IP Router Configuration 
Router Configuration Guide 15
The implementation supports four network-domains within any given VPLS. 
Network-domain configuration at the SDP level is ignored when the given SDP is used for 
Epipe, Ipipe, or Apipe bindings.
Network-domain configuration is irrelevant for Layer 3 services (Layer 3 VPN and/or IES 
service). It can be defined in the base routing context and associated only with network 
interfaces in this context. Network domains are not applicable to loopback and system 
interfaces.
The network-domain information will only be used for ingress VPLS sap queue-allocation. 
It will not be taken into account by routing during SDP setup. As a consequence, if the given 
SDP is routed through network interfaces that are not part of the configured network domain, 
the packets will be still forwarded, but their QoS and queuing behavior will be based on 
default settings. In addition, the packet will not appear in SAP stats.
There will be always one network-domain that exists with reserved name default. The 
interfaces will always belong to a default network-domain. It will be possible to assign given 
interface to different user-defined network-domains. The loopback and system interface will 
be also associated with the default network-domain at the creation. However, any attempt to 
associate such interfaces with any explicitly defined network-domain will be blocked at the 
CLI level as there is no benefit for that association. 
Any SDP can be assigned only to one network domain. If none is specified, the system will 
assign the default network-domain. This means that all SAPs in VPLS will have queue 
reaching all fwd-complexes serving interfaces that belong to the same network-domains as 
the SDPs.
It is possible to assign/remove network-domain association of the interface/SDP without 
requiring deletion of the respective object. 
System Interface
The system interface is associated with the network entity (such as a specific router or 
switch), not a specific interface. The system interface is also referred to as the loopback 
address. The system interface is associated during the configuration of the following entities:
• The termination point of service tunnels
• The hops when configuring MPLS paths and LSPs 
• The addresses on a target router for BGP and LDP peering