felbinger · Jul 12, 2026
diff --git a/tests/README.md b/tests/README.md
@@ -6,6 +6,7 @@
 | bgp-extended-nexthop                      | FRR, BIRD3                 |
 | bgp-frr-unnumbered                        | FRR                        | <!-- Add BIRD when unnumbered peerings are supported -->
 | bgp-frr-vpn-route-leak                    | FRR                        |
+| bgp-frr-srv6                              | FRR, (GoBGP)               |
 | bgp-md5                                   | FRR, BIRD3                 |
 | bgp-prefsource                            | FRR, BIRD3                 |
 | bgp-simple                                | FRR, BIRD3, GoBGP          |

diff --git a/tests/bgp-frr-srv6/README.md b/tests/bgp-frr-srv6/README.md
@@ -0,0 +1,59 @@
+# bgp-frr-srv6
+
+This integration test implements a basic service-provider topology to test IPv6 Segment Routing (SRv6) behavior end-to-end.
+
+The provider network consists of four routers (P1, PE1, PE2, and PE3) and uses only ipv6. Customers A and B are connected to the provider through customer-edge routers: CE1 and CE2 for customer A, and CE3 and CE4 for customer B. In this setup, CE1 and CE3 connect into PE1, while CE2 connects into PE2, and CE4 connects into PE3.
+
+```mermaid
+flowchart LR
+  CE1["CE1
+  (A)"]
+  CE2["CE2
+  (A)"]
+  CE3["CE3
+  (B)"]
+  CE4["CE4
+  (B)"]
+
+  CE3 --20--- PE1
+  CE1 --10--- PE1
+  PE1 --3--- P1
+  P1 --4--- PE2 --11--- CE2
+  P1 --5--- PE3 --21--- CE4
+  PE2 --6--- PE1
+```
+
+## Addresses
+
+| System | IPv4                    | IPv6                          |
+|--------|-------------------------|-------------------------------|
+| P1     |                         |                               |
+| PE1    |                         | 2001:db8:1::/48 (lo: :ffff::1)|
+| PE2    |                         | 2001:db8:2::/48 (lo: :ffff::1)|
+| PE3    |                         | 2001:db8:3::/48 (lo: :ffff::1)|
+| CE1    | 10.10.1.0/24 (lo: .100) | 3fff:aaaa:1::/48 (lo: ::100)  |
+| CE2    | 10.10.2.0/24 (lo: .100) | 3fff:aaaa:2::/48 (lo: ::100)  |
+| CE3    | 10.20.1.0/24 (lo: .100) | 3fff:bbbb:1::/48 (lo: ::100)  |
+| CE4    | 10.20.2.0/24 (lo: .100) | 3fff:bbbb:2::/48 (lo: ::100)  |
+
+
+## Software Selection
+| System | Network Implementation    | Routing Daemon   |
+|--------|---------------------------|------------------|
+| P1     | legacy networking options | FRR (isisd)      |
+| PE1    | legacy networking options | FRR (isisd,bgpd) |
+| PE2    | systemd-network           | FRR (isisd,bgpd)*|
+| PE3    | ifstate                   | FRR (isisd,bgpd) |
+| CE1    | systemd-network           | FRR (bgpd)       |
+| CE2    | legacy networking options | BIRD             |
+| CE3    | legacy networking options | FRR (bgpd)       |
+| CE4    | ifstate                   | FRR (bgpd)       |
+
+\* GoBGP planned
+
+## Resources
+This test was only possible because of these blog posts:
+- https://onvox.net/2022/06/27/srv6-frr/
+- https://onvox.net/2024/02/01/srv6-vyos/
+- https://onvox.net/2024/12/16/srv6-frr/
+- https://onvox.net/2024/12/26/srv6-vyos-revisit/
diff --git a/tests/bgp-frr-srv6/ce1.nix b/tests/bgp-frr-srv6/ce1.nix
@@ -0,0 +1,66 @@
+{
+  virtualisation.interfaces.eth1 = {
+    vlan = 10;
+    assignIP = false;
+  };
+  systemd.network = {
+    enable = true;
+    networks = {
+      "10-lo" = {
+        matchConfig.Name = "lo";
+        address = [
+          "10.10.1.100/32"
+          "3fff:aaaa:1::100/128"
+        ];
+      };
+      "20-eth1" = {
+        matchConfig.Name = "eth1";
+        address = [
+          "192.0.2.129/30"
+          "2001:db8:10:128::1/64"
+        ];
+      };
+    };
+  };
+  services.frr = {
+    bgpd.enable = true;
+    config = ''
+      route-map set-src permit 10
+        set src 10.10.1.100
+      exit
+
+      route-map set-src-6 permit 10
+        set src 3fff:aaaa:1::100
+      exit
+
+      ip protocol bgp route-map set-src
+      ipv6 protocol bgp route-map set-src-6
+
+      ip route 10.10.1.0/24 reject
+      ipv6 route 3fff:aaaa:1::/48 reject
+
+      router bgp 65001
+        no bgp ebgp-requires-policy
+        no bgp reject-as-sets
+        no bgp default ipv4-unicast
+        no bgp network import-check
+        neighbor 192.0.2.130 remote-as 65000
+        no neighbor 192.0.2.130 enforce-first-as
+        neighbor 2001:db8:10:128::2 remote-as 65000
+        no neighbor 2001:db8:10:128::2 enforce-first-as
+
+        address-family ipv4 unicast
+          network 10.10.1.0/24
+          neighbor 192.0.2.130 activate
+          neighbor 192.0.2.130 soft-reconfiguration inbound
+        exit-address-family
+
+        address-family ipv6 unicast
+          network 3fff:aaaa:1::/48
+          neighbor 2001:db8:10:128::2 activate
+          neighbor 2001:db8:10:128::2 soft-reconfiguration inbound
+        exit-address-family
+      exit
+    '';
+  };
+}
diff --git a/tests/bgp-frr-srv6/ce2.nix b/tests/bgp-frr-srv6/ce2.nix
@@ -0,0 +1,97 @@
+{
+  virtualisation.interfaces.eth1 = {
+    vlan = 11;
+    assignIP = false;
+  };
+  networking.interfaces = {
+    lo = {
+      ipv4.addresses = [
+        {
+          address = "10.10.2.100";
+          prefixLength = 32;
+        }
+      ];
+      ipv6.addresses = [
+        {
+          address = "3fff:aaaa:2::100";
+          prefixLength = 128;
+        }
+      ];
+    };
+    eth1 = {
+      ipv4.addresses = [
+        {
+          address = "192.0.2.133";
+          prefixLength = 30;
+        }
+      ];
+      ipv6.addresses = [
+        {
+          address = "2001:db8:10:132::1";
+          prefixLength = 64;
+        }
+      ];
+    };
+  };
+  services.bird = {
+    enable = true;
+    config = ''
+      log syslog all;
+      router id 10.10.2.100;
+
+      protocol device {
+        scan time 10;
+      }
+
+      protocol kernel kernel4 {
+        ipv4 {
+          import none;
+          export filter {
+            krt_prefsrc = 10.10.2.100;
+            accept;
+          };
+        };
+      }
+      protocol kernel kernel6 {
+        ipv6 {
+          import none;
+          export filter {
+            krt_prefsrc = 3fff:aaaa:2::100;
+            accept;
+          };
+        };
+      }
+
+      protocol static static4 {
+        ipv4;
+
+        route 10.10.2.0/24 unreachable;
+      }
+      protocol static static6 {
+        ipv6;
+
+        route 3fff:aaaa:2::/48 unreachable;
+      }
+
+      protocol bgp pe2_v4 {
+        local as 65002;
+        neighbor 192.0.2.134 as 65000;
+
+        ipv4 {
+          import all;
+          export all;
+        };
+      }
+
+      protocol bgp pe2_v6 {
+        local as 65002;
+        neighbor 2001:db8:10:132::2 as 65000;
+
+        ipv6 {
+          import all;
+          export all;
+        };
+      }
+    '';
+  };
+}
diff --git a/tests/bgp-frr-srv6/ce3.nix b/tests/bgp-frr-srv6/ce3.nix
@@ -0,0 +1,54 @@
+{
+  virtualisation.interfaces.eth1 = {
+    vlan = 20;
+    assignIP = false;
+  };
+  networking = {
+    interfaces = {
+      lo = {
+        ipv4.addresses = [
+          {
+            address = "10.20.1.100";
+            prefixLength = 32;
+          }
+        ];
+        ipv6.addresses = [
+          {
+            address = "3fff:bbbb:1::100";
+            prefixLength = 128;
+          }
+        ];
+      };
+      eth1 = { }; # set interface up
+    };
+  };
+  services.frr = {
+    bgpd.enable = true;
+    config = ''
+      ip route 10.20.1.0/24 reject
+      ipv6 route 3fff:bbbb:1::/48 reject
+
+      router bgp 65003
+        no bgp ebgp-requires-policy
+        no bgp reject-as-sets
+        no bgp default ipv4-unicast
+        no bgp network import-check
+        neighbor eth1 interface remote-as 65000
+        no neighbor eth1 enforce-first-as
+        no neighbor eth1 capability link-local
+
+        address-family ipv4 unicast
+          network 10.20.1.0/24
+          neighbor eth1 activate
+          neighbor eth1 soft-reconfiguration inbound
+        exit-address-family
+
+        address-family ipv6 unicast
+          network 3fff:bbbb:1::/48
+          neighbor eth1 activate
+          neighbor eth1 soft-reconfiguration inbound
+        exit-address-family
+      exit
+    '';
+  };
+}
diff --git a/tests/bgp-frr-srv6/ce4.nix b/tests/bgp-frr-srv6/ce4.nix
@@ -0,0 +1,65 @@
+{
+  virtualisation.interfaces.eth1 = {
+    vlan = 21;
+    assignIP = false;
+  };
+  networking = {
+    ifstate = {
+      enable = true;
+      settings = {
+        parameters.ignore.ifname = [
+          "eth0"
+        ];
+        interfaces = {
+          eth1.link = {
+            state = "up";
+            kind = "physical";
+          };
+          loopback = {
+            addresses = [
+              "10.20.2.100/32"
+              "3fff:bbbb:2::100/128"
+            ];
+            link = {
+              state = "up";
+              kind = "dummy";
+            };
+          };
+        };
+        sysctl.all = {
+          ipv4.forwarding = 1;
+          ipv6.forwarding = 1;
+        };
+      };
+    };
+  };
+  services.frr = {
+    bgpd.enable = true;
+    config = ''
+      ip route 10.20.2.0/24 reject
+      ipv6 route 3fff:bbbb:2::/48 reject
+
+      router bgp 65004
+        no bgp ebgp-requires-policy
+        no bgp reject-as-sets
+        no bgp default ipv4-unicast
+        no bgp network import-check
+        neighbor eth1 interface remote-as 65000
+        no neighbor eth1 enforce-first-as
+        no neighbor eth1 capability link-local
+
+        address-family ipv4 unicast
+          network 10.20.2.0/24
+          neighbor eth1 activate
+          neighbor eth1 soft-reconfiguration inbound
+        exit-address-family
+
+        address-family ipv6 unicast
+          network 3fff:bbbb:2::/48
+          neighbor eth1 activate
+          neighbor eth1 soft-reconfiguration inbound
+        exit-address-family
+      exit
+    '';
+  };
+}