nx.os.and.cisco.nexus.switching.2nd.edition.1587143046

Figure 14-3. Updated Topology Configuration
Design Note
L3 routing will be migrated prior to turning up the vPC from Scotland to the Nexus
aggregation devices. The reasoning behind this decision is that you want to keep the
traffic pattern the same for as long as you can to minimize disruptions to the existing
flows. Assuming that Denmark is the active HSRP router, the hosts connected to
Scotland have a L2 path of Scotland to Denmark to get to their default gateway. If the
vPC is turned up between Scotland and Egypt/Italy, the link between Denmark and
Scotland would become blocked by STP, and the L2 path for hosts connected to
Scotland would be Scotland to Egypt/Italy to Denmark to get to their default gateway.
Doing it this way ensures that servers must take only the extra hop to aggregation after
their default gateway resides there.
The next step in the process is to convert the Switched Virtual Interface (SVI) interfaces
from the 6500 access switches to the Nexus 7000 aggregation devices. Start by examining
the existing 6500 configuration and making the necessary changes to move these interfaces to
the Nexus 7000. Example 14-24 shows the current SVI configuration from Denmark.
Example 14-24. SVI Configuration on Denmark
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