Cisco Cisco Nexus 5010 Switch Guida Alla Progettazione
Design Guide
© 2010 Cisco Systems, Inc. All rights reserved. This document is Cisco Public Information.
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Depending on the severity of the misconfiguration, vPC may either warn the user (Type 2 misconfiguration) or
suspend the PortChannel (Type 1 misconfiguration). In the specific case of a VLAN mismatch, only the VLAN that
differs between the vPC member ports is going to be suspended on all the vPC PortChannels.
suspend the PortChannel (Type 1 misconfiguration). In the specific case of a VLAN mismatch, only the VLAN that
differs between the vPC member ports is going to be suspended on all the vPC PortChannels.
You can verify the status of consistency between the vPC peers by using the command show vpc consistency-
parameter global
, as follows:
tc-nexus5k02# show vpc consistency-parameter
Inconsistencies can be global or interface specific:
●
Global inconsistencies: Type 1 global inconsistencies affect all vPC member ports (but don’t affect non-vPC
ports).
ports).
●
Interface-specific inconsistencies: Type 1 interface-specific inconsistencies affect only the interface itself.
Examples of global inconsistencies include spanning-tree mode mst on one peer and spanning-tree mode rapid-
pvst
on the other peer. Another example of a global inconsistency is mismatched MST regions.
vPC Peer Link
The vPC peer link is the most important connectivity element of the vPC system. This link is used to create the
illusion of a single control plane by forwarding BPDUs or LACP packets to the primary vPC switch from the secondary
vPC switch. It is also used for forwarding traffic that originates at or is destined for orphan ports. It carries flooded
frames, and in the case of the Cisco Nexus 7000 Series, Hot Standby Router Protocol (HSRP) frames.
illusion of a single control plane by forwarding BPDUs or LACP packets to the primary vPC switch from the secondary
vPC switch. It is also used for forwarding traffic that originates at or is destined for orphan ports. It carries flooded
frames, and in the case of the Cisco Nexus 7000 Series, Hot Standby Router Protocol (HSRP) frames.
vPC Peer-Keepalive or Fault-Tolerant Link
The peer-keepalive link is used to resolve dual-active failures (that is, failures where the peer link between vPC peers
is lost). The keepalive can be carried over a routed infrastructure; it does not need to be a direct point-to-point link,
and, in fact, it is desirable to carry the peer keepalive traffic on a different network than on a straight point-to-point
link.
is lost). The keepalive can be carried over a routed infrastructure; it does not need to be a direct point-to-point link,
and, in fact, it is desirable to carry the peer keepalive traffic on a different network than on a straight point-to-point
link.
vPC VLANs, vPC Ports, and Orphaned Ports
The concept of a vPC VLAN is important when a peer link is lost and is mostly relevant for the Cisco Nexus 7000
Series case. For a VLAN to be categorized as a vPC VLAN, it is sufficient that this VLAN is configured on the peer
link. By default, being configured on the peer link makes a VLAN a vPC VLAN. As an example in Figure 8, VLANs 10,
20, 30, 40 and 50 are vPC VLANs.
Series case. For a VLAN to be categorized as a vPC VLAN, it is sufficient that this VLAN is configured on the peer
link. By default, being configured on the peer link makes a VLAN a vPC VLAN. As an example in Figure 8, VLANs 10,
20, 30, 40 and 50 are vPC VLANs.