Service Manual

• QSFP port 0 is connected to a QSA with SFP+ optical cables plugged in.
• QSFP port 4 is connected to a QSA with SFP optical cables plugged in.
• QSFP port 8 in fanned-out mode is plugged in with QSFP optical cables.
• QSFP port 12 in 40 G mode is plugged in with QSFP optical cables.
For these congurations, the following examples show the command output that the show interfaces
tengigbitethernet transceiver, show interfaces tengigbitethernet, and show inventory media
commands displays:
NOTE: In the following show interfaces tengigbitethernet commands, the ports 1,2, and 3 are inactive and no
physical SFP or SFP+ connection actually exists on these ports. However, Dell Networking OS still perceives these ports
as valid and the output shows that pluggable media (optical cables) is inserted into these ports. This is a software
limitation for this release.
Link Dampening
Interface state changes occur when interfaces are administratively brought up or down or if an interface state changes.
Every time an interface changes a state or aps, routing protocols are notied of the status of the routes that are aected by the
change in state. These protocols go through the momentous task of re-converging. Flapping; therefore, puts the status of entire
network at risk of transient loops and black holes.
Link dampening minimizes the risk created by apping by imposing a penalty for each interface ap and decaying the penalty
exponentially. After the penalty exceeds a certain threshold, the interface is put in an Error-Disabled state and for all practical
purposes of routing, the interface is deemed to be “down.” After the interface becomes stable and the penalty decays below a
certain threshold, the interface comes up again and the routing protocols re-converge.
Link dampening:
• reduces processing on the CPUs by reducing excessive interface apping.
• improves network stability by penalizing misbehaving interfaces and redirecting trac.
• improves convergence times and stability throughout the network by isolating failures so that disturbances are not propagated.
Important Points to Remember
• Link dampening is not supported on VLAN interfaces.
• Link dampening is disabled when the interface is congured for port monitoring.
• You can apply link dampening to Layer 2 and Layer 3 interfaces.
• You can congure link dampening on individual interfaces in a LAG.
Enabling Link Dampening
To enable link dampening, use the following command.
• Enable link dampening.
INTERFACE mode
dampening
Examples of the show interfaces dampening Commands
To view the link dampening conguration on an interface, use the show config command.
R1(conf-if-gi-1/1)#show config
!
interface GigabitEthernet 1/1
ip address 10.10.19.1/24
dampening 1 2 3 4
no shutdown
324
Interfaces