Cisco Cisco ONS 15454 SONET Multiservice Provisioning Platform (MSPP) Guía De Diseño

OL-4556-01

 

142

Circuits terminated by two ML-Series cards 

STS-1, STS-3c, STS-6c, STS-9c, STS-12c, 
and STS-24c 

Circuits terminated by G-Series card and 
ML-Series card 

STS-1, STS-3c, STS-6c, STS-9c, STS-12c 

Circuits terminated by ML-Series card and 
External POS device 

STS-3c and STS-12c 

 

 
VPN Routing/Forwarding Lite (VRF Lite) is an ML-Series specific implementation of a VPN 
routing/forwarding instance (VRF).  Unlike standard VRF, VRF Lite does not contain Multi-
Protocol internal BGP (MP-iBGP). 
 
Standard VRF is an extension of IP routing that provides multiple routing instances and separate 
IP routing and forwarding tables for each VPN.  It provides a separate IP routing and forwarding 
table to each VPN.  VRF is used in concert with internal MP-iBGP.  MP-iBGP distributes the VRF 
information between routers to provide Layer 3 Multiprotocol Label Switching (MPLS)-VPN.  
However, ML-Series VRF implementation is without MP-iBGP.  With VRF Lite, the ML Series is 
considered as either a PE-extension or a customer equipment (CE)-extension.  It is considered a 
PE-extension since its has VRF (but without MP-iBGP); it is considered a CE-extension since this 
CE can have multiple VRFs and serves many customer with one CE box. 
 
VRF Lite stores VRF information locally and does not distribute the VRF information to connected 
equipment.  VRF information directs traffic to the correct interfaces and subinterfaces when the 
traffic is received from customer routers or from service provider router(s). 
 
VRF Lite allows an ML-Series card, acting as customer equipment, to have multiple interfaces 
and subinterfaces with service provider equipment.  The customer ML-Series card can then 
service multiple customers.  Normal customer equipment serves a single customer. 
 
Under VRF Lite, an ML-Series CE can have multiple interfaces/subinterfaces with PE for different 
customers (while a normal CE is only for one customer).  It holds VRFs (routing information) 
locally; it does not distribute the VRFs to its connected PE(s).  It uses VRF information to direct 
traffic to the correct interfaces/subinterfaces when it receives traffic from customers’ routers or 
from Internet service provider (ISP) PE router(s).  Figure 5-22 shows an example of a VRF Lite 
configuration.