Cisco Cisco IOS Software Release 12.2(27)SBC
ISSU and SSO—DHCP High Availability Features
Prerequisites for DHCP High Availability
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Cisco IOS Release 12.2(31)SB2
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Prerequisites for DHCP High Availability
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The Cisco IOS In-Service Software Upgrade (ISSU) process must be configured and working
properly. See the
properly. See the
feature module for more
information.
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Stateful Switchover (SSO) must be configured and working properly. See the
feature module for more information.
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Nonstop Forwarding (NSF) must be configured and working properly. See the
feature module for more information.
Restrictions for DHCP High Availability
The DHCP high availability features do not support DHCP accounting or DHCP authorized Address
Resolution Protocol (ARP).
Resolution Protocol (ARP).
Information About DHCP High Availability
This section describes the following concepts:
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ISSU
The ISSU process allows Cisco IOS software to be updated or otherwise modified while packet
forwarding continues. In most networks, planned software upgrades are a significant cause of downtime.
ISSU allows Cisco IOS software to be modified while packet forwarding continues, which increases
network availability and reduces downtime caused by planned software upgrades.
forwarding continues. In most networks, planned software upgrades are a significant cause of downtime.
ISSU allows Cisco IOS software to be modified while packet forwarding continues, which increases
network availability and reduces downtime caused by planned software upgrades.