LISP Protocol - Locator identification/Separator Protocol in Cisco SD- Access

Today we are going to talk about LISP protocol. Many of you heard about using the LISP in the Cisco SD access environment for the campus with the DNA center and some of you know about the deployment of the LISP protocol in the datacenter environment.

What is LISP Protocol ?
LISP or so called as Locator identification/Separator Protocol separates the region and the identifier of the community hosts, hence making it viable for digital machines to move across subnet limitations whilst maintaining their IP deal with. 

LISP is composed of a community architecture and a set of protocols that permit new semantics for IP addressing by way of creating namespaces

  • Endpoint Identifiers (EIDs): EIDs are assigned to give up hosts.
  • Routing Locators (RLOCs) : RLOCs are assigned to routers that make up the worldwide routing device.
Fig 1.1- Sample LISP Scenario

The introduction of those separate namespaces provides several advantages, including the following:

  • Topologically aggregated RLOCs permit improved routing system scalability .
  • IP portability .
  • less complicated IPv6 transition .
  • IP mobility, the host EIDs can pass with out changing the IP cope with of the host or digital gadget; most effective the RLOC changes on a bunch pass.

LISP integrates well into the current network infrastructure and requires no changes to the end host stack. It fosters a simple, incremental, network-based implementation with most of the deployment at the network edge devices.

LISP Frame Format
A LISP frame’s outer encapsulation is a UDP frame where the destination and source IP addresses are the addresses of the Ingress Tunnel Router (ITR) and Egress Tunnel Router (ETR), respectively. For Layer 3 LISP, the destination UDP port number is 4341. The LISP header has the Locator reachability bits and the nonce fields.

LISP Routing
As a bunch transmits a packet, if the destination of the packet is in every other LISP area, it reaches the LISP ITR. The ITR maps the vacation spot endpoint id (EID) to an RLOC with the aid of looking up the vacation spot in a map server. Using this facts he ITR encapsulates the packet with an outer header. 

The destination RLOC is ETR at the back of which the destination host exists.  when the destination ETR is understood, the ITR encapsulates the packet, putting the destination deal with to the RLOC of the vacation spot ETR lower back with the aid of the mapping infrastructure.

In addition to LISP routing, the location and EID separation provides flexible and unmatched mobility for IP endpoints without any subnet boundary limitation allowing IP endpoints, regardless of their IP addresses, to be deployed anywhere. These EIDs can freely move within and across data center racks and across geographical and organizational boundaries. The LISP Mobility solution has the following characteristics:

  • Optimal shortest path routing .
  • Both IPv4 and IPv6 addresses are supported .
  • Support for load balancing and multi homing .
  • Provides a solution that is transparent to both EIDs and the core network .

By allowing IP endpoints to change location while maintaining their assigned IP address,

LISP mobility solution enables the IP endpoints to move between different subnets, while guaranteeing optimal routing to the IP endpoint.