tests: EVPNv6 MH v6 aware BGP numbered test

IPv6 VTEP address, BGP GUA address

Signed-off-by: Chirag Shah <[email protected]>

Author: chiragshah6

tests/topotests/bgp_evpn_mh_v4_v6_num/ipv6/README.md

@@ -0,0 +1,273 @@
+# BGP EVPN Multihoming with IPv4/IPv6 VTEPs and EBGP Numbered Peering
+
+## Overview
+
+This test validates BGP EVPN Multi-Homing functionality using:
+- **IPv6 VTEP addresses** for VXLAN tunnel endpoints (IPv4 support planned)
+- **EBGP numbered peering** with explicit IPv6 neighbor addresses
+- **Unified FRR configuration** using `service integrated-vtysh-config`
+- **PIM6** for IPv6 multicast BUM traffic handling
+
+## Topology
+
+```
+                    +--------+  +--------+
+                    | spine1 |  | spine2 |
+                    | AS6500 |  | AS6500 |
+                    +---+----+  +----+---+
+                        |  \/        |
+                        |  /\        |
+                    +---+----+  +----+---+
+                    | leaf1  |  | leaf2  |
+                    | AS6510 |  | AS6510 |
+                    +---+----+  +----+---+
+                        |  \/        |
+                        |  /\        |
+         +--------------+--++--------+---+--------------+
+         |              |              |                |
+      +--+---+     +----+---+     +----+---+       +----+---+
+      |torm11|     |torm12  |     |torm21  |       |torm22  |
+      |AS6500|     |AS6500  |     |AS6500  |       |AS6500  |
+      |  2   |     |    3   |     |    4   |       |    5   |
+      +--+---+     +----+---+     +----+---+       +----+---+
+         |  \          /  |           |  \            /  |
+         |   \        /   |           |   \          /   |
+         |    \      /    |           |    \        /    |
+      +--+---+ +----+---+ |        +--+---+ +------+---+ |
+      |hostd11 |hostd12  |         |hostd21| |hostd22   |
+      +--------+----------+         +--------+-----------+
+         (Rack 1)                       (Rack 2)
+```
+
+## Key Features
+
+### 1. IPv6 VTEP Addressing
+
+All VXLAN tunnel endpoints currently use IPv6 addresses:
+- **torm11**: `2001:db8:100::15/128`
+- **torm12**: `2001:db8:100::16/128`
+- **torm21**: `2001:db8:100::17/128`
+- **torm22**: `2001:db8:100::18/128`
+
+### 2. IPv6 Point-to-Point Links (/127)
+
+All inter-router links use `/127` addressing for efficient IPv6 P2P:
+- **spine1 ↔ leaf1**: `2001:db8:50::0/127` and `::1/127`
+- **spine1 ↔ leaf2**: `2001:db8:51::0/127` and `::1/127`
+- **spine2 ↔ leaf1**: `2001:db8:60::0/127` and `::1/127`
+- **spine2 ↔ leaf2**: `2001:db8:61::0/127` and `::1/127`
+- **leaf1 ↔ torm11**: `2001:db8:1::0/127` and `::1/127`
+- **leaf1 ↔ torm12**: `2001:db8:2::0/127` and `::1/127`
+- And so on...
+
+### 3. AS Number Scheme (EBGP Numbered)
+
+- **Spine layer**: AS 65001
+- **Leaf layer**: AS 65101
+- **TOR Rack 1**: AS 65002 (torm11), AS 65003 (torm12)
+- **TOR Rack 2**: AS 65004 (torm21), AS 65005 (torm22)
+
+### 4. BGP Configuration
+
+All BGP sessions use:
+- IPv6 neighbor addresses (EBGP numbered)
+- `capability extended-nexthop` for IPv4 over IPv6 BGP sessions
+- `no bgp default ipv4-unicast` (IPv6-only underlay for now)
+- L2VPN EVPN address family for EVPN routes
+
+### 5. PIM6 for IPv6 Multicast
+
+TOR routers use PIM6 for handling BUM (Broadcast, Unknown Unicast, Multicast) traffic:
+- IPv6 multicast group: `ff0e::100`
+- PIM6 enabled on uplink interfaces
+- Multicast termination device: `ipmr-lo`
+
+### 6. EVPN Multihoming
+
+Each rack has:
+- Two TORs acting as PEs (Provider Edge)
+- Dual-attached hosts with LACP bonds
+- ES-ID (Ethernet Segment Identifier) per host
+- ES system MAC for MH coordination
+
+**Rack 1 ES Configuration:**
+- ES system MAC: `44:38:39:ff:ff:01`
+- hostd11 ES-ID: 1
+- hostd12 ES-ID: 2
+
+**Rack 2 ES Configuration:**
+- ES system MAC: `44:38:39:ff:ff:02`
+- hostd21 ES-ID: 1
+- hostd22 ES-ID: 2
+
+## Configuration Structure
+
+### Unified FRR Configuration
+
+Each router uses a single `frr.conf` file with:
+```
+frr defaults datacenter
+service integrated-vtysh-config
+hostname <router-name>
+!
+# Interface configurations
+# Routing protocol configurations
+!
+end
+```
+
+This approach:
+- Simplifies configuration management
+- Matches production deployments
+- Uses modern FRR best practices
+
+## IPv6 Addressing Plan
+
+### Loopback Addresses (VTEP)
+- `2001:db8:100::/64` - VTEP loopback addresses
+  - ::13 - spine1
+  - ::14 - spine2
+  - ::15 - torm11 (VTEP)
+  - ::16 - torm12 (VTEP)
+  - ::17 - torm21 (VTEP)
+  - ::18 - torm22 (VTEP)
+
+### Spine Loopbacks
+- `2001:db8:200::/64` - Leaf/spine additional loopbacks
+  - ::13 - leaf1
+  - ::14 - leaf2
+
+### Point-to-Point Links
+- `2001:db8:1::/127` through `2001:db8:8::/127` - TOR to Leaf links
+- `2001:db8:50::/127`, `2001:db8:51::/127` - Spine1 to Leaf links
+- `2001:db8:60::/127`, `2001:db8:61::/127` - Spine2 to Leaf links
+
+### SVI (Switched Virtual Interface)
+- `2001:db8:45::/64` - VLAN 1000 SVI subnet
+  - ::1 - Anycast gateway
+  - ::2-::5 - TOR SVI addresses
+  - ::11, ::12, ::21, ::22 - Host addresses
+
+## Test Coverage
+
+The test suite validates:
+
+1. **ES Peering** (`test_evpn_es`)
+   - Local ES peer discovery via Type-1 EAD routes
+   - Remote ES PE list correctness
+
+2. **EAD Route Updates** (`test_evpn_ead_update`)
+   - Link flap handling
+   - EAD route withdrawal and re-advertisement
+
+3. **MAC Learning** (`test_evpn_mac`)
+   - Local MAC sync between PEs
+   - Remote MAC installation
+
+4. **DF Election** (`test_evpn_df`)
+   - Designated Forwarder role assignment
+   - DF preference changes
+
+5. **Uplink Tracking** (`test_evpn_uplink_tracking`)
+   - Access port protodown on uplink failure
+   - Recovery on uplink restoration
+
+## Running the Tests
+
+```bash
+cd /work/penta-01/chirag/docker-home/tree/up/fr/frr/tests/topotests/bgp_evpn_mh_v4_v6_num
+
+# Run all tests (fixture will run IPv6; IPv4 is currently skipped)
+pytest test_evpn_mh_v4_v6_numbered.py -v
+
+# Run specific test
+pytest test_evpn_mh_v4_v6_numbered.py::test_evpn_es -v
+
+# Run with debug output
+pytest test_evpn_mh_v4_v6_numbered.py -v -s
+```
+
+## Requirements
+
+- **FRR**: 8.1 or later (with mgmtd support)
+- **Kernel**: 4.19 or later (for MH support)
+- **IPv6**: Fully enabled with forwarding
+- **Modules**: VXLAN, bridge, bonding, PIM6
+
+## Key Differences from Original test_evpn_mh
+
+1. **IPv6 VTEP first**: Uses IPv6 for VXLAN tunnel endpoints (IPv4 VTEPs can be added later)
+2. **EBGP Numbered**: Explicit IPv6 neighbor addresses instead of unnumbered
+3. **Unified Config**: Single `frr.conf` per router instead of separate daemon configs
+4. **PIM6**: Uses IPv6 PIM instead of IPv4 PIM
+5. **IPv6 Multicast**: Uses `ff0e::100` instead of `239.1.1.100`
+6. **Pytest Fixture**: `tgen_and_ip_version` parametrizes the test for `"ipv4"` / `"ipv6"` underlay (IPv4 currently skipped)
+7. **Critical Fixes**: Includes IPv6 forwarding and DAD configuration before daemon startup
+
+## Known Issues and Workarounds
+
+### IPv6 DAD (Duplicate Address Detection)
+
+DAD is disabled globally and per-interface to prevent address configuration delays:
+```python
+router.run("sysctl -w net.ipv6.conf.all.accept_dad=0")
+router.run("sysctl -w net.ipv6.conf.all.dad_transmits=0")
+```
+
+### mgmtd Requirement
+
+Modern FRR requires mgmtd to be loaded before other daemons:
+```python
+router.load_config(TopoRouter.RD_MGMTD, "")
+```
+
+### IPv6 Forwarding
+
+Must be enabled BEFORE starting FRR daemons:
+```python
+router.run("sysctl -w net.ipv6.conf.all.forwarding=1")
+```
+
+## Debugging
+
+### View BGP EVPN ES Information
+```bash
+vtysh -c "show bgp l2vpn evpn es"
+vtysh -c "show bgp l2vpn evpn es detail"
+```
+
+### View MAC Addresses
+```bash
+vtysh -c "show evpn mac vni 1000"
+```
+
+### View BGP IPv6 Neighbors
+```bash
+vtysh -c "show bgp ipv6 unicast summary"
+```
+
+### View EVPN Routes
+```bash
+vtysh -c "show bgp l2vpn evpn route"
+```
+
+### View PIM6 Status
+```bash
+vtysh -c "show ipv6 pim interface"
+vtysh -c "show ipv6 mroute"
+```
+
+## References
+
+- Original test: `tests/topotests/bgp_evpn_mh/`
+- IPv6 VTEP reference: `tests/topotests/bgp_evpn_three_tier_clos_topo1/`
+- FRR EVPN MH documentation: https://docs.frrouting.org/en/latest/evpn.html
+
+## Authors
+
+- Original test: Anuradha Karuppiah (Cumulus Networks)
+- IPv4/IPv6 VTEP and EBGP numbered adaptation: Chirag Shah (Nvidia), 2025
+
+## License
+
+SPDX-License-Identifier: ISC