EVPN Configuration Guide for Cisco 8000 Series Routers, IOS XR Release 24.1.x , 24.2.x
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You can now proactively monitor connectivity and verify faults and isolate them for EVPN services. This is because Ethernet
Connectivity Fault Management (CFM) is now available for EVPN and provides end-to-end service level OAM (Operations, Administration,
and Maintenance) for EVPN services.
This feature is supported only on routers with Q200 and P100 based line cards..
Ethernet Connectivity Fault Management (CFM) is an end-to-end per-service-instance Ethernet layer operation, administration,
and management (OAM) protocol. It includes proactive connectivity monitoring, fault verification, and fault isolation for
large networks.
For more information about Ethernet CFM, refer to the Configuring Ethernet OAM chapter in the Interface and Hardware Component Configuration Guide for Cisco 8000 Series Routers.
The CFM is now available for EVPN and provides end-to-end service level OAM (Operations, Administration, and Maintenance)
for EVPN services. You can monitor the connections between the nodes using CFM in an EVPN network.
CFM is supported on EVPN network running with the following services.
EVPN E-LAN: CFM on EVPN E-LAN is critical for service providers and enterprises to ensure high availability and reliability of their
distributed Ethernet services.
EVPN E-Line: CFM on EVPN E-Line ensures that service providers can monitor and maintain the health of point-to-point Ethernet services
over a packet-switched network.
Restrictions for CFM on EVPN
There is a possibility of unusual or unexpected results (also known as artifacts) appearing in the loopback or linktrace results.
Either a loopback or linktrace may report multiple results for the same instance, or consecutive instances of a loopback and
linktrace between the same two endpoints may produce different results.
Supported Offload Types and Timer Values
Continuity Check Messages (CCMs) are heartbeat messages exchanged periodically between all the Maintenance End Points (MEPs)
in a service. Each MEP sends out multicast CCMs, and receives CCMs from all the other MEPs in the service. This allows each
MEP to discover its peer MEPs, and to verify that there is connectivity between them. The offload type depends on where the
CCMs are processed.
Only Non-offload is supported, where the CCMs are generated and processed by the CPU. The CCM timers for a CFM session on
a or Bundle Interfaces are 1 second or greater.
CCM timers are the intervals in which CCMs are sent and received. If the CCMs are not received within the configured interval,
the CFM MEP goes down. The following are the supported CCM timers for the Non- offload type:
1 sec
10 sec
1 min
10 min
CFM on EVPN E-LAN Single-Homing
You can configure CFM on a network running with EVPN Emulated Local Area Network (E-LAN) services on single-homed devices
to monitor the E-LAN services, thereby providing high-speed Layer 2 services with high resiliency.
Restrictions for CFM on EVPN E-LAN
CFM on EVPN E-LAN is supported only on single-homed devices.
Configure CFM on EVPN E-LAN Single-Homing
Figure 1. CFM on EVPN E-LAN: Full Mesh Topology
Nodes 1, 2 and 3 in this topology are Cisco routers and are connected to each other.
Configuring CFM on EVPN E-LAN involves the following tasks:
Enabling CFM service continuity check.
Configuring Maintenance End Point (MEP) cross-check to validate the liveliness and consistency of remote MEPs in the network.
Enabling CFM for the interface.
Configuration Example for CFM on EVPN E-LAN: Full Mesh Topology
/* Enable CFM continuity check */
Router# ethernet cfm
Router(config-cfm# domain bd-domain level 1 id null
Router(config-cfm-dmn)# service bd-domain bridge group bg-elan bridge-domain bd-elan id icc-based MC MCMC
Router(config-cfm-dmn-svc)# continuity-check interval 10s
/* Configure MEP cross-check */
Router(config-cfm-dmn-svc)# mep crosscheck
Router(config-cfm-dmn-svc)# mep-id 1112
Router(config-cfm-dmn-svc)# mep-id 1113
Router(config-cfm-dmn-svc)# commit
Repeat the above configurations for node 2 and node 3, with the respective mep-id values. For node 2, configure MEP cross-check
with respective mep-id values of node 1 and node 3 (1111 and 1113 respectively, in this example). For node 3, configure MEP
cross-check with respective mep-id values of node 1 and node 2 (1111 and 1112 respectively, in this example).
/* Enable CFM on the interface */
Router(config)# interface TenGigE 0/0/0/2.100 l2transport
Router(config-subif)# description bg-elan
Router(config-subif)# encapsulation dot1q 100
Router(config-subif)# rewrite ingress tag pop 1 symmetric
Router(config-subif)# ethernet cfm
Router(config-if-cfm)# mep domain bd-domain service bd-service mep-id 1111
Router(config-if-cfm-mep)# commit
You must repeat the above configurations for node 2 and node 3, with the respective mep-id values (that is, 1112 for node 2 and 1113 for node 3, in this example).
Running Configuration for CFM on EVPN E-LAN: Full Mesh Topology
This sections shows the running configuration on node 1.
ethernet cfm
domain bd-domain level 1 id null
service bd-domain bridge group bg-elan bridge-domain bd-elan id icc-based MC MCMC
continuity-check interval 10s
mep crosscheck
mep-id 1112
mep-id 1113
!
!
!
!
interface TenGigE 0/0/0/2.100 l2transport
description bg-elan
encapsulation dot1q 100
rewrite ingress tag pop 1 symmetric
ethernet cfm
mep domain bd-domain service bd-service mep-id 1111
!
Verification
The following outputs show the CFM configuration.
Router# show run ethernet cfm
ethernet cfm
domain bd-domain level 1 id null
service bd-domain bridge group bg-elan bridge-domain bd-elan id icc-based MC MCMC
continuity-check interval 10s
mep crosscheck
mep-id 1112
mep-id 1113
Router# show run interface TenGigE 0/0/0/2.100
interface TenGigE 0/0/0/2.100 l2transport
description bg-elan
encapsulation dot1q 100
rewrite ingress tag pop 1 symmetric
ethernet cfm
mep domain bd-domain service bd-service mep-id 1111
Figure 2. CFM on EVPN E-LAN: Hub and Spoke Topology
Nodes 1, 2 and 3 in this topology are Cisco routers. Node 1 acts as the hub, whereas Node 2 and Node 3 are connected to the
hub, Node1.
Configuration Example for CFM on EVPN E-LAN: Hub and Spoke Topology
The CFM configuration for the hub and spoke topology remains the same as that of full mesh topology mentioned above, except
for these additional steps for SLA profile configuration to be done under the interface. You need to configure the SLA profile
between the hub and the spokes to ensure continuous network services.
/* 1112 and 1113 in this example, are the mep-id values of node 2 and node 3 */
Router(config)#interface TenGigE 0/0/0/2.100 l2transport
Router(config-subif)# ethernet cfm
Router(config-if-cfm)# mep domain bd-domain service bd-service mep-id 1111
Router(config-if-cfm-mep)# sla operation profile test-profile1 target mep-id 1112
Router(config-if-cfm-mep)# sla operation profile test-profile2 target mep-id 1112
Router(config-if-cfm-mep)# sla operation profile test-profile1 target mep-id 1113
Router(config-if-cfm-mep)# sla operation profile test-profile2 target mep-id 1113
Router(config-if-cfm-mep)# commit
Running Configuration for CFM on EVPN E-LAN: Hub and Spoke Topology
This sections shows the running configuration on node 1.
/* Enable Ethernet CFM continuity check for another domain and service */
Router(config)# ethernet cfm
Router(config-cfm)# domain evpn-bd2 level 3 id null
Router(config-cfm-dmn)# service evpn-bd2 bridge group BG2 bridge-domain BD2 $
Router(config-cfm-dmn-svc)# continuity-check interval 10s
You can configure CFM on a network running with EVPN E-Line single-homed devices to monitor the E-Line services, that provides
high-speed Layer 2 services with high resiliency.
Restrictions for CFM on EVPN E-Line
CFM up MEP is supported only on single-homing Layer 2 main and subinterfaces.
Configure CFM on EVPN E-Line Single-Homing
Figure 3. CFM on EVPN E-Line: Full Mesh Topology
Nodes 1, 2 and 3 in this topology are Cisco routers and are connected to each other.
Configuring CFM on EVPN E-Line involves the following tasks:
Enabling CFM service continuity check.
Configuring Maintenance End Point (MEP) cross-check to validate the liveliness and consistency of remote MEPs in the network.
Enabling CFM for the interface.
Configuration Example
/* Enable CFM continuity check */
Router# ethernet cfm
Router(config-cfm# domain xcup1 level 7 id null
Router(config-cfm-dmn)# service xcup1 xconnect group evpn_vpws_Bundle_ether203 p2p evpn_vpws-100 id number 4001
Router(config-cfm-dmn-svc)# continuity-check interval 1s
/* Configure MEP cross-check */
Router(config-cfm-dmn-svc)# mep crosscheck
Router(config-cfm-dmn-svc)# mep-id 4001
Router(config-cfm-dmn-svc)# commit
Repeat the above configurations for node 2 and node 3, with the respective mep-id values. For node 2, configure MEP cross-check
with respective mep-id values of node 1 and node 3 (2001 and 3001 respectively, in this example). For node 3, configure MEP
cross-check with respective mep-id values of node 1 and node 2 (4001 and 2001 respectively, in this example).
/* Enable CFM on the interface */
Router# configure
Router(config)# interface Bundle-Ether203.2001 l2transport
Router(config-subif)# encapsulation dot1q 2001
Router(config-subif)# ethernet cfm
Router(config-if-cfm)# mep domain xcup1 service xcup1 mep-id 2001
Router(config-if-cfm-mep)# commit
You must repeat the above configurations for node 2 and node 3, with the respective mep-id values.
Running Configuration
This sections shows the running configuration on node 1.
ethernet cfm
domain xcup1 level 7 id null
service xcup1 xconnect group evpn_vpws_Bundle_ether203 p2p evpn_vpws-100 id number 4001
continuity-check interval 1s
mep crosscheck
mep-id 4001
!
!
!
!
interface Bundle-Ether203.2001 l2transport
encapsulation dot1q 2001
ethernet cfm
mep domain xcup1 service xcup1 mep-id 2001
!
Verification
The following example shows CFM configuration.
Router# show ethernet cfm services
Summary for Domain xcup1 (level 7), Service xcup1
=============================================================================
Domain MIB index: 1, Service MIB index: 1
Domain ID: NULL, Service ID: UINT: 4001
Service configured on P2P cross-connect evpn_vpws-100 in group evpn_vpws_Bundle_ether
CCM interval: 1s
Local MEPs: 1 total
Peer MEPs: 2 total
MIPs: 0, MIP creation rule: always