RX 0 759500888 0
2 1 0x237 FAB RX 1 0 0
2 1 0x27B FAB TX 0 4545890286 0
2 1 0x27F FAB TX 1 0 0
2 1 0x350 REPLICATION ML3 0 0
2 1 0x351 REPLICATION ML2 0 0
2 1 0x352 RECIRC L2 68615145 1047 <<< L2 Recirculation
2 1 0x353 RECIRC L3 0 0
2 1 0x34C SPAN TX 0 0 0
2 1 0x34D SPAN TX 1 0 0
2 1 0x34E SPAN RX 0 0 0
2 1 0x34F SPAN RX 1 0 0
2 1 0x354 SPAN TERMINATION 0 0
解决方案
1) 配置没有影响的是受此限制的一非分布式EtherChannel。
要验证此理论， EtherChannel在同样模块(非DEC)的接口配置，并且注意到以数据包速率和上述一样，接口没有看到任何超出增加。这可以是绕过此问题的应急方案。
6500#show fabric utilization
slot channel speed Ingress % Egress %
2 0 20G 0 0
2 1 20G 99 0
3 0 20G 0 0
3 1 20G 0 99
5 0 20G 0 0
TenGigabitEthernet2/1 is up, line protocol is up (connected)
Hardware is C6k 10000Mb 802.3, address is 0002.fcc1.21ac (bia 0002.fcc1.21ac)
MTU 1500 bytes, BW 10000000 Kbit, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 251/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 10Gb/s, media type is 10Gbase-SR
input flow-control is on, output flow-control is off
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output 00:00:06, output hang never
Last clearing of "show interface" counters 00:36:12
Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
30 second input rate 9868487000 bits/sec, 822374 packets/sec
30 second output rate 3000 bits/sec, 6 packets/sec
1783710310 packets input, 2675565466500 bytes, 0 no buffer
Received 0 broadcasts (0 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 0 multicast, 0 pause input
0 input packets with dribble condition detected
13115 packets output, 946206 bytes, 0 underruns
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
TenGigabitEthernet2/2 is up, line protocol is up (connected)
Hardware is C6k 10000Mb 802.3, address is 0002.fcc1.21ad (bia 0002.fcc1.21ad)
MTU 1500 bytes, BW 10000000 Kbit, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 251/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 10Gb/s, media type is 10Gbase-SR
input flow-control is on, output flow-control is off
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output 00:00:11, output hang never
Last clearing of "show interface" counters 00:37:31
Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
30 second input rate 9868462000 bits/sec, 822371 packets/sec
30 second output rate 3000 bits/sec, 6 packets/sec
1849499775 packets input, 2774249662500 bytes, 0 no buffer
Received 0 broadcasts (0 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 0 multicast, 0 pause input
0 input packets with dribble condition detected
13599 packets output, 980928 bytes, 0 underruns
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
2) 万一L2 DEC要求，请使用Catalyst 6500交换机在PFC 3C/3CXL模式。
注意：万一现有的模块运行DFC3A/ DFC3B/ DFC3BXL， DFC硬件升级将要求。
3) 如果您的设计和配置适用于在CSCti23324的条件请升级IOS版本。
此bug修复放松L2 DEC的再通行需求或Catalyst 6500交换机的多模块EtherChannel用67xx仅模块。此bug在Cisco IOS版本12.2(33)SXJ1和以上被解决。 注意适用于此bug的下列问题。
a) bug修复放宽L2 DEC或多模块EC的再通行需求仅Catalyst 6500交换机67xx模块的。万一Catalyst 6500交换机有在所有更旧的DFC 67xx和6516/6818模块间的模块(即6516/6816)或组合的至少一个L2 DEC，再通行为在系统配置的所有L2 DEC将强加。万一Catalyst 6500交换机有所有更旧的模块和配置与L2在67xx仅模块的DEC，不会强加再通行。
b) 所有67xx线卡出现不是去除DEC的再通行需求的足够。例如，如果有在2 6704在6748 CFC和另一Port-Channel间的DEC配置的DFCs，系统将检查Supervisor转发引擎(CFC模块)使用再通行，和开始。
c) 对于VS-SUP720-10G，此bug修复在L2 DEC至少一个端口在CFC线路卡/Supervisor的方案不工作。在此方案中再通行仍然发生。另外，邻接没有升级，并且再通行到位，即使您从Port-Channel取消supervisor/CFC可用的端口。在这样方案中，重新加载要求重编程序硬件，并且删除&重新配置Port-Channel/redundancy switchover/删除L2 VLAN等等不帮助。
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