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Layer 3 Handoff

Location in GUI: Provision » SD-Access » Fabric Sites » Fabric Infrastructure » Border Node » Configure » Layer 3 Handoff

Diagram
NameTypeConstraintMandatoryDefault Value
l3_handoffsList[l3_handoffs]No

l3_handoffs (catalyst_center.fabric.border_devices)

Section titled “l3_handoffs (catalyst_center.fabric.border_devices)”
NameTypeConstraintMandatoryDefault Value
nameStringYes
interfacesList[interfaces]Yes

interfaces (catalyst_center.fabric.border_devices.l3_handoffs)

Section titled “interfaces (catalyst_center.fabric.border_devices.l3_handoffs)”
NameTypeConstraintMandatoryDefault Value
nameStringYes
virtual_networksList[virtual_networks]Yes

virtual_networks (catalyst_center.fabric.border_devices.l3_handoffs.interfaces)

Section titled “virtual_networks (catalyst_center.fabric.border_devices.l3_handoffs.interfaces)”
NameTypeConstraintMandatoryDefault Value
nameStringYes
local_ip_addressIPNo
peer_ip_addressIPNo
peer_ipv6_addressIPNo
local_ipv6_addressIPNo
tcp_mss_adjustmentIntegermin: 500, max: 1440No
vlanIntegermin: 2, max: 4093Yes

Example-1: Basic Layer 3 Handoff with Multiple Virtual Networks

This example demonstrates how to configure a basic Layer 3 handoff on an SD-Access border device for connecting fabric virtual networks to external Layer 3 infrastructure. Layer 3 handoffs enable routing between SD-Access fabric virtual networks and external networks through IP Transit connections.

The Layer 3 handoff configuration includes:

  • Border device specification (BR01) with Layer 3 and Layer 2 functionality
  • IP Transit name (IP_TRANSIT) for external connectivity identification
  • Physical interface assignment (TenGigabitEthernet1/1/4) for high-bandwidth connectivity
  • Multiple virtual network mappings with dedicated IP addressing and VLAN segmentation
  • Point-to-point IP addressing for each virtual network (local and peer IP addresses)
  • VLAN tagging (120, 121, 122) for traffic segregation across virtual networks
catalyst_center:
fabric:
border_devices:
- name: BR01
border_types:
- LAYER_3
- LAYER_2
default_exit: true
import_external_routes: false
local_autonomous_system_number: 65001
l3_handoffs:
- name: IP_TRANSIT
interfaces:
- name: TenGigabitEthernet1/1/4
virtual_networks:
- name: SDA_VN_USERS
local_ip_address: 10.0.0.1/24
peer_ip_address: 10.0.0.2/24
vlan: 120
- name: SDA_VN_PRINTERS
local_ip_address: 11.0.0.1/24
peer_ip_address: 11.0.0.2/24
vlan: 121
- name: SDA_VN_CORPORATE
local_ip_address: 12.0.0.1/24
peer_ip_address: 12.0.0.2/24
vlan: 122

Note The l3_handoffs name must match the name of the IP Transit.

Example-2: Single Virtual Network Layer 3 Handoff

This example shows how to configure a simplified Layer 3 handoff with a single virtual network for environments with basic external connectivity requirements and single-tenant scenarios including tcp-mss adjustment.

catalyst_center:
fabric:
border_devices:
- name: BR01
border_types:
- LAYER_3
default_exit: true
import_external_routes: true
local_autonomous_system_number: 65001
l3_handoffs:
- name: CORPORATE_TRANSIT
interfaces:
- name: GigabitEthernet1/0/1
virtual_networks:
- name: CORPORATE_VN
local_ip_address: 192.168.1.1/30
peer_ip_address: 192.168.1.2/30
vlan: 100
tcp_mss_adjustment: 1400

Example-3: High-Availability Layer 3 Handoff with Redundant Interfaces

This example demonstrates how to configure Layer 3 handoffs across multiple physical interfaces for high availability and load balancing in critical network environments.

catalyst_center:
fabric:
border_devices:
- name: BR01
border_types:
- LAYER_3
- LAYER_2
default_exit: true
import_external_routes: false
local_autonomous_system_number: 65001
l3_handoffs:
- name: PRIMARY_TRANSIT
interfaces:
- name: TenGigabitEthernet1/1/1
virtual_networks:
- name: PRODUCTION_VN
local_ip_address: 10.1.1.1/30
peer_ip_address: 10.1.1.2/30
vlan: 101
- name: TenGigabitEthernet1/1/2
virtual_networks:
- name: PRODUCTION_VN
local_ip_address: 10.1.2.1/30
peer_ip_address: 10.1.2.2/30
vlan: 102

Example-4: Multi-Border Layer 3 Handoff Configuration

This example shows how to configure Layer 3 handoffs across multiple border devices for distributed fabric architecture with redundant external connectivity points.

catalyst_center:
fabric:
border_devices:
- name: BR01
border_types:
- LAYER_3
- LAYER_2
default_exit: true
import_external_routes: false
local_autonomous_system_number: 65001
l3_handoffs:
- name: NORTH_TRANSIT
interfaces:
- name: TenGigabitEthernet1/1/1
virtual_networks:
- name: ENTERPRISE_VN
local_ip_address: 172.16.1.1/30
peer_ip_address: 172.16.1.2/30
vlan: 201
- name: BR02
border_types:
- LAYER_3
- LAYER_2
default_exit: false
import_external_routes: false
local_autonomous_system_number: 65001
l3_handoffs:
- name: SOUTH_TRANSIT
interfaces:
- name: TenGigabitEthernet1/1/1
virtual_networks:
- name: ENTERPRISE_VN
local_ip_address: 172.16.2.1/30
peer_ip_address: 172.16.2.2/30
vlan: 202

Example-5: Layer 3 Handoff with External Route Import

This example demonstrates how to configure a Layer 3 handoff with external route import enabled for learning routes from external networks and propagating them throughout the SD-Access fabric.

catalyst_center:
fabric:
border_devices:
- name: BR01
border_types:
- LAYER_3
- LAYER_2
default_exit: true
import_external_routes: true
local_autonomous_system_number: 65001
l3_handoffs:
- name: WAN_TRANSIT
interfaces:
- name: TenGigabitEthernet1/1/3
virtual_networks:
- name: BRANCH_CONNECTIVITY_VN
local_ip_address: 203.0.113.1/30
peer_ip_address: 203.0.113.2/30
vlan: 300
- name: INTERNET_ACCESS_VN
local_ip_address: 198.51.100.1/30
peer_ip_address: 198.51.100.2/30
vlan: 301

Example-6: Service Provider Layer 3 Handoff Configuration

This example shows how to configure Layer 3 handoffs for service provider environments with customer-specific virtual networks and multi-tenant isolation requirements.

catalyst_center:
fabric:
border_devices:
- name: SP_BR01
border_types:
- LAYER_3
- LAYER_2
default_exit: true
import_external_routes: false
local_autonomous_system_number: 65100
l3_handoffs:
- name: CUSTOMER_A_TRANSIT
interfaces:
- name: TenGigabitEthernet1/1/5
virtual_networks:
- name: CUSTOMER_A_PROD_VN
local_ip_address: 10.100.1.1/30
peer_ip_address: 10.100.1.2/30
vlan: 1001
- name: CUSTOMER_A_DEV_VN
local_ip_address: 10.100.2.1/30
peer_ip_address: 10.100.2.2/30
vlan: 1002
- name: CUSTOMER_B_TRANSIT
interfaces:
- name: TenGigabitEthernet1/1/6
virtual_networks:
- name: CUSTOMER_B_PROD_VN
local_ip_address: 10.200.1.1/30
peer_ip_address: 10.200.1.2/30
vlan: 2001