Extreme Networks ExtremeWare 7.3.0, Command Reference Manual

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230 ExtremeWare Software 7.3.0 Command Reference Guide
Commands for Configuring Slots and Ports on a Switch
configure msm-failover link-action
configure msm-failover link-action [keep-links-up {preserve-state [l2 |
l2_l3]} | take-links-down]
Description
Configures external port response when MSM failover occurs.
Syntax Description
Default
Take-links-down.
Usage Guidelines
When MSM failover occurs, external ports will not be reset if the
keep-links-up
option is configured.
When the
keep-links-up
option is configured, peer connections will not notice a link-down indication.
The
keep-links-up
and
take-links-down
options are available on the “ i ” series switches only.
If you enter
l2
, additional ESRP configuration is required to preserve the ESRP state. By default, the
ESRP failover action is none . Configuring the slave to “inherit” the master’s configuration and setting
the preserve state to l2 or l2_l3 is not sufficient to preserve the ESRP state.
If you enter
l2_l3
, the unicast hardware IP FDB is also preserved, but the full route table and routing
protocol databases for OSPF, BGP, RIP, etc. are not preserved.
After a hitless failover has completed, the routing protocols initialize like they do on a full reboot. The
neighboring routers see that the router has restarted and the neighbors re-route IP traffic to alternate
routes until the switch has reestablished it’s routing databases.
Since existing IP traffic flows are preserved in the FDB, data continues to be forwarded for these flows
during the start of the hitless failover and the traffic re-route. This has the effect of shortening or
eliminating traffic hits for these flows.
The design of the neighboring router and/or the network traffic load determines whether a network
re-routing operation is or is not hitless.
If you enter
l2_l3
, you also need to configure ESRP for hitless failover to preserve the ESRP state.
keep-links-up Configures the external ports to not be reset when MSM failover occurs. This
option is available on the “
i ” series switches only.
preserve-state Configures the preservation of the link up and down states
l2 Preserves layer 2 FDB and states (MAC FDB, load sharing, STP, EAPS, and
ESRP)
l2_l3 Preserves layer 2 FDB and states plus layer 3 states (IPFDB, ARP, access
lists, etc.)
take-links-down Configures the external ports to be reset when MSM failover occurs. This
option is available on the “
i ” series switches only.