Dot1Q/L2P通道上的封包遺失

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已更新: 2012 年 11 月 6 日

文件 ID:113632

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關於此翻譯

思科已使用電腦和人工技術翻譯本文件，讓全世界的使用者能夠以自己的語言理解支援內容。請注意，即使是最佳機器翻譯，也不如專業譯者翻譯的內容準確。Cisco Systems, Inc. 對這些翻譯的準確度概不負責，並建議一律查看原始英文文件（提供連結）。

簡介

本檔案將討論疑難排解Cisco IOS^®中由於Dot1Q/L2P通道上的網路設計不良而導致的封包遺失，並提供個例研究。

必要條件

需求

思科建議您瞭解以下主題：

有關Dot1Q隧道的基本知識
OSPF基礎知識

採用元件

本檔案所述內容不限於特定軟體或硬體版本。

本文中的資訊是根據特定實驗室環境內的裝置所建立。文中使用到的所有裝置皆從已清除（預設）的組態來啟動。如果您的網路正在作用，請確保您已瞭解任何指令可能造成的影響。

慣例

如需文件慣例的詳細資訊，請參閱思科技術提示慣例。

網路圖表

在此網路設定中，路由器7600-Core的介面Gi1/44和Gi1/43的路由器分別與3400-Metro-1的Fa0/13和Fa0/12位於單臂設定中。在7600-Dot1Q交換器中，介面Gi9/44和Gi 9/45使用Dot1q通道模式啟用。在3400-Metro Edge上建立了SVI VLAN介面，並將Fa0/13和Fa0/12配置為中繼埠。路由器使用OSPF相互通訊。

7609核心
! version 15.0 hostname 7609-CORE interface GigabitEthernet1/43 mtu 9216 no ip address no ip redirects no ip proxy-arp load-interval 60 carrier-delay 2 flowcontrol send off storm-control broadcast level 1.00 ! interface GigabitEthernet1/43.3503 encapsulation dot1Q 3503 ip address 172.16.41.17 255.255.255.252 no ip redirects no ip proxy-arp ip mtu 1500 ip ospf authentication-key 7 072C0E6B6B272D ip ospf network point-to-point ip ospf hello-interval 3 ip ospf dead-interval 10 ! ! interface GigabitEthernet1/44 mtu 9216 no ip address no ip redirects no ip proxy-arp load-interval 60 carrier-delay 2 flowcontrol send off storm-control broadcast level 1.00 ! interface GigabitEthernet1/44.3803 encapsulation dot1Q 3803 ip address 172.16.73.137 255.255.255.248 secondary ip address 172.16.41.21 255.255.255.252 no ip redirects no ip proxy-arp ip mtu 1500 ip ospf authentication-key 7 072C0E6B6B272D ip ospf network point-to-point ip ospf cost 5 ip ospf hello-interval 3 ip ospf dead-interval 10 !--- Output omitted. ! end

7609核心

!
version 15.0
hostname 7609-CORE
interface GigabitEthernet1/43
 mtu 9216
 no ip address
 no ip redirects
 no ip proxy-arp
 load-interval 60
 carrier-delay 2
 flowcontrol send off
 storm-control broadcast level 1.00
!
interface GigabitEthernet1/43.3503
 encapsulation dot1Q 3503
 ip address 172.16.41.17 255.255.255.252
 no ip redirects
 no ip proxy-arp
 ip mtu 1500
 ip ospf authentication-key 7 072C0E6B6B272D
 ip ospf network point-to-point
 ip ospf hello-interval 3
 ip ospf dead-interval 10
!
!
interface GigabitEthernet1/44
 mtu 9216
 no ip address
 no ip redirects
 no ip proxy-arp
 load-interval 60
 carrier-delay 2
 flowcontrol send off
 storm-control broadcast level 1.00
!
interface GigabitEthernet1/44.3803
 encapsulation dot1Q 3803
 ip address 172.16.73.137 255.255.255.248 secondary
 ip address 172.16.41.21 255.255.255.252
 no ip redirects
 no ip proxy-arp
 ip mtu 1500
 ip ospf authentication-key 7 072C0E6B6B272D
 ip ospf network point-to-point
 ip ospf cost 5
 ip ospf hello-interval 3
 ip ospf dead-interval 10

!--- Output omitted.

!
end

7609 DOT1Q
! version 12.2 ! interface GigabitEthernet9/44 switchport switchport access vlan 24 switchport mode dot1q-tunnel mtu 9216 load-interval 60 carrier-delay 2 flowcontrol send off storm-control broadcast level 1.00 l2protocol-tunnel cdp l2protocol-tunnel stp l2protocol-tunnel vtp no cdp enable spanning-tree portfast disable spanning-tree bpdufilter enable ! ! interface GigabitEthernet9/45 switchport switchport access vlan 24 switchport mode dot1q-tunnel mtu 9216 load-interval 60 carrier-delay 2 flowcontrol send off storm-control broadcast level 1.00 l2protocol-tunnel cdp l2protocol-tunnel stp l2protocol-tunnel vtp no cdp enable spanning-tree portfast disable spanning-tree bpdufilter enable ! !--- Output omitted. ! end

7609 DOT1Q

!
version 12.2
!
interface GigabitEthernet9/44
  switchport
 switchport access vlan 24
 switchport mode dot1q-tunnel
 mtu 9216
 load-interval 60
 carrier-delay 2
 flowcontrol send off
 storm-control broadcast level 1.00
 l2protocol-tunnel cdp
 l2protocol-tunnel stp
 l2protocol-tunnel vtp
 no cdp enable
 spanning-tree portfast disable
 spanning-tree bpdufilter enable
!
!
interface GigabitEthernet9/45
 switchport
 switchport access vlan 24
 switchport mode dot1q-tunnel
 mtu 9216
 load-interval 60
 carrier-delay 2
 flowcontrol send off
 storm-control broadcast level 1.00
 l2protocol-tunnel cdp
 l2protocol-tunnel stp
 l2protocol-tunnel vtp
 no cdp enable
 spanning-tree portfast disable
 spanning-tree bpdufilter enable
!

!--- Output omitted.

!
end

3400-Metro-1
! version 12.2 ! interface FastEthernet0/3 port-type nni switchport trunk allowed vlan 1052,3503 switchport mode trunk load-interval 60 ! interface FastEthernet0/4 port-type nni switchport trunk allowed vlan 1052,3803 switchport mode trunk load-interval 60 ! ! interface FastEthernet0/12 port-type nni switchport trunk allowed vlan 2-4094 switchport mode trunk ! interface FastEthernet0/13 port-type nni switchport trunk allowed vlan 2-4094 switchport mode trunk ! end

3400-Metro-1

!
version 12.2
!
interface FastEthernet0/3
  port-type nni
 switchport trunk allowed vlan 1052,3503
 switchport mode trunk
 load-interval 60
!
interface FastEthernet0/4
 port-type nni
 switchport trunk allowed vlan 1052,3803
 switchport mode trunk
 load-interval 60
!
!
interface FastEthernet0/12
 port-type nni
 switchport trunk allowed vlan 2-4094
 switchport mode trunk

!
interface FastEthernet0/13
 port-type nni
 switchport trunk allowed vlan 2-4094
 switchport mode trunk
!
end

3400-Metro Edge
! version 12.2 ! interface FastEthernet0/12 port-type nni switchport mode trunk load-interval 60 storm-control broadcast level 1.00 spanning-tree portfast disable spanning-tree bpdufilter disable ! interface FastEthernet0/13 port-type nni switchport mode trunk load-interval 60 storm-control broadcast level 1.00 spanning-tree portfast disable spanning-tree bpdufilter disable ! ! interface Vlan3503 ip address 172.16.41.18 255.255.255.252 no ip redirects no ip proxy-arp ip ospf authentication-key 7 072C0E6B6B272D ip ospf network point-to-point ip ospf hello-interval 3 ip ospf dead-interval 10 ! interface Vlan3803 ip address 172.16.73.139 255.255.255.248 secondary ip address 172.16.41.22 255.255.255.252 no ip redirects no ip proxy-arp ip ospf authentication-key 7 072C0E6B6B272D ip ospf network point-to-point ip ospf cost 5 ip ospf hello-interval 3 ip ospf dead-interval 10 ! !--- Output omitted. ! end

3400-Metro Edge

!
version 12.2
!
interface FastEthernet0/12
 port-type nni
 switchport mode trunk
 load-interval 60
 storm-control broadcast level 1.00
 spanning-tree portfast disable
 spanning-tree bpdufilter disable
!
interface FastEthernet0/13
 port-type nni
 switchport mode trunk
 load-interval 60
 storm-control broadcast level 1.00
 spanning-tree portfast disable
 spanning-tree bpdufilter disable
!
!
interface Vlan3503
 ip address 172.16.41.18 255.255.255.252
 no ip redirects
 no ip proxy-arp
 ip ospf authentication-key 7 072C0E6B6B272D
 ip ospf network point-to-point
 ip ospf hello-interval 3
 ip ospf dead-interval 10
!
interface Vlan3803
 ip address 172.16.73.139 255.255.255.248 secondary
 ip address 172.16.41.22 255.255.255.252
 no ip redirects
 no ip proxy-arp
 ip ospf authentication-key 7 072C0E6B6B272D
 ip ospf network point-to-point
 ip ospf cost 5
 ip ospf hello-interval 3
 ip ospf dead-interval 10
!

!--- Output omitted.

!
end

觀察

當封包通過Dot1Q通道時，會發生隨機Ping捨棄。但是，介面上沒有輸入/輸出丟棄，也沒有物理層問題的症狀。發出show interface <interface> 命令，以檢查介面上的輸入/輸出捨棄專案：

7609-Dot1Q#show interface gi9/44 

!--- Output omitted.

 Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
    0 input errors, 0 CRC, 1 frame, 0 overrun, 0 ignored
    0 output errors, 0 collisions, 1 interface resets
    0 lost carrier, 0 no carrier, 0 PAUSE output

!--- Output omitted.

從Metro-Edge發出大約100個Ping的ICMP流量時，核心區只收到95個回應，這表明路徑中丟棄了ICMP資料包。

Metro-Edge#ping 172.16.41.21 re 100

Type escape sequence to abort.
Sending 100, 100-byte ICMP Echos to 172.16.41.21, timeout is 2 seconds:
.....!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Success rate is 95 percent (95/100), round-trip min/avg/max = ½/9 ms

注意：7609中的show ip traffic命令顯示僅接收到95個回波，而在Metro-edge中，該命令顯示傳送了100個回波。

show ip traffic
在Metro-Edge ICMP statistics: Rcvd: 0 format errors, 0 checksum errors, 0 redirects, 0 unreachable 0 echo, 95 echo reply, 0 mask requests, 0 mask replies, 0 quench 0 parameter, 0 timestamp, 0 info request, 0 other 0 irdp solicitations, 0 irdp advertisements Sent: 0 redirects, 0 unreachable, 100 echo, 0 echo reply 0 mask requests, 0 mask replies, 0 quench, 0 timestamp 0 info reply, 0 time exceeded, 0 parameter problem 0 irdp solicitations, 0 irdp advertisements !--- The above output shows that 100 echos are sent !--- but received 95 replies from 7609-Core. 在7609-Core ICMP statistics: Rcvd: 0 format errors, 0 checksum errors, 0 redirects, 0 unreachable 95 echo, 0 echo reply, 0 mask requests, 0 mask replies, 0 quench 0 parameter, 0 timestamp, 0 info request, 0 other 0 irdp solicitations, 0 irdp advertisements Sent: 0 redirects, 0 unreachable, 0 echo, 95 echo reply 0 mask requests, 0 mask replies, 0 quench, 0 timestamp 0 info reply, 0 time exceeded, 0 parameter problem 0 irdp solicitations, 0 irdp advertisements

show ip traffic

在Metro-Edge

ICMP statistics:
  Rcvd: 0 format errors, 0 checksum errors, 0 redirects, 0 unreachable
        0 echo, 95 echo reply, 0 mask requests, 0 mask replies, 0 quench
        0 parameter, 0 timestamp, 0 info request, 0 other
        0 irdp solicitations, 0 irdp advertisements
  Sent: 0 redirects, 0 unreachable, 100 echo, 0 echo reply
        0 mask requests, 0 mask replies, 0 quench, 0 timestamp
        0 info reply, 0 time exceeded, 0 parameter problem
        0 irdp solicitations, 0 irdp advertisements

!--- The above output shows that 100 echos are sent !--- but received 95 replies from 7609-Core.

在7609-Core

ICMP statistics:
  Rcvd: 0 format errors, 0 checksum errors, 0 redirects, 0 unreachable
        95 echo, 0 echo reply, 0 mask requests, 0 mask replies, 0 quench
        0 parameter, 0 timestamp, 0 info request, 0 other
        0 irdp solicitations, 0 irdp advertisements
  Sent: 0 redirects, 0 unreachable, 0 echo, 95 echo reply
        0 mask requests, 0 mask replies, 0 quench, 0 timestamp
        0 info reply, 0 time exceeded, 0 parameter problem
        0 irdp solicitations, 0 irdp advertisements

疑難排解

驗證是否正確得知MAC位址，以排解封包捨棄的疑難問題。

使用show mac address table命令驗證MAC地址條目。

成功Ping

7609-DOT1q#sh mac-address-table address E05F.B972.1F00 all
Legend: * - primary entry
age - seconds since last seen
n/a - not available
vlan mac address type learn age ports
------+----------------+--------+-----+----------+--------------------------
Active Supervisor:
* 24 e05f.b972.1f00 dynamic Yes 0 Gi9/44

!--- This output displays the MAC address learnt !--- and its associated port, in this case the associated !--- port for successful ping is Gi9/44.

對於故障Ping

7609-DOT1q#sh mac-address-table address E05F.B972.1F00 all
Legend: * - primary entry
age - seconds since last seen
n/a - not available
vlan mac address type learn age ports
------+----------------+--------+-----+----------+--------------------------
Active Supervisor:
* 24 e05f.b972.1f00 dynamic Yes 5 Gi9/45

!--- This output displays the MAC address learnt !--- and its associated port, in this case, !--- the port number is Gi9/45.

要檢視詳細的MAC索引程式設計，請使用show mac-address-table命令。

7609-DOT1q#sh mac-address-table address E05F.B972.1F00 det

MAC Table shown in details
========================================

PI_E RM RMA Type Alw-Lrn Trap Modified Notify Capture Flood Mac Address Age Pvlan SWbits Index XTag
----+---+---+----+-------+----+--------+------+-------+------+--------------+----+------+------+----

Active Supervisor:

Yes No No DY No No Yes No No No e05f.b972.1f00 0xE0 24 0 0x22C 0

發出Remote login switch和test mcast ltl-info index <Index number>命令，以瞭解前一個HEX值指示的埠號。

7609-DOT1q-sp#test mcast ltl-info index 22B
index 0x22B contain ports 9/44
7609-DOT1q-sp#test mcast ltl-info index 22C
index 0x22C contain ports 9/45

!--- The output shows that hex number 22B !--- points to 9/44 port and hex 22C points to 9/45.

對於失敗的ping，源和目標索引是相同的埠，因此丟棄了。在7600上使用mac-address-table notification mac-move 命令啟用Mac-move時，它顯示兩個不同連線埠之間的MAC擺動，並且出現以下錯誤消息：

註：由於6500/7600使用交換機的一個公用MAC地址，因此在不同埠之間分配相同的MAC地址。show catalyst 6000 chassis-mac-address 命令會顯示保留的交換機MAC地址。

* Jul 2 10:29:44.011: %MAC_MOVE-SP-4-NOTIF: Host e05f.b972.1f00 in 
vlan 24 is flapping between port Gi9/45 and port Gi9/44

!--- The previous error message indicates !--- that the same MAC address is assigned between !--- two different ports: Gi9/45 and port Gi9/44.

解決方案

上一個網路是全網狀網路設定，在同一交換機上具有DOT1Q隧道終端。在這種網路設定中需要MAC擺動。為了避免MAC擺動，可以實施這些解決方案之一。

將通道端點移動到不同的交換器，例如，封裝和解除封裝應在不同的交換器中進行。
可以執行VLAN修剪來調節任何中繼埠中的VLAN。

Dot1Q/L2P通道上的封包遺失

下載選項

無偏見用語

關於此翻譯

目錄

簡介

必要條件

需求

採用元件

慣例

網路圖表

組態

觀察

疑難排解

解決方案

相關資訊

修訂記錄

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