Advantages and benefits LISP provides highlighted in this post are simplified traffic engineering, multihoming, overlay tunnel, and AF over AF.

Locator/ID Separation Protocol (LISP) is an IP in UDP tunnel protocol that separates the identity of a device from its location on the network. It allows sites to create tunnels between them and identifies devices using Endpoint Identifiers (EIDs). Traffic then enters and exits the network through Routing Locators (RLOCs).

For more specific information please check out the sources this post was based off of: Cisco Configuring LISP RFC 6830

Private LISP Minimal Configuration#

Relevant Terminology

  • Endpoint Identifiers (EIDs): Server/VM/Host IP address.
  • Routing Locators (RLOCs): Router’s link IP address.
  • Mapping Database (M-DB): Association between EID and RLOC.
  • MS/MR: The combined roles seen below.
    • Map Server (MS): Holds EID to RLOC mappings.
    • Map Resolver (MR): Responds to map-request messages
  • xTR: The combined roles seen below.
    • Ingress Tunnel Router (iTR): Asks Map Resolve for EID to RLOC mapping and is responsible for LISP/UDP packet encapsulation.
    • Egress Tunnel Router (eTR): Registers EID/RLOC mapping to Map Server and is responsible for LISP/UDP decapsulation and forwarding the packet to the destination.
Setting the MS/MR and expected EID registration# 
MS-MR(config)# router lisp
MS-MR(config-router-lisp)# ipv4 map-server
MS-MR(config-router-lisp)# ipv4 map-resolver
MS-MR(config-router-lisp)# site A
MS-MR(config-router-lisp-site)# eid-prefix x.x.x.x/24 accept-more-specifics
MS-MR(config-router-lisp-site)# authentication-key APASS
MS-MR(config-router-lisp)# site B
MS-MR(config-router-lisp-site)# eid-prefix x.x.x.x/24 accept-more-specifics
MS-MR(config-router-lisp-site)# authentication-key BPASS
    • The use of eid-prefix lets our MS/MR know who to expect registration from accept-more-specifics allows our MS/MR to accept registration for more specific prefixes such as /24-/32 within the specific range.
  • Passwords must be unique from site to site.
Setting the xTR For A site#

Ingress Load Balancing#

LISP to Non-LISP#

Relevant Terminology

  • PxTR: The combined roles seen below.
    • Proxy Ingress Tunnel Router (PiTR): iTR that connects LISP to Non LISP
    • Proxy Egress Tunnel Router (PeTR): eTR that connects LISP to Non LISP

AF over AF#