IETF explores and adds the new path technology LISP

What is LISP?

LISP logically uses enterprises through its edgeVroIP address blocks broadcast to the global Internet are divided into two functions: one is used to identify the system that uses IP addresses, and the other is used to identify where these systems are connected to the Internet. This distinction allows LISP to aggregate location information without storing it in the core router.

LISP works through dynamic encapsulation. Each packet entering the core router will get a new IP encapsulation, which carries information about the destination service provider's network, rather than the end user's IP address. When the package arrives at the destination service provider, the package will be deleted from the package.

LISP can be used with Border Gateway Protocol (BGP. The Border Gateway Protocol is the main communication mechanism between the edge router and the core router. Our problem is to assign the IP address to the host, instead of assigning the IP address according to the structure. This means that the core router on the service provider's network must carry routes of all specific sites. We are trying to separate the importance of the address structure from the Address Allocation program. In this way, the routing table of the Border Gateway Protocol is reduced.

LISP supporters say this technology allows enterprises to easily switch carriers without getting new IP addresses, because even if the location information changes, the recognition function remains unchanged. LISP will be able to provide enterprises with additional traffic engineering capabilities. More enterprises need to connect their websites to multiple carriers, and they want to save money.

However, at present, enterprises need a lot of overhead to do so, because they must use the Border Gateway Protocol and release the route to the core router. Using the LISP protocol, we will place the routing policy on the edge router so that users can control the bandwidth they bought. The key issue with LISP is how the site negotiates their multi-host policy in an independent and open manner.

According to LISP developers, this protocol will be deployed to the edge router in the form of software upgrade, and the running of this software does not require hardware upgrade. They said the Protocol can be deployed gradually and used together with the current version of IPv4 protocol and future IPv6 protocol. It has been two years since LISP developers developed the LISP protocol. The main LISP file is currently in version 12th. Cisco engineers stressed that they have not yet released any products related to LISP.

The LISP protocol is still in adolescence. LISP developers expect the LISP working group to getIETF. After that, they will continue to develop prototype products and optimization protocol files. The IETF leader makes it clear that LISP is a test. The Charter of the working group said that LISP may have a harmful impact on Internet communication traffic transmitted by routers. At this stage, LISP is not recommended outside the test environment.

Route table Growth

LISP is a by-product by which IETF's sister Working Group's Internet research task team reconsider the Internet infrastructure. The routing research group of the Internet research task group has a common objective with LISP: to reduce the size of the route table of the Border Gateway Protocol.

The Border Gateway Protocol route table is a main table stored in the backbone router, used to determine the optimal available path between one network and another. Experts are worried that the growth of the Border Gateway Protocol route table will limit the processing and memory requirements of core Internet routers.

The increase in the route table of the Border Gateway Protocol is important because it will require the operator to continuously purchase a router with larger memory, thus increasing the carrier's cost. A key factor driving the increase in route tables is that more and more enterprises connect their networks to multiple carriers to improve reliability.

The Border Gateway Protocol route table has 0.288 million input items, and is growing at a rate of 14% per year. He predicts that 26 thousand large enterprises will connect their networks to multiple carriers. When they switch network communication traffic between their Internet service providers, the route table notification will be sent to the core internet router.

Moore's law of hardware theory in the computer industry said the number of transistors on the chip will double each year. So far, Moore's law has allowed routers to handle the increase in route table input caused by multi-host technology, Huston said. He believes that once the router cannot keep up with the growth of the route table, LISP will be a backup plan.

Currently, no statistics indicate that the route table growth may cause problems. Anything that causes a routing problem that requires the LISP protocol is disastrous-If 0.3 million routes change to 2 million at night, the method we currently use will become unusable. At present, each core router knows the possible destination or route table input to prevent problems. Using LISP, the core router only knows the routing information required for the current data packet flow.

LISP theory sounds good. However, in practice, it creates a network that has a lot to do with our current network. He added that tunnels produce overhead and may simplify network traffic. LISP has changed things around timing and cost, making it hard to understand where the application is and how it will survive. LISP relies on tunnels, which are not 100% perfect. Tunnel often transmits too large data packets, and the data packets transmitted by the sender or receiver disappear without a trace. Once this happens, this will be a bad thing.

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