Nowadays Internet has scalability problems: Routing Tables (RTs) are growing too fast. Therefore better implementation of some routing techniques is needed, such as multihoming and traffic engineering.
Two representative solutions for the routing scalability problem are NNC and LISP.
Clean slate: NNC
NNC is a clean slate solution which defines a new routing paradigm: routing on content name instead of on content address. NNC improves delivery efficiency and solves the problems such as content availability, security, content location dependence, where vs what, named hosts vs named data and host-to-host vs many-to-many:
- The communications are built on named data with no notion of the hosts.
- The content node model have two types of packets: interest and data.
- Storage databases: Forwarding Information Base (FIB), content store and Pending Interest Table (PIT).
- Transport operates on top of unreliable packet delivery services, has a flow control and the CNN can take advantage of multiple interfaces.
- Intra-Domain Routing works with link state IGP, customizes link-state announcements and a CNN content advertiser can reach some of the content matching a prefix.
The Locator Identifier Separation Protocol minimizes required changes to Internet. It doesn’t require hardware and software changes to endsystems (hosts) and is incrementally deployable. The principles of LISP are:
- IP addresses have two complementary roles: identifier role and locator role. LISP defines a router-based solution where current IP addresses are separated in two different spaces: EndPoint Identifies (EID), to identify end hosts, and Routing Locators (RLC), to attach to routers.
- A mapping mechanism allows to map an EndPoint Identifier onto the routing Locators of the site routers.
- Routers encapsulate the packets received from hosts before sending them towards the destination RLOC.
- LISP site can control incoming traffic with Weight and Priority.
- Data-Plane: hosts and majority of routers are unaffected
- Control-Plane: no changes within stub and core networks but the introduction of a Mapping System is required.
- Tunnel Routers (TR): the introduction of these routers at border between edge and core.