Configuring Vlan Consistency Checking; Overview Of Vlan Consistency Checking; Vlan Consistency Checking Guidelines And Limitations - Cisco Nexus 9000 Series Configuration Manual
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- Configuration manual (562 pages) ,
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Configuring VLAN Consistency Checking
Configuring VLAN Consistency Checking
Overview of VLAN Consistency Checking
In a typical multihoming deployment scenario, host 1 belonging to VLAN X sends traffic to the access switch
and then the access switch sends the traffic to both the uplinks towards VTEP1 and VTEP2. The access switch
does not have the information about VLAN X configuration on VTEP1 and VTEP2. VLAN X configuration
mismatch on VTEP1 or VTEP2 results in a partial traffic loss for host 1. VLAN consistency checking helps
to detect such configuration mismatch.
For VLAN consistency checking, CFSoIP is used. Cisco Fabric Services (CFS) provides a common
infrastructure to exchange the data across the switches in the same network. CFS has the ability to discover
CFS capable switches in the network and to discover the feature capabilities in all the CFS capable switches.
You can use CFS over IP (CFSoIP) to distribute and synchronize a configuration on one Cisco device or with
all other Cisco devices in your network.
CFSoIP uses multicast to discover all the peers in the management IP network. For EVPN multihoming VLAN
consistency checking, it is recommended to override the default CFS multicast address with the cfs ipv4
mcast-address <mcast address> CLI command. To enable CFSoIP, the cfs ipv4 distribute CLI command
should be used.
When a trigger (for example, device booting up, VLAN configuration change, VLANs administrative state
change on the ethernet-segment port-channel) is issued on one of the multihoming peers, a broadcast request
with a snapshot of configured and administratively up VLANs for the ethernet-segment (ES) is sent to all the
CFS peers.
When a broadcast request is received, all CFS peers sharing the same ES as the requestor respond with their
VLAN list (configured and administratively up VLAN list per ES). The VLAN consistency checking is run
upon receiving a broadcast request or a response.
A 15 seconds timer is kicked off before sending a broadcast request. On receiving the broadcast request or
response, the local VLAN list is compared with that of the ES peer. The VLANs that do not match are
suspended. Newly matched VLANs are no longer suspended.
VLAN consistency checking runs for the following events:
• Global VLAN configuration: Add, delete, shut, or no shut events.
• CFS events: CFS peer added or deleted or CFSoIP configuration is removed.
• ES Peer Events: ES peer added or deleted.
The broadcast request is retransmitted if a response is not received. VLAN consistency checking fails to run
if a response is not received after 3 retransmissions.
VLAN Consistency Checking Guidelines and Limitations
See the following guidelines and limitations for VLAN consistency checking:
• The VLAN consistency checking uses CFSoIP. Out-of-band access through a management interface is
Cisco Nexus 9000 Series NX-OS VXLAN Configuration Guide, Release 7.x
124
Port channel VLAN configuration: Trunk allowed VLANs added or removed or access VLAN changed.
mandatory on all multihoming switches in the network.
Configuring VXLAN EVPN Multihoming
- Quick Links:
- Configuring Vxlan
- Configuring Q-In-Vni
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