Overlay Tunnels - Cisco Location ID Seperation Protocol

12 important questions on Overlay Tunnels - Cisco Location ID Seperation Protocol

Cisco created LISP, what is it and what is it used for?

LISP is Location/ID Separation Protocol. It's a routing architecture and a data and control plane protocol.
It was created to address the routing scalability issues on the internet, however can be used in other scenarios as well.

In Cisco LISP, what is a EID?

Endpoint Identifier, the IP address of an endpoint within a LISP site.

A Cisco LISP Router performs 1 or more of the 4 LISP Routing functions. What is the function of the Ingress Tunnel Router or ITR?

The LISP Ingress Tunnel Router LISP-encapsulate packets that are coming from an EID in a LISP site and are destined outside the LISP site.
Sending it from a LISP site into the RLOC space.
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A Cisco LISP Router performs 1 or more of the 4 LISP Routing functions. What is the function of the Ingress Tunnel Router or ITR?

The LISP Ingress Tunnel Router LISP-encapsulate packets that are coming from an EID in a LISP site and are destined outside the LISP site.
Sending it from a LISP site into the RLOC space.

In LISP, what is a Router Locator or RLOC?

An IPv4 or IPv6 address of an ETR on the RLOC Space facing side.

In LISP, what is a MAP server?

Network device that learns EID/Prefix-to-RLOC mapping entries from an ETR and stores them in the local EID/Prefix-to-RLOC mapping database.

In LISP, what is a MAP Resolver?

A network device that receives map requests from an ITR and answers with RLOC IP address of an ETR by consulting MAP Server

A Cisco LISP Router performs 1 or more of the 4 LISP Routing functions. What is the function of the Egress Tunnel Router or ETR?

The LISP Egress Tunnel Router de-encapsulate LISP-encapsulates packets that are coming from sites outside the LISP site and are destined to an EID in the the LISP site.
Sending it from the RLOC space into the LISP site.

A Cisco LISP Router performs 1 or more of the 4 LISP Routing functions. What is the function of the Proxy Ingress Tunnel Router or PITR?

It performs the same function as the ITR, LISP-encapsulating packets which come into the RLOC space, but for Non-LISP sites like the internet.

A Cisco LISP Router performs 1 or more of the 4 LISP Routing functions. What is the function of the Proxy Egress Tunnel Router or PETR?

It performs the same function as the ETR, de-encapsulating LISP-encapsulated packets which go out of the RLOC space, but for Non-LISP sites like the internet.

The LISP Architecture contains 3 seperate spaces. Seperated by the (Proxy) Ingress and (Proxy) Egress Tunnel Routers, which 3 are there?

1. LISP Sites (Contain the EIDs)
2. RLOC Space (Contains the MS and MR and the RLOC IPs of the tunnel routers)
3 Non-LISP sites (Sites like the internet)

What is the protocol and port used by default by the LISP data plane?

It uses UDP with destination port 4341

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