https://community.cisco.com/t5/network-security/failover-link/m-p/2673725#M190871 <P>Rohan,</P><P>"state" refers to the status of certain elements in the active&nbsp;ASA's memory that&nbsp;represent, generally speaking, connections through it and resources currently allocated. Most commonly we think of things like the NAT table, TCP connections and UDP flow "state". A complete list of the things that are included is in the configuration guide (<A href="http://www.cisco.com/c/en/us/td/docs/security/asa/asa94/configuration/general/asa-general-cli/ha-failover.html#pgfId-1495008">link</A>).</P><P>When we replicate those elements from the active to the standby unit, that is considered stateful. The link used to do so can be the same one as is used for "basic" (stateless) failover or it can be a dedicated one.&nbsp;</P><P>By using stateful failover we minimize the impact to data flows when a failover occurs. The goal&nbsp;is to not lose any and not even cause a TCP session&nbsp;to be reset or UDP packet to be lost.</P> Mon, 08 Jun 2015 05:50:35 GMT Marvin Rhoads 2015-06-08T05:50:35Z https://community.cisco.com/t5/network-security/failover-link/m-p/2673724#M190869 <P>what is the differnce between failover link and stateful failover link</P><P>&nbsp;</P><P>and also between stateful and stateless</P><P>&nbsp;</P> Tue, 12 Mar 2019 06:04:07 GMT https://community.cisco.com/t5/network-security/failover-link/m-p/2673724#M190869 rohan jadhav 2019-03-12T06:04:07Z https://community.cisco.com/t5/network-security/failover-link/m-p/2673725#M190871 <P>Rohan,</P><P>"state" refers to the status of certain elements in the active&nbsp;ASA's memory that&nbsp;represent, generally speaking, connections through it and resources currently allocated. Most commonly we think of things like the NAT table, TCP connections and UDP flow "state". A complete list of the things that are included is in the configuration guide (<A href="http://www.cisco.com/c/en/us/td/docs/security/asa/asa94/configuration/general/asa-general-cli/ha-failover.html#pgfId-1495008">link</A>).</P><P>When we replicate those elements from the active to the standby unit, that is considered stateful. The link used to do so can be the same one as is used for "basic" (stateless) failover or it can be a dedicated one.&nbsp;</P><P>By using stateful failover we minimize the impact to data flows when a failover occurs. The goal&nbsp;is to not lose any and not even cause a TCP session&nbsp;to be reset or UDP packet to be lost.</P> Mon, 08 Jun 2015 05:50:35 GMT https://community.cisco.com/t5/network-security/failover-link/m-p/2673725#M190871 Marvin Rhoads 2015-06-08T05:50:35Z