What Should I Do If CE Switches Interconnected Through an Eth-Trunk Cannot Go Up?

Latest reply: Jul 15, 2018 15:20:55 277 3 0 0

 

Ethernet link aggregation, also called Eth-Trunk, bundles multiple physical links into a logical link to increase link bandwidth. The bundled links back up each other, increasing reliability.

 

                               Step 1      Checking Whether the Physical Status of a Member Interfaces Is Up

Run the display interface interface-type interface-number command in any view to check whether the interface enters the Up state.

<HUAWEI> display interface 10ge 1/0/1
10GE1/0/1 current state : Up (ifindex: 5)         
Line protocol current state : Up  
Description: 
Switch Port, TPID : 8100(Hex), The Maximum Frame Length is 9216
IP Sending Frames' Format is PKTFMT_ETHNT_2, Hardware address is 1020-3040-5061
Port Mode:    COMMON COPPER,     Port Split/Aggregate:         DISABLE
Speed:                 AUTO,     Loopback:                        NONE
Duplex:                FULL,     Negotiation:                  DISABLE
Input Flow-control: DISABLE,     Output Flow-control:          DISABLE
Mdi:                   AUTO,     Fec:                             NONE
  ---- More ----

If the physical status of a member interface is not Up, see Optical Interface Interconnection Is Abnormal on CE Switches or Copper Interface Interconnection Is Abnormal on CE Switches.

                               Step 2      Checking Whether Physical Connections Are Correct

When a switch connects to a remote device through an Eth-Trunk, incorrect connections between Eth-Trunk member interfaces often occur. You are advised to enable LLDP on the switch and run the display lldp neighbor brief command to check whether the switch is correctly connected to the remote device and whether interfaces between devices are connected. If connections are incorrect, adjust connections.

# Enable LLDP.

<HUAWEI> system-view
[~HUAWEI] lldp enable
[*HUAWEI] commit

# Check physical connections.

<HUAWEI> display lldp neighbor brief 
Local Interface         Exptime(s) Neighbor Interface      Neighbor Device     
-------------------------------------------------------------------------------
10GE2/0/0                      91  10GE3/0/0               128_69.55             
10GE2/0/1                      91  10GE2/0/1               128_69.56            
10GE2/0/2                      91  10GE2/0/2               128_69.56            
10GE2/0/3                      91  10GE2/0/3               128_69.56            
10GE2/0/5                       4  10GE2/0/5            

                               Step 3      Check Whether the Threshold Number of Active Interfaces Is Configured

Run the display eth-trunk command in any view to check whether the lower threshold for the number of active interfaces is set on an Eth-Trunk interface. If the number of Up member interfaces on the Eth-Trunk is smaller than the threshold, the Eth-Trunk becomes Down.

<HUAWEI> display eth-trunk 10 
Eth-Trunk10's state information is: 
Working Mode: Normal        Hash Arithmetic: profile default 
Least Active-linknumber: 2  Max Bandwidth-affected-linknumber: 16 
Operating Status: down      Number of Up Ports in Trunk: 0 
-------------------------------------------------------------------------------- 
PortName                      Status      Weight 
10GE1/0/40                    Down        1           
10GE1/0/41                    Down        1   

Least Active-linknumber: indicates the lower threshold for the number of active links in the Eth-Trunk. In the preceding example, the threshold is 2, which indicates that link aggregation goes Up when two member interfaces are Up.

Run the least active-linknumber link-number command in the Eth-Trunk view to change the lower threshold for the number of active interfaces.

                               Step 4      Checking the Link Aggregation Configuration

1.         Run the display this command in the Eth-Trunk interface view to check whether the link aggregation mode is consistent. The Eth-Trunk becomes Up only when both ends of the Eth-Trunk use the same link aggregation mode.

<HUAWEI> system-view
[~HUAWEI] interface eth-trunk 2
[~HUAWEI-Eth-Trunk2] display this 
#
interface Eth-Trunk2
 mode lacp-static
#
return

           If the remote device is also a Huawei device and the link aggregation mode of the Eth-Trunk is different, run the mode { lacp-static | lacp-dynamic | manual [ load-balance ] } command to change the link aggregation mode.

20180712150630090001.jpg

When the manual load balancing mode is changed to LACP, the mode of the Eth-Trunk is changed successfully after 90s so that services are not affected.

           If the remote device is a non-Huawei device, check the link aggregation modes of both devices based on the following mapping. CE switches are mainly connected to devices of Cisco, Juniper, and H3C. The following describes link aggregation modes when Huawei devices are connected to third-party devices. Check whether the link aggregation modes at both ends are correct.

Table 1-1 Mapping between link aggregation modes on a Cisco device and a Huawei device

Working Mode on a Cisco Device

Working Mode on a Huawei Device

on

manual (default mode)

active (LACP)

lacp-static

passive (LACP)

lacp-static

auto (PAgP)

Interworking is not supported.

desirable (PAgP)

Interworking is not supported.

 

20180712150631225002.jpg

If a Huawei device still fails to interwork with a Cisco device after the preceding mapping is enabled, configure the no spanning-tree etherchannel guard misconfig command on the Cisco device.

Table 1-2 Mapping between link aggregation modes on a Juniper device and a Huawei device

Working Mode on a Juniper Device

Working Mode on a Huawei Device

Manual mode

manual (default mode)

LACP

lacp-static

 

Table 1-3 Mapping between link aggregation modes on an H3C device and a Huawei device

Working Mode on an H3C Device

Working Mode on a Huawei Device

Manual mode

manual (default mode)

LACP

lacp-static

 

2.         Run the display this command in the Eth-Trunk interface view to check whether the lower threshold for the number of active interfaces is set.

<HUAWEI> system-view
[~HUAWEI] interface eth-trunk 2
[~HUAWEI-Eth-Trunk2] display this
#
interface Eth-Trunk2
 mode lacp-static
 least active-linknumber 2
#
return

When there is the least active-linknumber command configuration, the lower threshold for the number of active interfaces is set. If the number of active interfaces is smaller than the threshold, the Eth-Trunk becomes Down. Check the physical status of member interfaces.

                               Step 5      Checking Whether Protocol Exchange on Member Interfaces Is Normal

1.         When the physical status of member interfaces is normal and LACP is enabled, check whether protocol exchange of member interfaces is normal.

Run the display lacp statistics eth-trunk trunk-id command repeatedly in any view to check whether the statistics on LACPDUs increase.

<HUAWEI> display lacp statistics eth-trunk 9
 Eth-Trunk9's PDU statistics is:
 -------------------------------------------------------------------------------
 Port                       LacpRevPdu  LacpSentPdu  MarkerRevPdu  MarkerSentPdu
 10GE2/0/0                     16            36          0              0
 10GE2/0/7                     18            36          0              0

2.         When the statistics on LACPDUs increase, if an exception occurs on the interface, check whether packet information is correct.

Run the display eth-trunk trunk-id command in any view to check packets sent by the remote device. Normally, the values of SysPri, SystemID, and PortKey of all member interfaces should be consistent.

<HUAWEI> display eth-trunk 9
Eth-Trunk9's state information is:
Local:
LAG ID: 9                       Working Mode: Static
Preempt Delay: Disabled         Hash Arithmetic: profile default
System Priority: 32768          System ID: 1020-3040-5061
Least Active-linknumber: 1      Max Active-linknumber: 32 
Operating Status: up            Number Of Up Ports In Trunk: 2
Timeout Period: Slow          
--------------------------------------------------------------------------------
ActorPortName          Status   PortType PortPri PortNo PortKey PortState Weight
10GE2/0/0              Selected 10GE     32768   1      2369    10111100  1     
10GE2/0/7              Selected 10GE     32768   2      2369    10111100  1     
 
Partner:
--------------------------------------------------------------------------------
ActorPortName          SysPri   SystemID        PortPri PortNo PortKey PortState
10GE2/0/0              32768    0000-1280-1002  32768   1      2369    10111100 
10GE2/0/7              32768    0000-1280-1002  32768   2      2369    10111100

If the values of SysPri, SystemID, and PortKey are inconsistent. The possible causes are as follows:

           Eth-Trunk member interfaces are not connected to the same device.

           Rates of Eth-Trunk member interfaces are different.

Check physical connections and ensure that Eth-Trunk member interfaces are connected to the same device, and check the configuration of Eth-Trunk member interfaces and ensure that rates of Eth-Trunk member interfaces are the same.

----End

 

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Martian_superman
Created Jul 15, 2018 09:20:11 Helpful(0) Helpful(0)

generally speaking, when troubleshooting LACP issue, we always need to confirm if LACP packets are sent out or received.

we can use "display lacp statistics eth-trunk xx" to check the LACP packet at the control plane.

we also can make a packet capture to check if the LACP packets are received at the forwarding level.

most time, the LACP can't go up were caused by that LACP packets can't be received. the peer device couldn't send LACP packets properly.
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FigoLiu
Created Jul 15, 2018 14:23:10 Helpful(0) Helpful(0)

if the cpu usage is very high, it maybe also cause lacp status flapping
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IbrYsf
Created Jul 15, 2018 15:20:55 Helpful(0) Helpful(0)

Follow this RoT, very informative and systematic; enjoy.
http://support.huawei.com/onlinetoolsweb/ptmngsys/Web/tsrev_s/en/content/s/02_edesk_link_aggregation_Interconnection_failure/edesk_link_aggregation_Interconnection_failure_edesk000.html
  • x
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