Shulou(Shulou.com)06/02 Report--

Dynamic routing-OSPF routing Protocol

First, internal gateway protocol and external gateway protocol

Ospf is a link-state routing protocol

Ospf Open shortest path first chooses the protocol

OSPF Multicast address: DR/BDR 224.0.0.5

​ other (other): 244.0.0.6

OSPF: features: suitable for large-scale networks

​ routing changes converge quickly

​ has no routing ring

​ supports variable length subnet mask VLSM

​ supports zoning

​ supports sending protocol packets at multicast addresses.

Backbone area: Area 0

Standard area (non-backbone area): Area1, Area2

The selection method of two DR BDR

​ 1, automatic election

The router with the largest router id on the ​ segment will be elected dr, and the second largest router will be elected bdr

​ 2, hand-selected

The priority range of ​ 1 is 0MMI 255. The higher the value, the higher the priority. The default value is 1.

​ 2 if the priority is the same, this compares to touter id.

​ 3 if the router priority is 0, he will not participate in the selection of DR BDR

Note: router priority can affect the election process, but it cannot force the replacement of existing DR, BDR

Three! [] (D:\ footage\ dynamic routing-ospf\ Wechat Picture _ 201910221905287.png)

! [] (D:\ material\ dynamic routing-ospf\ Wechat Picture _ 201910221905288.png)

! [] (D:\ material\ dynamic routing-ospf\ Wechat Picture _ 201910221905286.png)

Ports in down state can only receive hello packets but not send hello packets when they receive hello packets and activate init state.

After the router system is loaded, it will enter the 2way state from init.

You can either receive hello packets or send hello packets in the 2way state and elect the two largest router id (but DR BDR will not be elected)

When exchange status interaction DBD packet is received at the same time, there will be lsack packet.

Loading status is the busiest, including the most kinds of LSR LSU, etc.

FULL steady state starts forwarding packets

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