Configuring Ports for Fabric Communication

Netvisor vFlows used to match fabric traffic do so based on the packet protocol, TCP or UDP, plus the Layer 4 destination port. That means any existing TCP or UDP traffic that happens to use the same Layer 4 destination port matches the vFlows.

You can now configure a port range for TCP or UDP traffic in order to avoid traffic conflicts with existing TCP or UDP traffic. A new command allows this functionality:

(CLI network-admin@Spine1)>fabric-comm-ports-modify


Specify a port range from 1024 to 65435.

(CLI network-admin@Spine1)>fabric-comm-port-show

switch:                          techpub-accton-2

range-start:                     23300

fabric-port:                     23399

notify-port:                     23398

proxy-port:                      23397

fabric-keepalive-port:           23394

filesystem-replication-port:     23392

cluster-traffic-forwarding-port: 23391

vport-statistics-port:           23390

l2-encap-port:                   23389

igmp-encap-port:                 23388

icmpv6-encap-port:               23387

arp-encap-port:                  23386

cluster-analytics-port:          23385


When you modify the port range, you must do so on each node in the fabric which temporarily interrupts fabric communication until you configure each node with the same port range. There is no forwarded traffic loss if the interruption is brief. Because application of this command prevents communication with other nodes, you must log in to each node directly and separately to apply the command.


Configuring Link Aggregation Control Protocol (LACP)

Link Aggregation Control Protocol (LACP) is part of the IEEE specification 802.3ad that allows you to bundle several physical ports to form a single logical channel. When you change the number of active bundled ports on a port channel, traffic patterns reflect the rebalanced state of the port channel.

LACP supports the automatic creation of Gigabit Ethernet port trunks by exchanging LACP packets between ports. It learns the capabilities of port groups and informs the other ports. Once LACP identifies correctly matched Ethernet links, it facilitates grouping the links into Gigabit Ethernet port trunks.

LACP performs the following functions on the switch:

LACP packets are exchanged between ports in these modes:

Active and passive modes allow LACP to negotiate between ports to determine if they can form a port channel based on criteria such as port speed and trunking state.

To enable or disable LACP, or change the system priority, use the following command:

CLI network-admin@switch > lacp-modify enable system-priority 35000

The default system priority value is 32768 with a range from 0 to 65535.

Understanding LACP Priority

LACP port priority is configured on each port using LACP. You can use the default value, 32768, or configure a specific value from 0 to 65535. LACP uses the port priority with the port number to form the port identifier. The port priority determines which ports should be in standby mode when there is a hardware limitation that prevents all compatible ports from aggregating.

LACP system priority can be configured automatically or using the CLI. LACP uses the system priority with the device MAC address to form the system ID and also during negotiations with other systems. The range of LACP system priority is from 0 to 65535. The default value is 32768.

To create a trunk with LACP, use the following command:

CLI network-admin@switch > trunk-create name trunk23 port 20-36 lacp-mode active

To modify a trunk with LACP, use the following command:

CLI network-admin@switch > trunk-modify name trunk23 lacp-mode passive

To modify a port configuration and add LACP priority to the port, use the following command:

CLI network-admin@switch > port-config-modify port 33 lacp-priority 34