LISP Control Plane Internet Connectivity Enterprise Fabric
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Solution Overview
Problem
In enterprise fabric networks, internet connectivity is hindered when client endpoint-identifiers and default gateways are in different virtual networks, leading to issues with extranet communication.
Innovation Solution
Implementing a Locator/Identifier Separation Protocol (LISP) with negative map replies and modified map replies to determine instance identifiers and proxy egress tunnel router locator addresses, allowing packets to be routed correctly across virtual networks, including external networks like the internet, without the need for a fusion router.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional routing is used in enterprise fabric networks, then network simplicity is maintained, but internet connectivity fails when client endpoint-identifiers and default gateways are in different virtual networks
Solution Approach 1:
The patent segments the routing function into two distinct parts: endpoint identifier (EID) routing and locator (RLOC) routing. LISP encapsulates packets with EIDs in the inner packet and RLOCs in the outer packet header, allowing separate handling of virtual network identification and physical network routing. This segmentation enables internet connectivity across different virtual networks while maintaining routing simplicity through protocol automation.
2Adaptability or versatility
If fusion routers are deployed to enable extranet communication, then connectivity between different virtual networks is achieved, but device complexity and cost increase
Solution Approach 1:
LISP introduces proxy egress tunnel routers (PETRs) as intermediary devices that mediate communication between clients in one virtual network and the internet. The PETR receives LISP-encapsulated packets from ingress tunnel routers, performs decapsulation, and forwards to the appropriate destination. This intermediary approach enables extranet communication without requiring complex fusion routers at every network boundary.
Solution Approach 2:
The patent replaces the mechanical approach of deploying physical fusion routers with sophisticated routing capabilities with a protocol-based solution. LISP uses encapsulation and a distributed mapping system to provide the same extranet communication functionality through software-based routing logic, eliminating the need for specialized hardware routers and reducing overall device complexity.
3Reliability
If multiple gateway routers are used to maintain virtual network isolation, then security is enhanced, but network cost and device complexity increase
Solution Approach 1:
LISP creates a universal routing mechanism that handles multiple virtual network routing requirements through a single protocol framework. The same LISP encapsulation and mapping system serves both internal virtual network routing and external internet connectivity needs, eliminating the requirement for separate gateway routers for each virtual network while maintaining isolation through EID-to-RLOC mapping.
Data Source
AI summary
In one embodiment, a method is performed at a first node. The method may include receiving, at a first node, a request from a source host associated with a network to communicate with a destination host. The first node may determine whether the destination host is associated with the network. If the destination host is not associated with the network, the first node may determine an instance identifier (IID) and a proxy egress tunnel router (PETR) locator address used to communicate with the destination host. The first node may send an indicator to an ingress tunnel router (ITR) to encapsulate a packet with the IID and the PETR locator address before sending the packet from the source host to the destination host.