Protocol packets and link state advertisement 3.OSPF

0x01.OSPF message

| Link Layer Header | IP packet Header | OSPF Protocol Packet | Frame Checksum |

(1) IP protocol number is 89, used to identify the OSPF

(2) OSPF Protocol Packet = OSPF Protocol Header (header) + OSPF Packet Types (details of a certain type of package)
Here Insert Picture Description


(1) Version: 2 (default)

(2)Message Type:5种

(3)Packet Length

(4)Source Router ID

(5)Area ID


(7)Auth Type

(8)Auth Data

// As shown below, the OSPF packet header:
Here Insert Picture Description
// Check capture binding OSPF packet header:
Here Insert Picture Description


(1) certification purposes: to fulfill the legality (is legal for end equipment)

(2) the results of authentication: OSPF neighbors can be established, as well as updating and redness LSA, otherwise no neighbors (there will be no routing)

(3) a simple plain text authentication (password: huawei)

int s1/0/0
ospf authentication-mode simple plain huawei
int s1/0/0
ospf authentication-mode simple plain huawei

// combination of packet capture to view plain text authentication:
Here Insert Picture Description


(1) hello packets (discover and maintain neighbor relationships)

(2) DB Description (database description, sending link-state database summary)

(3) LS Request (LS Request message, requesting a particular link state information)

(4) LS Update (LS Update message sent detailed link state information)

(5) LS Acknowledge (LS acknowledgment message, the acknowledgment message transmitted)

0x02. Link state advertisement, LSA


(1) LSA, the LSA

(2) LSA is not the LS Acknowledge message

(3) LSA belongs to the LSU some entries


(1) Class 1 LSA: Router-LSA, router LSA (produced by each router; description port link status, the area flooding)

(2) Class 2 LSA: Network-LSA, network LSA (DR generated; network broadcast / NBMA; described which devices belong to the network, flooding the area)
Here Insert Picture Description


(1) Who? (Who produced the type of LSA)
(2) Where? (LSA its scope of action where)
(3) doing? (LSA This used to do)


(1)dis ospf lsdb
Here Insert Picture Description
(2)dis ospf lsdb router
Here Insert Picture Description
(3)dis ospf lsdb network
Here Insert Picture Description

Published 150 original articles · won praise 34 · views 10000 +

Guess you like