The Nokia Provider Edge (PE) router must be configured to enforce the split-horizon rule for all pseudowires within a virtual private local area network services (VPLS) bridge domain.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-283909 | NOKI-RT-000980 | SV-283909r1203976_rule | CCI-000366 | low |
| Description | ||||
| A virtual forwarding instance (VFI) must be created on each participating PE router for each customer VLAN using VPLS for carrier Ethernet services. The VFI specifies the VPN ID of a VPLS domain, the addresses of other PE routers in the domain, and the type of tunnel signaling and encapsulation mechanism for each peer PE router. The set of VFIs formed by the interconnection of the emulated virtual circuits (VCs) is called a VPLS instance, which forms the logic bridge over the MPLS core network. The PE routers use the VFI with a unique VPN ID to establish a full mesh of emulated VCs or pseudowires to all the other PE routers in the VPLS instance. The full-mesh configuration allows the PE router to maintain a single broadcast domain. With a full-mesh configuration, signaling and packet replication requirements for each provisioned virtual circuit on a PE can be high. To avoid the problem of a packet looping in the provider core, thereby adding more overhead, the PE devices must enforce a split-horizon principle for the emulated virtual circuits; that is, if a packet is received on an emulated virtual circuit, it is not forwarded on any other virtual circuit. | ||||
| STIG | Date | |||
| Nokia Service Router OS 25.x Router Security Technical Implementation Guide | 2026-06-15 | |||
Details
Check Text (C-283909r1203976_chk)
Review the PE router configuration to verify split horizon is enabled.
Verify the VPLS is using mesh-sdp using the command below:
- show service id 100 base | match "Service Access & Destination Points" post-lines 4
Service Access & Destination Points
-------------------------------------------------------------------------------
Identifier Type AdmMTU OprMTU Adm Opr
-------------------------------------------------------------------------------
sdp:40:100 M(4.4.4.4) Mesh 0 9190 Up Up
If the VPLS service SDP type is not mesh, this is a finding.
Fix Text (F-88379r1203975_fix)
Enable split horizon on all PE routers deploying VPLS in a full-mesh configuration.
Configure VPLS service using mesh-sdp to have split-horizon function on the pseudowire using the example below:
- configure service vpls 100 customer 1 vpn 100 create
- config>service>vpls# mesh-sdp 40:100 create
- config>service>vpls>mesh-sdp$ no shutdown
- config>service>vpls>mesh-sdp$ exit
- config>service>vpls# no shutdown
- config>service>vpls# exit all