Use Case and Reference Architecture

The modern service provider networks have two main segments referred to as core and edge ( Figure 1 ). The solution uses a reference design that implements core and edge segments within a single flat IS-IS Level 2 domain, using the default IS-IS instance. Additionally, the Multi-Service Edge (MSE) service complex is placed in a separate domain, with BGP-only reachability.

Appropriate redistribution policies, with or without summarization, are provisioned between an IS-IS and a BGP domain to provide end-to-end IPv6 connectivity between loopbacks and locators.

The reference architecture deploys an infrastructure designed to support traditional service provider topologies with edge services termination.

The major components under consideration include:

• SP reference architectures
• Seamless Segment Routing across SP edge and core domains (Inter-AS BGP + SRv6 locator redistribution/summarization between domains)
• Fast failover and detection TI-LFA, MLA, BFD, ECMP, and so on.
• SRv6 SID with IS-IS
• Flex-Algo Application Specific Link Attribute (ASLA) TE and Delay metrics
• Flex-Algo Prefix Metric (FAPM)
• Transport Classes
• Strict and Cascade Transport Class Resolution schemes Inter-AS BGP Transport
• VPN Service Mapping to transport Flex-Algo
• Redundant Route Reflectors
• EVPN-VPWS with A/A and A/S Multihoming
• Inter-AS Option C
• TWAMP light for delay measurement