ESRP Host Attach

ESRP host attach (HA) is an optional ESRP configuration that allows you to connect active hosts directly to an ESRP master or slave switch.

Normally, the Layer 2 redundancy and loop prevention capabilities of ESRP do not allow packet forwarding from the slave ESRP switch. ESRP HA allows configured ports that do not represent loops to the network to continue Layer 2 operation independent of their ESRP status.

ESRP HA is designed for redundancy for dual-homed server connections. HA allows the network to continue Layer 2 forwarding regardless of the ESRP status. Do not use ESRP HA to interconnect devices on the slave ESRP switch instead of connecting directly to the ESRP master switch.

The ESRP HA option is useful if you are using dual-homed network interface cards (NICs) for server farms, as shown in the following figure. The ESRP HA option is also useful where an unblocked Layer 2 environment is necessary to allow high-availability security.
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ESRP Host Attach

ESRP VLANs that share ESRP HA ports must be members of different ESRP groups. Each port can have a maximum of seven VLANs.

If you use load sharing with the ESRP HA feature, configure the load-sharing group first and then enable HA on the group.

Other applications allow lower-cost redundant routing configurations because hosts can be directly attached to the switch involved with ESRP. HA also requires at least one link between the master and the slave ESRP switch for carrying traffic and to exchange ESRP hello packets.



Do not use the ESRP HA feature with the following protocols: STP or VRRP. A broadcast storm may occur.

ESRP domains that share ESRP HA ports must be members of different ESRP groups.

To configure a port to be a host port, use the following command: configure esrp ports ports mode [host | normal]