What is vPC protocol?
vPC (Virtual Port-Channel), also known as multichassis EtherChannel (MEC) is a feature on the Cisco Nexus switches that provides the ability to configure a Port-Channel across multiple switches (i.e. vPC peers). vPC is similar to Virtual Switch System (VSS) on the Catalyst 6500s.
Does vPC use LACP?
They are used to carry control, configuration, and keepalive data between the two. As shown, since a vPC uses LACP for signalling (it could also use no signalling and just be manually configured), a virtual port channel can connect to regular Ethernet switches as well as servers that support regular port channels.
What is back to back vPC?
A back-to-back vPC is a way of connecting two pairs of Nexus switches with vPC. Depending on the documentation, it is also known as Multi-Layer vPC or Double-Sided vPC. When a device connects to a pair of switches, it will do so with a regular port channel or LAG. It is unaware that there is a vPC at the other end.
How does STP work in vPC?
STP Behavior in vPC: vPC system is created to avoid the STP blocked ports and hence provide the loop free layer -2 topology. In vPC STP provide the following function: Protect the Layer 2 network by detection and breaking any loops before vPC configuration. Provides the loop free path for non-vPC attached device.
What is Bridge assurance in VPC?
Spanning-tree Bridge Assurance is one of those STP features that help to prevent bridging loops in your network. When bridge assurance is enabled, BPDUs are sent on all interfaces of your switch, including blocked interfaces like the alternate or backup port. Bridge assurance is only supported by PVRST+ and MST.
What is Bridge assurance in vPC?
How many switches can be in a vPC domain?
two
The maximum number of switches in a vPC domain is two. The maximum number of vPC peers per switch or VDC is one. When Static routing from a device to vPC peer switches with next hop, FHRP virtual IP is supported. Dynamic routing adjacency from vPC peer switches to any Layer3 device connected on a vPC is not supported.
What is STP bridge assurance?
What is STP port state?
There are five STP switchport states; these are: Disabled – The result of an administrative command that will disable the port. Blocking – When a device is connected, the port will first enter the blocking state. Listening -The switch will listen for and send BPDUs. Forwarding – The port is forwarding traffic.
Can a VPC switch be used for routing?
That is, VPC is not a no-brainer, if you want to mix it with routing you must design for that. You can also do this sort of thing with two switches at the bottom of the picture, e.g. pair of N5K to pair of N7K’s. Or even VSS 6500 pair to VPC Nexus pair.
Where does the VPC go on a router C?
The router C at the bottom has a (VPC) port channel. It has to decide which uplink to forward the packet over to get it to the MAC address of the Nexus A at the top left. Approximately 50% of the time, based on L2 port channel hashing, the bottom L3 switch C will use the left link to get to Nexus A. That works fine.
Can a forward the frame out of a VPC link?
A is only allowed to forward the frame out a VPC member link if the paired link on Nexus B is down. Forwarding out a non-member link is fine. So the problem is in-on-member-link, cross-peer-link, out-another-member-link: no go unless paired member link is down. Routing does not alter this behavior.
Can a layer 3 packet travel over a VPC link?
But Layer-3 packets can still travel over these vPC links. Consider the example topology below. One host is connected with vPC. The other host is connected to only one of the switches (an orphan port). These hosts still send packets to each other, just like they would over any normal switch.