# MPLS Configuration Module

MPLS configuration module implements:

* LDP-based label distribution
* BGP labeled unicast over IBGP and/or EBGP sessions for IPv4 and IPv6
* MPLS/VPN vpnv4 and vpnv6 address families for IBGP and EBGP (inter-AS option B) sessions
* 6PE over IBGP and/or EBGP sessions

Segment routing for MPLS is implemented in a [separate configuration module](sr-mpls.md).

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```

## Platform Support

The following table describes per-platform support of individual MPLS label distribution features:

### Label Distribution Protocol (LDP)

| Operating system      | LDP   | Exp.Null | IGP sync | Advertise<br>filter | CsC |
| ----------------------| :---: | :------: | :--: | :--: | :--: |
| Arista EOS            |   ✅  |   ✅    |   ❌  |   ❌  |   ❌  |
| Aruba AOS-CX          |   ✅  |   ✅    |   ❌  |   ❌  |   ❌  |
| Cisco IOS             |   ✅  |   ✅    |   ❌  |   ❌  |   ❌  |
| Cisco IOS XE          |   ✅  |   ✅    |   ❌  |   ❌  |   ❌  |
| FRR                   |   ✅  |   ✅    |   ❌  |   ❌  |   ❌  |
| Juniper vMX           |   ✅  |   ✅    |   ❌  |   ❌  |   ❌  |
| Juniper vPTX          |   ✅  |   ✅    |   ❌  |   ❌  |   ❌  |
| Mikrotik RouterOS 6   |   ✅  |   ✅    |   ❌  |   ❌  |   ❌  |
| Mikrotik RouterOS 7   |   ✅  |   ✅    |   ❌  |   ❌  |   ❌  |
| Nokia SR Linux        |   [❗](caveats-srlinux)  |   ❌    |   ✅  |   ❌  |   ❌  |
| Nokia SR OS           |   ✅  |   ✅    |   ✅  |   ❌  |   ❌  |
| VyOS                  |   ✅  |   ✅    |   ❌  |   ❌  |   ❌  |

**Notes:**
* LDP is enabled on all non-VRF intra-AS interfaces with IPv4 addresses.
* To disable LDP on an intra-AS interface, or to enabled it on a VRF interface, use **ldp** link/interface parameter.

### BGP Labeled Unicast (BGP-LU)

| Operating system      | BGP LU | Exp.Null | Disable<br>unlabeled |
| ----------------------| :----: | :------: | :------: |
| Arista EOS            |   ✅   |    ❌   |    ✅    |
| Cisco IOS             |   ✅   |    ✅   |    ❌    |
| Cisco IOS XE          |   ✅   |    ✅   |    ❌    |
| Mikrotik RouterOS 6   |   ❌   |    ❌   |    ❌    |
| Mikrotik RouterOS 7   |   ❌   |    ❌   |    ❌    |
| Nokia SR OS           |   ✅   |    ✅   |    ❌    |
| VyOS                  |   ❌   |    ❌   |    ❌    |

**Notes**
* Cisco IOS merges labeled and unlabeled BGP routes.
* You might have to disable unlabeled address families on Arista EOS
* Nokia SR OS supports these features, but not implemented in Netlab yet

(mpls-l3vpn-supported-platforms)=
### BGP/MPLS L3VPN

| Operating system      | VPNv4 | VPNv6 |
| ----------------------| :---: | :---: |
| Arista EOS            |   ✅  |   ✅  |
| Aruba AOS-CX          |   [❗](caveats-aruba)  |   ❌  |
| Cisco IOS             |   ✅  |   ✅  |
| Cisco IOS XE          |   ✅  |   ✅  |
| FRR                   |   ✅  |   ✅  |
| Juniper vMX           |   ✅  |   ✅  |
| Juniper vPTX          |   ✅  |   ✅  |
| Mikrotik RouterOS 6   |   ✅  |   ❌  |
| Mikrotik RouterOS 7   |   ✅  |   ❌  |
| Nokia SR OS           |   ✅  |   ✅  |
| VyOS                  |   ✅  |   ✅  |

**Notes**
* VPNv4 and VPNv6 address families are enabled on IPv4 IBGP/EBGP sessions
* On Mikrotik RouterOS BGP configuration/implementation, adding the VPNv4 AFI will completely overwrite the AFI supported list for the peer with "ip,vpnv4" (current template limitation). Given the general limitations of ROSv6 on IPv6, this should not be such a big problem.

### 6PE

| Operating system      | 6PE |
| ----------------------| :-: |
| Arista EOS            | ✅  |
| Cisco IOS             | ✅  |
| Cisco IOS XE          | ✅  |
| Nokia SR OS           | ✅  |

**Notes**

* You cannot enable 6PE and IPv6 BGP-LU on the same node.

## Configurable Global and Node Parameters

* **mpls.ldp** -- enable LDP on intra-AS links (see [common routing protocol features](routing.md)) for more details.
* **mpls.bgp** -- enable BGP Labeled Unicast address families. BGP-LU is disabled by default.
* **mpls.vpn** -- enable VPNv4 and VPNv6 address families. BGP/MPLS L3VPN is disabled by default.
* **mpls.6pe** -- enable 6PE on IBGP and/or EBGP sessions (default: IBGP only). 6PE is disabled by default.

LDP is enabled by default on all nodes using **mpls** configuration module, and can be disabled by setting **mpls.ldp** node parameter to *False*.

## Configurable Link and Interface Parameters

* **mpls.ldp** (boolean) -- enable or disable LDP and MPLS encapsulation on the interface.

LDP is enabled by default on all intra-AS interfaces in global routing table. To enable LDP on a VRF interface, set **mpls.ldp** link- or interface parameter to *True*.

## Configurable LDP Parameters

**mpls.ldp** global/node setting could be a boolean (*True*: enable LDP) or a dictionary of parameters:

* **router_id** -- Router ID to be used for LDP. Should correspond to a reachable loopback IP address.
* **igp_sync** (boolean) -- Enable LDP/IGP synchronization
* **explicit_null** (boolean) -- Enable Explicit Null advertisement
* **advertise** -- list of link roles to advertise (including *loopback* pseudo-role). The default behavior is device-specific.

## Configurable BGP LU Parameters

**mpls.bgp** could be a boolean (*True* to enable all possible BGP LU sessions), or a dictionary of parameters:

* **ipv4** -- enable BGP LU for IPv4 unicast address family
* **ipv6** -- enable BGP LU for IPv6 unicast address family
* **explicit_null** -- advertise Explicit Null labels on BGP LU sessions
* **disable_unlabeled** -- disable IPv4/IPv6 address families when enabling BGP-LU address families.

**ipv4** and **ipv6** parameters could be:

* Boolean value *False* to disable BGP-LU sessions for an address family within node data (overwriting global defaults)
* Boolean value *True* to enable BGP-LU on IBGP and EBGP sessions
* A string or a list of *ibgp/ebgp* keywords

In the following example, BGP-LU is enabled on IBGP and EBGP sessions for IPv4 and for IBGP sessions for IPv6:

```
mpls:
  bgp:
    ipv4: True
    ipv6: [ ibgp ]
```

## Configurable BGP/MPLS L3VPN Parameters

**mpls.vpn** could be a boolean (*True* to enable all possible L3VPN address families on IBGP sessions), or a dictionary of parameters:

* **ipv4** -- enable VPNv4 address family
* **ipv6** -- enable VPNv6 address family

**ipv4** and **ipv6** parameters could be:

* Boolean value *False* to disable VPN address family within node data (overwriting global defaults)
* Boolean value *True* to enable VPN address family on IBGP sessions
* A string or a list of *ibgp/ebgp* keywords

To enable intra-AS MPLS/VPN, set **mpls.vpn** to *True*. The VPN address families will be enabled according to the address families configured in VRFs.

```
mpls.vpn: True
```

To enable inter-AS MPLS/VPN (Option B), set **mpls.vpn** to `[ ibgp, ebgp ]`. You can enable inter-AS MPLS/VPN for an individual address family or for all address families configured in VRFs.

The following example enables inter-AS MPLS/VPN for the whole lab topology and disables it for VPNv6 address family on PE1:

```
mpls.vpn: [ ibgp, ebgp ]

nodes:
  pe1:
    mpls.vpn.ipv4: [ ibgp, ebgp ]
    mpls.vpn.ipv6: [ ibgp ]
```

## Configurable 6PE Parameters

**mpls.6pe** is a global or node parameter that could be a boolean (*True* to enable 6PE on IBGP sessions) or a list of session types (*ibgp* and/or *ebgp*).