Cisco Cisco IOS XE 3.5E Manual Técnico
• Flexible NetFlow
• Cisco TrustSec (CTS)
• Mediatrace
Recommended Best Practices
The following are the best practices in the context of working with Cisco Catalyst 3850 Series Switches:
• Enter the non zero source IP addresses in ARP requests to eliminate duplicate IP addresses that are created due to IP Device
Tracking.
• Delay the ARP probes that are dependent on IP Device Tracking and are triggered by a link-up.
• Disable IP Device Tracking on trunk ports.
Enabling IPDT on a trunk port implies that all hosts connected to the neighboring switch over the trunk
port may be tracked. This is typically the reason why IPDT may have a large device tracking table and
can cause some issues as listed below:
port may be tracked. This is typically the reason why IPDT may have a large device tracking table and
can cause some issues as listed below:
Note
• Officially IPDT supports only around 2048 hosts from the original design. Operation on a large
table, such as searching a host will consume more CPU time. In a stack switch, device tracking table
is synced between active and standby switch. If a trunk port flaps, or if there are frequent entry
insertion or deletion, the state of all the entries learnt from the port needs to be updated and synced
to the standby, which could result in a large number of notification flooding the standby and will
impact other features.
is synced between active and standby switch. If a trunk port flaps, or if there are frequent entry
insertion or deletion, the state of all the entries learnt from the port needs to be updated and synced
to the standby, which could result in a large number of notification flooding the standby and will
impact other features.
• With IPDT turned on, ARP probes are sent to connected hosts if no activities such as ARP or DHCP
packets are detected within a certain period of time (this time length is configurable, and its default
value is 30 seconds). Large number of tracked hosts will increase the network traffic and degrade
switch performance. In addition, activities of a host connected indirectly through another switch
over a trunk port may not come to this switch at all. As a result, the probability of the need to probe
a remote host is higher.
value is 30 seconds). Large number of tracked hosts will increase the network traffic and degrade
switch performance. In addition, activities of a host connected indirectly through another switch
over a trunk port may not come to this switch at all. As a result, the probability of the need to probe
a remote host is higher.
• IPDT tracks the host by sending ARP probe periodically. By enabling IPDT on trunk port, probes
may actually be sent by a remote switch connected to the local switch via trunk ports. This could
increase the chance of Duplicate IP Address issue introduced by IPDT probes. Further more, it is
more difficult to pin down the real source of the probe causing the Duplicate IP address error.
increase the chance of Duplicate IP Address issue introduced by IPDT probes. Further more, it is
more difficult to pin down the real source of the probe causing the Duplicate IP address error.
Supported Platforms and Releases
The following feature is available for Cisco Catalyst 3850 Series Switches:
Table 1: Supported Platforms and Releases
CLI to Disable
Disable Method
Feature Name
Supported Platforms
3