Route Control

sidebar_position: 2 sidebar_label: Route Control

Diagram

Classes

Examples

In this example, we can see the relation between policies defined under vxlan.overlay_extensions.route_control. Policies are grouped in one group named: external_policies_RCtrlGrp under vxlan.overlay_extensions.groups. Finally this group is attached to two leaf switches under vxlan.overlay_extensions.switches.groups

Example-1

This example will create route maps, prefix lists and community-list, which are commonly used in BGP (Border Gateway Protocol) routing configurations to manipulate and control route attributes. Here’s a detailed explanation:

Route Maps

A route map allows for conditional matching and manipulation of routes. It is used to define how routes are handled based on specific conditions.

1. route-map rm-bgp permit 10:
   • match ip address prefix-list IPPREF1: This matches routes that fit the criteria specified in the prefix list named IPPREF1.
   • match community CL-LPREF110: This matches routes that have the community attribute specified in the community list CL-LPREF110.
   • set local-preference 110: If a route matches both the IP prefix list and community list, its local preference is set to 110. Local preference is used to prioritize routes within an autonomous system; higher values are preferred.
2. route-map rm-bgp permit 20:
   • match ip address prefix-list IPPREF2: This matches routes using the prefix list IPPREF2.
   • match community CL-LPREF120: This matches routes with the community attribute specified in CL-LPREF120.
   • set local-preference 120: Routes matching these criteria will have their local preference set to 120, giving them a higher priority compared to those set by sequence 10.
3. route-map rm-bgp permit 100: This line permits any other routes that do not match the above criteria without any modifications.

Prefix Lists

Prefix lists define IP address ranges to be matched against.

• ip prefix-list IPPREF1:

  • seq 10 permit 172.16.0.0/16: This allows any IP address within the 172.16.0.0/16 network.
  • seq 20 permit 172.17.0.0/19: This permits any IP address within the 172.17.0.0/19 network.

• ip prefix-list IPPREF2:

  • seq 10 permit 10.0.0.0/24: This allows the specific network 10.0.0.0/24.
  • seq 20 permit 10.100.0.0/19 le 24: This permits any IP address within the 10.100.0.0/19 network, allowing prefix lengths up to /24 (which means it can match subnets of this range with subnet masks between /19 and /24).

Community Lists

Community lists define BGP community attributes used to tag routes for various routing policies.

• ip community-list standard CL-LPREF110:
  • seq 10 permit 65000:110: This matches routes tagged with the BGP community 65000:110.
• ip community-list standard CL-LPREF120:
  • seq 10 permit 65000:120: This matches routes tagged with the BGP community 65000:120.

route-map rm-bgp permit 10
  match ip address prefix-list IPPREF1
  match community CL-LPREF110
  set local-preference 110
route-map rm-bgp permit 20
  match ip address prefix-list IPPREF2
  match community CL-LPREF120
  set local-preference 120
route-map rm-bgp permit 100
!
ip prefix-list IPPREF1 seq 10 permit 172.16.0.0/16
ip prefix-list IPPREF1 seq 20 permit 172.17.0.0/19
ip prefix-list IPPREF2 seq 10 permit 10.0.0.0/24
ip prefix-list IPPREF2 seq 20 permit 10.100.0.0/19 le 24
!
ip community-list standard CL-LPREF110 seq 10 permit 65000:110
ip community-list standard CL-LPREF120 seq 10 permit 65000:120

---
vxlan:
  overlay_extensions:
    route_control:
      standard_community_lists:
        - name: CL-LPREF110
          entries:
            - seq_number: 10
              operation: permit
              communities:
                - 65000:110
        - name: CL-LPREF120
          entries:
            - seq_number: 10
              operation: permit
              communities:
                - 65000:120

      ipv4_prefix_lists:
        - name: IPPREF1
          entries:
            - seq_number: 10
              operation: permit
              prefix: 172.16.0.0/16
            - seq_number: 20
              operation: permit
              prefix: 172.17.0.0/19
        - name: IPPREF2
          entries:
            - seq_number: 10
              operation: permit
              prefix: 10.0.0.0/24
            - seq_number: 20
              operation: permit
              prefix: 10.100.0.0/19
              le: 24

      route_maps:
        - name: rm-bgp
          entries:
            - seq_number: 10
              operation: permit
              match:
                - ipv4:
                    address_prefix_list:
                      - IPPREF1
                - community_list:
                    community: CL-LPREF110
              set:
                - local_preference: 110
            - seq_number: 20
              operation: permit
              match:
                - ipv4:
                    address_prefix_list:
                      - IPPREF2
                - community_list:
                    community: CL-LPREF120
              set:
                - local_preference: 120
            - seq_number: 100
              operation: permit
      groups:
        - name: external_policies_RCtrlGrp
          standard_community_lists:
            - name: CL-LPREF110
            - name: CL-LPREF120
          ipv4_prefix_lists:
            - name: IPPREF1
            - name: IPPREF2
          route_maps:
            - name: rm-bgp

      switches:
        - name: netascode-leaf21
          groups:
            - external_policies_RCtrlGrp
        - name: netascode-leaf22
          groups:
            - external_policies_RCtrlGrp