Nsf Re-Convergence Timing; Medium Configuration - Dell PowerConnect PC7024 Technical White Paper

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