VPC in Mixed Chassis Mode
What is Mixed Chassis Mode ?, A chassis which contains both M and F Line cards is called as Mixed Chassis Mode.
M cards provides the Layer 2 and Layer 3 function and F1 module supports Layer 2 function and the interoperability between M1 and F1 ports are provided by L3 Internal proxy routing and this is provided by M1. When traffic enters at F1 ports and are needed to be routed (Inter VLAN routing or sent to outside DC), M1 line cards provides that proxy routing function.
Layer 3 Internal Proxy Routing:
Following are the Layer 3 internal Proxy routing characteristics.
- For Unicast traffic: Proxy Routing for all F1 module can be done by all M1 interface in the VDC.
- For Multicast Traffic: Proxy layer 3 replication for F1 module can be done by all M1 replication engines.
As soon as M and F cards are available in particular Chassis, the internal Proxy routing is enabled by default and any user can modify the proxy routing configuration by following commands:
Hardware proxy layer-3 routing
Since NX-OS 5.1(2) release maximum number of proxy forwarders for Layer 3 traffic for F1 has increased from 16 to 128.
sh hardware proxy layer-3 counters brief gives some statistics data about the usage of L3 forwarders.
Mixed Chassis Mode vPC:
When we mix the M1 and f1 cards they provide great benefits:
- F1 cards provide capability for Bridge traffic only
- Any routed traffic coming from F1 card are proxies to M1 cards ports for inter VLAN routing or sending Traffic outside DC.
In Mixed Chassis mode, any card F1 or M1 cards are used for Peer-link configuration. Below is the figure which provides the complete picture of vPC system in Mixed Chassis Mode.