NSF Re-convergence Timing, Parameter Timing

Stacking Dell PowerConnect 7000 Series Switches

NSF Re-convergence Timing

As mentioned in the previous section, NSF protects against failures by check-pointing information to a standby unit. In an NSF-protected stack, the worst-case scenario is when the master unit fails. The following statistics show representative re-convergence times of an NSF-enabled standby switch as measured from the detection of failure. With NSF enabled, data plane forwarding continues non-stop on the non-failed switches while the standby unit converges the control plane protocols using the check-pointed information. The re-convergence times given below include re-establishing communication with the upper layer protocol peers, synchronization of shared information with the peer, and re-establishment of any data plane forwarding paths around the failed master unit.

Medium Configuration

•8 switches stacked

•100 VLANs, all ports are members of all VLANs

•4/4 static/dynamic lags with 8 members each

•3 MSTP instance with VLANs

•30 ACLs applied on 30 interfaces

•10 Diffserv service interfaces with policies on 10 interfaces

•6 VLAN routing interfaces

•128 L2 Multicast group entries

•512 ARP entries

•128 Unicast routes

Parameter	Timing
L2 loss duration (non-failed or rerouted stack member)	0 msec
L2 loss duration (failed/rerouted stack member)	10 msec
L3 loss duration (failed/rerouted stack member)	12 msec
IPMC loss duration (failed/rerouted stack member)	12 msec
L2 convergence time	25.70 sec
L3 convergence time	25.410 sec
IPMC convergence time	25.420 sec
Total convergence time	25.420 sec

Page 30