Overview of routing information protocols (1)

Route information protocol (RIP)

The routing information protocol was originally designed for Xerox PUPPARC universal protocol. In 1981, the Xerox network system protocol was collectively referred to as "GWINFO" and defined as RFC 1988 in 1058 ". The routing information protocol is easy to configure and works very well in small networks. However, in large networks, the routing information protocol is inefficient. As I said to myself, the routing information protocol will split your network. In a large network environment, there is a protocol that replaces the routing information protocol.

The routing information protocol has the following features:

· Open protocols are widely used and stable.

· Suitable for small networks and easy to configure.

· There is a distance vector routing protocol similar to the routing information protocol for Novell and AppleTalk software.

· Internal Gateway Protocol IGP)

· IP route information protocol updates are broadcast once every 30 seconds. All multicast addresses on the RIPv2 router are 224.0.0.9 ).

· UDP User Datagram Protocol) Port 520.

· The manageable distance is 120.

· A single measurement criterion is that the maximum number of computing hops is 15 and the count is infinite)

· Timer helps adjust performance:

-Update timer-the frequency of Route updates.

-A complete route table is sent every 30 seconds based on the horizontal split. IPX route information protocol sends route tables every 60 seconds ).

-Invalid timer-No refreshed content in route update. The routing information protocol waits for 180 seconds, and then marks a route as illegal and immediately puts the route in a restrained timing state.

-Keep timing and trigger updates-help with stable routing in the Cisco phantom. Suppressing timing ensures that normal updates do not properly cause route loops. Vrouters do not respond to superior information within a specific period of time. The suppression time of the routing information protocol is 180 seconds.

-Refresh timer-the route information protocol takes an additional 240 seconds before deleting the route from the route table.

· Other stable functions that help route loops include:

-Horizontal split

-Toxicity reversal

· Bellman-Ford Algorithm

· R12002 supports VLSM and automatic summarization.

Internal Gateway Routing Protocol/Enhanced Internal Gateway Routing Protocol IGRP/VPN)

The internal gateway routing protocol is a Cisco proprietary protocol developed in the middle of 1980s. It helps overcome the defects of routing selection information protocols such as a single measurement standard for computing hops. The Internal Gateway Routing Protocol has stable functions, similar to the Internal Gateway Routing Protocol, such as the suppression of timers, horizontal split, and toxicity reversal. The scheduled time is as follows: 270 seconds are invalid, 280 seconds are blocked, and 630 seconds are refreshed. The Internal Gateway Routing Protocol also includes the mechanism that affects route selection and load balancing of non-equivalent values. IGRP/VPN is measured as follows:

· Bandwidth

· Relay

· Reliability

· Load

· MTU Information Transmission Unit)

The internal gateway routing protocol is an internal gateway protocol. It is a distance vector routing protocol based on the Bellman-Ford algorithm. This algorithm broadcasts route update information every 90 seconds on IP Protocol 9. The internal gateway routing protocol is very suitable for small and medium networks. However, Cisco has enhanced its performance and added support for the VLSM variable-length subnet mask of the VPN.

In early 1990s, Cisco developed an enhanced internal gateway routing protocol to overcome the limitations of the routing information protocol and the internal gateway routing protocol. Cisco said that the Internal Gateway Routing Protocol will be deleted from the IOS Internet Operating System. The enhanced Internal Gateway Routing Protocol applies to the current large network and supports multiple routing protocols. The enhanced internal gateway routing selection protocol consumes less bandwidth because it adopts partial and bundled updates. It is one of the fastest aggregation routing protocols. The enhanced Internal Gateway Routing Protocol has the following features:

· Cisco proprietary protocol.

· Suitable for small to large networks.

· Easy to set. Use an autonomous system number.

· Supports multiple layer-3 routing protocol stacks, such as IP, Novell IPX, and AppleTalk.

· Advanced distance vector routing protocol.

· Because of its ability to gradually update and quickly aggregate, it is usually called hybrid.

· IGP Internal Gateway Protocol ).

· Occasionally launch Multi-broadcast updates at the 224.0.0.10 address.

· IP Protocol No. 88.

· The internal management distance is 90, and the external management distance is 170.

· Bandwidth, relay, reliability, load, and information transmission units are measured.

· Supports equivalent and non-equivalent load balancing.

· Other stability functions supporting routing loops include horizontal split and toxicity reversal.

· Use the diffusion update algorithm (DUAL) to select routes without route loops and quickly aggregate them.

· Supports VLSM and automatic summary without category ).

· Automatically classify the boundary summary.

· Manually send abstract updates to various interfaces.

· If the number of the autonomous system is the same, it will be automatically released using the internal gateway routing protocol.

· Policy-based routing.

The enhanced internal gateway routing selection protocol gets reliability from the Reliable Transport Protocol (RTP. It not only retains the route table, but also has neighbors and Topology tables. The enhanced internal gateway routing selection Protocol also retains the alternative route as the successor route table) and the feasible successor topology table) for quick aggregation. The following are the data packet types used for neighbor communication: hellos Multicast) and acks unidirectional broadcast), update multicast or unidirectional broadcast), query Multicast), and reply to unidirectional broadcast) and request multicast or unidirectional broadcast ). Packets are arranged during transmission and each Protocol has a separate neighbor table and a completely separate process.