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VPP XConnect Configuration
VPP XConnect provides direct Layer 2 packet forwarding between two interfaces with maximum transparency and minimal overhead. XConnect creates a simple point-to-point bridge that forwards all Layer 2 packets bidirectionally without MAC learning or flooding, making it ideal for transparent connectivity scenarios.
XConnect operates as a super-transparent bridge, forwarding all frames between the connected interfaces without any packet inspection or modification. This provides the simplest possible Layer 2 forwarding with VPP’s high-performance packet processing.
Comparison with Bridges
XConnect: Point-to-point only, no MAC learning, maximum transparency, minimal overhead
Bridge: Multi-port, MAC learning, broadcast handling, more features but higher overhead
Choose XConnect when you need simple point-to-point Layer 2 forwarding with maximum performance and transparency. Use bridges when you need multi-port switching with MAC learning and broadcast handling.
Basic Configuration
Creating an XConnect Interface
Create an XConnect interface where <vppxconN> follows the naming
convention vppxcon1, vppxcon2, etc.
Add an interface as a member of the XConnect. Exactly two member interfaces must be configured to create bidirectional forwarding.
Basic Example:
set interfaces vpp xconnect vppxcon1
set interfaces vpp xconnect vppxcon1 member interface eth0
set interfaces vpp xconnect vppxcon1 member interface eth1
This configuration creates transparent forwarding between eth0 and eth1,
where any packet received on either interface is immediately forwarded to
the other without any processing.
Interface Configuration
Configuration Examples
Physical Interface XConnect
# Connect two physical interfaces
set interfaces vpp xconnect vppxcon1
set interfaces vpp xconnect vppxcon1 description "Transparent wire between ports"
set interfaces vpp xconnect vppxcon1 member interface eth0
set interfaces vpp xconnect vppxcon1 member interface eth1
This creates a transparent wire between two physical ports, effectively making them function as a single cable.
Tunnel to Physical XConnect
# Connect tunnel to physical interface
set interfaces vpp xconnect vppxcon2
set interfaces vpp xconnect vppxcon2 description "GRE tunnel to physical bridge"
set interfaces vpp xconnect vppxcon2 member interface vppgre1
set interfaces vpp xconnect vppxcon2 member interface eth2
This forwards all traffic from a GRE tunnel directly to a physical interface and vice versa.
Mixed Interface Types
# Connect different interface types
set interfaces vpp xconnect vppxcon3
set interfaces vpp xconnect vppxcon3 description "VXLAN to bonding bridge"
set interfaces vpp xconnect vppxcon3 member interface vppvxlan1
set interfaces vpp xconnect vppxcon3 member interface vppbond0
This demonstrates XConnect’s flexibility in connecting various VPP interface types.