Cisco Cisco IOS Software Release 12.2(14)ZA
Features
21
Cisco IOS Release 12.2(14)ZA6
Stateless Backup
Stateless backup provides high network availability by routing IP flows from hosts on Ethernet networks
without relying on the availability of a single Layer 3 switch. Stateless backup is particularly useful for
hosts that do not support a router discovery protocol (such as the Intermediate System-to-Intermediate
System [IS-IS] Interdomain Routing Protocol [IDRP]) and do not have the functionality to shift to a new
Layer 3 switch when their selected Layer 3 switch reloads or loses power.
without relying on the availability of a single Layer 3 switch. Stateless backup is particularly useful for
hosts that do not support a router discovery protocol (such as the Intermediate System-to-Intermediate
System [IS-IS] Interdomain Routing Protocol [IDRP]) and do not have the functionality to shift to a new
Layer 3 switch when their selected Layer 3 switch reloads or loses power.
Stateful Backup
Stateful backup enables IOS SLB to incrementally backup its load-balancing decisions, or “keep state,”
between primary and backup switches. The backup switch keeps its virtual servers in a dormant state
until HSRP detects failover; then the backup (now primary) switch begins advertising virtual addresses
and processing flows. You can use HSRP to configure how quickly the failover is detected.
between primary and backup switches. The backup switch keeps its virtual servers in a dormant state
until HSRP detects failover; then the backup (now primary) switch begins advertising virtual addresses
and processing flows. You can use HSRP to configure how quickly the failover is detected.
Stateful backup provides IOS SLB with a one-to-one stateful or idle backup scheme. This means that
only one instance of IOS SLB is handling client or server flows at a given time, and that there is at most
one backup platform for each active IOS SLB switch.
only one instance of IOS SLB is handling client or server flows at a given time, and that there is at most
one backup platform for each active IOS SLB switch.
GPRS load balancing without GTP cause code inspection enabled does not support stateful backup.
The Home Agent Director does not support stateful backup.
Active Standby
Active standby enables two IOS SLBs to load-balance the same virtual IP address while at the same time
acting as backups for each other. If a site has only one virtual IP address to load-balance, an access router
is used to direct a subset of the flows to each IOS SLB using policy-based routing.
acting as backups for each other. If a site has only one virtual IP address to load-balance, an access router
is used to direct a subset of the flows to each IOS SLB using policy-based routing.
IOS SLB firewall load balancing does not support active standby. That is, you cannot configure two pairs
of firewall load balancing devices (one pair on each side of the firewalls), with each device in each pair
handling traffic and backing up its partner.
of firewall load balancing devices (one pair on each side of the firewalls), with each device in each pair
handling traffic and backing up its partner.
Exchange Director Features
IOS SLB supports the Exchange Director for the Cisco Mobile Exchange (CMX) for Catalyst 6500
Family Switches and Cisco 7600 Internet Routers. The Exchange Director provides the following
features:
Family Switches and Cisco 7600 Internet Routers. The Exchange Director provides the following
features:
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