• Ethernet loopback sessions are supported only of EFPs (service instances, Ethernet flow points, EVCs).

• Dot1q tags are not configured for default and untagged EFPs.

• Ethernet loopback sessions are supported on dot1q or QinQ or untagged and default EFPs.

• Internal loopback sessions configured must be within the 1 GB reserved bandwidth.

• Internal loopback can be launched even when the physical interface port state is down.

• Data plane loopback on routed port infrastructure is not supported.

• Etype, src-mac, or llc-oui based loopback traffic filtering is not supported.

• Port-level QoS is not bypassed. The egress port shaper cannot be bypassed.

• Port shaper on the ingress port in both external and internal loopback cannot be bypassed.

• Ethernet loopback is not supported on a range of dot1q tags.

• Default EFP loopback is not supported in the shutdown state.

• Loopback sessions cannot be initiated on a port configured with SPAN or RSPAN.

• During Internal loopback, MAC swap is not supported for multicast or broadcast traffic.

• Only one Ethernet loopback (terminal or facility) session can be active on an EFP at any instance.

• Egress span on the port and internal loopback on an EFP on the same port cannot be configured at the same time.

• Egress ACL is not supported on the EFP.

• A maximum number of 20 facility loopback sessions can be created per system, provided 16 sessions are with Dot1Q and 4 sessions are with Dot1Q and destination MAC address. This scale reduces if SPAN or RSPAN is configured.

• A maximum number of 12 terminal loopback sessions can be created per system, provided 8 sessions are with Dot1Q and 4 sessions are with Dot1Q and destination MAC address. This scale reduces if RSPAN or SADT is configured .

• Internal Ethernet Data Plane Loopback session can also be launched when the interface or port is in down state.

• It is recommended to avoid performing any dynamic changes to the interface state when the Ethernet Data Plane Loopback is configured on a port that is in the down state.

• Ethernet Data Plane Loopback is not supported with the XConnect service when the physical interface port state is down.

• Ethernet Data Plane Loopback will be affected on STP enabled interface.

• Dynamic addition of rewrite ingress tags with default EFP is not supported.

• Dynamic changes at EFP and interface level are not supported when Ethernet Data Plane Loopback is active.

• dot1q tag inclusion in the configuration for default and untagged EFP disables the Ethernet Data Plane Loopback.

• When loopback is configure for a default EFP on the the interface, then all the traffic (ingressing) in this interface will get looped back.

• BFD flaps on enabling internal loopback and traffic looped back with line rate as both the traffic passes through the HPCT queue.

ELB is Supported with MAC Filter for UP-MEP Session

In the following scenario, ELB is supported using a MAC filter for UP-MEP session. If you starting ELB with out MAC filter, the UP-MEP session will go DOWN.

enable
configure terminal
service instance 800 ethernet 800
encapsulation dot1q 800
service-policy input <NAME>
xconnect 2.2.2.2 880 encapsulation mpls
cfm mep domain <NAME> mpid 200
cos 7
ethernet loopback permit external
ethernet loopback permit internal

Router#ethernet loopback start local interface gi0/0/0 service instance 800 internal dot1q 800 destination mac-address f078.1685.313f timeout none

This is an intrusive loopback and the packets matched with the service will not  be able to pass through. Continue? (yes/[no]): yes

Router#show ethernet cfm maintenance-points remote
--------------------------------------------------------------------------------
MPID  Domain Name                                 MacAddress          IfSt  PtSt
 Lvl  Domain ID                                   Ingress
 RDI  MA Name                                     Type Id             SrvcInst
      EVC Name                                                        Age
      Local MEP Info
--------------------------------------------------------------------------------
220   CCI                                         f078.1685.313f      Up    Up
 0    CCI                                         Gi0/0/0:(2.2.2.2, 880)
 -    800                                         XCON N/A            800
      800                                                             0s
      MPID: 200 Domain: CCI MA: 800

Total Remote MEPs: 1

Related Documents

Standards and RFCs

MIBs

Technical Assistance

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

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