Multiple Ingress Interfaces; System Health Monitoring; Health Of An Interface Connected To A Node; Peer Synchronization - Cisco Nexus 9000 Series Configuration Manual

Configuring ITD

Multiple Ingress Interfaces

You can configure the ITD service to apply traffic redirection policies on multiple ingress interfaces. This
feature allows you to use a single ITD service to redirect traffic arriving on different interfaces to a group of
nodes.
Beginning with Cisco NX-OS Release 7.0(3)I7(3), the same ingress interface can be included in two ITD
services, allowing one IPv4 ITD service and one IPv6 ITD service.
Including the same ingress interface in both IPv4 and IPv6 ITD services allows both IPv4 and IPv6 traffic to
arrive on the same ingress interface. An IPv4 ITD policy is applied to redirect the IPv4 traffic, and an IPv6
ITD policy is applied to redirect the IPv6 traffic.
Note Make sure that the same ingress interface is not referenced in more than one IPv4 ITD service or more than
one IPv6 ITD service. The system does not automatically enforce it and it is not supported.

System Health Monitoring

ITD monitors health of the nodes and applications running on those nodes periodically to detect any failures
and to handle the failure scenarios.
ICMP, TCP, UDP, DNS and HTTP probes are supported.

Health of an Interface Connected to a Node

Beginning with Cisco NX-OS Release 7.0(3)I3(1), ITD leverages the IP service level agreement (IP SLA)
feature to periodically probe each node. In earlier releases, ITD uses the Internet Control Message Protocol
(ICMP) to periodically probe each node. The probes are sent at a 10-second frequency by default and can be
configured down to 1 second. They are sent simultaneously to all nodes. You can configure the probe as part
of the pool group configuration.
A probe is declared to have failed after retrying three times. At this point, the node state becomes "Failed,"
and its status becomes "PROBE_FAILED."
Node Failure Handling
Upon marking a node as down, the ITD performs the following tasks automatically to minimize traffic
disruption and to redistribute the traffic to remaining operational nodes:
• Determines if a standby node is configured to take over from the failed node.
• If the standby node is operational, it is identified the node as a candidate node for traffic handling.
• Redefines the standby node as active for traffic handling, if an operational standby node is available
• Programs automatically to reassign traffic from the failed node to the newly active standby node.

Peer Synchronization

The peer synchronization feature synchronizes the node health status across two ITD peer services in sandwich
mode. It is useful in preventing traffic loss if a link on one of the ITD peer services goes down.
Cisco Nexus 9000 Series NX-OS Intelligent Traffic Director Configuration Guide, Release 9.x
Multiple Ingress Interfaces
11