First of all it is a brief look at what is dhcp
1.DHCP dynamic address assignment protocol for network management workload is less manual configuration to reduce the error rate.
2.DHCP process client requests an IP address from the DHCP server will be four packets are generated:
Client: Send DHCP discover packet is used to discover DHCP server
server: DHCP offer response message to the client from their IP in a pool is not allocated out of his address and related parameters (subnet mask, DNS, etc.), sent mounted in the offer.
The client: the server sends a DHCP request message, the client receives the DHCP offer will receive a request to send a request to the address included in the offer, this time the client has not really got the address, so it needs to be to the server application
server: DHCPack send messages to the client to confirm this address can be assigned to the client
Next to tell you about ospf
routing protocol 1. Open Shortest Path First protocol is a dynamic routing table entries to establish, within the enterprise to quickly build a shortest, acyclic, Layer 3 forwarding path; divided into backbone area and non-backbone area.
2. Work process: first establish ospf adjacency list; secondly ospf database synchronization; the final calculation ospf routing table.
3.ospf generated in operation five packets;
(. 1) for discovering Hello packets, maintenance, removal neighbor
(2) dd: database description packets
(3) lsr; link state request packet, the face request by the terminal end of the end is not updated or LSA
(. 4) LSU; link state update packet, update counterparty LSA
(. 5) LSAck; link state acknowledgment packet, to confirm receipt of the LSU
4. run ospf protocol the device port after a neighbor build a successful experience seven states,
(1) Down: fault or not running
(2) init: one-way communication status (party received the Hello)
(3) TWO-Away: two-way communication status (both sides have received Hello)
(. 4) ExStart: initialization state exchange (dd packet ready to send, it needs to negotiate whoever hair root id determined according to, the greater the priority)
(. 5) exchang: begin exchanging status (dd transmitted packets described database summary).
(. 6) loading: loading status
(7) full: adjacency state
role in ospf lsa type and corresponding to introduce about 5. Here
(1) routers lsa: each router will generate a class lsa advertisement, such lsa include routers all links or interfaces known ,, and all neighbors on the link ospf, Class 1 indicates the router also lsa or is not abr asbr, and spread throughout the interior region.
(2) network lsa: DR class 2 is generated by LSA, the link state of the local description, and is only spread in the area belongs.
(3) Network Summary lsa: produced by ABR, a route segment in the region descriptor, and notified to the non-published or totally stub area or nssa lsa received the
complete absence of the tip region is three lsa, nssa region does not class 5 and class 3 lsa, more than seven classes lsa.
(. 4) Summary asbr lsa: abr generated by the route described asbr advertised to other regions except the region where asbr.
(5) as-external-lsa : generated by the ASBR, described to as an external route advertised in all regions (except stub and nssa region)
(. 6) nssa-LSA: generated by the ASBR, describes the route to as outside, only propagates within nssa area.