nx.os.and.cisco.nexus.switching.2nd.edition.1587143046

Chapter 13. LISP
This chapter covers the following topics:
• LISP overview
• LISP terminology
• LISP prerequisites
• LISP control plane
• Communicating between LISP and non-LISP sites
• LISP Host Mobility with an Extended Subnet
• Deployment of best practices
LISP Overview
Locator/ID Separation Protocol (LISP) is a new routing architecture and paradigm shift that
decouples the server identity and the server location. This decoupling enables mobility,
scalability, and security. As endpoints become detached from the physical infrastructure and
are mobile, the LISP routing architecture enables IP addresses to move freely and efficiently
across the infrastructure. Although more server virtualization is deployed within the
Enterprise and the service providers, the movement of the virtualized workloads to meet
high availability and disaster recovery is significantly increasing. LISP decouples the server
identity and the server location into two different address spaces: The Endpoint Identifier
(EID) is the server identity and the server location is the Routing Locator (RLOC).
Although LISP has many use cases in addition to workload mobility, the focus of this
chapter is only for server mobility and how to influence the ingress routing to these mobile
resources.
This chapter assumes that you have Layer 2 extended between a data center location via
Overlay Transport Virtualization (OTV) or another L2 extension technology. The challenge
that arises when Layer 2 virtual local area networks (VLANs) are extended between data
centers is that the upper routers to do not know that the subnets and VLANs are shared;
hence, this results in nonoptimal and asymmetric traffic flows. The consequences of
nonoptimal, asymmetrical traffic flows follow:
• Utilization of expensive interconnect transport.
• State devices see only half connections and drop the connections.
With LISP Host Mobility, the network can detect movement and provide optimal routing
between clients and the IP end point that moved, regardless of its location.
LISP Terminology
LISP is an overlay routing protocol that encapsulates the original packet and adds an
additional 36 bytes for IPv4 and 56 bytes for IPv6. The LISP encapsulation is dynamic and
does not require static tunnels to be predefined, which enables LISP to be scalable. A LISPenabled
network includes the following components: