Nexus Rapid Pvst+ And Mxl Pvst - Remainder Of Test Observations; Summary - Spanning Tree Observations; Table 2. Results - Spanning Tree Observations - Dell Force10 C150 Manual

Deploying the Dell Force10 MXL into a Cisco Nexus Network Environment
Te 1/43 Root 128.228 128 2000
Te 1/45 Dis
Nexus Rapid PVST+ and MXL PVST – Remainder of Test Observations
After the Local Port Failover and Failback scenarios were observed, the following 4 scenarios were
also observed
1) Failover: Uplink Failure Simulation (Uplink Fast). In this test a shutdown was issued on N5K1's
interface 1/5. This caused MXL2 to place its interface 1/45 into a status of Discarding and its
interface 1/43 in to the role of Root. This scenario was observed with only a single ping being lost
during the failover, indicating that the re-convergence took about 1 second
2) Failback: Uplink Failure Simulation (Uplink Fast). In this test a no shutdown on N5K1's interface
1/5 was issued. This caused PVST on MXL2 to place its interface 1/43 into a Role of Alternate and
its interface 1/45 in to the Role of Root since it has the lowest path cost to the Root Bridge. This
scenario was observed with only a single ping being lost during the failback, indicating that the re-
convergence took about 1 second.
3) Failover: Backbone Failure Simulation (Backbone Fast). In this test a shutdown on N5K1's
interface 1/25 was issued. This caused MXL2 to place its interface 1/43 interface into the Role of
Designated. This scenario was observed with only a single ping being lost, indicating that the re-
convergence took about 1 second.
4) Failback: Backbone Failure Simulation (Backbone Fast). In this test a no shutdown was issued on
NX5K1's interface 1/25. This caused PVST on MXL2 to place its interface 1/43 into a role of
Alternate. This scenario was observed with only a single ping being lost, indicating that the re-
convergence took about 1 second.
Summary – Spanning Tree Observations
The first and primary role of any Spanning Tree Protocol is to prevent loops. The second role is to
recognize network topology changes (link failures) and re-converge the network as quickly as possible.
In each of the scenarios observed, the Dell Force10 MXL switch indeed proved that it is more than
capable of doing just that and doing so in conjunction with Nexus switches.
Local Port Failover
(Uplink Fast)
Local Port Failback
(Uplink Fast)
Uplink Failover
(Uplink Fast)
42
128.230 128 2000 DIS
Table 2. Results – Spanning Tree Observations
Scenario Nexus MSTP / MXL
FWD 2002 P2P
2002 P2P
Nexus Rapid PVST+
MSTP
1s
1s
1s
No No
No No
/ MXL PVST
1s
1s
1s