trace mac-8021ag mep

Function

The trace mac-8021ag mep command helps you locate a connectivity fault between the local MEP and the MEP or MIP at the same maintenance level on other devices. The operation is called 802.1ag MAC trace.

Format

trace mac-8021ag mep mep-id mep-id md md-name ma ma-name { mac mac-address | remote-mep mep-id mep-id } [ -t timeout | ttl ttl ] ^*

Parameters

Parameter	Description	Value
mep-id mep-id	Specifies the ID of a MEP. The MEP must have been created using the mep mep-id command.	An integer ranging from 1 to 8191.
md md-name	Specifies the name of an MD. The MEP and the specified destination node must be in the same MD.	The value is a string of 1 to 43 characters, excluding spaces, a hyphen (-), or a question mark (?).
ma ma-name	Specifies the name of an MA. The MEP and the specified destination node must be in the same MA.	The value is a string of 1 to 43 case-sensitive characters. Question marks (?), hyphens (-) are not supported. The total length of MA and MD names must be no greater than 44 characters.
mac mac-address	Specifies the MAC address of the destination node. The destination node can be a MEP or a MIP. An MP's MAC address can be a bridge MAC address or the MAC address of the interface on which the MP resides, depending on the configured MP address model: If the shared MP address model is configured on the destination MP, mac-address is a bridge MAC address. If the individual MP address model is configured on the destination MP, mac-address is the MAC address of the interface on which the destination MP resides.	Expressed as a 12-digit hexadecimal number, in the format of H-H-H. Each H is 4 digits. It cannot be a broadcast MAC address or a multicast MAC address.
remote-mep mep-id	Specifies the ID of a destination RMEP. The destination RMEP must have been created using the remote-mep command, and the bridge MAC address of the device on which the REMP resides must have been specified.	The ID is an integer that ranges from 1 to 8191.
-t timeout	Specifies the timeout period for waiting for an LTR.	An integer ranging from 1 to 65535, in ms. The default value is 2000 ms.
ttl ttl	Specifies the maximum hop of LTMs.	An integer ranging from 1 to 255. The default value is 64.

Views

All views

Default Level

0: Visit level

Task Name and Operations

Task Name	Operations
sla	execute

Usage Guidelines

Usage Scenario

Similar to traceroute or tracert, 802.1ag MAC trace monitors a path between a local device and a destination device or locates faulty nodes by sending test packets and receiving reply packets.

You can use the trace mac-8021ag mep command to check the forwarding path or locate link faults between a MEP and another MEP at the same maintenance level or between a MEP and a MIP at the same maintenance level.

Prerequisites

When implementing 802.1ag MAC trace, ensure that:

MEPs are configured in the MA.
If an outbound interface is specified, it cannot be configured with an inward-facing MEP.

Precautions

802.1ag MAC trace is initiated by a MEP in the MA and destined for a MEP or a MIP at the same maintenance level on other devices. The source node and the destination node can be within different MAs.
In a QinQ termination scenario, you must specify a proper timeout period to prevent test failures or timeouts. If 100 QinQ termination VLAN tag pairs are configured for an unloaded device, set the timeout period to 5s. The timeout period must be increased by 5s every time 100 QinQ termination VLAN tag pairs are added.
For example, if 300 QinQ termination VLAN tag pairs are configured, set the timeout period to 15s.

Example

# Trace a MEP from an outward-facing MEP in the MA named macustomer.

<HUAWEI> system-view
[~HUAWEI] cfm enable
[*HUAWEI] trace mac-8021ag mep mep-id 1 md mdcustomer ma macustomer remote-mep mep-id 8
Tracing the route to 00e0-fc12-3458 over a maximum of 64 hops:
 Hops  Ingress Mac    Ingress Port                Ingress Action    Relay Action
       Egress Mac     Egress Port                 Egress Action     Ismep
 1     00e0-fc23-3459 GigabitEthernet0/1/1        IngOK             RlyFDB
       00e0-fc22-3459 GigabitEthernet0/1/2        EgrOK             NoMep
 2     --             --                          --                RlyHit
       00e0-fc12-3458 GigabitEthernet0/1/3        EgrOK             IsMep
Info: Succeeded in tracing the destination address 00e0-fc12-3458.

# Trace a MEP with MAC address 00e0-fc24-3459 from an MEP in the MA named macustomer and set the maximum TTL of test packets to 64.

<HUAWEI> system-view
[~HUAWEI] cfm enable
[*HUAWEI] trace mac-8021ag mep mep-id 1 md mdcustomer ma macustomer mac 00e0-fc24-3459 ttl 64
Tracing the route to 00e0-fc24-3459 over a maximum of 64 hops:
 Hops  Ingress Mac    Ingress Port                Ingress Action    Relay Action
       Egress Mac     Egress Port                 Egress Action     Ismep
 1     00e0-fc12-3459 GigabitEthernet0/1/0.1      IngOK             RlyFDB
       --             --                          --                NoMep
 2     00e0-fc24-3459 GigabitEthernet0/1/0        IngOK             RlyHit   
       --             --                          --                IsMep
Info: Succeeded in tracing the destination address 00e0-fc24-3459.

# Trace a MEP with interface MAC address 00e0-fc12-3457 from an inward-facing MEP in the MA named macustomer and set the maximum TTL of test packets to 64.

<HUAWEI> system-view
[~HUAWEI] cfm enable
[*HUAWEI] trace mac-8021ag mep mep-id 1 md mdcustomer ma macustomer mac 00e0-fc12-3457 ttl 64
Tracing the route to 00e0-fc24-3459 over a maximum of 64 hops:
 Hops  Ingress Mac    Ingress Port                Ingress Action    Relay Action
       Egress Mac     Egress Port                 Egress Action     Ismep
 1     00e0-fc12-3456 GigabitEthernet0/1/0        EgrOK             IsMep
 2     00e0-fc12-3457 GigabitEthernet0/1/0        IngOK             RlyHit   
       --             --                          --                IsMep
Info: Succeeded in tracing the destination address 00e0-fc24-3459.

**Table 1** Description of the **trace mac-8021ag mep** command output
Item	Description
Hops	Number of hops.
Ingress Mac	MAC address of the MIP or MEP on the inbound interface of trace packets. This MAC address is a Layer 3 interface MAC address. If the inbound interface does not have any MIP or MEP, hyphens -- are displayed in this field.
Ingress Port	Inbound interface of trace packets. If the inbound interface does not have any MIP or MEP, hyphens -- are displayed in this field. If the length of this field exceeds 26 characters, information will be displayed in more than one line.
Ingress Action	How the inbound interface processes LTMs: IngOK: The inbound interface forwards LTMs successfully. IngDown: The inbound interface does not forward trace packets. --: The inbound interface does not have any MIP or MEP.
Relay Action	How the device processes LTMs. The value can be: RlyFDB: LTMs are forwarded to the next hop device from this device. RlyHit: LTMs reach the destination device.
Egress Mac	MAC address of the MIP or MEP on the outbound interface of trace packets. This MAC address is a Layer 3 interface MAC address. If the outbound interface does not have any MIP or MEP, hyphens (--) are displayed in this field.
Egress Port	Name of an outbound interface of trace packets. If the outbound interface does not have any MIP or MEP, hyphens (--) are displayed in this field.
Egress Action	How the outbound interface processes LTMs: EgrOK: The outbound interface forwards trace packets successfully or that the outbound interface's MAC address is the destination MAC address of trace packets. EgDown: The outbound interface fails to forward trace packets. --: The outbound interface does not have any MIP or MEP.
Ismep	Whether at least one of the inbound and outbound interfaces has MEP configurations: No. Yes.